520H overcharging

[Jeff K 0]

My 520H seems to be overcharging to 17 18 vdc. I am thinking that it must be the Regulator to build more voltage than the apx 14 vdc normal. Any ideas to check and I looked on Parts tree and the regulator is not avalible according to the site. Thanks Jeff

[Save Old Iron 1,571]

Jeff,

your right on track but do not condemn the regulator assembly too soon.

Loss of a good ground to the regulator case (finned aluminum) can cause a loss of regulator function.

For a quick check on the grounding issue, run a jumper wire with alligator clips on both ends from the regulator case directly to the battery negative terminal.

If the voltage settles in at less than 15 volts, you found the problem. From there, remove the regulator from the chassis and clean the reg / chassis area of rust or paint to re-establish a good chassis ground.

[Save Old Iron 1,571]

Check this out also

http://www.wheelhorseforum.com/index.php?...t=0entry92850

plenty of stuff here about regulator performance issues.

[rmaynard 16,218]

:ychain: Jeff. Here's another thread on over-voltage. It confirms the theory that a bad ground (corrosion under the regulator) can cause the problem you are experiencing:

http://www.wheelhorseforum.com/index.php?...95&hl=regulator

Bob

[sorekiwi 761]

If in fact you do need a regulator, this is about the cheapest I have found:

http://www.amazon.com/Lawn-Mower-Part-Regu...7/dp/B001OK9YRU

I've had 2 dead Onan Regulators, and they didnt charge at all.

[Jeff K 0]

Update I did this last weekend have the chance to double check the ground on the regulator. I had already removed and cleaned it so this time I did just run a clip jumper from the battery negative to the regulator and the voltage stayed at 17 to 18 vdc. I assume the regulator is bad and have ordered one online. I will keep you posted and thanks for all the help. Jeff

[Jeff K 0]

Update again, I got the new voltage regulator and installed it last night and the voltage was at about 3000 rpu 15.4 vdc. This seemed a little high to me so I measured the ac portion and it was around 45 vac. Do these voltages seem ok or is this some other issue I need to dig for? Thanks Jeff

[Save Old Iron 1,571]

two other questions,

does the output voltage of 15.4 DC stay at 15.4 if you raise the engine RPM's to 3600?

it should.

is the battery in a fully charged state when you are measuring the 15.4 ?

a sulfated battery or battery with a low charge may be allowing the regulator to "open up" with a little higher charge voltage to help charge the battery a little quicker - some of the newer style regulators are known to do that. As soon as the battery voltage approaches a full charge state, the regulator voltage may start to taper off to a more "normal" 14.6 DC and stay there.

Again, I can't emphasize enough how important a clean ground is to proper voltage regulation. 520's can be a nightmare with electrical issues. Try the direct jumper wire once again. Attach the jumper from the reg case directly back to the battery negative terminal.

Keep us updated.

[W9JAB 156]

45vac sounds high to me I would

think you should see more like 22-28vac :ychain:

[Save Old Iron 1,571]

45vac sounds high to me I would

think you should see more like 22-28vac

thought so too,

but I have seen a C160 with near 40VAC at full throttle.

measured with a Simpson 260 and not confirmed with any other meter.

AC measurements have A LOT TO DO with the multimeter itself and if its reads average. true RMS, etc.

the readings can vary wildly from one style meter to the next.

Maybe a good idea to measure the household wall outlet and confirm your meter is operating correctly. (only if you feel comfortable doing so - no fingers touching the meter lead metal points)

an indication of 115 - 120 VAC would confirm the meter is most likely accurate and reading RMS voltage.

Measure the battery voltage in your car with the car running. You should see 14.something volts DC. This is a good check of the DC reading accuracy of the meter.

[Jeff K 0]

Update; I did have a discharged battery when I first took my voltage readings. I have since charged the battery and rechecked the voltage readings and they have leveled off at 15.2 vdc and to answer the question the 15.2 stays steady from 2500 rpm to 3600 rpm and without lights, and turn on lights it stays about the same. I did check the AC and it fluctuates from 25 vac at about 2500 to 45 vac at 3600 and the dc stays steady so I think the regulator is working? I dont know what else to check and I will keep my eye on the voltage to see if it changes more.

Thanks for the support

JEff

[Save Old Iron 1,571]

Hmmmmmm....

well the regulator is a regulatin' as the output stays constant when the input is changing.

other than claiming the regulator set point to be "suspicious", I would again have you attempt to connect a ground wire DIRECTLY from the regulator mounting screws to the battery negative terminal to see if the voltage dropped somewhere in the 14.something range.

This drop may take a few minutes as the battery will probably have developed a little overcharge already. Run the tractor at idle with the headlights on and see what voltage is seen across the battery terminals.

Just as a sanity check, you are reading the 15.2 across the battery with a multimeter correct ? this is not an interpretation off the dashboard voltage gauge ?

:ychain:

[Martin 2,133]

If in fact you do need a regulator, this is about the cheapest I have found:

http://www.amazon.com/Lawn-Mower-Part-Regu...7/dp/B001OK9YRU

I've had 2 dead Onan Regulators, and they didnt charge at all.

 

just an update to this thread if somebody is looking for a replacement regulator, here is another one from amazon, took a gamble and so far its doing what its supposed to.......

 

Made in Taiwan sold by DB electrical.

 

http://www.amazon.com/dp/B0081S8PD2/ref=pe_385040_128020140_TE_3p_dp_1

 

$17.80 + free ship.

Edited February 11, 2015 by Martin

[MAH 50]

A bad cell in the battery can cause over charge voltage. Doesn't happen often but can happen. The other question is are you taking the readings directly after startup. If so let the tractor idle for a dew.minutes and recheck. I still wouldn't expect more than 14.5 give or take, my 518 charges at 14.4 all out and my dads 520 14.8. Nif i let them run off idle for a few minutes without lights the voltage usually settles 12.8. Check your connections are clean, grounds good. I'd be interested in the battery voltage reading on the battery terminal of the regulator (center wire) with and without the tractor running compared to voltage readings at the battery.