LiPo questions...
 

Being new to LiPo's.. what exactly does it mean to say that the maximum charge current should be limited to their 1C value.?? what is 1C? I have a 3cell 11.1v 21oo mah. I have been charging at 1 amp. zzzzzzzzzzz. what about a balancer , is this really needed?

RE: LiPo questions...
 

Your pacj should be charged at 2.1 amps or less. 1C is one times the capacity in mAh. So theoretically if it is discaharged you shoudl charge in for one hour at 2100 mA. Most chargers will taper the charge so it will actually take more than one hour and the rate will drop off at the end.

If a battery says it can be charged at 3C and it is a 2100 mAh pack, you can charge it a 6.3 amps.

I have never messed with any balancer and think they are unnecessary.

RE: LiPo questions...
 

'C' means capacity, the number before it means how many times, 2C means 2 times capacity. Hence for a 1,000 mAh battery you will see it has a 15C rating, means the battery will be able to DISCHARGE up to 15A. Charging is always NO MORE than 1C.

RE: LiPo questions...
 

Balancing is becoming more the norm, look at the manufacturers now offering charge jacks for that very purpose. On a 3cell pack the center cell cannot dissipate heat as efficiently as the outer packs which can be a factor in the cells getting out of balance. Once out of balance the charger will overcharge some cells while it is trying to bring the whole pack up to where it thinks it should be. Without being able to charge the cells individually you have no idea what shape your packs are in and can easily shorten their useful life span.

Balancing is simply the act of charging the cells individually as opposed to charging the whole pack.

RE: LiPo questions...
 

aahhh. thanks.

RE: LiPo questions...
 

also, what about them holding a charge for a few days before flying.. any top off needed?

RE: LiPo questions...
 

Yes.

RE: LiPo questions...
 

Balancing is really only a concern if you push the batteries close to their limits. Balancing is suppose to make sure that each cell in the pack is nearly equal in voltage to the others. This way, they will all charge to the smae voltage, but more importantly, it will make sure that any one cell won't be overcharged because it had more voltage to begin with. However, if your cells never get out of balance, then balancing is not really necessary. They get out of balance if you push them. For example, if your motor draws 10 amps and you have a 1500mah(1.5A) lipo with a 10C discharge (minimum nowadays), then the battery is capable of handling 15 amps (10x1.5A) continous draw, which means the motor will not get close to taxing the packs' capability. If you have a closer gap in those numbers , then your cells could get out of balance, and of course, a balancer would be a good inverstment. You really have to know what your motor is drawing from the pack you are using. Also, the more cells you have in a pack, the more i would tend to go with a balancer. Bottom line is, if you spend more than $50 on one lipo pack, go ahead and get the balancer. If you use 2 cell lipos with small 370 or 400 motors that draw <10 amps, i don't think balancers are essential. Keep in mind that the propeller you use will also affect amps drawn, not drastically, but enough to make a difference.

RE: LiPo questions...
 

I heard from a shop that using a balancer is not necessary. If the pack needs balancing, you can charge at a very low rate (.1-.2 C maybe) and that will take care of any inbalances in the cells. Is this true?

RE: LiPo questions...
 

No it's not rue. Either the person doesn't know what they are talking about or they don't sell anything that will allow you to balance your pack so they are blowing smoke up your ass.

RE: LiPo questions...
 

lol Thanks for the info.