What's your battery system?

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What battery chemistry do you use? (check all that apply)

Alkaline
22
25%
Lithium primaries(non-rechargeable)
8
9%
NiMH
17
19%
NiMH (Low self discharge)
19
22%
Li-ion (standard form factors)
7
8%
Li-ion (specialized form factor)
9
10%
I use carbide
6
7%
Other (?)
0
No votes
 
Total votes : 88

Re: What's your battery system?

Postby Marduke » Jun 23, 2010 2:30 pm

In order to properly terminate a smart charger looks for a -dV signal from the cells. They only reliably produce this signal when charged at 0.5-1.0C.

The biggest mistake people make is charging at 0.1-0.3C, thinking this slower rate is "more gentle". The problem is, however, that most cells have almost no -dV signal at this rate, so the charger misses termination and you overcharge your cells, cooking them.

The default rate for the BC900(9) is 200mA, which is too slow for most cells. You have to make sure to change the rate to match the cells you are charging. Now, cells that are still in reasonably good shape can be charged a little slower, but without atypical "battery skills", that is hard to judge.

It's counterintuitive, but charging faster at 1C can actually be better for your cells, and they can terminate at a cooler temperature than at a slower rate that you think is "more gentle".
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Re: What's your battery system?

Postby NZcaver » Jun 23, 2010 2:36 pm

Once again, thank you for sharing your wisdom with us. :clap: :bow:
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Re: What's your battery system?

Postby Marduke » Jun 23, 2010 7:10 pm

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Re: What's your battery system?

Postby Chads93GT » Jun 23, 2010 8:55 pm

isnt the 700 mah setting what you should use on the bc900 for charging duraloops?
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Re: What's your battery system?

Postby Marduke » Jun 23, 2010 9:12 pm

Chads93GT wrote:isnt the 700 mah setting what you should use on the bc900 for charging duraloops?


I sometimes do with my BC900 because my cells are still in good shape, and the BC900 is a "hot" charger. It uses a linear constant current regulator which in turn uses PWM to adjust the "average" charge current on the cells. So for ALL cells the actual charge current is ~2A, but it uses PWM to average it down to the user selected value.

However, for AA Duraloops, 1A-1.8A would be the ideal for a charge current on the BC900. Since I am usually charging 3-4 cells, I typically use 1A (the max available).
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Re: What's your battery system?

Postby harrym » Mar 1, 2012 5:43 pm

Okay....

I've been using rechargeable AA Enloops and a Maha charger now for over two years. I'm sold on the rechargeable battery thing.

A few questions:

1. How do you keep track of each battery's performance over time? Since I use Enloops in my underwater camera and strobes, I have 42 AAA and 8 AAA batteries to monitor.

2. How you make sure that you group batteries with similar charges when you place them in your lights? You wouldn't want to place a battery that averages 1850 mAh with batteries that averages 1990 mAh would you?

3. Maha has some low-discharge AAA NiMH batteries that are rated higher (950 mAh) than the Enloop AAA batteries (800 mAh). Any comments?

4. Can anyone comment on the MAHA MH-C808M AA - AAA - C - D Battery Charger? Or any other C cell smart charger?

5. Can anyone comment on the Maha Imedion C Cell 5000mAh NIMH rechargeable batteries? I am thinking of using rechargeable C cells for my backup lights.

I have some ideas, but I wanted to see what everyone else has to say before I open my mouth.

Harry Marinakis
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IUS Commission on Volcanic Caves
NACD Full Cave Diver
Monongahela Grotto, West Virginia
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