Can NiMh AA's That Have Been Fast Charged Be Saved By Going To Overnight Charge?

Robert, as others have already mentioned here - you need the Maha C-9000 charger. Best thing I ever did for my batteries!

Rudi wrote in post #6483088
Robert, as others have already mentioned here - you need the Maha C-9000 charger. Best thing I ever did for my batteries!

Thanks Rudi.

What I'm not clear on is this....

If I get the C-9000 to condition and analyze, can I then also use one of the Maha chargers that will charge 8 batteries at one time? I keep coming back to this because I always need/want to go out with at least 8 (2 sets of 4 for 2 SB-800 flashes) AA's, if not more.

Charging 4 batteries overnight won't cut it and even if I wanted to plan ahead I might not have the time it takes to charge 8 batteries. What do you do?

TMR Design wrote in post #6483138
Thanks Rudi.

What I'm not clear on is this....

If I get the C-9000 to condition and analyze, can I then also use one of the Maha chargers that will charge 8 batteries at one time?

Yes! In fact, that is exactly the combination that I use to keep on top of my AA recharging needs when things get busy.

The 8-cell models do have conditioning features built-in, but they're not as comprehensive as the C-9000, which has real tools to analyze and recondition batteries (if at all possible).

Thanks Rudi. That's what I think I'm going to do then. I'll get all new batteries, a C-9000 and one of the 8 cell chargers.

I can also vouch for the C-9000, it works well. I have a C-9000 and a C-801. I use the breakin cycle to help bring old cells up to capacity, then after that I use the 801 to charge things quickly. You're apparently meant to run a charge/discharge/charg​e cycle one time in ten, the 801 can do that it just doesn't have all the analyser or breakin features of the 9000. But the 801 works well as a standard charger that can also do a refresh cycle.

I wouldn't charge overnight on a regular basis. The best way to charge is in 1-2 hours. Constant slow charging will build up crystals inside the cell which will degrade performance. Slow charging also makes it harder for the charger to sense the peak. Maha says not to charge at less than .5C (2 hours) to ensure proper peak detection on the C-9000.

OK but if I shoot an event and have 8 AA's that all need a full charge then how do I do that? I'm using the term 'over night' just to differentiate from fast charge or 15 minute charge.

If the batteries are almost drained and need a full charge for the next days event then how long does it take for a full charge?

It depends on how fast you charge them. the C-9000 lets you set that. Charging them in an hour is no problem. Personaly I tend to do it in about an hour and a half or two hours, I'm not in a hurry most of the time.

1C is kind of like 1/f except it multiplies instead of divides. C is the capacity of the cell in amphours. Say you have a 2000mah cell. 2C = 2*2000mah = 4000ma(or 4amps). A rate of 4amps will charge or discharge the cell in approx. a half hour. .5C = .5*2000mah = 1000ma(1amp). That will charge the cell in 2 hours.

.25C = 4 hours
.5C = 2 hours
1C = 1 hour
2C = 30 minutes
3C = 20 minutes
4C = 15 minutes

and so on.

Stregone wrote in post #6486957
It depends on how fast you charge them. the C-9000 lets you set that. Charging them in an hour is no problem. Personaly I tend to do it in about an hour and a half or two hours, I'm not in a hurry most of the time.

1C is kind of like 1/f except it multiplies instead of divides. C is the capacity of the cell in amphours. Say you have a 2000mah cell. 2C = 2*2000mah = 4000ma(or 4amps). A rate of 4amps will charge or discharge the cell in approx. a half hour. .5C = .5*2000mah = 1000ma(1amp). That will charge the cell in 2 hours.

.25C = 4 hours
.5C = 2 hours
1C = 1 hour
2C = 30 minutes
3C = 20 minutes
4C = 15 minutes

and so on.

Very interesting. I never knew how any of this worked. I assume all of this is documented in the Maha instructions that come with the chargers?

I don't know, I don't have a maha charger. Its just information I have picked up on the internet. Mostly over here: http://www.candlepower​forums.com/vb/forumdis​play.php?f=9

Its a forum for flashlights, that is a topic mostly about batteries, and the information discussed there applies to anything you use batteries in.

Yes the maha chargers come with good instructions. The 801 has less features but can charge 8 cells at a time, which is handy. If you regularly need to charge many batteries overnight get the 801 over the 9000. If you want the breakin capability get a C-9000 as well. Breakin takes 3 days to run on a set of 4 cells. A standard charge is done in a couple of hours on either unit.

tim wrote in post #6488996
Yes the maha chargers come with good instructions. The 801 has less features but can charge 8 cells at a time, which is handy. If you regularly need to charge many batteries overnight get the 801 over the 9000. If you want the breakin capability get a C-9000 as well. Breakin takes 3 days to run on a set of 4 cells. A standard charge is done in a couple of hours on either unit.

Thank you Tim.

overnight charges have refreshed some of my AA battery sets, though they still don't retain the full charge.

The break in cycle is what you use to refresh batteries on the C-9000, it takes about 3 days. I'm not exaggerating.

The break-in cycle is a much deeper conditioning than just a refresh, Tim. The C-9000, as you know, has an "Analyze and Refresh" cycle, too, which only takes a few hours. The break-in is designed to deeply condition brand new or very old batteries. If the break-in cycle won't work, nothing will!