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Jul 25, 2001, 01:14 PM
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Do I charge in Parallel or in series if I .....


want to charge 2 150 mah nimh packs at the same time?

I'm tlking about Rayovac 9 volts here that are connected in Parallel for flight and I was hoping I could you the same connection to charge the batteries in between flights.

Any thoughts?
Jamie.
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Jul 25, 2001, 01:20 PM
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asperkins's Avatar
I'm assuming that these are actually 8.4v or 7 cells.

If you charge them in parallel charge them like a 7 cell 300 mah battery.

If you charge in series then it will look like a 14 cell 150 mah battery.

If your charger will not do 14 cells then just charge them in parallel. Either way should work.
Jul 25, 2001, 01:51 PM
Registered User
Thats great news. I'll do them in Parallel as I only have a 4 - 8 cell charger on the way.

Thanks
Jamie
Jul 25, 2001, 03:40 PM
Registered User
Quote:
Originally posted by Jamie-:
Thats great news. I'll do them in Parallel as I only have a 4 - 8 cell charger on the way.

Thanks
Jamie
I hate to disagree but the rule of thumb is to NEVER, NEVER, NEVER charge in parallel. There is just too much that can go wrong. If the packs don't peak at precisely the same time the one that has peaked will suddenly take on most of the charge current and quickly overheat.

Jul 25, 2001, 03:43 PM
Registered User
Good Point......and its been taken. I'll just charge them one at a time!

Thanks
Jamie
Jul 25, 2001, 03:45 PM
Registered User
Quote:
Originally posted by Chris True:
I hate to disagree but the rule of thumb is to NEVER, NEVER, NEVER charge in parallel. There is just too much that can go wrong. If the packs don't peak at precisely the same time the one that has peaked will suddenly take on most of the charge current and quickly overheat.

This is true in theory, but in practice, if the packs are always used together in parallel and always charged together in parallel you are UNLIKELY to get into trouble. Personally, I wouldn't recommend it.