Worsedog
Well-known member
I have a Husqvarna 38" ride on mower I bought off the classifieds on the local dial-up internet provider about 20 years ago. It looked nearly new and the seller brought it to the house after I told him I was going to ride it home. It was probably a mile or so. I really don't much care for the yard work aspect of home ownership, but am far to cheap to pay someone else to do it. But by the same cheap token, I wasn't interested in spending what at the time was a ridiculous amount of money for a new one. Back then the department and box store clones that likely all came out of the same factory in different colors were right around $1K. It is an LTH120.
It's been relatively trouble free over the years. But the one thing that would never last was batteries. When they were $20, $10 a year wasn't too bad, but a U1 battery runs $30-120 depending on the chemistry and the name on it. Refer back to the cheap part above. So for the last four years, I just jump started it with the battery charger and had to deal with not shutting it off. After procrastinating far too long, I decided to address the problem. Something I should have done after the first two batteries was at least figure out why they didn't last. I just assumed that they weren't charging and when it started cranking slowly, just charged the battery. Turns out that was just making it worse. Turns out it was charging over 18v.
Looking at a wiring diagram the charging system was just one of three coils under the flywheel, one to run the ignition, one for the lights, such that they are. and the one to charge the battery. It also had a diode to rectify the coil output to DC. No regulation whatsoever, other than engine speed. At idle it still charged nearly 15v, but wound up to speed to turn the blades, well 18+ volts.
My neighbor gave me the old auxiliary battery from his Chrysler minivan. Not sure why he felt the need to change it, as it tested just over spec. Anyway, in the interest of getting maximum value from my free battery, I thought there must be some simple way to regulate the charging voltage. A bit of research showed that the higher line mowers had an actual voltage regulator. So I bought this Chinese special from Amazon.
Two wires, and the case must be grounded. After I received this one, I found there is one available that would have just plugged into the existing harness, but it was twice as much. Refer back to "cheap".
Because everyone like photos:
The mounting bolt is one of the ones that holds the starter solenoid in place, just had to use a longer one. Rather than counting on the mounting to provide the ground, I ran a wire to a chassis bolt that tested as good ground. Now it charges about 14.1v with the engine wound up.
It's been relatively trouble free over the years. But the one thing that would never last was batteries. When they were $20, $10 a year wasn't too bad, but a U1 battery runs $30-120 depending on the chemistry and the name on it. Refer back to the cheap part above. So for the last four years, I just jump started it with the battery charger and had to deal with not shutting it off. After procrastinating far too long, I decided to address the problem. Something I should have done after the first two batteries was at least figure out why they didn't last. I just assumed that they weren't charging and when it started cranking slowly, just charged the battery. Turns out that was just making it worse. Turns out it was charging over 18v.
Looking at a wiring diagram the charging system was just one of three coils under the flywheel, one to run the ignition, one for the lights, such that they are. and the one to charge the battery. It also had a diode to rectify the coil output to DC. No regulation whatsoever, other than engine speed. At idle it still charged nearly 15v, but wound up to speed to turn the blades, well 18+ volts.
My neighbor gave me the old auxiliary battery from his Chrysler minivan. Not sure why he felt the need to change it, as it tested just over spec. Anyway, in the interest of getting maximum value from my free battery, I thought there must be some simple way to regulate the charging voltage. A bit of research showed that the higher line mowers had an actual voltage regulator. So I bought this Chinese special from Amazon.
Amazon.com: KyuerWK Voltage Regulator Rectifier, 12V Voltage Regulator for Briggs Stratton Lawn Mower Engine, OEM #794360, 491546, 691188, 793360 : Automotive
Buy KyuerWK Voltage Regulator Rectifier, 12V Voltage Regulator for Briggs Stratton Lawn Mower Engine, OEM #794360, 491546, 691188, 793360: Rectifiers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Two wires, and the case must be grounded. After I received this one, I found there is one available that would have just plugged into the existing harness, but it was twice as much. Refer back to "cheap".
Because everyone like photos:
The mounting bolt is one of the ones that holds the starter solenoid in place, just had to use a longer one. Rather than counting on the mounting to provide the ground, I ran a wire to a chassis bolt that tested as good ground. Now it charges about 14.1v with the engine wound up.