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Post by higbe33 on Feb 16, 2008 1:53:00 GMT 1
I just bought a new charger and don’t know enough about electricity to use it. The batteries I want to charge are 9.6v 8-cell 1400mah 10C NiMH. I’ve read a lot, but getting more confused the more I read.
The Manual says; In Manual Mode, you set the charge rate and hit start. So what is the charge rate for this battery? HZ says to set their car charger at 1.2amp for the stock battery. Is that the charge rate? Read somewhere you can charge NiMH between 3-5amp.
In Auto Mode you set the current limit. What is the current limit for this battery? Maybe the current limit is the amps?
Between these two modes of charging, which would be the best? Thanks for any help and please keep it simple.
Hig
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Post by cjg on Feb 16, 2008 15:35:38 GMT 1
What kind of charger is it?
Compute a battery capacity in amps by dividing the mah by 1000. A 1400mah battery is therefore 1.4 amps.
1400 mah batts can safely and easily be charged up to 1 times their rating, also known as "1C rate" (1400 mah = 1.4 amps charge rate). It will take 1 hour to charge a completely empty battery at 1C. Charging at 2C (2800mah) would take 1/2 hour. Charging at .5C (700mah) would take 2 hours. Does this make sense?
The higher the charge rate the harder it is on the battery. I would not charge a 1400 mah NIMH at 3-5 amps. Most likely it will overheat and possibly ruin battery. That would be a "4C rate". Larger 3000mah -4000 mah batteries could be charged at this rate since for them it would be about 1C.
Dont' know what is meant by current limiit on your charger, without knowing what brand, etc. I'm assuming it is a peak charger, one that will automatically stop charging when the battery is full. This is in contrast to a timer charger, where you set the time for the charge and it will merrily keep charging and cooking your battery even if it is full.
If it is a peak charger you could set the manual charge rate to 1.4amps and be ok with your 1400mah batter.
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Post by higbe33 on Feb 16, 2008 16:52:34 GMT 1
It's a Bantam BC8. I was using an Infinity 2 and just plugged the battery in and hit start. It would vary the charge up to 5amp and then pause or adjust. Came out a bit warmer then I thought was good, but new to this. I'll stick to your 1.4 on Manual until I hear more. Thanks a bunch.
Hig
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Post by finchkid24 on Feb 16, 2008 23:54:44 GMT 1
If the battery is a bit warm off the charger...its okay. I have been charging NiMH and Nicad batteries for years now (airsoft) and I have used a speed charger for the last two or so years. I charge all my batteries at 2amps, including my stock SC batteries. They take about 40 or so minutes to charge using Deans connectors.
I have the standard blue fast charger. It charges 1 or 2 amps, is a peak/smart charger and is all around a very good charger for the money.
-Finch
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Post by higbe33 on Feb 17, 2008 1:14:23 GMT 1
Thanks Finch and I'm getting a warm and fuzzy now. Same question in a different forum said pretty much the same as cjg. C1 (1.4amp) was best and C2 (2.8amp) would be okay in the field for a quicker turn around. Your 2 amp idea falls right in there, so I'm in the ballpark anyway. Thanks much for your input.
Hig
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Post by SCC on Feb 17, 2008 12:12:28 GMT 1
Hi Hig You have one of the best chargers on the market. Theres also a thread on rc groups that did a review on the BC6 BC8. It's a good place to get answers on these chargers.  |
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Post by higbe33 on Feb 17, 2008 13:46:59 GMT 1
SCC - I read both of those and that is what sold me on that charger. Evan at rc accessory has been great in answering my emails with stupid questions also. I plan on moving up in this hobby and wanted to buy a charger I wouldn't have to upgrade later. The menu is a bit of a challenge for someone that doesn't have a clue about the care and feeding of a battery, but now I have some numbers and it's much easier.
Hig
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Post by higbe33 on Feb 17, 2008 17:12:16 GMT 1
cjg - I have this same question on another forum and getting great input. The article I read about charging between 3-5amps was from a Trinity car racer and I have since been told the car guys use much higher mah batteries, so that might be 1C for them. It's all starting to make sense now.
I get conflicting information about slow charging a NEW pack of NiMH. Would you cycle them a few times to bring them up to capacity, or would you slow charge the first charge and go from there? If you like the slow charge idea, what charge would you use? I liked your info on the .5C would take 2 hours and I can try a .2C. I can't leave it on overnight because I haven't learned how to shut the timer off yet. It has a 120 minute safety feature so I need to be awake to reset. Looking forward to anyones advise.
Hig
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