Looking for the fastest AA NiMH charger out there

[KevinL]

I came across this Sanyo 30-minute charger here, and they mention its capability to charge Sanyo 2300mAH cells in just 30 minutes. I have a large investment in Sanyo cells, too.

It sounds pretty impressive. 4.6 amps per cell charging current - wow! Not quite the Rayovac 15-minute system, but this leverages my current investment in cells (all 24 of them) because otherwise I'd have to purchase ROV IC3 cells and it could add up quick.

They say it has a 15-minute charge function that runs exactly 15 minutes, but I suspect that they terminate the charge at 15 minutes, which will 'top up' the cells to 50% or thereabouts so that you have at least some power to start using straight away. It doesn't accelerate it any further. Good for half-drained cells, though.

How does this stack up against our 'gold reference standard' of the Maha C401FS? I only own the C777Plus2.

 

[paulr]

Re: Sanyo 30-minute charger: Worth it?

The cs401fs is not much of a gold standard any more (see the Lacross LC500 at jsburlys.com). If I wanted an ultrafast charger I'd probably get the Eveready 15 minute charger which is $25 at Costco (or online) including four 2500 mah cells, half the price of the Ray-o-vac and doesn't need special cells. I don't see that much difference between a 1 hour charger and a 1/2 hour charger, but 15 minutes starts to be almost realtime.

 

[KevinL]

Re: Looking for the fastest AA NiMH charger out th

Oh yeah, thanks for reminding me of that option. Hmmm..

The Energizer 15-minute sounds good especially since they say it can do it for all cells. Is this an international charger capable of 110-240VAC?

(edit: subject changed to reflect my current requirements).

I just looked at the LaCrosse charger, very nice - agreed, does threaten to obsolete the Maha. It wins hands down in the features department, but it's a standard 70-90 minute charger, and I'm looking for something that is going to slam a huge amount of amps into my cells in very little time..

The Energizer does look good however, because the technical datasheet says DC input voltage of 11-16V, 4A. Anybody smell an automotive application here? This will nicely accomodate even car voltage spikes. Knowing me I will use one of my regulated +12VDC ports off a computer though /ubbthreads/images/graemlins/grin.gif


Also, I'm aware that the fast charge will probably shorten their lifecycle, but unfortunately there are those days where time is simply not on my side. For those days when time IS on my side, the Maha C777Plus2 and my upcoming Hitec USL charger will treat the cells very gently.

 

[KevinL]

Re: Looking for the fastest AA NiMH charger out th

/ubbthreads/images/graemlins/bumpit.gif still looking for comments. /ubbthreads/images/graemlins/smile.gif

Anybody got good suggestions or experience with the Energizer stuff?

 

[cheesehead]

Re: Looking for the fastest AA NiMH charger out th

I have the one hour charger and use it with the 15 minute batteries (these 15 min batteries do have more current than the other NiMH I have and heat up less when being used). I think when you are recharging cells at 30 minutes or less, they need to be specially designed (i.e. lower total power, but higher current cells). I usually have 2 sets of NiMH, so I don't need them charged up as quick and figured a slow charge is better for the batteries. Plus, prices of NiMH have really dropped.

 

[kitelights]

Re: Looking for the fastest AA NiMH charger out th

I'm not convinced of the tradeoff of the 15-30 minute chargers, either. I suspect that both, incomplete charging and shortened life is taking place. I don't want to argue against your need, but it seems to me that it would be more practical to have a larger quantity of cells to rotate with a proven 1 hour charger.

 

[SilverFox]

Re: Looking for the fastest AA NiMH charger out th

Hello Kitelights,

I was thinking along similar lines, until I had a chance to try the IC-3 system...

Heat kills NiMh batteries. The best way to check if you are abusing a cell is to check the temperature. Over charging to too high a voltage results in heat, over charging at too high a charge rate results in heat, over discharging at too high a rate results in heat.

