public
join:2002-01-19
Santa Clara, CA | reply to shdesigns
Re: effect of high charging current on NiMHs said by shdesigns:said by public:Fast charging nimh quickly degrades capacity, in spite of what product ads claim
For best results use 0.1C charge current.
The problem with that is NiMh do not like being overcharged. NiCads handle it much better. Preventing overchargeing is not easy on lower charge rates. 0.5C is not bad. Most smart charges charge at 1-5C (have seen 10C used). That will degrade them. If you charge 2500mAh AA cell at 1C that is 2.5A. It will be sizzling hot and quickly ruined. |
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 shdesignsPowered By Infinite Improbabilty DrivePremium
join:2000-12-01
Stone Mountain, GA | Yes, i do AA's at 750ma regardless of capacity. That is enough to peak charge. If I'm in a hurry i use 1.25A, again the 0.5C level.
I have seen 3000mah A cells charged at 10 amps. Then again they are designed for it and are discharged at 25+ amps. |
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public
join:2002-01-19
Santa Clara, CA | said by shdesigns:I have seen 3000mah A cells charged at 10 amps. Then again they are designed for it and are discharged at 25+ amps.
Typical nimh aa cell will run hot when loaded at 1A. Which AA cells can supply 25A? |
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shdesignsPowered By Infinite Improbabilty DrivePremium
join:2000-12-01
Stone Mountain, GA | said by public:said by shdesigns:I have seen 3000mah A cells charged at 10 amps. Then again they are designed for it and are discharged at 25+ amps.
Typical nimh aa cell will run hot when loaded at 1A. Which AA cells can supply 25A? I did not say AA, I said A cells (often 5/4 A). Yes, they get hot enough when discharged you cant hold them in your hands very long. I remember they were Sanyo. Used in R/C plane, flight time of 6 to 8 minutes.
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Scott Henion
Embedded Systems Consultant,
SHDesigns home - DIY Welder |
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