http://www.pegasusrc.com/forum/ Wed, 27 Aug 2008 21:24:18 -0700 MyBB http://www.pegasusrc.com/forum/showthread.php?tid=72 Tue, 19 Aug 2008 19:00:44 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=72 http://www.pegasusrc.com/forum/showthread.php?tid=70 Sun, 13 Jul 2008 12:25:13 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=70
You can check out the pictures and video right here

The event web page is here


Cheers,
Steve]]>
You can check out the pictures and video right here

The event web page is here


Cheers,
Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=69 Sat, 21 Jun 2008 20:51:52 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=69
These have been reduced in size (originals were nearly 4MB each). If you want the full sized ones, let me know.
Pic #1 - The Pegasus Airfield
Pic #2 - Flight line from the west
Pic #3 - Flight line from the North
Pic #4 - Wide shot, but there are two planes in flight in the upper right corner and one in the corn with someone searching for it in the lower right.]]>
These have been reduced in size (originals were nearly 4MB each). If you want the full sized ones, let me know.
Pic #1 - The Pegasus Airfield
Pic #2 - Flight line from the west
Pic #3 - Flight line from the North
Pic #4 - Wide shot, but there are two planes in flight in the upper right corner and one in the corn with someone searching for it in the lower right.]]> http://www.pegasusrc.com/forum/showthread.php?tid=68 Mon, 16 Jun 2008 13:21:47 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=68
you get the transmitter, reciever (they are on channel 52 on 72 mega hertz)

i will even include 8 new batterys for the transmitter :D

i will sell this for $50, or the best offer

just leave a reply :D if you are interested]]>
you get the transmitter, reciever (they are on channel 52 on 72 mega hertz)

i will even include 8 new batterys for the transmitter :D

i will sell this for $50, or the best offer

just leave a reply :D if you are interested]]> http://www.pegasusrc.com/forum/showthread.php?tid=67 Mon, 16 Jun 2008 09:10:29 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=67
What I had in mind are little tidbits to entice or share with one another. I have included a poll so we can see if there is interest in this. If you have more ideas, please share!

Since we are having a "dawn patrol" on the camping day, well have that theme covered, but still need an idea for the event - something 'camping' related, like flying around with Coleman lanterns hanging from the plane or attaching insect repellent to the planes and "crop dusting" :D

Cheers,
Steve


With the Official announcement of the Camp-n-fly made for the upcoming weekend, I think that the official NEXT dawn patrol announcement be made!

All you early risers!!!

It is with great pleasure that I announce the next mission for the DAWN PATROL!

It is rumored that an invading army has infiltrated the Area of Operation and set up bivouac nearby.

Our mission will be to provide escort duty for the overhead surveillance aircraft. This Intel will provide Headquarters the needed information so that they may mount an assault.

Our ground spies report that the enemy has brought it's own air force but difficulties with the pilots gorging themselves on locally prepared sundries has prevented them from flying until later!

Now is our chance to make a decisive victory in the war effort! So "up and at 'em boys"


All pilots must report to the airfield by 0630L for mission briefings and hot coffee!]]>
What I had in mind are little tidbits to entice or share with one another. I have included a poll so we can see if there is interest in this. If you have more ideas, please share!

Since we are having a "dawn patrol" on the camping day, well have that theme covered, but still need an idea for the event - something 'camping' related, like flying around with Coleman lanterns hanging from the plane or attaching insect repellent to the planes and "crop dusting" :D

Cheers,
Steve


With the Official announcement of the Camp-n-fly made for the upcoming weekend, I think that the official NEXT dawn patrol announcement be made!

All you early risers!!!

It is with great pleasure that I announce the next mission for the DAWN PATROL!

It is rumored that an invading army has infiltrated the Area of Operation and set up bivouac nearby.

Our mission will be to provide escort duty for the overhead surveillance aircraft. This Intel will provide Headquarters the needed information so that they may mount an assault.

Our ground spies report that the enemy has brought it's own air force but difficulties with the pilots gorging themselves on locally prepared sundries has prevented them from flying until later!

Now is our chance to make a decisive victory in the war effort! So "up and at 'em boys"


All pilots must report to the airfield by 0630L for mission briefings and hot coffee!]]> http://www.pegasusrc.com/forum/showthread.php?tid=66 Mon, 16 Jun 2008 08:50:53 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=66
I am still writing the electric planes info, so hold on to that thought....]]>
I am still writing the electric planes info, so hold on to that thought....]]> http://www.pegasusrc.com/forum/showthread.php?tid=64 Mon, 16 Jun 2008 03:39:41 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=64
With that, I'd like to welcome all of you to Pegasus and to share some common info on LiPO's..

Lithium batteries are the preferred power sources for most electric modelers today. They offer high discharge rates and a high energy storage/weight ratio. However, using them properly and charging them correctly is no trivial task. There are many things to consider before using lithium cells for e-flight. But none is more important than safety.

1. Charging/Safety IMPORTANT!
Until you are willing to follow all safety precautions, DO NOT use lithium batteries. If your a type of person that prefers to push the limits of products, or be haphazard about following safety requirements. Lithium technology is not for you. Read on to find out why.

Lithium cells must be charged very differently than NiCad or NiMH. They require a special charger specifically designed to charge lithium cells. In general any charger that can charge lithium ion can charge lithium polymer, assuming that the cell count is correct. You must NEVER charge lithium cells with a NiCad or NiMH only battery charger. This is dangerous. Charging cells is the most hazardous part of using lithium batteries. EXTREME care must be taken when charging them. It is important to set your charger to the correct voltage or cell count. Failure to do this can cause the battery to spew violent flames. There have been many fires directly caused by lithium batteries. PLEASE BE RESPONSIBLE when charging lithium batteries.

