studysession

I know this is probably a NOOB question but here it goes anyway -
I have RC cars, not planes. With the cars we charge while the batteries sit in the car. But I have been hesitating if this is good or not for Li-Po's. A few of my cars I have the batteries mounted in a way where it is not easy to take in and out. I know it would be safer to take the batteries out to charge but sometimes that could be a lot of work.

What does everyone recommend - take the Li-Po's out of the vehicle or leave them in when charging?

Thanks -
SS

mrasmm

if you charge them in the car there is a chance your car could catch on fire, that's just the way it goes =) Usually it's not that big of a risk, and there are several things you can do to reduce the risk. You want to make sure to give the pack plenty of cool off time and ventalation when it is running. I usually wait until the lipo is below 80F internally at the hottest place (usually takes about 10 to 15 min with the pack out of the RC). You definately don't want to be charging it at 90 or 95F, which might be hard in the summer time, especially outside. Make sure you get rid of your packs when they can only ouput about 80% of what they originally cycled at, or if they swell or buble or anything. If you can see or feel the pack when it is still in the rc, defiantely check for these things before charging. Other than that, make sure to balance them and I think that should probably do it, or atleast that's the way I would do it =)

studysession

Thanks again -
I got a ballencer from Model Electronics corp. Usually I go to another RC before my LiPo's drain unless it's my Mini-T. THat one I need more than one pack because I can run it a few times and drain them to the cut-off voltage setting. But my onroad speed cars - usually they have pleanty of time to sit and cool between charges and take the bodies off for extra venting and such.

The drag car is what you're helping me with in the other thread. That one I want to mount the LiPo's in where they would be charged in the car. Once the car is ballanced and such, it's a lot of work redoing it all over again everytime you take out and put back in the batteries. That car ballance is a big issue and don't want to keep having to redo it all. Takes a lot of time.

Thanks -
SS

mrasmm

yeah, I know what you mean on that balancing thing. I can understand why you wouldn't want to do that =)

I forgot one thing, but it sounds like you already know. You want to cut off your lipos so that when you take an open circuit reading, you get nominal voltage, or 3.7v per cell, that will leave about 20% in the pack. Also you don't want to go under 3.0v per cell under load, but it sounds like you already know about it =) I just thought I would mention it just in case =)

studysession

Thanks -

For RCU Magazine I am trying to use this for two articles.

My MTroniks, Quark and Maba ESC's all have battery/LiPo cutoff voltage settings. My BK Warrior ESC's do not. So I have LipoShield from Dimensions Engineering that is supposed to take care of this for the ESC's that don't have the setting.

Then there is distance. I have NoiseSink to test. This is supposed to prevent and eliminate glitches. Also allow you to control the RC with more distance before losing the signal.

We will see how it goes. Good stuff....

mrasmm

sounds good, good luck with it [8D]

studysession

Thanks and thanks for all the help in both threads.