E-bike battery for lawn mower?

I need a new lawn mower at home and was thinking of buying a Bosch Rotak 43 li. They often sell them with two 4Ah batterys but I am not sure that will be enough. You can also buy it without battery and charger and save 200-300 usd.

I have a 36V 15Ah battery on the bike my girlfriend uses (not used very often). I was thinking of also using this on the lawn mover. Do you think this is possible, or can you see any problems with this?

I have not find any electric scheme to it but I know i will have to open it up to fit new connections. I think the original battery has more than two connections, not sure why...

I was hoping to just fit battery + and - with correct cables in the lawn mower...


My battery:

https://bmsbattery.com/ebike-battery/232-36v15ah-li-ion-alloy-05-case-ebike-battery-pack-ecitypower-battery.html

Should be possible. In general, the drills, mowers, etc are sold as "whatever volt" stating the fully charged voltage. So the 40v stuff is in fact using 36v nominal, or something close to it. 9 or 10s is my guess.

How to wire it is up to you to dope out. When I gutted the lead out of my old B&D mower, it got a bit complicated because of the on board lead charger. I was able to keep the on off switch on the handle, but lost the blade brake circuit. So now my 24v mower is dangerous, the blade keeps spinning a long time when you stop the power. I just use common sense and don't stick a hand down the discharge chute when it's turning, but wouldn't ever lend the motor out.

FWIW, if your e bike battery does not work out, mowers run great on RC lipo. I use lipos that are old and worn, so my battery won't mow the whole lawn in one go. Oh, that's terrible, I just do the back one day, the front another.

This Bosch says 36V. Will check if I can find out what voltage it actually is. "43" is just the with in cm. Hope then that my 36V battery is not too much.

The battery is charged with a separate charger so I maybe it is simple. If there is no strange security that senses if it is a correct battery inserted.

Will try to check more next time I see it in the store.

What voltage is the mower now.
Hey
The mow I do the mow I like.

Along the same lines as these voltage questions the current demand going through thick grass can climb up surprisingly high, especially when blades become dull, so take that into account when matching the ebike pack with the mower, i.e. peak and cont current available with the battery, and what the mower demands should be taken into consideration.

That's true about my mower. It's brushed, with no controller. Just a battery hooked to the motor. As a result, the current spikes if I hit some thick grass are unbelievable.

The lead battery struggled with them, so that's part of why I switched to the RC lipo for my mower.

I have no idea if the newer 36v and above mowers are that primitive. But the old 24v ones from Black and Decker are.

It seems to have a controller, here is a person in this forum that sold one of them a few years ago:
https://endless-sphere.com/forums/viewtopic.php?p=681249&display_history=true

And here someone says they draw up to 30A:
https://endless-sphere.com/forums/viewtopic.php?p=985840&display_history=true
Edit: He says 10s, so maybe my battery is correct voltage. Will try to ask him if he know more.

But what the standard current is and how long the peaks are is the hard question. I dont want to buy if it's not possible to use my battery, but I cant measure what it needs before I have it Not the usual question here on endless-sphere.
In the future I might build a special battery for the lawn mower when I order cells for a bike battery but for now I would like to start with an existing battery. Otherwise it will have to be a gas/fuel engine anyway...

Swe said:

It seems to have a controller, here is a person in this forum that sold one of them a few years ago:
https://endless-sphere.com/forums/viewtopic.php?p=681249&display_history=true

And here someone says they draw up to 30A:
https://endless-sphere.com/forums/viewtopic.php?p=985840&display_history=true
Edit: He says 10s, so maybe my battery is correct voltage. Will try to ask him if he know more.

But what the standard current is and how long the peaks are is the hard question. I dont want to buy if it's not possible to use my battery, but I cant measure what it needs before I have it Not the usual question here on endless-sphere.
In the future I might build a special battery for the lawn mower when I order cells for a bike battery but for now I would like to start with an existing battery. Otherwise it will have to be a gas/fuel engine anyway...

Click to expand...

First off the 2 36v 4ah batteries that came with the mower should easily give you 1hour and half of run time. My greenworks 40v mower is perfect for mowing my half acre yard with 2 similar batteries. On n my greenworks battery there are 4 blade connectors that measure half the voltage of the pack one reads 41v and the middle one reads 20v. This is a1 10s pack and I have even run it on my bicycle a few times... LOL

I use 10s packs made from Model S cells for my lawnmower and weed eater. Works amazing. 6.2Ah and 12.4 Ah 2 packs in parallel. Then I run them in series to power my oscilloscope. More then 21 hr batt life on the scope. On the mower could probably do an acre. Lol

The two in series will also power other devices made to run from 110V AC that have switching power supplies.