Here are a few MANDATORY guidelines for charging/using LiPos (Lithium Polymer Batteries).


1. Use only a charger approved for lithium batteries. The charger may be designed for Li-Ion or Li-Poly. Both batteries are charged in exactly the same. Some older cell phone chargers may charge the batteries .1 volt to low (4.1 vs 4.2), but that will not harm the battery. However, inexpensive lithium chargers are widely available and the use of cellphone chargers is highly discouraged.
2. Make certain that the correct cell count is set on your charger. Watch the charger very closely for the first few minutes to ensure that the correct cell count continues to be displayed. If you don't know how to do that, get a charger that you do know how or don't charge the batteries.
3. Use the Taps. Before you charge a new Lithium pack, check the voltage of each cell individually. Then do this after every tenth cycle there after. This is absolutely critical in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced.
Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time. Make sure and get the appropriate connector to go into your taps. Don't try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells. Don't try to charge more than one cell at a time from the taps. Unless you have an isolated ground charging system, you'll short your batteries out. Refer to your individual cell maker for tap pin-outs.
4. NEVER charge the batteries unattended. This is the number one reason for houses and cars being burned to a crisp by lithium fires.
5. Use a safe surface to charge your batteries on so that if they burst into flame no damage will occur. Vented fire safes, pyrex dishes with sand in the bottom, fireplaces, plant pots, are all good options.
6. DO NOT CHARGE AT MORE THAN 1C unless specifically authorized by the pack vendor. I have personally had a fire in my home because of violating this rule. Today’s highest discharge batteries can supposedly be safely charged at greater than 1C, however so far in all cases doing so shortens the life of the pack. Better to buy 3 packs than to try to charge 1 pack 3 times quickly. This may change in the future but as of winter 2005 1C is still the recommended charge rate.
7. DO NOT puncture the cell, ever. If a cell balloons quickly place it in a fire safe place, especially if you were charging it when it ballooned. After you have let the cell sit in the fire safe place for at least 2 hours. Discharge the cell/pack slowly. This can be done by wiring a flashlight bulb of appropriate voltage (higher is voltage is ok, lower voltage is no) up to your batteries connector type and attaching the bulb to the battery. Wait until the light is completely off, and then throw the battery away.
8. If you crash with your lithium cells they may be damaged such that they are shorted inside. The cells may look just fine. If you crash in ANY way carefully remove the battery pack from the aircraft and watch it carefully for at least the next 20 min. Several fires have been caused by damaged cells being thrown in the car and then the cells catch fire later and destroys the car completely.
9. Charge your batteries in a open ventilated area. If a battery does rupture or explode hazardous fumes and material will spew from the battery.
10. Keep a bucket of sand nearby when you are flying or charging batteries. This is a cost effective way to extinguish fires. This is very cheap and absolutely necessary.
11. It can happen to you, do not think to yourself that “it won't happen to me” as soon as you do that it you'll be trying to rescue your kids from your burning house or car. I'm very serious about this.

Now that we have covered that important topic let's move on to lighter matters:

2. Lithium What?
Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. They are similar to Lithium Ion batteries in that they each have a nominal voltage of 3.6 volts, but dissimilar in that they do not have a hard metal casing but rather a flexible material encloses the chemicals inside. The "normal" lithium polymer batteries are thin rectangle shapes with two tabs on the top one positive one negative. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better.

3. Voltage and Cell Count:
LiPolys act differently than NiCad or NiMH batteries do when charging and discharging. Lithium batteries are fully charged when each cell has a voltage of 4.2 volts. They are fully discharged when each cell has a voltage of 3.0 volts. It is important not to exceed both the high voltage of 4.2 volts and the low voltage of 3.0 volts. Exceeding these limits can harm the battery.
The way to ensure that you do not go below 3.0 volts while flying is to set the low voltage cutoff (LVC) of your electronic speed control (ESC). It important to use a programmable ESC since the correct voltage cutoff is critical to the life of your batteries. Use the ESC's programming mode to set the LVC to 3.0 volts per cell with a hard cutoff, or 3.3 volts per cell with a soft cutoff. If your ESC does not have hard or soft cutoff, use 3.0 volts per cell. You will know when flying that it is time to land when you experience a sudden drop in power caused by the LVC.
If your ESC has an automatic lithium mode. Use it, it will correctly sense the number of cells and set the auto cutoff appropriately.
If you have previously been flying with NiCad or NiMH batteries, switching over to lithium polymer will result in a different number of cells being used. If you had 6 to 7 round cells then 2 lithium polymer cells will correctly duplicate the voltage of those cells. If you had 10-11 cells then 3 lithium polymer cells would be right for you. There are a lot of 8 cell flyer's out there that are stuck between 2 and 3 cells. In my experience the best option is to determine how many watts you were using before and duplicate that with your LiPos, Motor, and Prop. For example: If you were running 8 cells (9.6volts) at 10 amps on a speed 400 airplane, then you have 9.6 x10, 96 watts. So if you went with 2 lithium polymer cells (7.2 volts nominal) then you'd need to change your prop such that you used 13 amps. If you went to 3 LiPoly's (10.8 volts nominal) then you'd need to reduce the amperage to 8.9 amps. These estimates are approximate, and some experimentation is required for best results but conserving Watts is a good way to start.

