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Aussie

520H drains battery

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Aussie

I have a problem with my 520H. The last time I used it about a month ago it started and ran fine. Then I went to start it this week and the battery was dead flat. The battery is good and the tractor was parked with the ignition off and key removed. I put in another battery and it started straight up and ran fine. However, it wasn't charging with the volts gauge showing 11. I mowed for a couple of hours but the gauge didn't move, although the tractor ran fine. I haven't had any trouble with the gauge before and it usually reads around 13v when working.

I am clueless when it comes to electrical and am unsure what would cause the battery to completely discharge when parked, seems to be a short somewhere? I checked the fuses and all appear ok.

Any help greatly appreciated.

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rmaynard

Since they are fairly inexpensive, I would try replacing the voltage regulator.

$_35.jpg 

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Kurt-NEPA

I'm thinking you cooked a voltage regulator too.  I would replace it and see what happens.  It is located on the top of the engine toward the rear and bolted onto the sheet metal shroud.  Three connectors.  Center has a red wire, rear has two wires (black and gray) and front has a black wire.

 

Shop around for price, they vary widely.  Best price I found was on Amazon.

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squonk

Good chance a cooked reg would not only not charge the bat but discharge it when off.

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DougC

I gotta jump on the voltage regulator band wagon myself. I've had them fail and overcharge and ruin the battery and I've had them fail and not charge the battery. I bought my last one for less than twenty dollars American on either amazon or e-bay I can't remember which.

 

Now I will tell you that when you replace the voltage regulator if you don't hang on to it when you remove the bolt it will fall down into the engine shroud, bounce off the oil filter and find a nice terribly hard to get to spot. The sudden shock of that happening will cause you to also drop the bolt.............

 

After the swearing has taken place you need to figure out how to go fishing and get them out of there without removing the engine shroud......

After extracting the dropped regulator and bolt and installing the new regulator you will have a feeling of U 4 E UH. (can't spell it....) when you start it up and see the volt meter register 14V. after it runs for about ten seconds.  :)

Let us know how it goes and pictures are always welcome.  Remember to pick up all the empty beer cans before you take any pictures as this is a family forum....:lol:

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Cable

Yes on the voltage regulator.  One thing about the 520's electrical, they are never truly turned off, Even with the ignition switch in the off position there is a path for current to flow from the voltage regulator to the battery.  That is why a defective regulator can discharge a healthy battery. 

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wrightorchid

Is there one that is better than the another?  I think mine is doing the same thing.

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Cable

I assume you mean is one voltage regulator better than another?  Not in my experience.

 

If you look on the inside of the hood stand, there is a warning to not run the tractor without a battery installed.  A defect in either the 9-pin connector or fuse block creates an open circuit where the battery is not connected to the regulator.  It may be an intermittent open.   I have been asked to repair a lot of these connectors and fuse blocks.  The problem sometimes presents with a bad regulator that the owner didn't know was bad.  For some reason, the Onan regulators are a fairly high mortality item.

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Aussie

Just an update;

 

I couldn't get a voltage regulator locally so ordered one online. In the meantime I took a used one out of a spare Onan and fitted that. It didn't make any difference, still not charging. I looked at the information from Professor SOI that Digger66 provided the link to above. I checked the voltage at the B+ terminal and it was the same as battery voltage, so all ok there. Then went to start the engine to check the output voltage - wouldn't turn over. The dash lights came on with the key, but in start position they went out and nothing. Gave up and went fishing as suggested by DougC.

 

Late last week the new RR arrived. Yesterday I checked the fuse block, no signs of any overheating or corrosion in the wiring, all looked good but I replaced all three fuses. Then I checked the the 9 pin connector, all looked like new - no overheating or corrosion at all. Next I cleaned the battery terminals and leads and gave them all a dressing with a file. After that I fitted the new RR with an earth lead from the mounting bolt to the frame. Cleaned up the wiring terminals that fit on the RR. Tractor started right up and is charging - hooray!

 

I was going to mow today but the wind has been blowing like mad all day. Not sure what the problem was, although the second RR may have also been fried, I haven't ever run the engine it came off. The first one certainly looked suspect when I removed it, the resin had delaminated from the body. Not sure what caused it to not turn over but suspect it may have been due to a bad earth. Nothing obviously wrong with any of the wiring, the tractor has only done 200 hours and always been kept inside and the harness looks near new. All appears to be okay now, thank you to all who responded, and especially the Professor for his clear, easy to follow diagrams and explanations.

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