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Old Oct 9, 2002, 4:24 PM   #1
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Default MAHA MH-C204F help

Based on recommendations on postings on this site, I bought a MAHA MH-C204F charger. It came with 1800mAh PowerEX AA cells. The instructions worry me a bit. In BOLD letters the instructions emphasize that the Power Adapter must be plugged into the wall before connecting it to the charger and that the batteries are not to be placed into the charger until after the first two steps have been completed in order. The language suggests this is very important but it is not something I have seen before in other charger instructions or on this site. While I intend to follow the rules, can someone comment on what is the significance of this that caused them to emphasize it so? What happens if I put the batteries in befor plugging it in (explosion, dead batteries?). Equally oddly, the instructions do NOT tell the proper order for removing the cells and unplugging the unit.

Before I got the MAHA, I used the Sanyo 1850's and charger that was packed with the Minolta 7i. The instructions for this charger are quite clear that the batteries should be placed in the charger before it is plugged in and that the unit should be unplugged befor the batteries are removed. This is the opposite of the MAHA instructions. Is the difference a feature of the chargers or the batteries? I assumed I could charge the Sanyo batteries in the MAHA charger and visa-versa. Yes? Considering the huge array of battery brands out there I was hoping there was some sort of standards for interchangability. Too much to ask???

While I am asking silly questions: The MAHA charger warns that the batteries get quite hot (they do!) and that the hinged plastic cover should be left open during charging. They further instruct that the batteries NOT be stored in the charger so it seems the plastic cover was included to make the empty unit dustproof when in the box. Am I missing something? I recall discussions recommending the MAHA because it did not overheat the batteries as did another brand and that overheating was bad for the batteries. If this is true, why would anyone bother putting a cover on a charger and have to warn against using it?
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Old Oct 9, 2002, 4:59 PM   #2
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Here's a few suggestions. The power unit will use switch mode circuitry, it will probably have over current shut down protection which might be hard (i.e no output until adaptor removed).

They may think it better to plug in the power unit first off load, i.e no batteries on charge. If this is the case, removing batts while plugged in should be OK. I would think this is really an issue with absolutely flat batts. Alternatively the deltaV or delta T circuitry may be more stable if the juice is applied first without sensing batts (it might need to 'reset to zero' or something.

The only thing that really matters is the chemistry (NiMh or Nicad), the voltage, capacity in mAh, and physical format -AA AAA etc. Make and brand shouldn't be an issue, but some factors like leakage, no. of charges etc might vary.

All batteries fast charged will get warm. The watts in must cause heat! However some chargers terminate the fast charging when 80% charged and switch to trickle, thus gracefully increasing and then decreasing batt temp. The penalty is it takes longer.

Here's a thought. I don't know the MAHA charger, but it's probably got a temperature sensor, either as a fire precaution or as part of the end of charge detection. I'll bet if you leave the lid closed on a hot day, the thing might turn off with part charged batts!

Saw a clever circuit where a guy had built his own charger. The batts were clipped on to an ali plate. He knew the plate would equalise any temperature difference, prevent the damaging rapid rise in case temperature and provide a stable temp for the charge control circuit.
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Old Oct 9, 2002, 7:16 PM   #3
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i have 2 204f chargers
they are delta V units
i always have the units plugged in and thena add batts. never had an issue on charging. its been 2yrs now.
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Old Oct 17, 2002, 12:37 AM   #4
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I did the obvious and wrote MAHA. I received a helpful reply:
"Because the MH-C204F is microprocessor
controlled, the power must be plugged in first to avoid any surges in the
circuitry. There is no danger connecting the batteries before the power.
When removing the cells from the charger, you would want to remove the
batteries first. The power does not have to be disconnected every time
unless you need to move the charger to another outlet."
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Old Feb 28, 2003, 3:41 AM   #5
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Quote:
Originally Posted by dougsmit
I did the obvious and wrote MAHA. I received a helpful reply:
"Because the MH-C204F is microprocessor
controlled, the power must be plugged in first to avoid any surges in the
circuitry. There is no danger connecting the batteries before the power.
When removing the cells from the charger, you would want to remove the
batteries first. The power does not have to be disconnected every time
unless you need to move the charger to another outlet."
so i plan on leaving an extra set in the charger at all times, and switching with current set when needed. sometimes there are power outages in my area. will this be a problem?
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Old Feb 28, 2003, 5:32 AM   #6
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[quote="draggoon01so i plan on leaving an extra set in the charger at all times, and switching with current set when needed. sometimes there are power outages in my area. will this be a problem?[/quote]

My amount of battery use nowhere approaches yours so I have never considered leaving a set in the charger. Most of my images are taken with the AC adapter. I would suggest you do what I did and write MAHA asking that question and let us know what they say.
http://www.mahaenergy.com/misc/contact.htm
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Old Mar 9, 2003, 9:13 AM   #7
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Default well worth the money

I must say this charger was well worth the cost, it does charge battries fast and the discharge has renewed my Ni Cads used in my old Malibu solar lights. I thought the lights were all dead after 3 years so i pulled the battries and charged and then discharged all them twice and now they are back to full power. the lights stay on all night. Malibu lights need a lot of direct sun light to charge and being the winter we had this year they would not go back to full power but now they do. My regular portable telepower charger would never have worked since it could not discharge the battries after a charge. IF you ever want good solar lights go to Kmart and buy lights made by IDC called Sun-Glow, best solar lights i ever had.
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