4.10C from 3S4P? Naming conventions explained.
How fast a battery can discharge is it's maximum current capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. For instance 1 C discharges the battery in 1/1 hours or 1 hour. 2 C discharges the battery in ½ or half an hour. All RC batteries are rated in milli Amp hours. If a battery is rated at 2000 mAh and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The C rating of the battery is thus based on its capacity. A 2000mAh cell discharged a 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C( 2000mA x 3).
All batteries have limitations on how fast they can discharge. Because of this many LiPoly batteries are put in parallel to increase the current capacity of the battery pack. When 2 batteries are wired positive to positive and negative to negative they become like one battery with double the capacity. If you have 2 2000mAh cells and you wire them in parallel then the result is the same as 1 4000mAh cell. This 4000mAh cell has the same C rating as the original 2000mAh cells did. Thus if the 2000mAh cells could discharge at a maximum of 5C, or 10 amps then the new 4000mAh cell can also discharge at 5C or (4000mA x 5) 20 amps. This method of battery pack building allows us to use LiPoly batteries at higher currents than single cells could produce.
The naming convention that allows you to decipher how many cells are in parallel and how many are in series is the XSXP method. The number in front of the S represents the number of series cells in the pack so 3S means it's a 3 cell pack. The number in front of P means the number of cells in parallel. So a 3S4P pack of 2100mAh cells has a total of 12 cells inside. It will have the voltage of any other 3S pack since the number of cells in series determines the voltage. It will have the current handling of 4 times the maximum C rating of the 12 individual cells. So say our 3S4P pack had a maximum discharge of 6C. That means that it has a nominal voltage of 10.8 volts (3x3.6) and a maximum discharge rate of 50.4 amps (2100mAh x 6Cx4P ).

5. Which battery should you buy?
With so many choices out there it is difficult to decipher what is marketing hype, what is brand loyalty, and what is outright lies. Battery manufacturers are constantly trying to one up one another. While capitalism can drive prices down, it also can give cause to false claims about products.
One great way to find out what is the best battery is to look at graphs of the batteries performance. Looking at how low the voltage of the cell drops at various amperages will give you a metric to compare that battery to similar size/weight batteries.
If graphs aren't your thing then simply look at what other people are using in successful setups that are similar to your application. If a lot of people are reporting long flight times and lots of power from airplane X, with power system Y, and battery Z and you do the same, then if your setup is similar the same battery will probably work well for you.
It pays to learn something about Watts, Volts, and Amps. Understanding these concepts is beyond the scope of this document, but can serve you well in not only figuring out what battery is best but also in your electric aircraft hobby.
I'm not convinced that a 30C battery is really any better than a 10 or 20C battery. Sure a higher C rating means it can discharge faster. But at the same time a battery discharged at 20C continuously will be empty in 3 minutes. Do you really only want to use the battery for 3 minutes? I love having burst power in helicopters and boats, but in almost all other applications actually running a battery at or above 20C is useless to me. I prefer to run batteries at 8-10 C and have a little headroom if I need it.
A final note on choosing a battery: Don't cheap out. Confirm that your batteries are capable of running that the amperage level you plan to use them at. Running a cell at a higher C rating than the battery can handle can not only damage your batteries, but it can also damage your speed control. Castle Creations has an excellent article on how using a weak battery can destroy a perfectly good speed control of any brand. Better to buy a bit better battery than you need than to destroy your electronics.

6. Dealing with temperature.
Lithium batteries like heat, but not too much. In the winter time, try to keep your batteries from the cold as much as possible. Leave them in the car while your flying, or keep them in your cargo pants... etc. At the same time don't let them heat up too much. Try to keep your batteries from reaching 160F after use. This will prolong the life of the cells. A good way to measure temperature is a handheld IR meter, they can be found for around $50.00 at most hobby shops.

Videos of LiPo Container Tests.
....Battery containment tests by UtahFlyers:
http://www.utahflyers.org/index.php...id=16&Itemid=28
...Lipo Sack Test http://www.liposack.com/video.html
...Ammo Box Test 4s3p6000 http://www.rcgroups.com/forums/showthread.php?t=355739
...Brinks Box test - 3s3270
http://www.rcgroups.com/forums/showthread.php?t=316210
...Test of 500g lipo in a owner designed box. Post #6
http://www.rcgroups.com/forums/showthread.php?t=620298

Why Not to Puncture LiPo's
http://ribolabs.wordpress.com/2007/...ery-fire-video/ POKED PACK
http://www.rcgroups.com/forums/show...338&postcount=4
http://www.rcgroups.com/forums/show...575&postcount=1
http://www.rcgroups.com/forums/show...26&postcount=15



The Hows and Whys of Pack Balancing:
A complete guide on how and why to balance LiPo packs written by BEC. Covers everything from A to Z.
http://www.rcgroups.com/forums/showthread.php?t=599287
p=3320890&postcount=29[/url]
Parallel Charging Balancing: (RD Blakeslee)
http://www.rcgroups.com/forums/showthread.php?t=388233
Balance/Adaptor Plug Information (everydayflyer)
http://www.rcgroups.com/forums/show...90&postcount=29

Overdischarged battery?
http://www.rcgroups.com/forums/show...ged#post5708198

Battery Voltage versus Battery Charge Condition:
http://www.rcgroups.com/forums/show...01&postcount=11

How Many Amps Can I Draw from my Battery?
http://www.rcgroups.com/forums/show...670&postcount=3 (everydayflyer)

Disposal Instructions for Damaged Lipo:
http://www.rcgroups.com/forums/show...93&postcount=27

Parallel charging packs
http://www.rcgroups.com/forums/show...hlight=Parallel
http://www.rcgroups.com/forums/show...hlight=Parallel
http://www.rcgroups.com/forums/show...&postcount=8din


Storing Lipo's
http://www.rcgroups.com/forums/show...495&postcount=5
http://www.hardingenergy.com/pdfs/LiPolymer.pdf
http://www.batteryuniversity.com/partone-19.htm
Sanyo spec is 20-50C
Motorola recommends not to exceed 45C and states that lower temperatures give a longer cell life.
http://www.motorola.com/testservices/article1.htm

Low Votage Cutoff (LVC)
http://www.rcgroups.com/forums/show...168&postcount=1 (everydayflyer)
To rough check the LVC setting you are using, if the voltage is less than 3.7V/cell 20 min after flying, increase the LVC setting. If it is above 3.7V, decrease the LVC setting or leave it where it is if you are happy with the flight time. This is a rough check and you'll need to check pack temperature and capacity used to make sure the LVC is not set to low.

