MEP 002A BATTERY CHARGER QUESTION

[Jimbow]

I've looked in the manual and thru numerous posts but can't find the answer to this question. In the battery charger circuit, what is the value of the fuse. How many amps?

Mine wasn't charging so I checked and the fuse is blown. Going to start by replacing it with a circuit breaker. The fuse that came out was 15 A but I'm not sure it's correct.

 

[Chainbreaker]

Yes, the fuse is 15 amp 32 VDC (FO2A32V15A), it's called out as item #15 on printed page 122 of the -24P parts manual. If its blowing 15-amp fuses there is a problem that needs to be addressed. I would not replace a fuse with circuit breaker.

Need to determine what is causing fuse to blow & address that problem.

 

[Tinstar]

These things vibrate a LOT, so I would check to see if you might have wire chaffing issues.
I found one wire on mine in the control panel that was chaffing badly and caught it and fixed it before an issue appeared.
I would not recommend a circuit breaker. The charging system was not designed for one and replacing fried parts is expensive and some parts are difficult to find.

Like mentioned in the above post, figure out the "why" before changing anything.

 

[Jimbow]

You guys are of course right. Besides the circuit breaker I bought was 12V. I forgot about the voltage aspect. Went back and got a new fuse holder and started checking things out. The alternator windings are not open but when I check each lead to ground I get a Meg Ohm reading and I don't understand why. I also checked each terminal board screw to ground and get the same thing. I'm beginning to think it's a meter problem. I see by the wiring diagram there is also a resistor and capacitor, both to ground. Does it make sense to replace them just because.
It also looks like the yellow wire in the photos is the wire to the battery. It loops across the generator and ties into the starter solenoid with the hot lead to the battery which makes sense and jives with the wiring diagram.

now I just have to find fuses. . The one that came out of it was 15 A 32V.

 

[Triple Jim]

If the capacitor on the barrier strip is shorted it would be shorting the 24v battery to ground, which wouldn't continue for long! It's just for radio noise suppression though, so you can take if out if noise isn't a concern.

The fact that your fuse blew most likely means that the regulator failed and tried to short the 24v battery to ground. While you're looking for a replacement regulator, you can use a 24v battery charger connected to the main generator output, or even wire one in permanently.

Usually the cause of megohm readings when you expect no continuity is dirt and moisture. That's not usually a concern for voltages like 24 VDC. One megohm conducts only 24 microamps, which is so little it can be considered to be zero.

 

[Jimbow]

If the capacitor on the barrier strip is shorted it would be shorting the 24v battery to ground, which wouldn't continue for long! It's just for radio noise suppression though, so you can take if out if noise isn't a concern.

The fact that your fuse blew most likely means that the regulator failed and tried to short the 24v battery to ground. While you're looking for a replacement regulator, you can use a 24v battery charger connected to the main generator output, or even wire one in permanently.

Usually the cause of megohm readings when you expect no continuity is dirt and moisture. That's not usually a concern for voltages like 24 VDC. One megohm conducts only 24 microamps, which is so little it can be considered to be zero.

put a new fuse holder and fuse in.

Started the gen set and measured the AC voltage at the regulator from the stator. Got 25 or so vAC. Checked the fuse...not blown.

Shut the gen set down, disconnected the stator from the regulator, started the gen set back up and measured 55vAC at the stator leads. Again fuse not blown.

Checked the voltage, gen set not running, at the regulator output to the batteries to ground, got 25 or so vDC. Batteries are new.

 

[Triple Jim]

What's the DC voltage at the output of the regulator with the engine running? Keep in mind that the regulator output is only about 7 amps, so it can take quite a bit of time to bring the battery up to 26+ volts.

It's possible that a dirty fuse holder or other problem caused the fuse to get hot, so it blew even though nothing else is wrong.

 

[Guyfang]

So run it 2 hours and see if all is good.

 

[Jimbow]

What's the DC voltage at the output of the regulator with the engine running? Keep in mind that the regulator output is only about 7 amps, so it can take quite a bit of time to bring the battery up to 26+ volts.

It's possible that a dirty fuse holder or other problem caused the fuse to get hot, so it blew even though nothing else is wrong.

With it running I measured a little over 25 vDC at the output of the regulator( terminal strip) to ground and across the batteries got the same reading.

 

[Triple Jim]

After a couple hours it will probably come up to 26+ volts, but you should verify that if you want to be sure the charging system is working.

 

[Jimbow]

After a couple hours it will probably come up to 26+ volts, but you should verify that if you want to be sure the charging system is working.

I'll try that. Maybe the only thing wrong was the blown fuse.

 

[Jimbow]

I'll try that. Maybe the only thing wrong was the blown fuse.

Thought you guys would like a status. Looks like the fuse/fuse holder was the only problem. After putting the blower housing back on so I could run it longer I started it today. Non running voltage across the batteries 25.47 vDC. After running for about ten minutes measured 26.98 vDC and climbing slowly. The gage on the panel was just barely below the green. It's never been that high. The batteries I was using were almost fully charged. I think it's fixed. I want to thank you guys for the help.