Battery charger ?

What's the best charger for charging AA/AAA nimh battery? I'm looking for a charger that will fully charge them safely and doesn't run hot and won't over charged. Any recommendation will be appreciated.

Hello Carnage,

I have been using the MAHA C9000 for years and have been very pleased with its performance.

Tom

Yes, that is what I use, too ....

what I use and I'm a little surprised it's still recommended (why I came back today )

Thanks for the replies guys! Is the Maha called Powerex? In a google search It comes up as Powerex, I'm not sure if these are the same charger. you are talking about

I have two Maha C9000 myself, It`s the best charger for AAA or AA nimh battery`s

But make sure you don't put the battery in the wrong way around as it`s not supposed to have reverse polarity protection, One owner`s review on Amazon said it melted the plastic on the positive terminal when he put a battery in the wrong way around.

I have had C9000 for over 10 years, Slots dying seems to be a fault on these, One of the slots on my first C9000 would discharge but not charge, maybe i put a battery in the wrong way around by accident and that`s what killed my slot?

John.

Hi
I like to charge and analyze my batteries.
My recommend charger is the Opus-BT-C3100. It is helpful for matching batteries and knowing when the capacity is low.
Luck in your search!

Is the Maha C9000 is for beginners and easy to operate? Reading online does it leaves the batteries under charge?

carnage said:

Is the Maha C9000 is for beginners and easy to operate? Reading online does it leaves the batteries under charge?

Click to expand...

An old thread but the C9000 came 2nd place out of 22 chargers tested to how much energy they put into the battery.

http://www.candlepowerforums.com/vb/showthread.php?70935-Charger-Comparison

John.

Hello Carnage,

MAHA and Powerex are the same.

Ease of use for AA cells simply involves putting the cell into the charger and taking it out after the charge is complete. With AAA cells the default charge rate is a little high so you have to push a few buttons to reduce the charge rate but it is minimal effort once you have done it a couple of times.

Charge termination is done using dv/dt or when the cell reaches 1.47 volts. Usually the 1.47 volts is reached first. If you are in a hurry and pull the cell as soon as DONE is displayed, your cells will be slightly undercharged. However after the charge termination the charger applies a topping charge for the next 2 hours. This gently brings the cell up to full charge.

To keep track of what is going on you check the cells voltage display. If the voltage is going up after termination, the top off charge is underway. Once the voltage rate starts dropping the charge is complete.

There are a lot of features with this charger. If you simply want simple, just put the cells in, set a timer for 4 hours, and take them off. If you want to be more involved there are a variety of charge rate settings, discharge rate settings, and analyze, refresh, and break in modes that can be explored.

Tom

maha is overrated and i don't know why it constantly came up as recommended charger for nimh...maha is undercharging batteries, you have to calculate 2 hours more to top them off, and it is not very smart for one smart charger...and 1.47V cut off is not the happiest solution around...

right now, the best nimh charger is opus bt-c2000...no contest...if OP wants charger/analyzer...if he wants something for beginners i recommend ikea ladda, you can't find anything better for some 10-12 euros/dollars...

I was reading HKJ review and he wrote the battery might not always be filled. That why I'm asking that question.

TinderBox (UK) said:

[...] But make sure you don't put the battery in the wrong way around as [the Maha C9000] is not supposed to have reverse polarity protection, One owner`s review on Amazon said it melted the plastic on the positive terminal when he put a battery in the wrong way around.

Click to expand...

I strongly recommend against buying a charger without reverse polarity protection. It's not worth risking burning down your house simply to charge batteries.

Nowadays all decent chargers have reverse polarity protection (and even most of the dirt cheap ones too).

Gauss163 said:

I strongly recommend against buying a charger without reverse polarity protection. It's not worth risking burning down your house simply to charge batteries.

Nowadays all decent chargers have reverse polarity protection (and even most of the dirt cheap ones too).

Click to expand...

if I may ask. What is your recommendation on a charger?

The Opus C3100 is the best value nimh/li-ion charger analyser and many cpf member have one.

John.

Thanks for the replies! It looks like I'm going to read up on these chargers.

Over time I got to like OPUS BT-C700 and the more I use it the more I like it. I did not like it first, because it is ugly, made of flimsy hard plastic, the LCD display is of poor quality, it lacks the slot buttons, and I still have not figured out how to escape the "quick test" more on a single slot without changing the modes of all slots...

But I like it for its charging algorithm - it charges with full current up to 1.45Voc then it halves the current and terminates on 0dV. I think 0dV is better than -dV. And with just half the current in the final stage of charging process it is more gentle to the cells..

I also like the discharge function - it leaves the cell discharged and does not attempt to re-charge it. Therefor it is good for measuring remaining capacity in primary alkalines...

Also I find the internal resistance test (called quick test) pretty accurate (except the occasional readings when it shows unrealistically low values around 10-15 mOhm, but I just repeat the test and all is good).

Also I like its accuracy. It really seems to integrate (sum) the current over time to get the mAh, not just multiplying the charge rate by time as other chargers tend to do...

Also I like how it lowers the charge current for old cells with high internal resistance. Some chargers reject old cells, but this one does not care, it just charges them with lower current...

I never had any problems with it, never stopped charging prematurely, never missed the termination... Get one, you will like it

Some reviews:
- HJK's review of OPUS BT-C700
- AA Cycler's review of OPUS BT-C700

Cheers,
AA Cycler

As said above...the maha is the way to go.

Thanks for the replies!

Does anyone have any experience with the Opus BT-C700? Does it leaves the battery undercharge?