How to read CBA graphs- http://www.rcgroups.com/forums/show...989&postcount=2
(everydayflyer)

How Much Capacity Is Left In My Pack?
By measuring the pack voltage, a rough capacity check can be made.
http://www.rcgroups.com/forums/show...057&postcount=7

What is the Usable Capacity?
http://www.rcgroups.com/forums/showthread.php?t=628397

Parallel and Series Battery Wiring Diagrams
http://scriptasylum.com/rc_speed/_lipo.html

Life History of a Bent Pack
http://www.rcgroups.com/forums/showthread.php?t=733512

Protecting Mini Deans Connectors
http://www.rcgroups.com/forums/show...ini+deans+hoppy

Changing from a 2s to a 3s Lipo Pack - What you should know.
http://www.rcgroups.com/forums/show...705&postcount=4

Thoughts on the Safety of Charging Lipos Indoors -
http://www.rcgroups.com/forums/show...7&postcount=144

All above text was not written by me, but are cut from various threads that I have found informative.

Cheers and happy flying!

Steve]]>
With that, I'd like to welcome all of you to Pegasus and to share some common info on LiPO's..

Lithium batteries are the preferred power sources for most electric modelers today. They offer high discharge rates and a high energy storage/weight ratio. However, using them properly and charging them correctly is no trivial task. There are many things to consider before using lithium cells for e-flight. But none is more important than safety.

1. Charging/Safety IMPORTANT!
Until you are willing to follow all safety precautions, DO NOT use lithium batteries. If your a type of person that prefers to push the limits of products, or be haphazard about following safety requirements. Lithium technology is not for you. Read on to find out why.

Lithium cells must be charged very differently than NiCad or NiMH. They require a special charger specifically designed to charge lithium cells. In general any charger that can charge lithium ion can charge lithium polymer, assuming that the cell count is correct. You must NEVER charge lithium cells with a NiCad or NiMH only battery charger. This is dangerous. Charging cells is the most hazardous part of using lithium batteries. EXTREME care must be taken when charging them. It is important to set your charger to the correct voltage or cell count. Failure to do this can cause the battery to spew violent flames. There have been many fires directly caused by lithium batteries. PLEASE BE RESPONSIBLE when charging lithium batteries.

Here are a few MANDATORY guidelines for charging/using LiPos (Lithium Polymer Batteries).


1. Use only a charger approved for lithium batteries. The charger may be designed for Li-Ion or Li-Poly. Both batteries are charged in exactly the same. Some older cell phone chargers may charge the batteries .1 volt to low (4.1 vs 4.2), but that will not harm the battery. However, inexpensive lithium chargers are widely available and the use of cellphone chargers is highly discouraged.
2. Make certain that the correct cell count is set on your charger. Watch the charger very closely for the first few minutes to ensure that the correct cell count continues to be displayed. If you don't know how to do that, get a charger that you do know how or don't charge the batteries.
3. Use the Taps. Before you charge a new Lithium pack, check the voltage of each cell individually. Then do this after every tenth cycle there after. This is absolutely critical in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced.
Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time. Make sure and get the appropriate connector to go into your taps. Don't try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells. Don't try to charge more than one cell at a time from the taps. Unless you have an isolated ground charging system, you'll short your batteries out. Refer to your individual cell maker for tap pin-outs.
4. NEVER charge the batteries unattended. This is the number one reason for houses and cars being burned to a crisp by lithium fires.
5. Use a safe surface to charge your batteries on so that if they burst into flame no damage will occur. Vented fire safes, pyrex dishes with sand in the bottom, fireplaces, plant pots, are all good options.
6. DO NOT CHARGE AT MORE THAN 1C unless specifically authorized by the pack vendor. I have personally had a fire in my home because of violating this rule. Today’s highest discharge batteries can supposedly be safely charged at greater than 1C, however so far in all cases doing so shortens the life of the pack. Better to buy 3 packs than to try to charge 1 pack 3 times quickly. This may change in the future but as of winter 2005 1C is still the recommended charge rate.
7. DO NOT puncture the cell, ever. If a cell balloons quickly place it in a fire safe place, especially if you were charging it when it ballooned. After you have let the cell sit in the fire safe place for at least 2 hours. Discharge the cell/pack slowly. This can be done by wiring a flashlight bulb of appropriate voltage (higher is voltage is ok, lower voltage is no) up to your batteries connector type and attaching the bulb to the battery. Wait until the light is completely off, and then throw the battery away.
8. If you crash with your lithium cells they may be damaged such that they are shorted inside. The cells may look just fine. If you crash in ANY way carefully remove the battery pack from the aircraft and watch it carefully for at least the next 20 min. Several fires have been caused by damaged cells being thrown in the car and then the cells catch fire later and destroys the car completely.
9. Charge your batteries in a open ventilated area. If a battery does rupture or explode hazardous fumes and material will spew from the battery.
10. Keep a bucket of sand nearby when you are flying or charging batteries. This is a cost effective way to extinguish fires. This is very cheap and absolutely necessary.
11. It can happen to you, do not think to yourself that “it won't happen to me” as soon as you do that it you'll be trying to rescue your kids from your burning house or car. I'm very serious about this.

