36V Bosch tool battery for e-bike use

[StuartsProjects]

I have seen the expected YouTube videos on using these Bosch powertool batteries for eBikes. However as has been mentioed a few times these batteries do not have a eBike type BMS for protection.

There is the battery temperature sensor, and some newer batteries do appear to have individual cell monitoring.

Given that the different batteries are comapatible across the range of tools, the comms protocol must simple, that maybe just signals OK or not OK. Its unlikely that an old Bosch tool would have known that some years in the futute batteries with individual cell monitoring would be introduced.

Using a Bosch battery as an eBike battery without the eBike controller being able to read the good battery bad battery signal seems, to me at least, to be an unacceptable risk.

For a Brompton, a conversion based on the single 36V power tool battery on the luggage block seems ideal. I cannot see that a Brompton conversion using 2 x 18V batteries would be very practical.

 

[WheezyRider]

I wonder if a small standard BMS could be substituted for the Bosch control PCB in the pack.

 

[StuartsProjects]

Or maybe somthing as simple as this;

Resettable fuse carries 20A for Li-ion batteries

Bourns has introduced a series of miniature resettable thermal cut-off (TCO) devices for dense, high capacity lithium-ion battery packs. The Model AC

www.electronicsweekly.com

 

[lenny]

https://www.mouser.co.uk/ProductDetail/Bourns/AC77ABD?qs=55YtniHzbhAbFzbGWRl7PQ%3D%3D

£1.71	£1.71

 

[Nealh]

Controller lvc is variable , KT ones are set for 20/30/40v though one can also adjust the lvc value range by -2v to + 1.5v in 0.5v increments.

 

[lenny]

"Electric bike maker Aventon has dared to be bold and make the entirely logical move to enable its bikes (specifically the Pace 350, for now) to be powered by your bog-standard Worx power tool battery."

https://www.cyclingelectric.com/news/use-power-tool-batteries-to-power-e-bike-aventon

 

[Woosh]

I can see a place for tool batteries in a very lightweight specialist kit but not for a factory assembled e-bike. The weight saving is tiny compared to the overall weight of an equivalent bike with a more suitable bag or in-frame battery, the drop in safety and yield for the battery and is considerable and there is little cost saving. If you put two tool batteries on the bike then all the advantages disappear, you are left with only disadvantages.

 

[peterjd]

I think I am agreeing with the last contribution. My minimally adapted Mk1 Swytch kit using multiuse 2.6Ah 36V Bosch lawnmower batteries is still running well. I actually prefer the adapted old touring bike to my Decathlon 500E for local town use. Bike is light and reasonably well balanced and can handle moderate loads (eg shopping) even though it only has rim brakes. I have used it for longer rides with a spare battery carried in a pannier - only takes a couple of minutes to change the battery. Peter

 

[Wayners]

I keep thinking about this.
Using tool batteries to power bike as I've loads just sitting about. Well about 7 18v plus 4 at 12v.
I thought today I could just fit 2 18v batteries in 2 chargers permanently then wire that up to motor.
Plug in the chargers to 240v to charge.
I guess you would need to wire the batteries together to get 36v and at only 4ah will that be enough for my commute? It's the wiring of batteries together that's the problem I guess, plus the strain on the batteries with just the 2 that will cause a problem?
I've not seen anyone use the chargers as a holder as well.
I guess it's an unknown and possible fire risk