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View Full Version : My experience with MRC 977 charger and MRC support.


robl
06-28-2006, 07:12 AM
Guys, these letters below are what I sent to MRC and what I received back. With any luck, anyone who is thinking of buying one of these chargers will be saved, and if you really have to have one of these, I got one I'll sell you for a discount.

From: Rob [mailto:Rob@___world.com]
Sent: Saturday, June 17, 2006 8:48 PM
To: 'chargersupport@modelrectifier.com'
Cc: 'mrcsupport@modelrectifier.com'
Subject: MRC 977 Battery charger repair


Hello,

I sent in my MRC 977 battery charger about 3 weeks ago because it was overcharging my 3 cell 2100mah lipos as verified with a volt meter. I sent it in 2nd day air and you received it on a Friday. On Monday I called and you said you didn't have it. Doug finally found it after I told him who signed for it and 2:30PM Monday, the charger that you received Friday was finally located. Doug is none too friendly and answering the phone may not be the proper job for him. Before I sent the charger I had spoken to Jon who said it would take about 2 days to look over and be sent back. I called the Thursday after sending the charger to be told maybe they would look at it on Friday which is a full week after you received it. Finally I called the following Wednesday and was told by Jon that he couldn't find anything wrong. I told him that I had verified that my 11.1 volt Lipo that is not supposed to ever charge above 12.6 volts(it's a fire hazard you know) was being charged over 13 volts. He told me that I couldn't go by that and that I should just trust the charger. The charger was reading 12.39 volts at full charge. I also told him that after it was charged, the battery was reading 12.75 volts. Again this is over the safe limit of 12.6 volts. He said he would charge a battery and test the voltage afterwards. He said the voltage after charging was the same as my charger was showing and sent it back to me second day air as I requested at no charge after your company had my charger for at least a week longer than you said it would take. I figured maybe my voltmeter was bad so I tried another voltmeter and same thing, battery is at 12.75 volts at rest after charging and over 13 volts while charging. This leads me to believe that Jon flat out lied to me. Not to mention he is putting your company in a very bad position as you have now sent me back a fire hazard. I bought a Lipo balancer that will automatically cut off if the cell voltage gets above 4.25 volts. This is 12.75 volts. Guess what? It shuts down every time because your charger is charging the cells past the 4.2 volt maximum. This is 3 verifications that your charger is overcharging. 2 voltmeters and 1 battery balancer. Your engineer was supposedly looking at this. If you would like, I could have my friend who is an electrical engineer take a look and also confirm that it is overcharging the batteries. And your company has the nerve to put out another lipo charger, the 989. You haven't got the 977 right or the 969. It cost me 6 bucks to 2nd day air the charger to you and 9 bucks for you to send it back. I'm out 15 dollars and all you guys did was keep the charger for 3 weeks and lie to me. And you sent me back a fire hazard. Now, I kindly request that you refund my 15 dollars and send me a new charger that will correctly charge these lipos. A 977 would be nice but it's apparent that they do not charge correctly. If you could find one that does, it would be appreciated, otherwise, please send me a tested 989 and I will live with one output instead of 2. The last option would be to refund my 15 dollars plus the 105 dollars for this piece of junk. I expect a reply to this letter within one week with an acceptable solution or I will be calling whatever agencies I need to in order to prosecute your company for warranty fraud and false advertising.

Sincerely,

Robert Layton
555-555-5055
1313 NW mockingbird ave
Some Beach FL 33555


Mr. Layton,
Your letter was forwarded to me by John. I believe I have spoken to you before, my name is John Smith, and I'm the Customer Service Supervisor here at MRC. I must apologize for any bad experience you may have had while dealing with our company. Both in the length of time it took John to evaluate your charger, and for Doug's phone manners. Both are unacceptable, and I will deal with each of them to ensure that it won't happen again.
However, regarding your charger, it does take some time to evaluate these things properly. Each battery takes over an hour to charge, this is why it took as long as it did to fully evaluate your charger. John did a thorough job in going over your charger, and even asked my opinion and the opinion of our engineer. He did charge several LiPo batteries with it, including a 3 cell 700 mah battery, a 3 cell 1100 mah battery, and a 2 cell 700 mah battery. He also charged each of these batteries several times to be sure. None of these batteries were damaged in any way. I didn't notice the voltage reading you were referring to, but every battery is a little different than the next. The 12.75 volts is within reason for a 3 cell battery. For a fully charged 3 cell battery reading 12.75 volts, divide that by 3 cells, that is 4.25 volts per cell. This is a variance of 0.05 volts per cell, or 5 hundredths of a volt. Not enough to damage a battery. As far as your voltage readings during charging, in order to charge a battery with a voltage of 12 volts, the charger has to supply a slightly higher voltage than the battery is holding, over 13 volts. For example, your alternator on your car supplies your 12 volt car battery with 14.5 volts in order to charge it. If you take a voltage reading at the alternator, it will read 14.5 volts, this doesn't necessarily mean your car battery is 14.5 volts. Same thing with this charger. Just because the output of the charger is reading over 13 volts at the plug, this doesn't mean the battery is over 13 volts. Putting a balancer on the output of the charger is limiting the charging capabilities of the charger. The charger has to supply a higher voltage in order to charge these batteries, and the balancer in between is not allowing this to happen. I would certainly use the balancer occasionally before charging any multiple cell LiPo battery, this will prevent any one cell from being charged more than another, preventing damage to the battery, which from your own experience you know can happen. So, while the damage to the battery did occur while using our charger, through testing your charger and by consulting with our engineer, it is our conclusion that the damage occurred as a result of the battery not being balanced prior to charging, and that the charger is working properly and is not defective in any way.
Through the use of the LiPo batteries in the Hobby industry, they have come to learn that multiple cell LiPo's do have somewhat of a "memory" effect over time. And that if a multi cell pack is not properly balanced prior to charging, and one cell has more of a charge in it than others in the pack, then there is the risk of damaging the pack. I'm sure if you consult your friend that's an engineer, he will confirm what I have told you in this letter. If you have any questions please feel free to contact me at this email address, or I can be reached at 555-555-5555 ext 555.

