how can I test to see if a lipo battery is good or not with a multi meter? I have a couple of 2 cell and a couple 3 cells. Thanks.

I'm not sure what you mean exactly, but you want to check the balance end and measure two of them right next to each other and then measure all of them that way. All of them at the very very lowest should be greater than 2.75 volts, but preferably greater than 3. That's not really a good indication that the battery is good though. You really need a way to charge it and then discharge it to 3.0v per cell and have a way to measure how many mAh that it puts out. If it's about 80% or higher, then you are good (ie 640mAh or more on an 800mAh pack)


|____|____|___|
1......2......3.....4

this is a balance end measure 1 and 2 to start with, then 2 and 3, and then 3 and 4. You'll get 3 seperate readings because this is a balance connector for a 3s lipo. Hopefully that makes sense.

Hopefully this clears a few things up for you

I am so unelectricly knowledgeable... Can you measure mAh with a basic $10 multi meter? I have thrown away the manual for the multimeter...

it would be pretty difficult to do something like that. If you have a constant load that you could hook up, something around 1 to 2 amps (but no more than 2C, actually for measuring something like 1/10 to 1/5C is what the mfg uses, but that wouldn't be ideal for you because you have to sit and watch it). Put your ammeter function of the multimeter inline with the load and measure exactly what it is taking out with the particular pack, for more accuracy take this reading at even time intervals (like every 5 or 10 min), then at the end you are going to take them all and add them all up and divide that number by the number of numbers you have (whew that was a mouth full). Take that number and times it by the number of minutes the pack ran the load, and you will have mAh for the pack. Be very very careful though not to let it discharge greater than 3.0v under the load. You have to be watching it all of the time. Honestly this isn't a very good method because you can ruin your pack easy if you walk out of the room for 10 min and forget about it.

One other thing you can do is take the battery and take it down to 3.0v under a load (it's important that you take the load reading instead of the open circuit); you wont have to measure anything on this one. Then put it on the charger and time how long it takes to charge it back up. Take the minutes and divide it by 60 and then times that by the charge rate of your charger. For example if I had an 800mAh battery and I had a charger that charges at 800mAh, and my charge took me 53 min, the math would look like this. 53/60 is 0.8833 times 800mAh is about 707mAh (slightly less because of the inefficiency of charging), which is well above 80% (0.8 times 800mAh = 640mAh) of the batteries capacity, so the pack is still usable.

Hopefully that made sense. It might be worth it to ya to go buy a $50 balancing charger/discharger that does all of this automatically =)