Battery Charging Question

[MADDOG]

I read the FAQ but still need some clarification for larger than 4000 mah nimh batteries.

I have a 10.8v 4300 mah GP NIMH battery. (Custom)
My charger says it can do 9 cells and has automatic cut off when charging and discharging.
I can manually change the amps from .5 to 7 or 8

What is the optimal amp setting for fast charging this battery?
I think it is 4 to 5 amps

I have seen some forums (car racing) charging these batteries at 6+amps, can this be good and will it handle it?

Can someone confirm this?

Also, I know you don't have to discharge NIMH to charge them but if I was to cycle it on my charger (discharge then fast charge cycle) would this be ok or damage the cells. I have charged it about 15 times and it has never really been below 2/3 full at any one time. My worry is that topping it up all the time will cause problems without exercising the whole battery? (Does that make sense)


Thanks

MD

[LUTNIT]

Charging at 6+ amps is for special batteries that are designed for it. You'd be best staying 2-4 amps, I charge my 4200mAh packs at 3 amps and they don't heat up past 35'C (its safe all the way to ~47 or 48'C so long as you don't do it regularly.)

Its bad to discharge NiMh packs all the time but as far as I know its actually good for them to have it done every once in a while. Usually if they've been sitting around for a while (start of the season after winter storage) its a good idea to do a deep discharge and recharge from what I'm told.

If you really want to know details and exactly what to do send a PM to Kos-Mos, hes very knowledgeable when it comes to batteries.

[Kos-Mos]

No need to PM.

For large Ni-Mh packs, safe charge rate is 4A

Safe discharge is 30-35A

And cut-off discharge is 0.9v/cell, so your pack should be discharged down to 8.1v.

Now GP (or GoldPeak) is one of the top brands in battery. I think you could easilly charge it at 6A, but try to have it on an old computer fan. Will help keep it cooler, and make sure your pack stays under 120°F/48°C. I don't know exactly what is your charger, but I know that the Intellipeak I.C.E. and the Electrifly Triton both have an auto temperature cut.

You must keep in mind that the faster you charge your pack, the more punch you will get, but it will last slighly less time (maybe 200 bbs).

You don't have to cycle it everytime, but once in a while is good (like after 10-15 charges) You can "fast cycle" your pack, except when you have stored it for more than 2 months.

And when you store it, discharge your pack, then give it a 5 min charge. Just to make sure it is not completly empty.

What you do right now is perfectly fine. Your pack should last long!

[MADDOG]

Thanks for the input, I appreciate it.
Just wanted to double check everything.

My charger is an APEX Beta, but all the one's i see on the internet are for 4 to 8 cell.
This charger has the computer processor, etc same as the other ones but it states right on it 4 to 9 cells capability (much different from internet searches I have done).
The charger is about 7 years old so its specs may be different than more current models.

I always suspected it was not charging the batteries to full capability, any chance it could be mis-labeled, anyone have experience with this model? How can I confirm it is working properly still?

Thanks



MD

[Kos-Mos]

I just did a search on the internet.

Actually the Apex BETA is exactly the same charger as this one. Made in the same factory, just like the TLP ones. Apparently there is 3-4 "brands" of these chargers. They are good, but not the best. I had one before, but it took fire, and to what I know, I am not the only one who had this "misfortune".

Here is the link:
http://www.duratrax.com/caraccys/dtxp4100.html

And it is rated only for 8 cells.

The best one i can see is actually made by the same company. It's the one I have:
http://www.duratrax.com/caraccys/dtxp4170.html

[ThunderCactus]

I use a pirahna digital peak charger, it does whatever the heck i want, when i want, no questions asked, no batteries bent, no crappy chargers bursting into flames. does NiMH and NiCd, i can set amperage to within .1A, and has quick connects so as long as i have a mating connector i can charge any battery with a crazy connector (deans, large, mini, the crazy MP7 battery)

[Naerah]

Originally Posted by ThunderCactus

I use a pirahna digital peak charger, it does whatever the heck i want, when i want, no questions asked, no batteries bent, no crappy chargers bursting into flames. does NiMH and NiCd, i can set amperage to within .1A, and has quick connects so as long as i have a mating connector i can charge any battery with a crazy connector (deans, large, mini, the crazy MP7 battery)

now i know what i want for christmas lol!

[Kos-Mos]

it does NOT discharge and can only charge up to a rate of 5A.

I had one like that too. The Intellipeak Deluxe is WAY better than this one. (last one here: http://www.duratrax.com/caraccys/dtxp4100.html )

I must tell you something. Piranha is owned by the same company as Intellipeak. It is only the cheap, low budget line of chargers.

Here is the full line of Piranha chargers:

http://www.duratrax.com/caraccys/piranha.html

Noticed the same domain name?

Originally Posted by ThunderCactus

I use a pirahna digital peak charger, it does whatever the heck i want, when i want, no questions asked, no batteries bent, no crappy chargers bursting into flames. does NiMH and NiCd, i can set amperage to within .1A, and has quick connects so as long as i have a mating connector i can charge any battery with a crazy connector (deans, large, mini, the crazy MP7 battery)