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Thread: Maha MH C808M Charger

  1. #211
    Flashaholic Geogecko's Avatar
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    Default Re: Maha MH C808M Charger

    Wow, this thing is gigantic! I guess I should have figured that out with 8 D cells piled in this thing. Unfortunately, these low discharges come precharged, so I haven't used the thing yet...

    That said, what I mentioned about them having the electronics done isn't quite true. They would have to at least spin the board, in order to get the contacts at the right spacings...

    I enjoyed the previous post, it had a lot of good arguments.

    I'm hoping that the C cells will terminate fine on soft charging. For me, 4.5 hours is fine for charging, although from what ppl have said, even at the higher rate, things seem to remain fairly cool...

  2. #212
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Geogecko View Post
    Unfortunately, these low discharges come precharged, so I haven't used the thing yet...
    I would say, "Go for it!" From what I've read, "precharged" doesn't mean they are fully charged at the factory. Then add to that the normal discharge (albeit LSD) since manufacture, and the cells could be down to less than 1.3 volts, so the 808 shouldn't have any problem terminating on that. Or, a discharge-charge couldn't at all hurt a new cell that has been sitting unused for a spell, so this could be the perfect time to try out that refresh function. Keep in mind that with 8 cells, the total time to refresh could be up to 3 or 4 days for D-cells, depending on charge rate selected. Even at 2 amps, the new C-cells should stay pretty cool on the 808. Just avoid doing anything like soft charge (1A) into a 12 Ah D-cell with a cooling fan over it. I ran into termination problems with active cooling with soft charge. I've since learned active cooling is completely uneccesary with the 808 at any rate with any size cell. Active cooling was a bad habit I carried over from using my BC-900! I have since stopped using active cooling with the BC-900 unless charging at 1 amp or higher, as the cooling also prevents reliable termination. Now I have enough BC-900's that I can charge just a pair in each, just in the outer slots for good ventilation. The 808 has plenty of cell spacing for good cooling. Your 808 will get warmer in the right-side bays, so if I am charging fewer than 8 cells, I start from the left and fill rightward to avoid the warmer area on the right. I mean, I have to be anal about something on the 808, right?

  3. #213
    Flashaholic Geogecko's Avatar
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    Default Re: Maha MH C808M Charger

    Ah, you were correct. I loaded her up with 8 C cells, and they are currently soft charging, and the bottom bar is the only one lit up right now...

    Guess the crib aquarium will be coming in for a sooner than expected battery change. Oh, well. So far, there is no detectable change in battery temperature, but it's only been 15 minutes. I got my C9000 also charging some AA batteries.

    The other thing I am impressed with, are the contacts on these two chargers. They are very well built, compared with the normal spring type of contacts on most chargers. I think this is what helps keep the temperature down while charging, by reducing the resistance of the connections with the batteries.

    I think the price of the C808M is a little on the steep side, but I'm over all happy with it so far.

  4. #214
    Flashaholic* Turbo DV8's Avatar
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Geogecko View Post
    Oh, well. So far, there is no detectable change in battery temperature, but it's only been 15 minutes.
    Temps only rise appreciably very near the end of charge, although the older and more tired out the cell, the warmer overall it will become. Don't panic if the cells don't at first appear to terminate reliably on soft charge. I've read that it can sometimes take a couple cycles for some cells to provide reliable negative change in voltage at end of charge to trigger reliable termination.

  5. #215
    Flashaholic Geogecko's Avatar
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    Default Re: Maha MH C808M Charger

    They seemed to do all right, topped off after about an hour or so. They only got slightly warm.

  6. #216
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    Default Re: Maha MH C808M Charger

    Hi. I just got my c808m this week. Actually, I got 2, the first one was a dud, the last 3 bays keep flashing done even if I put healthy cells in them. So I returned it for a refund. I got my second one from another merchant. This one's really great. I'm refreshing my cells now for 3 days.

