Blake0090 6 #1 Posted April 21, 2017 How's everyone doing i am new here, I just picked up a 520h the gentle I got it from stated it stopped charging last year, the first thing I did was hooked up a fresh battery started it up and sure as heck it was not charging, I grabbed my multi meter and tested the voltage regulator it is putting out 13.6 volts. Checked the fuses I could find they are good, down under the battery are 3 relays, with a double orange wire feeding 2 of them, that wire is burned up pretty good, But I tested the wire and its not broken anywhere its getting current threwout, I will replace it but first thing first I need to get the charge going back to the battery like it should, I have not found a good charging system diagram to try and chase it any help would be greatly appreciated Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #2 Posted April 21, 2017 Welcome to the forum. The 520-H was made 1988-1997 and do not know if there were differences in the wiring. Garry 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #4 Posted April 22, 2017 Sounds like a bad voltage regulator 99% chance it's bad very common issue with the Onan, Jeff. 2 Share this post Link to post Share on other sites
cleat 4,984 #5 Posted April 22, 2017 If the voltage at the regulator is 13.6 and the battery is seeing less then yes, you have a break in the wire somewhere. The 88 & 89 models ran the charge wire from the regulator straight down to the starter motor battery cable through an in line 30A fuse. I have rewired all of mine that way. Gets the charge current out of the 9 pin connector. 1 Share this post Link to post Share on other sites
Ed Kennell 35,811 #6 Posted April 22, 2017 If it is an '88 or '89, check the 30 amp fuse at the front of the engine. The fuse may not be blown, but I have seen the legs of the fuse corroded away. so badly it will not carry the charging current. 2 Share this post Link to post Share on other sites
953 nut 51,737 #7 Posted April 22, 2017 I would add one more step to what Ed has suggested. You need to clean and tighten all electrical connections including grounds. Remove the voltage regulator and clean the connections including the mounting point to be sure it works properly. 2 Share this post Link to post Share on other sites
Blake0090 6 #8 Posted April 22, 2017 Will these operate like a car altenator where when the system is charging you can unhook the cables from the battery and it will stay running? Or will it die out wether its charging or not? Share this post Link to post Share on other sites
Kurt-NEPA 755 #9 Posted April 22, 2017 If you have 3 relays under the battery box you have a 1990 or later 520H. The 1988 and 1989 did not have these relays. 13.6 Volts at the regulator is about right at slow idle. It should come up to about 14.5 Volts at higher rpms. I assume you are not getting above 12.5 volts a the battery that is a sure sign of a bad connection or wire. The 520H regulators are prone to failure as these tractors age. They are cheap to replace (see Amazon) Good luck Share this post Link to post Share on other sites
953 nut 51,737 #10 Posted April 22, 2017 7 hours ago, Blake0090 said: Will these operate like a car altenator where when the system is charging you can unhook the cables from the battery and it will stay running? Or will it die out wether its charging or not? If you hve a magneto ignition system the engine doesn't care about voltage to run. Don't know if that would work, I think the regulator requires a 12 volt reference voltage. Give it a shot and let us know what happens. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #11 Posted April 22, 2017 Many tractors had a decal on them warning to not run without a battery connected. Garry Share this post Link to post Share on other sites
Cee245 754 #12 Posted April 23, 2017 Welcome to a great site for ALL Wheel Horse tractors! I agree with @WVHillbilly520H. I had a similar issue last year with my 416h and a few years ago on my dad's 416-8. Recently I ended up buying a parts tractor and I now have a spare. You can get them relatively cheap on ebay, less than $20. ~C 1 Share this post Link to post Share on other sites
cleat 4,984 #13 Posted April 23, 2017 The 520's Onan has a battery ignition that requires power to operate. There is a decal advising against operating without a battery. However, a bad connection in the charging circuit would in effect be the same thing. If you get more voltage at the regulator center terminal than what you see at the battery then the regulator may well be fine and you have a bad connection somewhere. If the regulator center terminal simply follows battery voltage of 12.5 or so volts or less as the battery slowly dies out then you need to verify the AC power feeding into the regulator. If you have good AC feeding the regulator and the regulator is properly grounded (at this point the tach should be reading as well) then the regulator is likely bad. Do these checks with the engine at high RPM where it's charge capacity is at it's greatest. Cleat 1 Share this post Link to post Share on other sites
bo dawg 477 #14 Posted April 23, 2017 I would replace R/R just so you know you have a new one. It just might be the problem. I had same issue on mine last week and it fixed it. Bought mine for $10 at emsglobaldirect from ebay 2 Share this post Link to post Share on other sites
