Maha MH C808M Charger

[Al]

My third Maha MH C808M charger just died. The first lasted about two months, the second about a month, and the third about 3 months. They all died the same way, after trying to condition AAA cells. I got this charger from Thomas Distributing; who have the best customer service I have every encountered. I would be willing to try a forth C808M, but if I do get one I will not try to condition AAA cells with it. Has anyone else encountered this problem? Note that prior to these failures the chargers worked great.

Uh-oh, I was ready to get a C808M ... will continue to wait ...

 

[Alin10123]

I've had two 808's fail while charging AAA's. Both Thomas Distributing and Maha have been helpful. My third unit has been running for about a week now, charging AAA's and AA's with no problem. I really hope this one lasts.

Jeff,
How are the AAA's and AA's charging in the 808 still? Is it still working for you? or is it still going bad?

thanks

 

[Al]

Two posts above reporting multiple failures of C808M chargers ... These aren't inexpensive chargers and they seem in general to be well regarded. Still, this is a concern and I have e-mailed Thomasdistributing and requested their observations.

 

[SilverFox]

I have been using my 808 since it came out. I use more AA cells, so end up charging that size more than the others. I only use 24 AAA cells on a regular basis, but I haven't had any problems charging or conditioning those cells.

It would be interesting to know how the charger failed. There were some reports of display problems, but this unit has been basically trouble free.

Until we have more information on the failure mode, this unit remains on my recommended list.

Tom

 

[Jeff_Bagley]

Alin10123
The new charger (my third) has been working perfectly. I have many more AA's than AAA's and I use the AA's more frequently. It may take a couple of months before I develope some confidence about the chargers reliability with the AAA's. These are very nice chargers. I hope that I've got a good one this time.

 

[eav2k]

It seems that the C808M charger fails, for me, when I try to condition AAA cells. I can't really pinpoint the issue more closely than that. It charges AAA cells just fine, it was only after trying to condition AAA cells that I run into problems. The unit is now blinking done on all bays, with no cells in any of the bays. I have placed every type of cell I have into bays one through eight and it still just blinks Done at me. Also tried disconnecting and reconnecting power with and without cells with no effect.

I only have three types of AAA cell, I do not know if it was a specific cell that caused the problem. I have 850 mah Energizer cells, 850 mah Lenmar NoMEM cells, and Rayovac 15 minute 800 mah cells.

So does anyone have any ideas as to what is going on?

 

[Al]

It seems that the C808M charger fails, for me, when I try to condition AAA cells. I can't really pinpoint the issue more closely than that. It charges AAA cells just fine, it was only after trying to condition AAA cells that I run into problems. The unit is now blinking done on all bays, with no cells in any of the bays. I have placed every type of cell I have into bays one through eight and it still just blinks Done at me. Also tried disconnecting and reconnecting power with and without cells with no effect.

I only have three types of AAA cell, I do not know if it was a specific cell that caused the problem. I have 850 mah Energizer cells, 850 mah Lenmar NoMEM cells, and Rayovac 15 minute 800 mah cells.

So does anyone have any ideas as to what is going on?

A thot .... You mention using Rayovac 15 min. cells. These have an internal disconnect feature that is pressure activated when the cells begin to reach full charge. As the cell cools down continuity through the cell is suddenly re-established. Could this behavior have damaged the charger?

 

[eav2k]

A thot .... You mention using Rayovac 15 min. cells. These have an internal disconnect feature that is pressure activated when the cells begin to reach full charge. As the cell cools down continuity through the cell is suddenly re-estabished. Could this behavior have damaged the charger?

I don't know. Could there be some sort of interaction between the high power of this charger and the disconnect feature of the cell? Still the charger is now completely non functional on any bay with any cell.

 

[eav2k]

One email to Thomas Distributing and they are sending me a new charger, with a mailing label to return the old one. Love the service. I will not however be charging AAA batteries in it. I have two other chargers I can use instead.

 

[SilverFox]

Hello Eav2k,

The shut off with the RayOVac cells should act as if you removed the cell and then re-inserted it. It should start the default charge again every time it trips. It happens quickly, and that may present a problem for the charger.

If the charger doesn't reset back to normal when you unplug it, leave it unplugged for a couple of minutes, then plug it back in, you should contact Maha and ask them what is going on.

The flashing Done indicates that the charge was terminated on high voltage, rather than the normal end of charge termination. This is often seen when charging NiCd cells. However, pulling the cell should eliminate the flashing Done signal.

Let us know what you find out from Maha.

Tom

 

[eav2k]

Hello Eav2k,

The shut off with the RayOVac cells should act as if you removed the cell and then re-inserted it. It should start the default charge again every time it trips. It happens quickly, and that may present a problem for the charger.

If the charger doesn't reset back to normal when you unplug it, leave it unplugged for a couple of minutes, then plug it back in, you should contact Maha and ask them what is going on.

The flashing Done indicates that the charge was terminated on high voltage, rather than the normal end of charge termination. This is often seen when charging NiCd cells. However, pulling the cell should eliminate the flashing Done signal.

Let us know what you find out from Maha.

Tom

The charger has been unplugged for days, when I plugged it in all the bays went to a flashing done, this is with no cells in any bay. If I put a cell in a bay the charger does not detect it, instead it continues to flash done.

I have not contacted Maha as Thomas Distributing has agreed to replace the charger.

ed

 

[dekelsey61]

eak 2k or Jeff Bagley,
When you were doing the condition on your AAA batteries with your C808M charger did you put the batteries in the charger side by side or did you leave empty slots between batteries in the charger?
Dan

My third Maha MH C808M charger just died. The first lasted about two months, the second about a month, and the third about 3 months. They all died the same way, after trying to condition AAA cells. I got this charger from Thomas Distributing; who have the best customer service I have every encountered. I would be willing to try a forth C808M, but if I do get one I will not try to condition AAA cells with it. Has anyone else encountered this problem? Note that prior to these failures the chargers worked great.