The batteries charged with the IC-3 charger remained cooler than batteries charged on other chargers that are using "delta V" charge termination. A NiMh charger (charging a 2000 mAh cell at 500 mA)will provide a full charge in about 4.5 hours and at the end the cells will warm up. The IC-3 system will charge the cells in 15 minutes and the cells will be cooler than the others.

The only way to get away from producing heat is to use a timed charge at a 0.1C rate. The problem with this is that it only works for fully discharged cells. If the cell is only partially discharged, you end up overcharging the cell and producing heat.

Another thing I found interesting was that the IC-3 cells are rated for 1000 cycles. That's twice what others are rated for.

I have not tried the Energizer system, but if it is based on a similar control system, I would expect similar results.

Tom

 

[KevinL]

Re: Looking for the fastest AA NiMH charger out th

I understand the part about shortened life, like I said, for the days when I have time I can slow-charge them on things like the Maha or the Hitec. 0.2A current.. (0.1C for a 2000mAH cell) very forgiving. Sometimes you can't carry enough cells and you're on the move so you can't charge them..

Energizer claims that their charger does not need special cells, and has a temperature cutoff. I can't seem to find it locally.

Maybe I should buy one and find out... /ubbthreads/images/graemlins/grin.gif

 

[KevinL]

Re: Looking for the fastest AA NiMH charger out th

Crap, Amazon has the best price and does not ship internationally (for this product). Any of you folks can get it locally and send one over to me?

This restriction is probably because the thing only has a 110VAC power supply, but I fear not the power supply difference for I have a solution.

 

[kitelights]

Re: Looking for the fastest AA NiMH charger out th

Kevin-
I'll be happy to, but we haven't had very good luck. I might even get one for myself. Email me if you want.

Tom-
What's the secret to the IC-3? Does it pulse, does it have a fan? How complete a charge does it do? Will it do all brand cells?

I have a 401 and when I use it on fast charge, I run a fan on it. Externally the cells get slightly warm.

 

[paulr]

Re: Looking for the fastest AA NiMH charger out th

The IC3 needs special cells with a temperature cutout built into the cell. Best price I've seen for IC3 cells is about $4 each, which is 4x as high as comparable normal NiMH cells.

There's a Sakar charger that claims to charge in 8.5 minutes. I think such high charge currents (even 15 minutes) is asking for trouble in normal circumstances. There's another thread about 15 minute chargers where it says normally they charge to 70% or so in 15 minutes, and then trickle charge. The cells just don't accept charge as fast once they're past about 70% full. So I'd say a 15 minute charger is best for when you need to run your device in a hurry, not for a normal situation where you want a full charge. I think I'm going to order the Lacrosse 70-90 minute charger.

 

[SilverFox]

Re: Looking for the fastest AA NiMH charger out th

Hello Kitelights,

I did a review on the Rav o Vac IC-3 charger that should cover most of your questions.

It is also mentioned in the charger thread.

Tom

 

[SilverFox]

Re: Looking for the fastest AA NiMH charger out th

Hello Paul,

I found the IC-3 charged the cells to 89% in 16 minutes. If you did a second round, it got up to 100% in another 6 minutes.

Tom

 

[KevinL]

Re: Looking for the fastest AA NiMH charger out th

kitelights, email sent. Thanks for your offer, I'll give it a shot and report my findings back to the rest of CPF. At the worst it's not going to be any slower than the rest of my chargers, and even if I only get 50 cycles out of the cells (as opposed to the nominal 500 rating), it will be good enough.

And that reminds me, I should share the good deal I found - Energizer 15 min at Amazon, $22.99. Comes with the 4 cells. I've got no connection with them, I just ran across it in Google while everbody else was offering prices in the $30-$40 range.

89% state of charge (SOC) is pretty good. The Energizer is supposed to be trickle-charge capable too, so even if it doesn't completely charge in 15 minutes, if you can afford the time to leave it, it will top up a little bit more.