Blake0090 6 #15 Posted April 23, 2017 Thanks everyone, I got the situation straightened out, it was a broken white wire at the regulator, to begin with, fixed that but had a bad battery I started it with a extra spare car battery I had laying around but when I would unhook the cables from the spare battery it would die out leading me to believe it was not charging. I purchased a new battery today it had 11.6volts in it when I put it in. Tested with a multi meter started it up ran it around the yard for about 45 mins and put it away tested battery again and it was at 12.7 after shutting it off. She's good to go for now. Broken wire and dead cell in battery which was 6 years old. 5 1 Share this post Link to post Share on other sites
6bg6ga 271 #16 Posted May 1, 2017 Did some testing with several Onan regulators on my bench. I fed it 17VAC off my variac to the AC terminals and 12VDC to the battery center terminal and it provided 14.6 VDC charge. Now, this is a no load situation but when you load the regulator you will find it will provide a full 14.6-14.7 at idle. The truth about the regulators for sale. I've seen new regulators for sale with Onan boxes and Onan part numbers and they are high priced. I've purchased several of the $10 ones off ebay and found the cheap ones charge the same as the expensive ones. I've tested a few on the bench and found they all output the same voltage and current. What I did notice is the cheaper ones were about .020 larger on one side than the stock regulator requiring a slight amount of filing to make it fit properly within the hole provided for its mounting. Share this post Link to post Share on other sites
Str8kustomz 10 #17 Posted July 15, 2020 On 4/21/2017 at 9:23 PM, WVHillbilly520H said: Sounds like a bad voltage regulator 99% chance it's bad very common issue with the Onan, Jeff. What replacement did you buy? Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #18 Posted July 16, 2020 18 hours ago, Str8kustomz said: What replacement did you buy? $10 unit from eBay. 1 Share this post Link to post Share on other sites
Horse Newbie 6,865 #19 Posted October 18, 2020 On 4/21/2017 at 9:28 PM, cleat said: If the voltage at the regulator is 13.6 and the battery is seeing less then yes, you have a break in the wire somewhere. The 88 & 89 models ran the charge wire from the regulator straight down to the starter motor battery cable through an in line 30A fuse. I have rewired all of mine that way. Gets the charge current out of the 9 pin connector. So if I rewired my 94 520h where the charger wire goes straight down to the starter I would just come from the B+ on the regulator down to the starter post that has the heavy cable from the battery ? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #20 Posted October 18, 2020 Yes but include a heavy duty 30 amp fuse holder and fuse in the wire. The original 30 amp fuse can be eliminated. 1st one 1988-89 520-H wiring 2nd one is 1994 Garry Share this post Link to post Share on other sites
Horse Newbie 6,865 #21 Posted October 18, 2020 9 hours ago, gwest_ca said: Yes but include a heavy duty 30 amp fuse holder and fuse in the wire. The original 30 amp fuse can be eliminated. 1st one 1988-89 520-H wiring 2nd one is 1994 Garry So this is it ? ...It helps me grasp it to draw it, and if you say this is it (see pic), then I am sure I know what to do now. Thank you Garry for taking the time to help us out ! Share this post Link to post Share on other sites
Horse Newbie 6,865 #22 Posted October 18, 2020 (edited) I may not run either the 30 amp charge wire or the 25 amp ignition circuit through the 9 pin connector. Sorry if I done wrong by jumping in on this thread...didn't mean to highjack. Thanks again for you alls help ! Tim Edited October 23, 2020 by Horse Newbie Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #23 Posted October 18, 2020 Your diagram is correct. Removing those two from the connector is not a bad idea. May save some grief later. Garry 1 Share this post Link to post Share on other sites
rick 216 #24 Posted October 20, 2020 Just a quick question here- is this problem only with 520 tractors? I have a 416 tractor with no discoloration of the nine pin connector, yet. I did have some yucky fuses that I replaced and cleaned up the block. PO never blew the tractor or engine off after use, I think. Share this post Link to post Share on other sites
Horse Newbie 6,865 #25 Posted October 20, 2020 (edited) 47 minutes ago, rick said: Just a quick question here- is this problem only with 520 tractors? I have a 416 tractor with no discoloration of the nine pin connector, yet. I did have some yucky fuses that I replaced and cleaned up the block. PO never blew the tractor or engine off after use, I think. It seems to be a problem with the 9 pin connector and I don't know if 520h' s is the only tractors that had the 9 pin connectors. I plan on altering my 1994 slightly by running a 12 gauge wire from the B+ on the regulator straight to the starter post where the battery cable hooks up, protected by a 30 amp fuse in a weather tight inline fuse. I also am going to run the 25 amp wire from the same post up through a 25 weather tight inline fuse to B on the ignition switch.Thus eliminating both the 30 and 25 amp circuits from my 9 pin connector. The only fuse I would have in the fuse block would be the 15 amp, but actually I'll probably put it in a weather proof inline fuse holder too eliminating the fuse block all together. Edited October 20, 2020 by Horse Newbie Share this post Link to post Share on other sites