Batteries for Dummies?

[kg0ew]

OK, I'm a bit lost by all of the battery terminology, facts and lore. Such as...

> What is the difference between a LiPo and an A123 battery (as in, how are they phyicically different, and what does that mean as relates to an electric heli?)

> What does 3S1P (and similar strings of numbers and letters used to describe a battery) actually mean? I've seen 3S1P and 4S1P and 6S2P used to describe batteries, but I have no idea what these designators mean!

> What are the right steps to take to maximize battery life, and avoid catching the house on fire? From all the dire warnings I've seen, it would appear that your average LiPo battery is about as stable as nitroglycerin, and if given its druthers, would really rather explode than go through one more charging cycle...

> How do I use a balanced charger? Can I charge two batteries in series? I just purchased a JB-1100 "Microcomputer Smart Charger" - from the description on the box, it will charge and balance my batteries, change the oil in my car and balance my checkbook - but there are no instructions in the box! Do all balanced chargers work more-or-less the same? Does there exist a basic (yet thorough) description on how to use a balanced charger?

> Can't I just run an extension cord to my heli? (OK, just kiddin' on this one.)

Somewhere there must be a some good information on line... a dummies guide to electric heli batteries... help!

(Thanks in advance for any and all advice.)

[DebianDog]

Did you read our sticky?
http://www.helifreak.com/showthread.php?t=32121

[kg0ew]

Did you read our sticky?
http://www.helifreak.com/showthread.php?t=32121
I have read your sticky - it is a useful, very basic, starting point. Unfortunately, it doesn't really answer my questions on the terminology, difference between battery types, etc. But it does help, and thanks for taking the time to put that info on line!

[gadawg58]

I have read your sticky - it is a useful, very basic, starting point. Unfortunately, it doesn't really answer my questions on the terminology, difference between battery types, etc. But it does help, and thanks for taking the time to put that info on line!
Don't know about the A123 but I can offer some input on the other questions...

The 3S1P talks about how the cells in the pack are wired. In this case you have 3 cells wired in series with a total of 3 cells. Wiring cells in series increases the voltage and wiring them in parallel increases the mah rating. For instance ... I run 4 11.1V 2500 mah FP batteries on my TREX 600. I have 2 pairs each of which are wired in series creating basically 2-22.2V packs of 2500mah each. I then wire those two "new" packs in parallel creating 1-22.2V 5000mah battery which flies fine. I chose this approach as those are the batteries I run in my 450se as well and my charger and balancer are good for 3 cell batteries so works out well. If you do stack batteries though you have to take thermal dissipation into account. I physically stack them in 2 pairs so each pair stay close to the same temp. If 1 pair were to get hotter then the resistence will drop causing that pack to drain first and leave you with a short flight time and possibly damaged packs! Also can lead to you learning how to Auto way sooner than you planned! :)

Speaking of taking care of the batteries...best bet is to not discharge more than 85% and to let cool well before charging. With new packs I never discharge below 50% for the first 5 flights which also are limited to easy hovering and slow flight. If you crash a battery make sure you inspect carefully for any physical damage before attempting to charge. If all looks fine I would charge at a lower rate and watch carefully for signs of swelling. If it swells at all its time to replace it.

Everyone has their own take on charging but I don't charge in series as I smoked 1 charger doing that. I would not do that unless the company states its built to do that. I got around that with a PolyCharge 4 charger which has 4 seperate outputs for charging and will charge up to 3000mah. It can charge a 5000mah pack will just take longer. I use an Astro blinky on each pack I'm charging so they always stay balanced and now have over 200 discharges on my original TP Packs. FP packs are looking strong as well after first 20 uses or so! However, if you use 6S packs then the PolyCharge won't work.

Hope this was useful and have fun flying!

[kg0ew]

George,
Thanks for some very good info! I need to check out just what is a "blinky"... I purchased a "microcomputer smart charger" on eBay. Decent price, but it will only charge one 11.1V LiPo. So, with two batteries, I'm guessing I'll be waiting awhile between flights - or buying a lot more batteries.

I've read several cautions about charging LiPos in series, and about charging packs that are used in series with two different chargers. Hmmm... I didn't think that there might be chargers that would charge two batteries simultaneously, without the need to wire the batteries in series. And now I need to find out what a blinky is. What a fascinating (and expensive!) hobby I have fallin into...