g0uihsteve
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- Sep 4, 2020
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Hi from Steve.
I’ve owned an MTD J/136 ride-on lawn tractor for a few years. About 2 years ago the battery went bad so I replaced it. During this current season, again I noticed the battery wasn’t in very good condition. It didn’t hold the charge until a few days ago gave up the ghost.
Thinking the charging circuit could be at fault, I investigated further. This particular Briggs and Stratton engine is a 13hp Intek with a dual circuit charging system. I’m familiar with electronics and electrical apparatus and am comfortable working in this environment so measured the output from the alternator.
There are 2 output wires on this setup, one is AC which runs the tractor lights, that shows a nice 14v AC under load dropping to around 11.5v on tick-over so all ok there, however the DC line includes a pretty crude rectifier diode affair [presumably to convert AC to DC] on the 12v line to the battery.
It looks like a 1N5408 from the various online info I have which is a 3A 1000v standard rectifier so nothing special. I have 100’s in the workshop.
Putting the DMM on the output shows 12.9v on tick-over, but 16.7v under load. In my book this is a recipe to wreck a battery pretty fast. If it was around 14.8v then I’d be looking elsewhere for the problem.
The current output is fine at 2.6A. Suppose I have a choice here. I could build a properly regulated output which would be fairly easy or the dirty method would be to use more than one diode in series to drop the voltage as each rectifier will drop the volts by 0.7v – to get more in the right area.
I have a bunch of 10 amp 1000v rectifiers [10A10] that would suit – rather overkill though.
My question is – does anyone have any info on what the [correct] charging output voltage is expected to be on this setup. Personally, I think anything over 15v could potentially shorten the battery life fairly quickly.
Best - Steve
I’ve owned an MTD J/136 ride-on lawn tractor for a few years. About 2 years ago the battery went bad so I replaced it. During this current season, again I noticed the battery wasn’t in very good condition. It didn’t hold the charge until a few days ago gave up the ghost.
Thinking the charging circuit could be at fault, I investigated further. This particular Briggs and Stratton engine is a 13hp Intek with a dual circuit charging system. I’m familiar with electronics and electrical apparatus and am comfortable working in this environment so measured the output from the alternator.
There are 2 output wires on this setup, one is AC which runs the tractor lights, that shows a nice 14v AC under load dropping to around 11.5v on tick-over so all ok there, however the DC line includes a pretty crude rectifier diode affair [presumably to convert AC to DC] on the 12v line to the battery.
It looks like a 1N5408 from the various online info I have which is a 3A 1000v standard rectifier so nothing special. I have 100’s in the workshop.
Putting the DMM on the output shows 12.9v on tick-over, but 16.7v under load. In my book this is a recipe to wreck a battery pretty fast. If it was around 14.8v then I’d be looking elsewhere for the problem.
The current output is fine at 2.6A. Suppose I have a choice here. I could build a properly regulated output which would be fairly easy or the dirty method would be to use more than one diode in series to drop the voltage as each rectifier will drop the volts by 0.7v – to get more in the right area.
I have a bunch of 10 amp 1000v rectifiers [10A10] that would suit – rather overkill though.
My question is – does anyone have any info on what the [correct] charging output voltage is expected to be on this setup. Personally, I think anything over 15v could potentially shorten the battery life fairly quickly.
Best - Steve