liths

[Murdoch]

ooh, nice find.

I'll pick up two of these chargers.

[bengali548]

alright how long am i supposed to run theese lithium cells before i have to charge them cuz i know youre supposed to not let it drop below a certain point of voltage just wondering how you guys know what point that is and if you have a estimate for me

The runtime depends on the batteries and the motor. AAA's fit in stock battery holders, but you have to rewire the holders to have two in series in parallel with the other two in series.

It's cheaper to do they AA as they have higher capacity and can squat the weight further down. That charger is going to take a long time to charge at 300mA. Mine charges li-ion at 750mA.

When soldering wires to batteries, you really have to be careful. If you heat up the battery too much, you'll damage it.

As for when to charge, you can either charge when the car shows first signs of slowing down or measure the output voltage with a multimeter. As soon as it's around 6.6V, I would give it a charge.

[Rez]

I'm not sure about LiIon, but for most batteries it's hard to measure capacity by voltage as the voltage doesn't change much over usefull battery life unless it's being measured under load. I would just go with when you start to notice slow down.

You can get LiIons with solder tabs attached, which can help protect them from damage. Batteryspace also has low voltage protection circuits that you can wire in. I unsuccessfully tried to add one to my gen1, I got the IC too hot I think. I should try again now that I have better equipment and more practice.