    I had some termination problems though, with new AAAs. But I'm sure it's the soft-charge on a 1000 mAH cell. The soft charge for AAA is 350mA, as I've read previously on this same thread. So that will make 0.35C, not suitable for termination.

    I'm waiting for another 2 months to make more money to buy the C9000. Can't wait!

    Thanks for the great posts on battery chargers. They all helped me to decide which charger to get. Especially to Silverfox, almost all info I know about rechargeables I got from him.

    Thanks!

  7. #217
    Flashaholic* Turbo DV8's Avatar
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by regor_nono View Post
    The soft charge for AAA is 350mA, as I've read previously on this same thread.
    Thanks for reminding me of that! Some of my ROV Hybrids won't terminate at 200 mA on my BC-900, and I don't like the higher 550 mA of the Duracell Mobile charger for AAA cells. I'll try the 808 on my AAA's at 350 mA and see how it works out.

  8. #218
    Flashaholic* Sub_Umbra's Avatar
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Turbo DV8 View Post
    Thanks for reminding me of that! Some of my ROV Hybrids won't terminate at 200 mA on my BC-900, and I don't like the higher 550 mA of the Duracell Mobile charger for AAA cells. I'll try the 808 on my AAA's at 350 mA and see how it works out.
    As clunky as it sounds, if you want to guarantee that your Maha C808M is charging at the gentler, "soft" setting you'll have have to take the extraordinary step of running it through a UPS.

    The Maha C808M doesn't like even the briefest half second dip in power and goes directly into amnesia at the slightest power interruption, reverting to back to it's default 'hard charge' setting no matter how you programmed it to charge your cells.

    This weakness could have been avoided with the addition of a cheap, mechanical Mode Switch or even just a few cents worth of flash memory, either of which would hold the user's choice over a power blink. They have not only not fixed this -- they have continued to design, manufacture and sell newer chargers with the very same weakness for years.

  9. #219
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Sub_Umbra View Post
    As clunky as it sounds, if you want to guarantee that your Maha C808M is charging at the gentler, "soft" setting you'll have have to take the extraordinary step of running it through a UPS.
    Yes, I'm also thinking of hooking up chargers to a UPS. Right now, I only have my charger hooked up to an automatic voltage regulator, as well as my other sensitive electronics (LCD TV, PS3, etc.), hoping it will be at least a temporary fix.

  10. #220
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    Default Re: Maha MH C808M Charger

    Anybody try making an adapter to allow charging telephone battery packs? The terminals on the battery pack are on the back and are the pressure type. If I take it apart, I destroy the battery. The handset has two metal tabs at the base which I can attach alligator clips to. The problem is on the mh-c808m charger - the negative terminals extend out enough that I can attach an alligator clip to but I can't do the same with the positive terminals. I figure an adapter about the size of a D cell with metal tabs at the ends that extend out so that I can attach alligator clips would work.

    Anybody seen anything like that? Good idea? Bad idea?

  11. #221
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by GMan4911 View Post
    Anybody try making an adapter to allow charging telephone battery packs? The terminals on the battery pack are on the back and are the pressure type. If I take it apart, I destroy the battery. The handset has two metal tabs at the base which I can attach alligator clips to. The problem is on the mh-c808m charger - the negative terminals extend out enough that I can attach an alligator clip to but I can't do the same with the positive terminals. I figure an adapter about the size of a D cell with metal tabs at the ends that extend out so that I can attach alligator clips would work.

    Anybody seen anything like that? Good idea? Bad idea?
    One easy solution would be to put rare earth magnets in the jaws of your alligator clips, turning them into magnetic leads (no dummy cells required.) I think 1/8 inch diameter cylinders would be ideal because they're around the size of a AAA's positive button and could be mounted in different directions, but I haven't tried it yet. Others around here would probably know better than me. (I've seen posts about soldering and welding magnets to wires, and there are "Magleads" out there, but they're a bit spendy.)

