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Reviews Categories | Batteries & Chargers for amateur radios. | MAHA / PowerEx MH-C777PLUS-II Help


Reviews Summary for MAHA / PowerEx MH-C777PLUS-II
MAHA / PowerEx MH-C777PLUS-II Reviews: 18 Average rating: 2.7/5 MSRP: $89.95
Description: Based on the invaluable inputs of thousands of PowerEx product users and engineers, the MH-C777PLUS-II is designed with you in mind. From its universal charging capability for almost any shape Lithium Ion, NiMH, and NiCD battery packs to its digital voltage and capacity display, the MH-C777 PLUS-II is a true winner. Best of all, with all of these advanced features the charger is available at a affordable consumer cost.

Product is in production.
More info: http://www.mahaenergy.com/products/prosumer/mhc777plus.htm
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N2KEN Rating: 3/5 May 24, 2004 22:10 Send this review to a friend
OK, but needs refinement  Time owned: 0 to 3 months
MAHA / PowerEx MH-C777PLUS-II:
The charger works, BUT. . . On the plus side, it recognized any battery I’ve placed into the holder. It successfully discharged them and then fully charges to full capacity while reporting progress. Some battery packs require significant repositioning and are very difficult to align with the pins. The stock packs for the Kenwood TH-F6A and Radio Shack HTX-202 are two examples. The HTX-202 pack has the positive terminal very near to the ground plate. I managed to short two of the pins on the charger and slightly melt the plastic on one of the sliding pin supports (“Floating Charging Contacts”) while experimenting for position. Poor charger design or operator error?? The manual encourages using the “trial and error” method to align the pins, but be careful.

The floating pin design needs some refinement. All of my battery cases have their unique, peculiar positions so the pins make proper contact. A weak magnet holds the battery case somewhat in position. However, several times the pin contact was lost along the way and I needed to reposition the battery – and lose the charging progress info. Following the advice in the manual, a rubber band helps keep some packs in their place. The temperature sensor also has a magnet to hold it in place on the battery. I haven’t experienced any overheating or overcharging with the cells I’ve charged. The diversity of the voltages and battery pack chemistry types adds flexibility. I was able to revive one old NICAD pack by running it through three discharge/recharge cycles. Then, I recharged the 3.7V Lithium Ion pack for my VX-2R. The mAh readout was consistent with the battery’s rated capacity in both situations.

Perhaps the design of the “C777Plus-MKIIG-ProII-D” version will improve the overall pin adjustment procedure. A better clamping and/or pin pressure method is needed. I’m sure Maha / Powerex will keep experimenting until they get it right. Otherwise, it does what it does OK – charge various types of battery packs.
73
N2KEN


 
KD6ICY Rating: 3/5 Apr 4, 2004 18:28 Send this review to a friend
okay but needs improvement  Time owned: 6 to 12 months
I bought this at the 'pacificon show' my faults with this charger are these. The adjustments for connecting a battery are hard to adjust! I would like to see other types of connectors, that would connect to various size aa batteries that have connector wires attached to them.

On the plus side I have not had any trouble with overcharging or heating my batteries. plus the manual could be a bit more informative. I look forward to improvements in future models.
 
WB9YCJ Rating: 2/5 Sep 19, 2003 22:46 Send this review to a friend
Bend Over !  Time owned: 0 to 3 months
$49.95 at Dayton Hamvention. This review is indeed for the new Plus 2 version.
The good thing(s): Discharge function seems to work as advertised. Automatically goes into charge after all the life is sucked out of a battery.
The Bad: You need to hire a babysitter (batterysitter) if you want to leave the area.
Example: I took an eight cell "aa" case filled with eight new individual 1600 mah "aa" depleted Sanyo cells and placed them in charge (nimh selected).
Everything seemed OK until the current input to the batteries (on the LCD) kept incrementing past 1700, 1800, 1900, 2000, 2100, and at 2200 mah, I threw in the towel and disconnected the battery pack where I preceded to "fry an egg" on the pack. Well, not really, but you get the point. Yes indeed, I had the temp sensor directly on top the pack. Next, I had a little better luck; I took a four cell "c" holder filled with individual 2800 mah "c" size sanyo nicads.
It seemed to indeed discharge them and then proceeded to run them up to 2600 (the cells were about ten yrs old). So, I am confused about this model since some give it good marks. This "overcharging complaint" seems to be common among all the models including the new plus two.
And ren=member, they say heat is the big enemy of NiMH cells.
These are good if you can buy a used one for $30, monitor the current and manually disconnect the battery when the injected current is about ten percent over the batteries stated rating. My charger usually didnt do it as advertised.

 
KE4RWS Rating: 4/5 Apr 17, 2003 01:30 Send this review to a friend
Decent so far  Time owned: 6 to 12 months
I use my charger for multiple types of batteries, and thus far it's done reasonably well. I too have noticed that it will go into some type of random beeping fit after charging certain types of high capacity batteries (usually for one of my H/T's). When this happens I've noticed the battery in question is VERY hot, and the error code is due to the heat. However, for the most part I've had pretty good luck with this unit considering all the different types of batteries I have to keep charged. I've also used the battery-conditioner feature, which I think works reasonably well. The small piezo speaker is obtrusively LOUD, and will wake the dead if your not careful! I opened the case and placed a piece of electrical tape of the piezo opening to tone the little bastard down a bit, which worked.

