Powermax PMBC-120 Power Suppy

Erwin Owner/Technician Barbados Posted   Latest   Edited  

I bought a Powermax PMBC-120 120 Amp 12 Volt Battery Charger/ Power Supply on eBay. 

While hooked up to a battery (on the first day I got it) I cranked the engine and now it is toasted.

Was that a very foolish thing to do with a power supply? 

Not that I would do it again, but generally, is that a no-no?

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Tom Owner/Technician
Idaho
Tom
   

I’ll bet there's internal fuses, open it up. My maintainer for programming will blow it's fuses if I try to charge a dead battery with it.

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Elias Owner/Technician
California
Elias
 

I have 2 shumachers and never had that happened to me. I try not to, but stuff happens.

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Jon Owner/Technician
California
Jon
 

That is basically a Kusmall that someone has bolted a handle to. We use them on fire trucks and there is a device that kicks the 120 vac cord out of the truck when its cranked to protect the charger from overcurrent and to prevent the driver from driving off with it. That said - I have cranked over hundreds of trucks with the charger going and never had an issue. All the fuses are external - did…

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Obie Technician
Washington
Obie
 

Manual states protection is the fuses. I would check them. They advertise reverse hook up and under/over current protection as well.

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Boruch Owner
Ohio
Boruch
 

It does not happen to my Snapon battery charger when it’s in Flash mode. I was worried the first time I cranked a a car with it in that mode but it was not a problem. I did it a few more times accidentally and it wasn’t an issue. So now I don’t worry about it.

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Glenn Owner/Technician
Texas
Glenn
 

Hello Erwin, Most maintainers are not designed to handle the sudden current demand of engine cranking. Open it up and see if it has a circuit board with a quick blow fuse. If it does, only replace it with the same rating and design. “Nothing ventured, nothing gained”. I have repaired a lot of my shop equipment over the years by performing a simple inspection to find a fuse blown or a wire…

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Victor Instructor
California
Victor
 

After the tool repair check the polarit on the cables,

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Dmitriy Analyst
Ontario
Dmitriy
   

The output fuses are external. The OP should check them first. diag​.​net/file/f6d4xslwi… ​

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Darren Owner/Technician
Arkansas
Darren
 

Pretty sure that is a repackaged RV power supply. I have several and usually they are fairly well protected from shorts/overloads. The usual weak spots other than fuses blown are an undersized trace on the circuit board that burns and the occasional sub par solder connection that fries. I have also seen the switches fry due to being under-rated for the actual extreme load.

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Allan Owner
Virginia
Allan
 

Over the years I’ve had 12 or so of the midtronics psc550 that looked like those. I’m dropped them, ran over them, picked them up by the cables, startwd Many cars I shouldn’t have with it and more abuse. Other than fixing the cables a few times and cutting the ram off after the cage is busted I’ve never had a problem. So, if starting a car toasted it it was junk to start with

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Justin Mobile Technician
Utah
Justin
 

I use the 100 amp unit the same way you describe. I haven’t had any issue when cranking cars. And it’s a lot of cars that I have done that with. I would say hundreds. The unit was defective if the fuses aren’t popped.

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Erwin Owner/Technician
Barbados
Erwin
 

I bought it because it was given top award 2020 by TST, so I also believe it was defective from start. I would have bought a more expensive one.

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Justin Mobile Technician
Utah
Justin
 

I bought the shumacher unit before I bought this one. That thing failed in short time. Customer service is non existent. It’s a wheel chock now. I think you just got a dud.

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Duane Owner
California
Duane
 

I have the 100 amp model and have started multiple cars while it was on with no problems. You should be able to return it. If it's been less than 30 days you are protected by ebay's warranty and don't have to pay shipping for returns. Say you hooked it up and it doesn't work.

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Erwin Owner/Technician
Barbados
Erwin
 

I contact the seller and they have already shipped a new one to me. They told me not to return it. All the fuses are intact. Here is what it does.

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Marti Owner/Technician
Michigan
Marti
 

I use this Black model also….very happy w the little use ive given it….however my 120V input cord is a bit different(straight plug). Glad to see the Mfr/Seller is taking care of U! Please post Results!

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Kelly Technician
California
Kelly
   

Yes, Ive blown the fuses twice on DC chargers. Once I wasnt looking carefully and reversed the terminals. Unit was not plugged in yet so Id think it wasnt mortal that way…but blew both fuses. 2 new blade fuses, back in service. The other was our maintainer at the trans shop. It was a small DC unit actually designed to put out 35 amps at car shows to keep the bosses car awake with radio and…

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Erwin Owner/Technician
Barbados
Erwin Update
 

The unit came set to 14.7 V in auto mode. Should I dial it down to 13.6 or so?

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