    My concern would be for the battery packs since they are wired in series. You would have to cut two holes in the shrink-wrap to have access to the single cells inside a 3-cell pack (as our chargers are only meant to handle one cell per channel.) I think this would be a clever way to condition or charge one cell at a time inside the pack, but there is the possibility of overheating because of the plastic enclosure and the fact it's far away from the charger's temperature sensors. At least you wouldn't have to take the pack apart.
    "The only legitimate use of a computer is to play games." - Eugene Jarvis

  12. #222

    Default Re: Maha MH C808M Charger

    I've had one for several years now, still works great. Does anyone know if maha has plans for a quality charger that will do cr123?

  13. #223
    Flashaholic* hank's Avatar
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    Default Re: Maha MH C808M Charger

    > ... to guarantee that your Maha C808M is charging at the gentler, "soft" setting you'll
    > have to take the extraordinary step of running it through a UPS.
    > ...
    > The Maha C808M doesn't like even the briefest half second dip in power and goes directly into
    > ... default 'hard charge' setting no matter how you programmed it to charge your cells.

    Yeek. That's vitally important as a bad failure mode that could screw up batteries.

    Is there any visible indication that it _has_ changed from soft to fast charge, can you even tell it's done that?


    -----
    Edit to add -- I did ask Maha if there were any versions, or any changes over time, for the way the charger works. Reply was no, no change at all in the model/version.
    Last edited by hank; 02-18-2012 at 02:27 PM.

  14. #224

    Default Re: Maha MH C808M Charger

    Quote Originally Posted by hank View Post
    Is there any visible indication that it _has_ changed from soft to fast charge, can you even tell it's done that?
    As far as I know, the only way to tell is to look at it periodically, and see if the little "SOFT CHARGING" text is present on--or missing from--the top right corner of the LCD.

    I haven't noticed that quirk with mine yet, but maybe we haven't had a power drop while it was in use. We've been pretty lucky in that regard this winter, only having the generator come on a couple of times besides its weekly self-tests.

  15. #225
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    Default Re: Maha MH C808M Charger

    Does anyone know if the MH C808M has had any upgades since this thread started? Possibly tweaking some things to address the issues / concerns some have brought up.

  16. #226

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    Default Re: Maha MH C808M Charger

    Hi!

    I have been using my Maha MH C808M Charger for a few years now and it has worked good. Until now. I think. I have tried to read the manual without explanation to the problem I recently faced.
    I placed 7AA and 1AAA(3xDuracell 2650mAh, 4xGP 2500 mAH and an Eneloop 750mAh) in the charger for conditioning. From the beginning it showed that all the cells were charging but after a while there was just nothing in the screen. Waited a night until next day and still no confirmation of finished process. Then I breaked the power and started it again. The same thing occured. What do you say; has the charger become faulty? Never seen this before. Just empty screen for several hours(and a night and day).

    Last edited by Swedpat; 08-08-2013 at 03:11 PM.

  17. #227

    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Swedpat View Post
    What do you say; has the charger become faulty? Never seen this before. Just empty screen for several hours(and a night and day).
    I've had something that caused the charger to constantly reset. It turned out to be a bad battery. It would charge and rest but discharging cause the unit to reset. Have you tried a single battery?

  18. #228

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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Mr Floppy View Post
    I've had something that caused the charger to constantly reset. It turned out to be a bad battery. It would charge and rest but discharging cause the unit to reset. Have you tried a single battery?
    Thanks for the reply!

    I tried to do the conditioning with only the 3xDuracell 2650mAh and it has been completed. After that I did the same with 4xGP 2500 mAH and it also succeeded. So I don't know why it didn't work the first time with all the batteries.

  19. #229

    Default Re: Maha MH C808M Charger

    Need a manual for my MH-808 charger - have been searching the web and can't find one. Can Someone point me to one??

    Thanks much!!

  20. #230

    Default Re: Maha MH C808M Charger

    Quote Originally Posted by Swedpat View Post
    Thanks for the reply!