 

[Jeff_Bagley]

dekelsey61

My first 808 failed while conditioning two aaa's. These cells were side by side, on the right hand side of the charger. The failure was indicated by a very small amount of smoke comming from the 7th from the left cell bay. After this occured, the display would ramain lit any time there was power applied to the charger wether or not any cells were present.

My second 808 failed while conditioning eight aaa's. The failure was indicated by flashing cell icons displayed for cell bays 4, 5, 6, 7, & 8 from the left. After this occured, any time a cell of any size is installed into cell bay 4, flashing cell icons are displayed for cell bays 4, 5, 6, 7, & 8 from the left wether or not any cells are installed in them.

My third 808 continues to run correctly while charging and conditioning aa's and aaa's.

 

[Alin10123]

dekelsey61

My first 808 failed while conditioning two aaa's. These cells were side by side, on the right hand side of the charger. The failure was indicated by a very small amount of smoke comming from the 7th from the left cell bay. After this occured, the display would ramain lit any time there was power applied to the charger wether or not any cells were present.

My second 808 failed while conditioning eight aaa's. The failure was indicated by flashing cell icons displayed for cell bays 4, 5, 6, 7, & 8 from the left. After this occured, any time a cell of any size is installed into cell bay 4, flashing cell icons are displayed for cell bays 4, 5, 6, 7, & 8 from the left wether or not any cells are installed in them.

My third 808 continues to run correctly while charging and conditioning aa's and aaa's.

hmm, maybe a bad batch of chargers? How often do you condition AAA cells in your chargers? I'm anxious to get them and will primarily be doing D and C cells but the occasional AAA cell for my LOD CE.

 

[eav2k]

I received my fourth charger, it is working well. Have not tried AAA cells in it yet.

 

[eav2k]

My fourth Maha C808M charger continues to work well. It has been used often for the past month without any problems.

I have not conditioned any AAA cells to this point, but have conditioned several sets of AA cells. The conditioning cycle will not restore the Energizer 2500 mah cells that have gone into rapid discharge mode. I am unsure of the effect conditioning mode has on other cells but those cells I have conditioned do seem to be working well.

I generally use slow charge mode when charging, but even this mode seems to be quite fast.

I recommend this charger despite having 3 of them fail on me; with the understanding that you should not try to condition cells which feature the internal disconnect that is activated when the cells begin to reach full charge.

I will try to keep the status of the charger updated.

 

[cam94z28]

How does the conditioning mode of this charger compare to that of the C-9000? I don't really need 8 bays as much as I need properly maintained, fast charging, and long lasting cells. If the 8 bay units will condition as nicely, I might go that route, as the C-801D is about the same price as the C-9000, and the C-800S (longer charging time) is even cheaper.

 

[Sub_Umbra]

How does the conditioning mode of this charger compare to that of the C-9000?....

AFAIK there is actually no way to force the Maha C808M to condition any cell of any type -- only an undocumented work-around that will fool it into a conditioning mode...if you have the time to watch it and fiddle with it.

To condition cells in the 808:

• Load cells into the bays and press 'condition'. The unit will first fully charge all cells.
• Many cells will trip out their bays and fail to condition. Keep pulling the cells that error off and put them aside, replacing them with more cells in the empty bays.
• Eventually (sometimes after a great many 'error-cells') one bay will actually go into condition mode. Then it's time to pull all other cells and replace them with the previously charged 'error-cells,' while the 808 is still in the mood.
• The 808 will not go back into charge-mode until cells in all bays are discharged so if you have more cells to condition you must keep swapping cells for discharge while the 808 is cooperating. If you fail to notice that cells in all bays have finished discharging, or if the power blinks out for half a second you will lose the condition mode and have to begin the process anew to get the 808 back into this work around conditioning mode.
• When the 808 has drained all of the cells in all of the bays (once you stop hot-swapping them) it will begin charging them. As each cell finishes charging pull it and replace it from your stack that you've already run through the machine to charge and discharge.

I think that pretty much sums up the steps to condition cells on the 808. If I've missed any steps I appologise for any omissions, while noting that the above instructions for the advertized conditioning feature are not even briefly mentioned in the instruction page that ships with the charger. I'm sure that Maha could do a better job than I of explaining it to their customers who buy the C808M if the issue was of any importance to them.

I have no experience with the condition modes of any other Maha models.

 

[cam94z28]

Sounds like a good enough reason to go with the c-9000. I just want to put the cells in, spend a few seconds on settings and walk away. Dont want to spend all day watching batteries. It seems the C-9000 would be more appropriate for me. Thanks for the info, I'm sure it will help out in this thread.

 

[SilverFox]

Hello Cam,

Welcome to CPF.

It is not quite as difficult as Sub Umbra makes it out to be. He, myself, and others are just put off by the inadequate instructions that came with this charger. It would have been nice to have this "undocumented" procedure "documented."

First, the problem.

Aged NiMh cells, and NiCd cells can end up with a higher voltage at the end of the charge. The 808 signals this termination on high voltage with a flashing "Done." So far, so good, but, the 808 will not go into conditioning mode from a flashing "Done" termination.

The solution.

The solution is to put a cell that the charge terminates with "Done" instead of a flashing "Done" in slot 1 and select the conditioning mode. The charger will charge that cell, then go into the discharge/conditioning mode. Once the charger goes into conditioning mode, you can add other cells as needed, and once other cells have been added, you can replace the cell in slot 1.

The C9000 allows you to set both the charging and discharging rates, so it is more versatile, but both chargers get the job done.

Tom