Hi Swordman, gee that sounds like a great idea :wink:
Ok, I used a MY1020 Unite, whatever batteries I had lying around (3 x 7Ah and 3 x 12Ah strung in a series string of parallel pairs for 36V 19Ah) and a switch and 30A automotive relay. The hardest part is coupling the motor to your newly fabricated drive shaft for the blades. The method I used is crude but effective. I also considered using a standard 3/8" drive socket universal if this one didn't work. Dom posted links to industrial drive couplings that would also have worked but I don't have either the links or Dom's contact details.
I never bothered to note run time until last time I mowed the lawn. It was overgrown (as usual) and wet in patches to really work the mower over. I use a grasscatcher so had to stop and empty that at least 6 times, total time to mow was over an hour. Obviously the mower wasn't running 100% of that time, but near enough. It still had plenty of go, though I don't have any metering on it so I was only going on performance.
Photo #1: Fabricated top adapter plate, upper bearing housing and motor mounts
Photo #2: Fabricated lower adaper plate, bearing housing (recycled though in hindsight it would have been quicker to machine one up from scratch), and new driveshaft. The driveshaft is an old motorcycle front axle I had lying around which happened to also fit some old bearings I had lying around. I shortened it and drilled and tapped the end to take a bolt
Photo #3: Made a spacer and an adapter for the base plate to fit on. There's another spacer which you can't see that goes in between the upper and lower bearings. Otherwise when I tightened the base plate bolt it would try and crush the upper and lower bearings together and under load they would fail quickly
Photo #4: I reused the original baseplate from the ICE because that made the most sense. I can use standard replacement blades and the cutting width is the same as original.
Photo #5: Here you can see the top of the drive shaft. It has a shoulder on it so it doesn't fall through, and with the spacers it takes the load when the base plate bolt is tightened so that the bearings don't have any undue load on them.
The two pins are welded to a piece of bar which fits inside the end of the driveshaft and is secured with the split pin.
The plate with two holes in it is probably secured to the motor shaft with a grub screw since the motor has a convienient flat on the shaft. I don't recall for sure, but that's how I normally do it.
The end of the drive shaft has two flats on it so that I can attach a spanner to tighten the base plate bolt.
Photo #6: The motor is mounted and ready to run.
Photo #7: Ready for a test run. It's charging using my 12V 1.6A smart charger. I switch from parallel for charging to series for power using 7 pin trailer plugs, at 1.6A it normally takes about 24hrs to recharge 57Ah (7Ah+12Ah = 19Ahx3 = 12V 57Ah) but since I have enough capacity in series (36V 19Ah) to mow the lawn it's not an issue. I just leave it on the charger until it's time to use it.
Photo #8: Dirty deeds, done dirt cheap. I spent another hour or two securing all the batteries properly and putting the finishing touches on the wiring but that's pretty much how the finished product looks.
I melted the first relay I used but I just replaced it with another 12V 30A one and haven't had any problems. There is one 30A fuse in the system which I haven't blown as yet. A couple of times the mower has nearly stalled on a hidden stick or rock but since it was towards the end of the mowing I assume the batteries can put out enough current to blow it.
The motor gets quite hot, last time after working hard in the hot sun it was hot enough that you could touch it but not leave your hand there, but as yet (maybe 1/2 a dozen uses, maybe more? I'm not keeping count) no problems.
Any questions, fire away!