    I tried to do the conditioning with only the 3xDuracell 2650mAh and it has been completed. After that I did the same with 4xGP 2500 mAH and it also succeeded. So I don't know why it didn't work the first time with all the batteries.
    There are some great tips and comments on Amazon regarding this charger. In one of the reviews the reviewer talks about using another "dumb" charger that will start chargering cells that appear to be "bad" and will charge them up to a level that is required "minimum" for the MAHA CH-808M to start chargeing. If the cells are below a certain voltage (easily done) the 808 will NOT BEGIN to charge. Not sure what a dumb charger would be all though - looking into that and will check back in if I find one.

  21. #231
    Flashaholic* Sub_Umbra's Avatar
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    Default Re: Maha MH C808M Charger

    Quote Originally Posted by shredmandan View Post
    Need a manual for my MH-808 charger - have been searching the web and can't find one. Can Someone point me to one??

    Thanks much!!
    There wasn't one when I bought mine. In no way could the one page of text that came with it be called a manual. If it weren't for threads at CPF I never would have ever found workarounds for some of the features claimed in the ads for it...and some of the workarounds are unreliable.

    I'm not saying it's a bad charger, only that MAHA should act less like a used car salesman and try to more accurately list actual features that work as advertised on a charger that they charged $100 for.

    No offense to any used car salesmen out there...

  22. #232

    Default Re: Maha MH C808M Charger

    Quote Originally Posted by shredmandan View Post
    Need a manual for my MH-808 charger - have been searching the web and can't find one. Can Someone point me to one??
    I bookmarked it! Pity the link is dead but here it is:
    http://web.archive.org/web/201211110...ad/mhc808m.pdf

  23. #233

    Default Re: Maha MH C808M Charger

    Did you test this to confirm that if you leave the cell on the 808 that when the voltage drops below a certain value by self discharge, the 808 starts the charge process again by itself ???

    Quote Originally Posted by SilverFox View Post
    One test I have not done is to leave a cell on the C808M charger for an extended period of time. It could be that when the self discharge of the cell dropped below a certain voltage, the charge process would begin again. T
    Tom

  24. #234
    Flashaholic Richwouldnt's Avatar
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    Default Re: Maha MH C808M Charger

    Link in post 232 is no longer dead. Just worked for me. Considering the start date of this thread it must be one of the oldest on CPF that is still relevant for a still produced product. Any one know what changes have been made to the product since it was introduced?

  25. #235
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    Default Re: Maha MH C808M Charger

    I bought it 2 years ago and it looks the same.. I think they haven't updated this charge one bit since when it came out at 2005???

  26. #236
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    Default Re: Maha MH C808M Charger

    Shame they never updated the C9000 to take advantage of LSD cells like Eneloops. i.e., Don't stop the charge at 1.47v (rely on -dV instead), and don't top-off or trickle. At least have a charging optional mode that does this, even if the default mode doesn't.

  27. #237

    Default Re: Maha MH C808M Charger

    My 808m died yesterday. All eight bays flashing done when empty. Went I put batteries in it just displays a box, not charging indicator , nothing. Four years old , paid 150cdn. I'm going back to the cheap chargers, I could have bought four for that price. It really burns my bag with people tout "Buy quality", my old CCRANE that is twelve years old is still working

  28. #238

    Default Re: Maha MH C808M Charger

    As a follow up Maha has agreed to replace the entire unit free. I purchased it in 2009. All I pay is shipping. Which I am ok with

    Very happy with the customer service

  29. #239

    Default Re: Maha MH C808M Charger

    That is awesome breamer. The MH C808M is one of the best investments I have made since I started out in this hobby.

  30. #240
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    Default Re: Maha MH C808M Charger

    I know this is an "Older" thread but it is VERY interesting that nobody has made a better charger for NiCd/Ni-MH batteries in 10+ years.
    I had asked about changing multiple D cells and every time people would recommend this charger.
    I have one in-coming along with C/D Tenergy cells. I look forward to being able to charge my Ni-MH's properly (and more then 4 at a time).
    I hope this thread will help others in the same quandary.

    Lateck,

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