It seems as though its time for my yearly update on the mower. I just replaced another battery last night. I'm now running all newer batteries. When I first got the mower put together I ran 3 group 31 batteries rated at 150 Ah (20hr rating). Then, I added another battery for more capacity, longer run times, and to lower the amp draw on the batteries. I toasted a few of those batteries due mainly to neglect over the years. When I originally purchased those batteries they were $95 a piece. Over the years, the price rose to around $150. So, I started searching around. The local Menards (big box home improvement store in the midwest) had deep cycle batteries for a great price. But, they didn't stock group 31 batteries and I didn't bother trying to bug them to get them in either. I just grabbed their group 27 battery on the shelf and gave it a go. Well, I just replaced the last group 31 battery last night with a group 27. These newer batteries are only rated for 105 Ah (20hr rating), but they get the job done just fine. I've since started to mow my yards in smaller sections between recharges to be kinder to the batteries anyways and these handle the smaller sections great.
These are the batteries I'm using now.
The mower does need a bit of work though, and I hope I get to it this year. The bearings in one of the mowing deck shafts are shot and making a good amount of noise. However, the shaft is also pretty shot. I tried taking it apart last year and the threads on it are pretty far gone. I'll try to find a replacement shaft before pulling it out this time. It could really use new blades too.
I also have one of my onboard soneil chargers that has gone bad. I think I've gone through about 3 of these. I'm pretty disappointed with how many have failed. They aren't super cheap. However, they do work amazingly well when they are working so I'll probably replace the bad one once again. In an effort to stop this from happening again, I think I am going to remove the chargers from the mower and leave them in the garage. That will stop them from having to be run around over all the bumps in the yard and hopefully extend their life. I'll add an 8 prong plug of some kind so its a simple plug in deal as it is now.