Good RC Battery FAQ page

[valliloves]

I have a question about lipo batteries. I'm not quite sure how to ask it.

Must we order the exact lipo battery again and again?

For example, we just bought another heli from Brookstone, the Stunt Copter 2.4ghz

It comes with a 3.7V 130mAh battery. When I go to Amazon, I can order a 2 pack.

Well, I also see that on Amazon, there are other lipo batteries that look the same with a higher mAh rating. Can I charge those using the same charger even though it doesn't come from Brookstone? And can I use a higher mAh rating in this copter?

My main point is, what are my lipo battery upgrade options? Or does it not matter as long as the voltage and connector is the same?

Thanks

[ddj74]

You can use higher mah and/or "C" rating as long as it's the same connector and voltage. Other limiting factor is if it fits or of it's too heavy. Yes you can use the same charger.

[apokathilwsis]

A question on li-po batteries

i have 3 new batteries 1 stock walkera 3s 20c 1000mah 1 chinese brand 3s 12c 1500mah and 1 zippy 3s 20c 1800mah
when i firstly charged them they all were good 12,6v and 4,2v per cell +/- 0.01v
after 4-5 cycles they start to charge at 4,25v and 12,75 total voltage

1st question
is there a problem with my charger ?
are the batteries 'motivated' somehow and they just take a bit more voltage?
is there a saftey issue about that?

2nd question
i dont have a voltage indicator on the heli but i immediately land it when i notice the slightest loss in power
i am timing my batts and they come out like that 1000mah 20c stock 8min
1500mah 12c!!! chinese 8,5 min
1800mah zippy 12,5 min !!!!!
the 1500mah doesn't last as long as it supposed to is that a problem due to its 12c or its a chinese faud????


Thanx everybody in advance....

[apokathilwsis]

Trying to post my questions on sticky related threads instead of opening a new thread for everything but this one seems to be pretty dead!

Anyone?????

[ArchmageAU]

Originally Posted by apokathilwsis

Trying to post my questions on sticky related threads instead of opening a new thread for everything but this one seems to be pretty dead!

Anyone?????

If it is a specific question, the a new thread is the way to go. Stickies are for general.

Originally Posted by apokathilwsis

A question on li-po batteries

i have 3 new batteries 1 stock walkera 3s 20c 1000mah 1 chinese brand 3s 12c 1500mah and 1 zippy 3s 20c 1800mah
when i firstly charged them they all were good 12,6v and 4,2v per cell +/- 0.01v
after 4-5 cycles they start to charge at 4,25v and 12,75 total voltage

1st question
is there a problem with my charger ?
are the batteries 'motivated' somehow and they just take a bit more voltage?
is there a saftey issue about that?

2nd question
i dont have a voltage indicator on the heli but i immediately land it when i notice the slightest loss in power
i am timing my batts and they come out like that 1000mah 20c stock 8min
1500mah 12c!!! chinese 8,5 min
1800mah zippy 12,5 min !!!!!
the 1500mah doesn't last as long as it supposed to is that a problem due to its 12c or its a chinese faud????


Thanx everybody in advance....

c is max discharge rate (and is battery makers fantasy). Cannot compare one make c rating to another. (and is based on mah of the battery anyway).

mah is really the rating you are looking for with that length flight time.

Assuming you are completely draining a lipo battery in 8.5min, you are discharging it at and average of 7C (usually you are only round 80% discharging, so that makes it 6C).

The heavier the battery, the more energy to fly (thrust vs weight). (this is probably why the 1800 zippy does not fly for 14 mins.

Usually with batteries, you get what you pay for. You do pay disproportionately more for name brands though. More expensive (and bigger) batteries last more cycles before building up internal resistance that makes them useless. Running to LVC, over discharging, storing for long times fully charged or over-charging also shortens battery life. Overcharging or too rapidly charging lipos, or charging damaged lipos are the most dangerous situations and can lead to lipo fires (runaway thermal reactions, no oxygen required, will only extinguish once fuel exhausted and gives of toxic smoke).

If your charger is putting 4.25v per cell on a lipo, check setting, and/or get a different charger. This is dangerous. (so yes safety issue).

Sorry to not specific answer your questions.

In short, if the battery still works, it's good to fly. Once it is no good to fly (or deos not provide the power, dispose of and get others.