Thread: Battery FAQ
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Old May 7th, 2007, 05:09   #23
Kos-Mos
 
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Join Date: Nov 2005
Location: Lévis (QC)
Well...


it is BETTER to discharge a battery as close of it's maximal rating as possible. 10A is actually good for 2/3A cells. Large packs should be discharged around 20-35A, depending on the pack.

It is a lot worst to discharge a pack at, say 1A than not to discharge it at all. Mostly because higher rated cells are able to recover from discharge faster than the actual load, so the pack will be dropped further than at a higher discharge rate.

As for the systemA Charger, I have not tried it yet, but I don't think it would be very good or usefull. That auto charging function, I have tried it on my ICE charger, and I found that the packs where charged a lot less and took a lot more time to be charged.

Plus, you should never leave a pack to be charged unattended (like when you sleep). You never know what can happen, if your pack got hit and have suffered enought damage to burst. (Yes I have seen a Ni-Cd pack explode, it send half a cell 10 feet away with burning acid spit everywhere.)

I agree with Scarecrow on at least one thing, if you have the time to slow charge it, take it. Not because your packs will last longer in lifetime (my 1400's are still packing close to 1600 after over a year of 3A charging), but because the slower you charge, the best run time you will get from it. If you charge your pack at 2A, you will get a little less run from a charge, but you will get a more intense run...(more punch). Slow charge is considered to be between 1/2C-1C. Older packs like the Ni-Cd that come with the stock guns are better been charged at about 400mA, when newer Ni-Mh packs can be slow charged at 1-1.4A. Slower than that is both a was of time and energy.
A slow charge is between 1 to 4 hours.

An other the reason why it is best to discharge the packs close to the maximum rating: Batteries are lazy, if you never ask it to give more than 2A, then i won't be able to give the actual 10A when you need it.

NTP* (Negative pulse) is not a feature used in a lot of chargers. I have it in my 200$ charger, and I almost never use it (it is called reflex charging in my case). The MOST important thing you want to look when shoping a charger is the charge terminaison mode. You need a peak detect or Negative Delta-V detection charger (both are the same, just names). Keep in mind that reflex charging is good but should not be used everytime. It is very usefull to recover old batteries, but it will reduce the effective cycle life of a new pack. It is exactly the same as discharging EVERY time....

For battery temperature, it is always best to keep the pack as cold as possible. But don't panic if your pack gets a bit warmer. A trick I found usefull to check a hot pack is to sit it on the inside of your forearm. If it is too hot to stay there, then the pack is really too hot. This is very subjective, but most people won't stand a temperature above 45°c, which is the approximate maximum a battery should ever reach.

Finally, if you are not sure about what to do with your batteries, stay away from Li-Po. If you think you know exaclty how to react to any situation with Nickel based cells, then do a lot of reseach or PM to have some infos. You need to have the right equipment and be prepared to fetch a good sum if you want to convert from Ni-... to Li-Po.

*Just one last thing, if anyone have anything to add to this FAQ, please send me some PM and we will discuss it. Right now there is more and more contrairy informations stacking in the tread. I tried to keep this as clean and as informative as possible. (One of the reasons I did not mentioned any brand of specific model in the original tread, not to push anyone to buy any charger, as they all have some good points and bad points) Scarecrow, you got mail!
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