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04-26-2020, 10:43 AM   #1
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Battery question for someone with a very bad memory...

Hi chaps,...


been ages since i was last here,... and am i pleased you are still here. okay,... the charger is a powerex mhc9000,.. i am aware of the rule of charging eneloops at 0.5 x capacity i.e. 0.5 x 2000 would give the standard (don't press any buttons) 1000 charge rate. but i am at a loss of how to charge eneloops rated at 750mah. would i still use the 0.5 x 750 = 375 nearest rate on the powerex is 400. or would i need to use a lower rating, i.e. 0.2 x or 0.3 x 750.

I'm aware its a dumb question guys but batteries are not exactly cheap. i did find a link on candlepower forums where someone linked to an amazon page saying that to correctly charge 750mah one would need to press "a" button seven times,... so i tested this equation,.. press charge,. = 1,. then charge amount pressing down button 6 times left me on 400mah. does this sound about right.

hope this is okay for me to post the link from candlepowers site linking to amazon review detailing what i just typed.
Maha MH-C9000 FAQ (i eventually managed to find where i got the link from),... its on the maha mh-c9000 support / faq from cacdlepowerforums.com page 40.

04-26-2020, 10:54 AM - 3 Likes   #2
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I doubt that the batteries are sensitive enough to charge amperage that they would know the difference between 375 and 400. They can be safely charged at any rate between .5c and 1c. Never charge below .3c
I've charged my 950mAh Powerex AAAs at 500mA rate for years.

There's some good information here: How to charge eneloops? The Ultimate 2020 guide | eneloop101.com
And especially here: Battery Question for UnknownVT?? - PentaxForums.com

Battery University has a wealth of information on batteries.

Last edited by Parallax; 04-26-2020 at 11:04 AM.
04-26-2020, 12:24 PM   #3
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Ditto what Parallax said. Charging significantly over the recommended rate can lead to lowered battery life but charging slightly over the recommendation will cause little harm - perhaps very slightly less battery life over the lifetime of the battery but my guess for your case it's "in the noise" and you wouldn't be able to measure any such drop in life. The actual capacity of any one battery can vary from its labeled value anyway. No worries
04-26-2020, 03:24 PM   #4
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Thanks chaps....

Appreciate the advice and link,... i have a feeling my eneloops may be on there way out,... I've charged them at 400 and (with the top up) they are coming out at 479 mah and 482 mah. so both nearly the same. i suppose the only way to get any more would be to do a refresh and analyse. (i searched through my old thread, and wished I'd asked previously about lower rated batteries).....

04-26-2020, 03:51 PM - 2 Likes   #5
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If you are using the 0.5C charge rate rule (1/2 of capacity) just round down to the nearest rate. The FAQ from Maha Energy's site used say that but is implied from the chart the currently available. Downloadable as a PDF (link in FAQ page)

FAQ - MH-C9000 Charger - Powerex Support

What are the recommended charging and discharging current for my battery?
The recommended charging current is 0.5C, or 0.5 times the battery capacity. The recommended discharging current is 0.25C, or 0.25C times the battery capacity. Here are some settings for common batteries:

2700mAh Charge: 1300mA Discharge: 700mA
2650mAh Charge: 1300mA Discharge: 700mA
2500mAh Charge: 1200mA Discharge: 600mA
2300mAh Charge: 1100mA Discharge: 600mA
2200mAh Charge: 1100mA Discharge: 600mA
2100mAh Charge: 1000mA Discharge: 500mA
2000mAh Charge: 1000mA Discharge: 500mA
1000mAh Charge: 500mA Discharge: 200mA
900mAh Charge: 400mA Discharge: 200mA
850mAh Charge: 400mA Discharge: 200mA

Note: For better life they used to recommend using a lower charging rate of 0.4C.which produces less heat during the charging cycle. The caution was if you went too low the charger might not detect the voltage spike the batteries produce to end the charging cycle.
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