In the end, I would recommend you NOT leave this charger unattended while charging a battery. Given the nature of this charger to heat certain batteries the way it does, you may come home to a pile of ashes if things don't go just right. And given the other reports of overheating it would make sense to stay with it while charging anything!!
 
KB7DXA Rating: 0/5 Apr 16, 2003 23:32 Send this review to a friend
Severe over charging  Time owned: 3 to 6 months
I bought a MH-C777PLUS-II. The batteries being charged with it seemed to me to be getting way too hot... About 50 to 70 degrees F above ambient.
I called Maha and spoke to the engineer. (Lucky for me the engineer answered the phone that evening, because later, when I spoke with anyone else they had no technical understanding of how this model is supposed to work, not even tech support.)
During our phone conversation the engineer and I determined that my MH-C777PLUS-II was overcharging. Maha arranged to send me a replacement unit. I received the replacement a week later. I tested the replacement unit, and it had the identical problem.
The problem is that these units overcharge the cells. The unit is supposed to stop rapid charging and switch to a float charge when the Negative Delta Voltage is at about .007 volts per cell. My tests have determined that the units do not switch to a float charge until the Negative Delta Voltage (NDV) is .065 volts per cell. (almost 10 times greater than spec.) I’m sure you’ll agree this is an unacceptable amount of overcharging and is harmful.
I have charged and recharged seven different battery packs many times. I have tested with five different brands of batteries. I have tried NiCd and NiMH. Sizes range from 1000 mAh to 2200 mAh. I have plotted Current, Voltage, and Temperature. The amount of overcharge is about the same on any battery pack, any brand, and either NiCd or NiMH chemistry. In total, I plotted about 50 charge cycles.
When charging SHOULD BE considered complete, (that is... the Negative Delta Voltage is at about .007 volts per cell) the temperature of a battery pack was typically at 85 to 95 degrees. Very reasonable temperatures for rapid charging at 800mA. In my tests, the ambient temperature was always around 70 degrees F.
HOWEVER... THE MH-C777PLUS-II KEEPS CHARGING ANYHOW ! By the time the MH-C777PLUS-II units stop overcharging and switch to a float charge, the battery case temperature has often risen to 140 degrees F. Certainly not healthy for the cells.
Just to clarify: The NDV is not erratic. It is always wrong about the same amount. Funny thing... the NDV is off by an amount very close to one decimal point! I wonder if that could be caused by a programming error of exactly one decimal point somewhere in the algorithm!! Could that be??
It seems unrealistic to assume that I have received two bad units, especially since they have serial numbers that are numerically far apart, different looking boxes, and reprinted manuals etc.
Five times I requested Maha to agree to test my units and confirm my findings. They never responded.
Please learn from my mistake. Do not buy one of these.



 
KC2IGY Rating: 0/5 Feb 26, 2003 17:48 Send this review to a friend
No better than the original  Time owned: 0 to 3 months
After sending back several defective MH-C777PLUS chargers to MAHA, they sent me a MH-C777PLUS-II.
It didn't take long to realize that this thing is no better than the original. I tested using some of my older packs, since the original liked to cook them. The results are the same. It charged a 1200mAh pack up to over 2000mAh before I decided to disconnect it before it melted. The temperature sensor obviously doesn't work. I tried to discharge a good pack, and it just froze up after a few minutes. Maybe by the time MAHA releases the C777PLUS-IV, they will get it right.
 
WA4OBJ Rating: 1/5 Oct 20, 2002 22:46 Send this review to a friend
Charging Li batteries is a disappointment  Time owned: 3 to 6 months
I've had this unit for about 6 months now. It seems to work OK on NiCads but be careful with Lithium Ion. My unit nevers completes a charge. Instead, it goes into a non-stop beeping mode after a couple of hours. Removing the battery doesn't help, you have to unplug it. I talked to the Maha people at Pacificon. They acknowledged there was a problem with all of the MH-C777 Plus chargers. Their recommended fix was to buy a MH-C777 Plus II and scrap my "old" unit. No trade in of course. Not exactly what I would call good customer support. I'm considering going after it with an ice pick to break the speaker so at least I don't have to listen to it. Another issue with this charger is that unless you are right on top of it when it finishes the battery condiditoning cycle, you will not know how your battery is doing. There should either be a "start charge" button or some way to recall the battery capacity at a later time. All in all, I wish I hadn't bought this charger and am quite disappointed.
 
KC8ADU Rating: 3/5 Sep 30, 2002 10:08 Send this review to a friend
nice but has some issues  Time owned: 3 to 6 months
for most folks this is a very usefull item.
i use mine a lot and while i like it it has some bugs.
1. it does not fully charge large packs.it shuts down early on anything over 3ah.takes 3 cycles to fully charge a 7 ah pack.
these are new packs that have been cycled 5 times so they are broken in.
this is starting with the pack properly discharged.
2. car cord is near useless.maha should have built in a step up.most of the packs i charge in the mobile are 9.6-12v
a workaround is to use a 12v laptop supply that outputs 24v.this works well.
3. ac adapter causes tvi.
it is a step up from the old 777 but needs some tweaking.
at least it did not melt down in discharge mode when i intentionaly interupted power like the 777plus is known to do.
fix these bugs and include settings for very small and very large packs and this would be a super product!
 
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