battery for bike lights

[davedent]

Just wondering if it's ok to join two of these batteries (Amax 7.2v 4300mah- NimH battery pack for rc toys.) in series to make one battery pack. If so can you recharge them as 1 battery or would you have to charge them seperately??

 

[tonycollinet]

You can join them in series no problem.

Charging is possible, but only if your charger is up to the job. If it is designed for one pack, then it probably is not.

 

[AndrewL]

charge togeather if you can

 

[Stregone]

Charging them together is definitely possible if you ALWAYS use them together. Charge them separately the first time.

 

[turbodog]

You guys have lost your minds. Using in parallel is fine. Charging is not.


One pack will always peak first. Then its voltage drops. Then it starts consuming even more of the current, so that the other pack never peaks.

Overcharging is the result on a good day. Cell venting and/or rapid expulsion of the internal parts happens on a bad day.

Even if you get *really* lucky and the charger shuts off when one pack peaks, you're missing out on achieving full capacity on the other pack.


I've blown up enough packs (and cleaned up exploded cell parts) to know about this in detail.

 

[imageicon]

Turbodog what are you talking about??

this is not lithium cells! ofcourse he can charge them in series if he ALWAYS run them in serie and have a charger that can actually handle that many cells!!

you know the pack comes with batteries just serie connected right he dont need to take it all apart to charge it same thing if he connects 2 packs together itll just be 1 larger pack!

 

[tonycollinet]

Confusion abounds

Charging in series is fine - as long as the charger can deliver enough volts and power.

Charging in paralell - as described above - is not advisable.

 

[davedent]

cheers for the help guys, just discovered my charger is not up to the job.. now looking into buying a new battery pack. is it possible to use camcorder batteries as i have a few decent capacity ones already if so how would i do this.. or am i better off buying a new Nimh/Li-ion.
I'm currently a poor student so budget is a factor don't want to spend a fortune!

 

[tonycollinet]

See my post here, for links to bits to build a battery pack