DieHard Battery Charger quit working....

[tlmartin84]

For starters this is my grandfathers charger, so I don't know if he reversed the leads or he did something else to affect it. Or maybe it just quit....

Regardless though, it will not work.

When I plug it in, it hums but there is nothing on the meter, nor is there any voltage shown across the leads when checked with a multimeter. I assumed a fuse had blown, but when I pulled the cover, both fuses are intact. Any ideas on where to start looking? Or should we just toss it?

 

[tester19]

With some battery chargers they need a load before they put out any amps. Maybe try hooking it to a battery as your meter will not provide a load.

Something to try before throwing it away.
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[Rinspeed]

I agree with it needing a load so hook it up to a battery and recheck it.

 

[dogdog]

Do you have the picture of it with the cover off ?

 

[Rinspeed]

I just noticed it has a switch for AGM so it can't be that old. Mine has a switch for 6V or 12V.

 

[zendriver]

I have one like that except it's maint free/deep cycle.

The "50 amp" setting is slightly better than useless, but the 10 and two work all right and the green light comes when fully charged.

Agree try it on a real battery.

 

[Mr_B]

no voltage on leads would indicate something wrong .
needs lid removed for visual inspection of transformer windings and diode board & if no visual clues then meter readings of diode output, transformer inputs/outputs and diode testing if transformer outputting to the diode bridge .
If it have electronic board charge control sensing then things get more of a pain repair simply .

 

[rooster59]

googleize your model # and “pdf”. Hopefully it’s just a bad circuit breaker. This might help-

https://c.searspartsdirect.com/mmh/lis_pdf/OWNM/L0305322.pdf

 

[Desertskyy]

I have the exact same battery charger.

As has been said I think you need a load on it. I hardly use mine anymore but I have never had any issues. I used it a lot more when I had a house in Idaho as the winters could be difficult on car batteries

I think it is also circuit protected so throw a weak battery on it to see what happens

I am sure I also have the original owners manual around if that would be some help.

Don't throw it away before thoroughly checking it out

 

[laser3kw]

Don't throw it away before thoroughly checking it out

Haha - half (or more) of my shelf space is filled(!) with "don't throw it away till...."
I'm a scrounge that always thinks there is something valuable to save. But then shows like American pickers makes it worse...

 

[tlmartin84]

no voltage on leads would indicate something wrong .
needs lid removed for visual inspection of transformer windings and diode board & if no visual clues then meter readings of diode output, transformer inputs/outputs and diode testing if transformer outputting to the diode bridge .
If it have electronic board charge control sensing then things get more of a pain repair simply .

It was tried on two batteries, one which was dead, the other which was fine...still nothing.

I did open it up, checked both fuses, both are fine. There is no sign of burns, etc on any of the boards.

It does produce a humm when plugged in.

Unfortunately yes it is an automatic charger, I am going to troubleshoot it a bit more as it maybe in a switch. But I think it is not sensing the load and kicking it on.

 

[Mr_B]

^
You may possibly be able to bypass the automatic control and get it working old school manual mode .
Some models had a switch between automatic and manual mode .
exactly what can do easily will depend how modular it is internally, so if the electronic control pretty much seperatly packaged will be easy remove it, if integrated all in with diode bridge then can be a pain, some of these low end chargers also only half rectified .
Googling user manuals could help on circuit layouts and expect few youtube vids on these chargers, probably few brands that same layout/guts .

 

[laser3kw]

picture of the inside?
Check the input side of the transformer for line voltage, the the output side for around 17 volts AC. If you can trace it through, it will go through either a pair of diodes or four diodes (or an IC diode bridge package). After that it will be DC voltage. With a 50 amp boost feature, there may be two sets of diodes, on set smaller for normal charging and a larger pair for boosting.

 

[dogdog]

It was tried on two batteries, one which was dead, the other which was fine...still nothing.

I did open it up, checked both fuses, both are fine. There is no sign of burns, etc on any of the boards.

It does produce a humm when plugged in.

Unfortunately yes it is an automatic charger, I am going to troubleshoot it a bit more as it maybe in a switch. But I think it is not sensing the load and kicking it on.

Trouble shooting is fairly simple right ?
Not sure what two fuse you checked. There should be only one there according to the manual. and it's labeled as Circuit Breaker. which is an automatic reset breaker @35Amp according to that manual in the parts diagram....

It looks like it's a multitap input transformer (if that is what they are called) and 3 wire output transformer ( center tap) usually for chargers it's 28Vac (in this case 14,15 in that diagram) on two of the leads, and 14vac on the others (14-17 and 15-17). 17 would be your ground negative. Verify the transformer output, hums on transformer is most likely fine. but you have to verify the output.

Verify the CB for continuity which is 7 on the diagram,,, it's the first thinggy magiggy on the negative output cable it connects to.

and verify the two diodes which is the 913 where the two transformer output (14, 15) connects to Typical center tap full bridge rectifier is 2 diodes.
and verify continunity or ohm on the meter. since this is a shunt type meter,, it would have a constance ohm to read the amp draws. if it fails at 267 in that parts diagram, it will fail to provide negative to the charger.

(PDF) SEARS Battery Charger 28.71222 - DOKUMEN.TIPS

OWNER'S MANUAL DieHard, BATTERY CHARGER 10/2 Amp Automatic ENGINE START 50 Amp Model No. 200.71222 CAUTION: Read all Safety Rules and Operating Instructions, and follow…

dokumen.tips

good luck, it looks the same as any other HF or Schumacher chargers of that time period. most failure are that CB though.

 

[jonesg]

toss it already.

 

[ChevyEFI]

To add to the discussion, what do does AGM selection settings generally do?

My last battery replacement was an AGM. O'Reilly said it was good. I was able to charge it overnight at home and it worked. The machine test at Sam's said it had 78 of 600 original CCA -goner. In the middle of that, I learned how to get an alt. out the top of a 2.4 Hyun/Kia eng. bay. And out the bottom. Wasn't the alt. lol

 

[mfewtrail]

Before you toss it, check the wiring where it's crimped at the clamps. I used to have one like this and the wire failed at both clamps. If I recall correctly, the wires broke because they were improperly secured to the clamps to begin with.

 

[Vvmvbb]

It‘s cool but today’s smart battery chargers are SOOOO much better in so many ways that I wouldn’t spend too much time on it

 

[fourjeepin]

It‘s cool but today’s smart battery chargers are SOOOO much better in so many ways that I wouldn’t spend too much time on it

I had one similar to the OP but it died a couple of years ago. The new smart one is great unless the battery is really dead, then it is a pita.

 

[Vvmvbb]

I had one similar to the OP but it died a couple of years ago. The new smart one is great unless the battery is really dead, then it is a pita.

The noco genius 10 will charge batteries from as low as 1V. Down to 0V in ‘force mode’.

 

[fourjeepin]

The noco genius 10 will charge batteries from as low as 1V. Down to 0V in ‘force mode’.

Good to know. I bought the NOCO GB40 about a month ago. It is great but won’t charge or work at that low of volts