Now that we have covered that important topic let's move on to lighter matters:

2. Lithium What?
Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. They are similar to Lithium Ion batteries in that they each have a nominal voltage of 3.6 volts, but dissimilar in that they do not have a hard metal casing but rather a flexible material encloses the chemicals inside. The "normal" lithium polymer batteries are thin rectangle shapes with two tabs on the top one positive one negative. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better.

3. Voltage and Cell Count:
LiPolys act differently than NiCad or NiMH batteries do when charging and discharging. Lithium batteries are fully charged when each cell has a voltage of 4.2 volts. They are fully discharged when each cell has a voltage of 3.0 volts. It is important not to exceed both the high voltage of 4.2 volts and the low voltage of 3.0 volts. Exceeding these limits can harm the battery.
The way to ensure that you do not go below 3.0 volts while flying is to set the low voltage cutoff (LVC) of your electronic speed control (ESC). It important to use a programmable ESC since the correct voltage cutoff is critical to the life of your batteries. Use the ESC's programming mode to set the LVC to 3.0 volts per cell with a hard cutoff, or 3.3 volts per cell with a soft cutoff. If your ESC does not have hard or soft cutoff, use 3.0 volts per cell. You will know when flying that it is time to land when you experience a sudden drop in power caused by the LVC.
If your ESC has an automatic lithium mode. Use it, it will correctly sense the number of cells and set the auto cutoff appropriately.
If you have previously been flying with NiCad or NiMH batteries, switching over to lithium polymer will result in a different number of cells being used. If you had 6 to 7 round cells then 2 lithium polymer cells will correctly duplicate the voltage of those cells. If you had 10-11 cells then 3 lithium polymer cells would be right for you. There are a lot of 8 cell flyer's out there that are stuck between 2 and 3 cells. In my experience the best option is to determine how many watts you were using before and duplicate that with your LiPos, Motor, and Prop. For example: If you were running 8 cells (9.6volts) at 10 amps on a speed 400 airplane, then you have 9.6 x10, 96 watts. So if you went with 2 lithium polymer cells (7.2 volts nominal) then you'd need to change your prop such that you used 13 amps. If you went to 3 LiPoly's (10.8 volts nominal) then you'd need to reduce the amperage to 8.9 amps. These estimates are approximate, and some experimentation is required for best results but conserving Watts is a good way to start.

4.10C from 3S4P? Naming conventions explained.
How fast a battery can discharge is it's maximum current capacity. Current is generally rated in C's for the battery. C is how long it takes to discharge the battery in fractions of an hour. For instance 1 C discharges the battery in 1/1 hours or 1 hour. 2 C discharges the battery in ½ or half an hour. All RC batteries are rated in milli Amp hours. If a battery is rated at 2000 mAh and you discharge it at 2000mA (or 2 amps, 1 amp = 1000mA) it will be completely discharged in one hour. The C rating of the battery is thus based on its capacity. A 2000mAh cell discharged a 2 amps is being discharged at 1C (2000mA x 1), a 2000mAh cell discharged at 6 amps is being discharged at 3C( 2000mA x 3).
All batteries have limitations on how fast they can discharge. Because of this many LiPoly batteries are put in parallel to increase the current capacity of the battery pack. When 2 batteries are wired positive to positive and negative to negative they become like one battery with double the capacity. If you have 2 2000mAh cells and you wire them in parallel then the result is the same as 1 4000mAh cell. This 4000mAh cell has the same C rating as the original 2000mAh cells did. Thus if the 2000mAh cells could discharge at a maximum of 5C, or 10 amps then the new 4000mAh cell can also discharge at 5C or (4000mA x 5) 20 amps. This method of battery pack building allows us to use LiPoly batteries at higher currents than single cells could produce.
The naming convention that allows you to decipher how many cells are in parallel and how many are in series is the XSXP method. The number in front of the S represents the number of series cells in the pack so 3S means it's a 3 cell pack. The number in front of P means the number of cells in parallel. So a 3S4P pack of 2100mAh cells has a total of 12 cells inside. It will have the voltage of any other 3S pack since the number of cells in series determines the voltage. It will have the current handling of 4 times the maximum C rating of the 12 individual cells. So say our 3S4P pack had a maximum discharge of 6C. That means that it has a nominal voltage of 10.8 volts (3x3.6) and a maximum discharge rate of 50.4 amps (2100mAh x 6Cx4P ).

5. Which battery should you buy?
With so many choices out there it is difficult to decipher what is marketing hype, what is brand loyalty, and what is outright lies. Battery manufacturers are constantly trying to one up one another. While capitalism can drive prices down, it also can give cause to false claims about products.
One great way to find out what is the best battery is to look at graphs of the batteries performance. Looking at how low the voltage of the cell drops at various amperages will give you a metric to compare that battery to similar size/weight batteries.
If graphs aren't your thing then simply look at what other people are using in successful setups that are similar to your application. If a lot of people are reporting long flight times and lots of power from airplane X, with power system Y, and battery Z and you do the same, then if your setup is similar the same battery will probably work well for you.
It pays to learn something about Watts, Volts, and Amps. Understanding these concepts is beyond the scope of this document, but can serve you well in not only figuring out what battery is best but also in your electric aircraft hobby.
I'm not convinced that a 30C battery is really any better than a 10 or 20C battery. Sure a higher C rating means it can discharge faster. But at the same time a battery discharged at 20C continuously will be empty in 3 minutes. Do you really only want to use the battery for 3 minutes? I love having burst power in helicopters and boats, but in almost all other applications actually running a battery at or above 20C is useless to me. I prefer to run batteries at 8-10 C and have a little headroom if I need it.
A final note on choosing a battery: Don't cheap out. Confirm that your batteries are capable of running that the amperage level you plan to use them at. Running a cell at a higher C rating than the battery can handle can not only damage your batteries, but it can also damage your speed control. Castle Creations has an excellent article on how using a weak battery can destroy a perfectly good speed control of any brand. Better to buy a bit better battery than you need than to destroy your electronics.