Sincerely,

John Smith
Customer Relations Supervisor



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From: Rob [mailto:Rob@___world.com]
Sent: Monday, June 26, 2006 6:02 PM
To: 'Tim'
Subject: RE: MRC 977 Battery charger repair


Thank you for getting back to me. I guess my email was messed up. The point that you haven't addressed is the fact that John said this charger was working correctly and that when it is saying 12.39 volts and cutting off, that my batteries are at 12.39 volts. That is not the case. I had John do a full battery charge and at the end he said the battery was reading 12.39 volts just like the charger. I have 3 voltmeters and a battery balancer here that prove he is lying. The fact that your company feels that a battery charging to over 13 volts when the max limit is 12.6 volts is assinine frankly. My batterys puff a bit every time your charger charges them. Don't tell me they aren't charging to that, they are 12.75 volts after resting. They are at 12.95 or so freshly off the charger, and that is over the max limit of 4.3 volts per cell. My balancer cuts off at 4.25 volts per cell and that should be telling you something, namely, every other lipo charger, does not overcharge the batteries, and my charger is certainly broken when it is displaying 12.39 volts for the battery and that same battery measured with a voltmeter at rest is 12.75 volts. I'm out 15 bucks and 3 weeks of time and you haven't fixed the problem and clearly, anyone that knows how these batteries should be charged and that is familiar with a voltmeter can realize there is a definate problem here
I also wanted to make clear that before I had the balancer, these packs were measured by me frequently at the balancer plugs and were always in balance. Of course after getting the balancer, they have been out of balance because your charger causes the balancer to hit the high voltage safety frequently leaving two cells at 4.2 and one at 4.25.

robl
06-28-2006, 06:06 PM
I got an email today saying they will send me a shipping label for my charger and they are sending me a brand new one so we shall see what will happen.

DebianDog
06-28-2006, 07:35 PM
Well MRC does usually take care of its customers.

robl
06-28-2006, 08:07 PM
hopefully, we will see, this all could have been avoided if they just believed me when I told them it wasn't working instead of telling me I damaged the batteries by not using a balancer.

WillJames
06-28-2006, 10:16 PM
Sounds like a mis communication and they are trying to satisfy. Good!!

Man I with I could make some headway like this with my Internet Provider. :DOH

Man, what a long last 2 days have been with terrible Internet I depend on for work and my Freak fix!!

robl
06-29-2006, 06:46 AM
I really hope the new charger works correctly. I mean like do you really think I would keep complaining if the thing worked? I just want to fly my heli with a minimum of hassle.

DebianDog
06-29-2006, 07:49 AM
I really hope the new charger works correctly. I mean like do you really think I would keep complaining if the thing worked? I just want to fly my heli with a minimum of hassle.

Stuff like that happens all the time with other venders too because people are always trying to screw them over to get free stuff.

I like MRC and have a Superbrain 969. But it is not my choice for charging lipos.

robl
06-29-2006, 06:32 PM
well all I know is if it says it charges them, it should charge them without destroying the packs, hopefully this will be the case with the new one.

Gary JP4
01-07-2007, 02:39 PM
How about an update. What was the outcome?

Mine did the same thing. LHS would not take it back the next day. I have not contacted the manufacture yet.

Pinecone
01-07-2007, 06:42 PM
I would have pointed out that I will continue to use the charger on their recommendation, but when my house burns down from a lipo fire, I will both sic my insurance comapny on them, as well as suing them myself, both the company and each person involved individually.

You probably would have had a new charger the next day.

robl
12-24-2007, 10:57 PM
hows this for an update, the new one still overcharges the 3s lipo, not too bad on the 2s lipo, further, here is the best one. I got a DX7 back around april, went to charge the transmitter and yes, pretty much cooked the tranny battery. so much for this thing charging nimh. And yes, I tried it again at the lowest MV peak setting and still the battery was smoking. And i'm not the only one to report this, someone on RC groups said the same thing in a post. So basically this thing will charge nicads and 2s lipos. Whoopie, it should be 50 bucks tops.

istandalone
01-02-2008, 03:12 PM
i've got the 977, and all of my 3 cell lipos charge to 12.39v according to the charger. i wonder though, after reading this. i'll have to check it with a meter next charge. i was also going to get the 989, as it will go up to 8 cell lipo, and is pretty cheap. they should have made that one dual output too i think. i just don't like the fact that none of mrc's products will balance.

robl
01-02-2008, 03:33 PM
yea, check it when it just finishes charging, your battery is most likley at 12.85v. It seems to not be as bad on 2s packs. My balancer that I'm using does not cut the charge off on 2s. On 3s, it errors out every time.