ym 240 battery keeps draining

[bassfishrman]

My battery on my ym240 will not stay charged. It is only 1 yr old and I had it checked today by Autozone. They said the battery is fine.

I can charge it overnight and it'll crank fine the next morning, but if i let it sit for 2 or 3 days, it will barely turn the engine over. The guy at autozone said something is draining it when not in use and I should unhook the negative cable to keep it from draining. First of all, I don't want to have to unhook the cable everytime i get off the tractor, and second of all, I would rather find out what is draining the battery. I always take the key out,, so I know that I am not leaving the key in the on position.

Any suggestions on what could be causing the battery to drain would be appreciated.

 

[mark777]

If I may make a suggestion? See (first) if your charging system is working. If the battery is charged I would check the input DC voltage with VOM from you battery leads while the tractor is running slightly above idle. If you get 13+volts than your charging system is good, if not then I would start with all the heavy connections and grounds. It could be your voltage regulator/current limiter if nothing else works...

Hope this helps.

Mark

 

[Mickey_Fx]

I think the only way your going to find the source of the problem is to get a VOM out and do some detective work.

I think the first thing I'd check is to see if it is possible one or more of the rectifiers in the VR have failed and are permitting current leakage. One way to test is to put the VOM on the battery with engine running above idle, check voltage D.C. (you should see close to 14V) and then would do same with meter set on A.C. If you see any voltage on A.C. setting, that would be a good indicator a rectifier is shot.

 

[bassfishrman]

I just checked the voltage with a meter.

With engine off, the battery is showing 12.38 volts
With engine slightly above idle speed it is showing 12.36 volts

Can I assume my charging system isn't working properly?

 

[mark777]

Yep, afraid so. And like Mickey said, if your VOM (set on AC) indicates any AC bleed than your Voltage regulator is bad.

Mark

 

[Jagmandave]

Hate to sound silly, but is you fan belt on, and tight?

 

[bassfishrman]

ac voltage registers 30 volts.....must be voltage regulator


thanks for the tips guys!

can anybody tell me where the voltage regulator is located on my ym240?

 

[SailorBob]

I suspect it is in the same place as my 1700. under the dash mounted on what would be the firewall on a car. A square black box about 3" X 4". You can follow the wires coming off the altenator to find it if it is different

 

[Mickey_Fx]

</font><font color="blue" class="small">( I just checked the voltage with a meter.

With engine off, the battery is showing 12.38 volts
With engine slightly above idle speed it is showing 12.36 volts )</font>

A fully charged 12v lead acid battery will read 12.7v after it has set about 4-6 hrs with no current flow in either direction.

Either your VR is shot or there is a bad wire someplace. I would spend a little time looking for a bad wire before replacing the VR. The place to begin is at the connector at the VR. If it's a bad connection or wire, it will still be there after the VR is replaced. Better to know beforehand.

 

[YanmarFever]

take a half an hour & trace all the wires specially from the rear lights forward looking for bare wires worn plastic ect.
Also check under the dash for mice pellets & nests, mice love to chew wires in the winter time
I find that usually thats where my problem lays half the time.

 

[kenmac]

good way to check to see if you have a short somewhere is to , take the pos. cable off the batt. then touch the pos. cable to the battery as if you were going to connect it to the battery . if you get a small or large arc is a good indication that you have a short somewhere.

 

[ym2610]

You can also check for a open circuit or short by taking the battery cable off (can't remember positive or negative) I think negative, use a test light between the post and the cable, if it lights up with the {switch off}, you have a open circuit or short, if it don't light up, you don't have a open circuit, to test this, if you don't have a short, leave it hooked up and turn on the switch, it will light up. hope this helps someone. be careful if you take the cable loose with it running or not, a battery can blow up with a spark, it will work like he said, just be careful, wear safety glasses or face shield God only gives us one set of eyes, but thats just my opinion. good luck........Robert

 

[Keoke]

Bassfisherman, if you are showing 30 AC volts at battery then most likely the rectifier diodes are fused and acting as a solid pieces of wire. The 30 volts are peak to peak (full wave) AC or 15 plus to 15 negative coming from the alternator.
On small alternators these diodes are usually built into voltage regulator. Follow wires from alternator to find the VR unit.
These diodes usually get fused when the battery is installed backwards electrically, or when one applies a battery boost for starting in reverse polarity.
These fused diodes will also drain the battery since you now have a direct connection between the battery and alternator to ground when engine is off.

cheers,

 

[djg]

All sorts of info in the parts repair forum, troubleshooting charging system.

 

[normde2001]

Depending on where you are reading the 30vac, you may, (probably), have a bad rectifier, (inside the alternator on the YM240). the voltage is rectified to dc inside the alternator, (ac generator), and sent to the regulator where it is reduced to 13.5-14.5vdc. If you need either part, it is said that a '72 Datsun 510, (Nissan), uses the same parts, for a small % of Yanmar prices.