Charging Questions...
 

I am trying to help a few kids in the neighborhood get in to RC and I am having a hard time explaining how to charge various packs for their cars is there some simple way to explain what settings to charge what types of packs? right now all they have are Nicd and Nimh packs. ranging from 1100 to 3800 or 4200 mah,

Im not up on all the charging stuff since im mostly a nitro guy and I just have to charge my rx pack.

any help is is greatly welcomed..

It's kinda hard to suggest what to say without knowing what chargers they have etc.

You could suggest a basic amp rates to charge at.... around 5 amps for sub-c batteries and about 1 amp for the small stuff, AA, 2/3A etc.

Higher rates will build more heat during charge and tend to give more punch if you use it hot off the charger. But newbies and bashers really don't need that, and it's harder on the batts long term.

I assume they are using peak chargers? There really isn't much to it with a peak charger. The packs should be warm when done charging... if not, keep charging.

Simply put; just tell them to get a decent peak-detection charger for their batteries. Most people are happy with a simple "get this" without the reason behind it. I find that once you start explaining about constant-current and such, the eyes start glazing over and interest wanders.

If they really want to know how it works, you can go into how the charger outputs a constant current across the cells and the packs voltage will slowly increase as it gets charged. Then, there is a circuit that monitors the max voltage of the pack, and when that voltage starts to drop, it cuts the charge cycle.

I tell people to stay far away from cheap chargers (~$10) as they are VERY basic. Most I've seen utilize a very small transformer and rectifier. As the pack voltage gets close to the "charger" voltage, the current drops until it is trickle charging. Most of these are designed with many (and sometimes incorrect) assumptions about the cell being charged and can overcharge or undercharge the pack.