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 | Electronics Weekly

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

 

[gcoll]

I have been using bosch 6 amp batteries, with moultons and crank drive and front wheel motors for 4 to 5 years. I try to average over 15 mph with legal speed with 250 watts.

time 01:00 distance 14.0 miles average 14.1 mph ascent 1,225 ft descent 1,250 ft
I return 1 or 2 bars remaining . Some of the batteries have reduced capacity.

2 or 3 times the batteries have refused to charge, I'm guessing from draining to far. The solution is fit
the battery to a bosch tool and run it briefly. I found this out through reading the motorhomefun forum. I had bought a new battery by then, but was happy to restore the defunct one.

Graham
https://www.komoot.com/tour/2257750000

 

[Wayners]

@gcoll

How do you mount batteries?

 

[gcoll]

I use small bike bags, these were from Halfords.
One adapter is a commercial product from USA, the second, which I prefer, is a battery holder with terminals made from copper pipe.

 

[StuartsProjects]

I have been using bosch 6 amp batteries, with moultons and crank drive and front wheel motors for 4 to 5 years. I try to average over 15 mph with legal speed with 250 watts.

Does the controller you are using read the temperature sensor comms from the Bosch battery and cut power if overheating is detected ?

 

[gcoll]

No, I am sure it doesn't, only two wires connected.

I have had the fuse blow when using this system with a tandem ( combined weight 170 kgs plus bike) trying to go to steep a hill. Another time with a loaded bike on a steep hill (komoot says 13%) I could smell things getting too hot on power setting 5 so I reduced to 4 and was able to continue.

The batteries don't get hot normally.