Upgrade to Maha MH-C9000?

[Hollow Man]

This is a debate I've been having with myself ever since I bought the Maha MH-C401FS in January of 2007.

I did a bit more research after that purchase, and discovered that on "slow" it would charge my cells too slow (the "fast" setting is hopeless because it really cooks batteries). I wrote Maha at the time, stating my concern that my sets of PowerEx AA 2700 mAh would be charging at .1C rather than the .4 to 1C that's generally recommended, but they insisted that everything would behave fine. To their credit, I haven't noticed any serious trouble (I have PowerEX AA 2700 and AAA 1000 mAh cells, Eneloop AAs, a variety of older Energizer AA and AAAs, and a really old set of Fuji AAs).

Fast forward to now. I needed to replace the AAs in my wife's computer mouse, so I bought a set of Japanese pre-charged Duracells at Wal-Mart (I dig my Eneloops, and this was the quickest solution for getting some). This gets me thinking about chargers again.

So I'm back to my thoughts from last year: what disservice, if any, am I doing to my 2700 and 2000 mAh batteries by charging them at around .1C? The nerd in me really wants the C9000 to fiddle with, but the practical side of me keeps saying that the C401FS is working fine.

Thanks in advance for your help, and all of the good information I've gotten from the forum over the last couple of years.

-HM

 

[Mr Happy]

The slow charge current is 300 mA. So that should take about 7 - 11 hours for a charge depending on the cell capacity. (The charger should stop at or before about 120% of capacity, so 1.2 * 2000 mAh / 300 mA would be about 8 hours max for a full charge, and 11 hours for a 2700 mAh cell.)

How long do you observe the charger to take before the green light comes on? If it is in the 7 - 11 hour range and the cells do not get more than a little warm at the end of charging, then everything is fine and you are not doing your cells any disservice. If it takes longer than 11 hours then it is probably missing termination and you might want a different charger.

 

[Hollow Man]

I would say that the slow charge feature seems to working as advertised. The cells are taking the time I expect.

Although there have been times where a faster charge would come in handy. The few times I've used it, the cells become unbelievably hot, so I avoid it.

-HM

 

[Yoda4561]

I love the c9000, lots of flexibility, but normally with my good cells I'll just pop them in and let them charge at the default 1000ma, which is a great balance between fast charging and keeping cells cool.

 

[Hollow Man]

1000 ma is what the fast setting on the C401FS does, but it cooks the batteries like you wouldn't believe. I do think I'd enjoy that speed, because it would charge my Eneloops in around 2 hours instead of 6-7 hours. How warm does the C9000 get at the default of 1000 ma for AAs?

-HM

 

[Yoda4561]

It doesn't get hot at all, just slightly warm. There's a huge amount of free space around the batteries to prevent heat from building up.

 

[Al Combs]

Although there have been times where a faster charge would come in handy. The few times I've used it, the cells become unbelievably hot, so I avoid it.

-HM

I have a friend who bought the C401FS years ago before the MH C-9000 or the BC-900 were available. He hasn't had any trouble with heat build up. Perhaps yours is defective? Do you leave the little clear plastic door open while charging? Sorry, I had to ask.

If you're eying the MH C-9000, have you given any thought to using a muffin fan instead? The Sunon Maglev KDE1204PKV3 for instance is whisper quiet at 18 db and only draws 30 ma. Yellow is the fan's tach sensor so just cut that off. Some of the larger fans get a little noisy. The wall wart is 12 volts just like the fan. Splice it directly into the wall wart or buy some stuff at Radio Shack to make a little extension you can wire it into.

Radio Shack sells muffin fans too, but no where near as good as a Sunon and probably more expensive. You could use just a piece of cardboard to test the idea. Remove the plastic door and tape one end of the cardbord to the charger. Have it blow straight down on the batteries and leave both ends open. Test it every 15 minutes to see if they still feel hot.

 

[Hollow Man]

Has your friend used the fast setting? A number of other comments I read regarding the C401FS indicate that the fast setting runs unbearably hot. Yes, I leave the cover open.

-HM

 

[Al Combs]

Has your friend used the fast setting? A number of other comments I read regarding the C401FS indicate that the fast setting runs unbearably hot. Yes, I leave the cover open.

-HM

Yes he's used both settings without problems. I really haven't followed this charger as far as your problem being unusual, or not. The only reason I knew about my friend who owns it is because he asked me to recommend a good one to him. At the time it was one of the better chargers without going into the hobby grade of specialty chargers.

