Charging

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David Drowns
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Charging

Post by David Drowns »

Here is my dilemma.
The stores don't Carry nicad Rx batteries any more, I have to get the Ni-NH packs now. My chargers were all for the nicads.

The 4 cell 4.8v 1200mAh pack says on it to charge for 14 to 16 hrs @120 mAh.

My chargers all charge the Rx at 55 Ma.

The question.
So how long do I need to charge at this rate? I'd like to be able to slow charge at least at first before I start using my field charger because it'll run them up real fast with a Ni-NH setting but I don't want to cook the battery right off the bat.

Help!

Currently electronically challenged.
David Drowns
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lightning
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Re: Charging

Post by lightning »

David,
If your NiCad charger will detect the peak on a NiMh you are good to go. The Hobbico field charger will do that OK.
I use my field charger to charge my 300MaH 2/3AAA NiMH packs. Lowest rate is 200Mah and I've got 5 year old batteries that are still good on my cycler.
I would quite happily charge a 1200Mah pack at 200 Mah. Let the charger detect the peak.
Now if you REALLY want to charge at close to 1/10C, (120Ma) use a "Y" harness to connect 2 of these batteries in parallel. They will equalize, then charge at 100Mah each.
But there's nothing wrong with leaving a battery to trickle at 55Mah, it will just take it a day to top up.
Keith Jones
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boiler
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Re: Charging

Post by boiler »

I regularly use my old wall charger that came with my nicd batteries (55mah) charge rate on my AAA battery packs. I usually give them a 16-24 hour charge before I leave for a meet. The first time I charge them for at least 24 hours. If I ever need to peak one, my Hobbico field charger MKII does a good job. I usually don't need to use it unless I forget to charge the packs before I go to the meet. My AAA packs are 900 mah. Easily good for 10 rounds of combat.
Bob (Longhaul) Loescher
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midair02
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Re: Charging

Post by midair02 »

Here is a link to Radical's site about NiMh battery charging.

http://www.radicalrc.com/nimhfaq.html

So, according to them.

1200 x 1.4 = 1680

1680 / 55 = 30.5 hours for a full charge.
William "Dominator" Drumm III
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David Drowns
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Re: Charging

Post by David Drowns »

Thanks for the help guys.
midair02 wrote:Here is a link to Radical's site about NiMh battery charging.

http://www.radicalrc.com/nimhfaq.html

So, according to them.

1200 x 1.4 = 1680

1680 / 55 = 30.5 hours for a full charge.
The Radical RC's link is where the education came in. It looks like I did the right thing making sure the first charge was slow.

First and foremost! NEVER NEVER put ANY new battery on a Peak Predictor / Delta Peak or any other type of fast charger without giving it a break-in charge at C/10. Capacity 10 is the overnight un-terminated safe charge rate for NiCad and NiMH cells. You can plug it in and forget it. If you have a 280mah pack of any cell count, the C/10 rate is 28mah. This rate or less is what you need to break in the pack. A 1400 mah pack needs a charge rate not over 140 mah for its first charge. The charge rate can be less than C/10 but should not be over. Your charge time will be (Capacity X 1.6) / charger output in MAH. This will give you the time to full in hours for a first charge.

If you take a new pack and put it on a Delta Peak or Peak detect charger or any other kind of NiMH rated fast charger it will not be filled up. I don't care what the instructions say. I'm sure they say to never charge a new un-conditioned battery on them. If they do not tell you not to charge new packs on them then they are wrong. The voltage curve is measured and calculated by these chargers in order to predict the peak. The voltage curve is not normal on a brand new pack. It needs one slow conditioning charge before the curve becomes stable. Try as you may, you can't fill up a new battery on one of these chargers. After it's first C/10 charge, it will work fine.


I found an old multi charger that had a 100 mA setting so it's on charge now and should be full by tomorrow morning just in time for combat this weekend. I feel a lot better about how I'm handling my batteries now after reading the radical RC link. Thanks William, Much appreciated. :wink:

I am now, no longer. completely electronically challenged.
David Drowns
RCCA #951
Member of Palomar RC Flyers Fallbrook CA
http://pfcombat.hyperboards.com
AMA #702910
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