6. Dealing with temperature.
Lithium batteries like heat, but not too much. In the winter time, try to keep your batteries from the cold as much as possible. Leave them in the car while your flying, or keep them in your cargo pants... etc. At the same time don't let them heat up too much. Try to keep your batteries from reaching 160F after use. This will prolong the life of the cells. A good way to measure temperature is a handheld IR meter, they can be found for around $50.00 at most hobby shops.

Videos of LiPo Container Tests.
....Battery containment tests by UtahFlyers:
http://www.utahflyers.org/index.php...id=16&Itemid=28
...Lipo Sack Test http://www.liposack.com/video.html
...Ammo Box Test 4s3p6000 http://www.rcgroups.com/forums/showthread.php?t=355739
...Brinks Box test - 3s3270
http://www.rcgroups.com/forums/showthread.php?t=316210
...Test of 500g lipo in a owner designed box. Post #6
http://www.rcgroups.com/forums/showthread.php?t=620298

Why Not to Puncture LiPo's
http://ribolabs.wordpress.com/2007/...ery-fire-video/ POKED PACK
http://www.rcgroups.com/forums/show...338&postcount=4
http://www.rcgroups.com/forums/show...575&postcount=1
http://www.rcgroups.com/forums/show...26&postcount=15



The Hows and Whys of Pack Balancing:
A complete guide on how and why to balance LiPo packs written by BEC. Covers everything from A to Z.
http://www.rcgroups.com/forums/showthread.php?t=599287
p=3320890&postcount=29[/url]
Parallel Charging Balancing: (RD Blakeslee)
http://www.rcgroups.com/forums/showthread.php?t=388233
Balance/Adaptor Plug Information (everydayflyer)
http://www.rcgroups.com/forums/show...90&postcount=29

Overdischarged battery?
http://www.rcgroups.com/forums/show...ged#post5708198

Battery Voltage versus Battery Charge Condition:
http://www.rcgroups.com/forums/show...01&postcount=11

How Many Amps Can I Draw from my Battery?
http://www.rcgroups.com/forums/show...670&postcount=3 (everydayflyer)

Disposal Instructions for Damaged Lipo:
http://www.rcgroups.com/forums/show...93&postcount=27

Parallel charging packs
http://www.rcgroups.com/forums/show...hlight=Parallel
http://www.rcgroups.com/forums/show...hlight=Parallel
http://www.rcgroups.com/forums/show...&postcount=8din


Storing Lipo's
http://www.rcgroups.com/forums/show...495&postcount=5
http://www.hardingenergy.com/pdfs/LiPolymer.pdf
http://www.batteryuniversity.com/partone-19.htm
Sanyo spec is 20-50C
Motorola recommends not to exceed 45C and states that lower temperatures give a longer cell life.
http://www.motorola.com/testservices/article1.htm

Low Votage Cutoff (LVC)
http://www.rcgroups.com/forums/show...168&postcount=1 (everydayflyer)
To rough check the LVC setting you are using, if the voltage is less than 3.7V/cell 20 min after flying, increase the LVC setting. If it is above 3.7V, decrease the LVC setting or leave it where it is if you are happy with the flight time. This is a rough check and you'll need to check pack temperature and capacity used to make sure the LVC is not set to low.

How to read CBA graphs- http://www.rcgroups.com/forums/show...989&postcount=2
(everydayflyer)

How Much Capacity Is Left In My Pack?
By measuring the pack voltage, a rough capacity check can be made.
http://www.rcgroups.com/forums/show...057&postcount=7

What is the Usable Capacity?
http://www.rcgroups.com/forums/showthread.php?t=628397

Parallel and Series Battery Wiring Diagrams
http://scriptasylum.com/rc_speed/_lipo.html

Life History of a Bent Pack
http://www.rcgroups.com/forums/showthread.php?t=733512

Protecting Mini Deans Connectors
http://www.rcgroups.com/forums/show...ini+deans+hoppy

Changing from a 2s to a 3s Lipo Pack - What you should know.
http://www.rcgroups.com/forums/show...705&postcount=4

Thoughts on the Safety of Charging Lipos Indoors -
http://www.rcgroups.com/forums/show...7&postcount=144

All above text was not written by me, but are cut from various threads that I have found informative.

Cheers and happy flying!

Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=63 Thu, 12 Jun 2008 15:51:28 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=63
It's time I let you in on a little secret...you know those power supplies you have at home to power your chargers that cost you an arm and a leg for 10 amps? Well, they are nothing more that switching power supplies like the ones in your home PC's! Now, 600W is a nice power supply, usually that translates into >25 Amps of 12 VDC that can be readily converted to power your high flalootin' NiCd, NiMH, Lipo, Pb, "I can do everything but walk your dog" charger!

Don't need all that power? what are you a wuss? you ALWAYS need MORE POWER!! Seriously though, If you fly electrics you are going to need a good Power supply for your charger so it can deliver the amps needed for that 10 AMP charger cycle - remember, input watts doesn't translate directly to OUTPUT watts! There is a big loss and your charger needs more watts in than it puts out.

So what is thread all about? Well, I am glad you asked...I have been testing some really high end computer power supplies that came out of a server rack:



These power supplies are extremely robust and extremely powerful-30 amps at 12 Volts!- and can be bridged to get even MORE power!

