# Sizing battery pack...for a mower? (and other mower questions)



## talonts (Apr 11, 2008)

I looked over the battery pack sizing FAQs, but unfortunately I have NO idea how to translate these to a riding mower. Obviously I can't just use the miles traveled, as the blades are probably going to chew up more capacity than the drive.

I'll be running a 2.4kW 24V 2400rpm Crown forklift motor to the 6spd rear and the blades, which should be enough to drive the 42" deck (I'm probably going to have to play with pulley sizes when I get new pulleys to fit the smaller stepped shaft of the Crown, to get the blade speed the same).

Obviously I have to wait for the motor/controller to arrive, then work on getting them onto the frame to see how much room I have left under the hood before knowing which route to take, but I'm going back and forth between 2 12V Optimas or similar, or 4 6V golfcart batteries (need to check Sam's Club to see if they have the PFGC2 Interstate U2200 equivalent at $60-65 as I've seen noted here and there on the web). Obviously the 4x6 is going to have WAY more capacity than the 2x12, but since I only have about 1 acre to mow at most, they could be complete overkill, assuming they'd even fit. Of course, if I can get them for $60-65 each, they're going to cost less than the 2 Optimas, so if they fit, I might as well take the larger capacity, as long as the frame can stand up to the weight (which it might not for all I know - I might want to box it to be sure).
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*Update:*
When checking out the size of the Energizer EGC2 6V golf cart batteries (Interstate U2200 equivalent) at Sam's Club, and realizing I doubt I can cram 4 into my riding mower, I saw a 12V Energizer that looks interesting.

Energizer 29HM Marine/RV battery (quasi-deep cycle?), Res Cap 210, 125AH, 13"Lx7"Wx9.5"H, $72.82

This battery is only a little bit bigger than an Optima Yellow Top, the RC is nearly *double*, and the price is less than *half*.

I'll be running the riding mower at 24V, and it looks like the 6V golfcart batteries are out, so I'm thinking that these 29HMs might be a good first try, assuming they even fit (still waiting on motor to arrive to place everything and know my total room available). Along with their pretty high AH (for a 12V), they're *dirt cheap*, which is good for a project where I'm trying to save money.
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Has anyone else converted a riding mower, and if so, what battery setup are you using, and what acreage does it do?

I really need to get the mowing done in one shot, I don't want to have to mow, charge, and mow the next day.


Also, I know I need at least a basic voltage gauge at the least, at least one contactor (probably 2), and some relays to have the ign switch work (and have a hidden cutoff switch). But beyond that, is there anything else I am missing, besides the wiring? 2ga should be sufficient for 100A max, right? The cable runs won't exactly be very long in a riding mower.


I'm trying to do this as cheaply as possible, as the mower and controller was free, the Crown about $200, and the batteries/cabling will hopefully be about $300 or less. Other misc will probably be about $100-150, but I'm hoping to keep that "other misc" as low as possible (to start with, I'll just isolate the batteries and charge them separately with 2 12V chargers, before popping for a 24V - don't want to spend the $$ on one until it's all working).


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## evnz (Jul 24, 2010)

did you finish your lawnmower? I am doing the same and after some information


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## ga2500ev2017 (Jun 12, 2017)

evnz said:


> did you finish your lawnmower? I am doing the same and after some information


Um, the original post was 12 years ago. Doubtful the OP is anywhere around anymore.

I did an implementation about 3 years ago. Took a Snapper rear engine rider, mounted the drive wheel to a Motenergy 48V 10HP motor and powered with a 48V Chevy Volt battery module. Used the mower's gearing system to control the speed. So, it had no controller. Electrical consisted of a 200 amp circuit breaker and a Tyco EV200 contactor to switch the motor on and off.

It worked OK, but it was a really dynamic system with tire, belt, and drive issues. Finally got frustrated with the project and took the opportunity to purchase a Ryobi 42 inch zero turn electric on sale. With that unit other than a busted blade it's operated flawlessly into its second season.

ga2500ev


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