# Battery charging rate??

Ok, so I've got my new battery charger. I can charge NiCads, LiPolys, etc. I can even set the charging rate (0-2 amps). How do I know how high a charging
rate I should use? Can I make some calculations based on capacity and number of cells in the pack? For example, I have a 2300 mah 5 cell NiCad pack. How fast can/should I charge it? How about for regular NiCad Tx and Rx batteries? The only instructions it came with said not to go higher than 1 amp on single small cells (AA's) and that it wouldn't allow you to go over 1 A on LiPoly's.
Thanks....
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First before anyone can give you some care and feeding instructions for your charger it would help to know what kind of an animal we are dealing with. But here are some rules of thumb.
Don't charge any faster than you absolutely need to. If you are not going flying until tomorrow morning charge at something in the C/10 rate. This is 1/10th of the rated capacity - in your case, charge 2300 mAh pack at 250 mA (unless you can set it exactly to 230). Lithium poly/ion packs usually don't give you the choice, you just set the number of cells (in series) and the charger will pick the voltage - if you can set the current it should be at the C rate (where C=the rated capacity, for a 2 Ah pack it would be 2 amps.) Fast charging when needed require a little more care, if you can set the peak detection for Ni-Cd at 10 mv/cell and 45 mv/cell for Ni-Mh.
-- Red S. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information.

etc.
charging
number
How
batteries?
single
LiPoly's.
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Not to sound like a smart alek, but have you read the instructions that came with your charger? They should include answers to all the questions you asked. I know that my Hobbico fast field charger is limited to 1 Amp for charging NiCd and about 1.5 for NiMh. Lithiums are about .5 or so according to the instructions. Instructions are amazing things when you read them.
Jim W
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Thanks, I did read them, and they pretty well passed the buck to dodge liability. They continue to say "charge at the recommended rate" over and over again. Unfortunately, all the stuff I have right now is used and I never had a chance to see if the battery manufacturer even specified a recommended (or maximum) charge rate.
Thanks to everyone who gave me some good guidelines to use.
Steve
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Hey, that's great! When I'm low on cash, I use VISA to charge my batteries....and other model necessities.

The rate is usually set by the bank, but there are lots of offers around for really low rates. Just the other week, I had yet another offer in the mail for a 2.9% rate, but it had limits, too. Bummer. :( As Red stated, a low charge rate is always best.
:) Dr.1 Driver "There's a Hun in the sun!"
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snipped-for-privacy@aol.com (S Casko) wrote in message

1A or 1C?
Charge rate will depend on the capacity of the pack, known as C. A safe charge rate for ALL types of packs is 1C, or one times the Capacity of the pack. If the charger can't be set to 1C, then set it as close as possible without exceeding 1C.
For example, a 2300mAh pack's C value is 2.3 Amps. The charge rate would be 2.3 Amps. Since your charger will only go to 2 Amps, that's what you'd use.
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Mathew, I woujld suggest you you read Red's post on the charging rate. There wont be much battery left if you charge at 2.3 amps. i.e. c=1/10 the rated capacity and not 10.

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There
rated
And if you read the OP's post you'd see that the charger has variable current up to 2A. Even though we don't know what model it is we can safely assume it'll be a fast charger with some kind of cutoff that'd stop overcharge unlike a dumb Walmart charger. Especially as it will charge Lipo's it will certainly have a peak detect circuit and both voltage and current control circuitry.
But in any case remember don't leave the charger plugged in and fast charging any battery unwatched, just in case. Especially if you don't kow the health of the batteries that you'll be charging.
Chris
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snipped-for-privacy@aol.com (S Casko) wrote in message

1A or 1C?
Charge rate will depend on the capacity of the pack, known as C. A safe charge rate for ALL types of packs is 1C, or one times the Capacity of the pack. If the charger can't be set to 1C, then set it as close as possible without exceeding 1C.
For example, a 2300mAh pack's C value is 2.3 Amps. The charge rate would be 2.3 Amps. Since your charger will only go to 2 Amps, that's what you'd use.
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