I bought a cheap 4 channel Duracell AA/AAA charger in WalMart that came with 4xAA's. It charges in about an hour. It's a 2 amp rate like the C9000. But nothing quite so fancy. The batteries only get warm to the touch towards the end of the charge cycle, not hot at all. I have no idea if it's a -delta V or not. I guess it must be to charge that fast. The C401FS is supposed to be.

Sounds like you've got a good excuse to go for the C9000. Good luck.

 

[Yoda4561]

I've found that two things lead to really hot batteries in a charger, one is that most rely on negative deltaV, which overcharges batteries a bit. The other is batteries that are going bad, like the 2500mah capacity batteries that were universally garbage. Once those started to develop high internal resistance the temps in my old maha 204w shot from warm to REALLY hot(2 amp charge rate, tight battery compartment and negative deltaV). The charger also sometimes missed termination when those batteries started to go bad. The same batteries in my c9000 do get hot but not cooking hot, and it's never missed a termination yet.

 

[Hollow Man]

I caved and bought the charger today from Thomas Distributing. I have quite a bit of cashback money from Discover, so it was effectively free.

I convinced myself to upgrade because I'd been giving charger advice to a friend of mine who wants little to do with learning about batteries (who I convinced to buy the Japanese made Duracell LSD cells for his new digital camera). The Soshine charger via DealExtreme looks nice, and this is the one I recommended (although I think he's going to go with the Sony equivalent). The Duracell charger (CEF21) was purchased by another friend of mine a year or so ago in Wal-Mart. He is an electrical engineer and understands batteries a lot more than I do, but is quite "frugal". He likes it quite a bit.

I toyed with the idea of these for me (since they're nice and cheap), but I'm really into the idea of being able to choose the current depending on the capacity of my batteries. And I have quite a few older cells that I'd be curious to throw through the break-in routine to see what happens.

Much thanks to all who responded,

-HM

 

[Aussie Cheese]

if your AAs are getting too hot to hold(45+ C) at 1A its time to get new batteries.

the c9000 does get the batteries noticeably warmer than the 808m (at 1A) but in no way does it get hot

YAY! 100 posts!

 

[Hollow Man]

As I said above, it seems the C401FS runs the batteries very hot on "fast". See SilverFox's comments on it here. The important bit:

"The fast charge rate on the Maha C-401FS is scary. Not only do the batteries heat up, but it appears that the slots charge unevenly. I will terminate the charge when the cells reach 130 degrees F. The cells on the Maha charger shot past 130 rapidly and as I was reaching to shut the charger down, the green light came on. The temperature continued to climb to 135 and was still going up when I pulled the cells from the charger and held them in my hand to cool them down."

-HM

 

[Aussie Cheese]

ditch the 401 it looks like a battery serial killer :devil:

 

[Hollow Man]

Works great on slow, but 300 mA is just a bit (ok, a lot) too slow for the newer capacity batteries, especially the 2700 mAh PowerEX AAs I have. My C9000 will be here Tuesday!

-HM

 

[Ocelot]

My C-9000 seems to either not charge the batteries properly or it kills them...

I've used the break-in mode, cycle mode, and plain charge mode and none seem to result in properly charged batteries.

I'm not sure if my unit is bad or not, however I'm not impressed so far...

 

[Mr Happy]

My C-9000 seems to either not charge the batteries properly or it kills them...

I've used the break-in mode, cycle mode, and plain charge mode and none seem to result in properly charged batteries.

I'm not sure if my unit is bad or not, however I'm not impressed so far...

That's not at all normal. Can you give more details? What brands, age and capacity of battery? What are the readings on the display during charging and discharging? What is the version number on the back of the unit?

 

[Aussie Cheese]

That's not at all normal. Can you give more details? What brands, age and capacity of battery? What are the readings on the display during charging and discharging? What is the version number on the back of the unit?

mine has similar issues, on the back it says 0FAB01, i dont know which batches has the termination problems.

 

[lengendcpf]

mine has similar issues, on the back it says 0FAB01, i dont know which batches has the termination problems.

Read about the serial numbers here

Extracted text:
"Units with numbers 0FAB01* and 0FAB02 have the original firmware, while 0G0B01 has the new firmware, which fixes the original's termination issues very nicely."

So yours have have the problem..

 

[Hollow Man]

Have all of these issues been ironed out with the C9000?

Mine shows up today, whee!

-HM