The Kicker? They cost $9.95 plus shipping! Click Here. Now I am not endorsing this seller in anyway other than I bought 4 of these puppies and they all work great and he shipped them fast. If you'd like to read up on others opinions of these, just click here.

Just trying to help you guys out...

Cheers,
Steve]]>
It's time I let you in on a little secret...you know those power supplies you have at home to power your chargers that cost you an arm and a leg for 10 amps? Well, they are nothing more that switching power supplies like the ones in your home PC's! Now, 600W is a nice power supply, usually that translates into >25 Amps of 12 VDC that can be readily converted to power your high flalootin' NiCd, NiMH, Lipo, Pb, "I can do everything but walk your dog" charger!

Don't need all that power? what are you a wuss? you ALWAYS need MORE POWER!! Seriously though, If you fly electrics you are going to need a good Power supply for your charger so it can deliver the amps needed for that 10 AMP charger cycle - remember, input watts doesn't translate directly to OUTPUT watts! There is a big loss and your charger needs more watts in than it puts out.

So what is thread all about? Well, I am glad you asked...I have been testing some really high end computer power supplies that came out of a server rack:



These power supplies are extremely robust and extremely powerful-30 amps at 12 Volts!- and can be bridged to get even MORE power!

The Kicker? They cost $9.95 plus shipping! Click Here. Now I am not endorsing this seller in anyway other than I bought 4 of these puppies and they all work great and he shipped them fast. If you'd like to read up on others opinions of these, just click here.

Just trying to help you guys out...

Cheers,
Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=62 Tue, 10 Jun 2008 09:27:17 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=62
We used to do this down at Reston RC back in the day and it was a hoot. Cook out at night, breakfast the next day. Lots of flying and good times.]]>
We used to do this down at Reston RC back in the day and it was a hoot. Cook out at night, breakfast the next day. Lots of flying and good times.]]> http://www.pegasusrc.com/forum/showthread.php?tid=61 Tue, 10 Jun 2008 07:46:43 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=61
I have recently upgraded some of my soldering supplies to include zinc flux, aluminum solder and the cell tabs for the A123 packs. Link) To help promote the use of these terrific cells in the electric community, and those Gas/glow guys who want robust receiver packs, I'd like to extend an offer to build your packs for you. I will only ask for the cost of resupply of items used (solder/flux/heat shrink) and charge no labor for this service. I can also obtain the A123 cells for around $10.00 per cell (for the 2300 mAh) which is about $6.00 less than the going rate should you not have the cells.

This offer is only for local club members who can either drop off the cells or meet me at the field.

If you have any other specialty soldering needs I can help you out with that as well - just ask!

**UPDATE 07/13/08**


I have 50 A123 cells inbound, so I can start making some packs for those of you who which get a pack made without having to buy the batteries.

Price will be $12.00 per cell for a built pack, i.e:
2 cell rvcr pack: $24.00
5 cell flight pack: $60.00
10 cell flight pack: $120.00

I can build any combo, all come with your choice of main leads (deans, APP) and Align style balance taps. They'll be covered in blue heat shrink and labeled.

2 cell example 6.6v 2300 mAh
3 cell example 9.9v 2300 mAh
4 cell example 13.2v 2300 mAh
5 cell example 16.5v 2300 mAh
6 cell example 19.8v 2300 mAh
7 cell example 23.1v 2300 mAh
8 cell example 26.4 2300 mAh
10 cell example 33.0v 2300mAh

-I can also build them "tube" style (like the old NiCd and NiMH packs)

-If you want a rcvr pack, you may need a voltage regulator to drop the voltage to 5 or 6 volts (depending on your servos/receiver) I can get the voltage regulator and install it in-line for the cost of the regulator.

-If you have a preference on balance taps I can accommodate about any style, but will have to order them at your cost. (minus $1.50)

-I am working on getting the 1100 mAh versions, but so far I haven't been able to get a good enough price on them.

NOTE: You do have to be a club member to take advantage of this offer. I am not making any profit on these, and don't plan on trying to make a business out of it - just doing a favor for my fellow fliers. PM me if you are interested.

Cheers,
Steve]]>
I have recently upgraded some of my soldering supplies to include zinc flux, aluminum solder and the cell tabs for the A123 packs. Link) To help promote the use of these terrific cells in the electric community, and those Gas/glow guys who want robust receiver packs, I'd like to extend an offer to build your packs for you. I will only ask for the cost of resupply of items used (solder/flux/heat shrink) and charge no labor for this service. I can also obtain the A123 cells for around $10.00 per cell (for the 2300 mAh) which is about $6.00 less than the going rate should you not have the cells.

This offer is only for local club members who can either drop off the cells or meet me at the field.

If you have any other specialty soldering needs I can help you out with that as well - just ask!

**UPDATE 07/13/08**


I have 50 A123 cells inbound, so I can start making some packs for those of you who which get a pack made without having to buy the batteries.

Price will be $12.00 per cell for a built pack, i.e:
2 cell rvcr pack: $24.00
5 cell flight pack: $60.00
10 cell flight pack: $120.00

I can build any combo, all come with your choice of main leads (deans, APP) and Align style balance taps. They'll be covered in blue heat shrink and labeled.

2 cell example 6.6v 2300 mAh
3 cell example 9.9v 2300 mAh
4 cell example 13.2v 2300 mAh
5 cell example 16.5v 2300 mAh
6 cell example 19.8v 2300 mAh
7 cell example 23.1v 2300 mAh
8 cell example 26.4 2300 mAh
10 cell example 33.0v 2300mAh

-I can also build them "tube" style (like the old NiCd and NiMH packs)

-If you want a rcvr pack, you may need a voltage regulator to drop the voltage to 5 or 6 volts (depending on your servos/receiver) I can get the voltage regulator and install it in-line for the cost of the regulator.

