Topic: Converting My 7.2V NiMH RC Batteries to 12V

[stevetoney]

Maybe some of you Sparkies out there can help me with some simple technical advice...   

Back when I had a SD-7XX, I bought a bunch of 7.2V NiMH batteries so I could run the 7XX all weekend long without a charge.  Here's what I've got...

3 each 7.2V 4500mah
3 each 7.2V 2500mah
3 each 7.2V 3600mah

I no longer have the 7xx, but have an emerging need for 12V remote power.

Each of the nine packs above terminates in a Tamiya connector and each pack is an array of six X 1.2V batteries.

So I have three questions...

1) Is there any reason why I can't take these apart and rewire them in series to make an array of ten x 1.2V to make a single 12V battery?

2)  Since I have 18 1.2V cells of each battery size (2500, 3600, and 4500) am I short two cells of each size to make a second separate 12V of each size, or can I combine say two of the small cells with eight of the larger sizes.

3)  Not a question, but can anyone please confirm that I need to buy a new charger specifically for 12V (IOW, I'm assuming that the charger I was using for the 7.2V batteries won't work with the new configuration).

Thanks in advance!!!

[fozzy]

1.) should not be a problem

2) do not mix batteries of different capacities

3) 99% of rc chargers are for 7.2 and 8.4 volts, you will need a 12v NiMH charger

can your gear run @ 14-15 volts?  i would leave the packs assembled and run 2 cells in a series.

[stevetoney]

Thanks a lot for the answers fozzy.  All confirmations of what I'd already thought.  Not sure if it will run on the higher voltage.  Thinking no...this would be for an AD1K (purchasing from marc), which I've heard tends to run hot anyway.

1.) should not be a problem

2) do not mix batteries of different capacities

3) 99% of rc chargers are for 7.2 and 8.4 volts, you will need a 12v NiMH charger

can your gear run @ 14-15 volts?  i would leave the packs assembled and run 2 cells in a series.

[ero3030]

deff run the ad1k at 14v.  ed