YM1802d-Electrical issue

[zorback]

Last year i had to replace the voltage regulator (melted down), when i did that i checked the output of the alternator. It was around 14 vac. Now my battery is low. Should i be able to disconnect the battery while the tractor is running and still have guages and lights etc? I also checked the voltage at the battery cables with them disconnected. Shouldn't there be 12 or so volts there for battery charging. Am i correct in thinking the voltage regulator is bad again?

 

[normde2001]

What was the charging voltage after you replaced the reg and what is it now, at about 1500rpm? How much voltage is in the battery, engine off?

 

[zorback]

Don't know, didn't check after regulator replacement. NOTE: I replaced the regulator almost a year ago. Battery voltage is fine. But with it disconnected from the machine i find no voltage on the battery leads, shouldn't there be charging voltage there? Also shouldn't the guages and lights be working?

 

[reb]

I wouldn't count on reading a voltage on the leads with the battery disconnected. Several years ago there was a thread here where one of the members posted a schematic diagram of the regulator in his (I think it was) 1610. As I recall after carefully analyzing the circuit (I was an electronic circuit designer in a previous life) I concluded the circuit required the battery to be connected to work. Your circuit might be the same.

If my memory serves correctly, the voltage from the dynamo (alternator) should be higher. I would recommend a search of this forum to verify that before replacing the regulator again.

 

[normde2001]

Don't know, didn't check after regulator replacement. NOTE: I replaced the regulator almost a year ago. Battery voltage is fine. But with it disconnected from the machine i find no voltage on the battery leads, shouldn't there be charging voltage there? Also shouldn't the guages and lights be working?

Couldn't tell you that. Never heard of anyone trying it. If battery voltage is fine, why do you think you have a problem? What is the charging voltage now at 1500rpm, and what is the battery voltage, engine off? No help without answers.

 

[zorback]

The battery voltage is 12.78 volts. Exactly what i have done is: Cecked the voltage at the battery connections with the tractor running 1500rpm and with the battery cables disconnected from the battery. There is a reading of "0vdc" there. Also with the battery disconnected there are no gauges operable or no lights.

 

[normde2001]

Too confusing for me:confused2:. You originally said "now my battery is low", now you are saying it is at 12.78 volts.

 

[clemsonfor]

The battery voltage is 12.78 volts. Exactly what i have done is: Cecked the voltage at the battery connections with the tractor running 1500rpm and with the battery cables disconnected from the battery. There is a reading of "0vdc" there. Also with the battery disconnected there are no gauges operable or no lights.

I'm pretty sure you need the battery connected to get any reading, it somehow will complete the circuit, at least thats my thinking. This is really easier than your making it.

Put the battery in your tractor, (unless its been on a charger, if it has wait 30 mins after you disconnect it), dont start tractor, now read the voltage with tractor off at the battery. If battery is good you should read around 12.6. Make sure your battery is good first, a bad battery can cause things to do funny things. Once you have the voltage even if its only like 12.4 it will still work.
Now start the tractor and let it idle then run it up to 1500rpms and after a min or so put your volt meter back to the battery posts. As long as your reading higher than the initial level your charging. Unless the battery was weak and drained while cranking you should see 13+ volts now on the battery if your charging correctly. If the battery is weak, give it 5 -10 mins at that 1500rpm and check it if your not seeing over 13rpm i would trouble shoot the battery again if you think it weak, but if you still dont have 13+ your charging system has a problem somewhere, either the reg or the alt.



Forget making up your own diagnostic tricks without batteries and dangling cables. The tractor will run forever without a battery and you will have all lights etc. You actually are supposed to run with the lights on if your running without a battery so that there is a load on the system since there is no battery to sink a charge to. At least i think i read that in one of the manuals at one point.

 

[Pete Judd]

Resting fully charged battery should be around 13.2 volts, charging can be up to 14.3 Volts without damage. But, lead-acid battery's will self discharge quick, so it is not uncommon to have one in the 12 volt range depending on age and condition, and temp.

 

[zorback]

You said that a tractor will run forevever without a battery, you are correct. You also said that one should run with lights on to load the system a little, you are correct. Only problem is like i said with the tractor running and battery disconnected i have no guages or lights. There is no output from the voltage reg and the alternator output is around 14vac. Is this the correct output for the alternator? Battery connected or not there should be voltage output from the reg, correct?