-If you have a preference on balance taps I can accommodate about any style, but will have to order them at your cost. (minus $1.50)

-I am working on getting the 1100 mAh versions, but so far I haven't been able to get a good enough price on them.

NOTE: You do have to be a club member to take advantage of this offer. I am not making any profit on these, and don't plan on trying to make a business out of it - just doing a favor for my fellow fliers. PM me if you are interested.

Cheers,
Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=59 Sun, 08 Jun 2008 12:48:25 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=59
[attachment=180][attachment=181][attachment=182][attachment=183][attachment=184]

To view the full sized picture(s), please click HERE]]>
[attachment=180][attachment=181][attachment=182][attachment=183][attachment=184]

To view the full sized picture(s), please click HERE]]> http://www.pegasusrc.com/forum/showthread.php?tid=58 Thu, 05 Jun 2008 14:02:13 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=58
Looking for something like this:



or these: (from Great Planes)



In 3 3/8 to 4"

Foam wheels from the GP 1/5th J-3 are good too!

PM me if you have a set!

Cheers,
Steve]]>
Looking for something like this:



or these: (from Great Planes)



In 3 3/8 to 4"

Foam wheels from the GP 1/5th J-3 are good too!

PM me if you have a set!

Cheers,
Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=57 Thu, 05 Jun 2008 13:54:34 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=57
Also potential members can see just what they need to adhere to before joining:cool:

All in favor??

Cheers,
Steve]]>
Also potential members can see just what they need to adhere to before joining:cool:

All in favor??

Cheers,
Steve]]> http://www.pegasusrc.com/forum/showthread.php?tid=56 Mon, 02 Jun 2008 15:34:32 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=56



(not actual picture of Pegasus Field at Dawn)

The Sun is now coming up early (I see blue skies at 5:00am) and the wind is still a few hours off, A nice peaceful time to bring out your electrics to the field and enjoy still air while you finalize your trim on your favorite plane. It is especially nice to fly those maidens on a calm morning when the sun is still at your back, you don't need a hat and the temperature is just right. (if it's still too cool for you, the fire pit or a jacket will help)

Imagine a picturesque sunrise as the light reflects off your starboard wing; you turn in for final and finish with a effortless glide into ground effect and a perfect landing. While you swap out your battery for another great flight you sip on hot coffee and chat with your comrades about life, politics and the pursuit of happiness (which happens to be R/C flying!) and wonder why you didn't do this before!

Now is your chance!

Look at all the benefits:

1. No Wind!
2. No Wind!
3. No Wi...... Ok, enough of that :D
4. perfect time to maiden
5. If you get there early enough you can night fly first!
6. If you crash, you can be back at the field with your bird repaired before most of the others members even show up!
7. If you have house stuff to do, you'll be back home by 9 or 10 and get a full days work in! -ok, some of you may not think this is a benefit...
8. Did I mention No Wind?!?

So...who is up for it?]]>



(not actual picture of Pegasus Field at Dawn)

The Sun is now coming up early (I see blue skies at 5:00am) and the wind is still a few hours off, A nice peaceful time to bring out your electrics to the field and enjoy still air while you finalize your trim on your favorite plane. It is especially nice to fly those maidens on a calm morning when the sun is still at your back, you don't need a hat and the temperature is just right. (if it's still too cool for you, the fire pit or a jacket will help)

Imagine a picturesque sunrise as the light reflects off your starboard wing; you turn in for final and finish with a effortless glide into ground effect and a perfect landing. While you swap out your battery for another great flight you sip on hot coffee and chat with your comrades about life, politics and the pursuit of happiness (which happens to be R/C flying!) and wonder why you didn't do this before!

Now is your chance!

Look at all the benefits:

1. No Wind!
2. No Wind!
3. No Wi...... Ok, enough of that :D
4. perfect time to maiden
5. If you get there early enough you can night fly first!
6. If you crash, you can be back at the field with your bird repaired before most of the others members even show up!
7. If you have house stuff to do, you'll be back home by 9 or 10 and get a full days work in! -ok, some of you may not think this is a benefit...
8. Did I mention No Wind?!?

So...who is up for it?]]> http://www.pegasusrc.com/forum/showthread.php?tid=55 Tue, 27 May 2008 13:39:07 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=55 http://www.pegasusrc.com/forum/showthread.php?tid=54 Fri, 23 May 2008 05:43:59 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=54 http://www.pegasusrc.com/forum/showthread.php?tid=52 Mon, 12 May 2008 13:52:41 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=52
wingspan 71 inches
length 39 inches
all up weight 16 to 21 oz]]>
wingspan 71 inches
length 39 inches
all up weight 16 to 21 oz]]> http://www.pegasusrc.com/forum/showthread.php?tid=49 Fri, 11 Apr 2008 00:42:32 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=49 will make up the difference in value with cash if worth it.

If interested,let me know watcha got.
reply in email or call Jody @ 240-818-1755]]> will make up the difference in value with cash if worth it.

If interested,let me know watcha got.
reply in email or call Jody @ 240-818-1755]]> http://www.pegasusrc.com/forum/showthread.php?tid=47 Fri, 04 Apr 2008 06:01:27 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=47 $30.00. 301-865-3557]]> $30.00. 301-865-3557]]> http://www.pegasusrc.com/forum/showthread.php?tid=46 Fri, 04 Apr 2008 05:57:34 -0700 http://www.pegasusrc.com/forum/showthread.php?tid=46