Possible to use the ST2 Stromer battery on another bike?

[aczmarshall]

Hello i have a stromer ST2, and i want to use the 48v 814wh battery that came with the bike on another project. If i try to get power out of the battery I get less that 1 volt on my multimeter, I have to go behind all of the circuitry to get a 48v reading out of the battery. So to use the battery elsewhere, do I have to remove and replace the programmable bms that is inside the battery? I am also wondering if the bms has some kind of amplifier or something on it since the voltage is straight 48 and not 52.2. Any advice going forward?

 

[Voltron]

As long as the project has about the same maximum amp draw as the bike, then yes, you can disconnect the BMS and run it straight off the positive and negative wires, esp if you're not going to swap them back and forth but just use it on the project. That being said, it makes you into the human BMS for making sure it doesn't over discharge, and being diligent about checking the balance between the groups, leaving you needing some way to top off low groups, or to bleed off the high ones, or having an aftermaket BMS you hook up now and then. Then there's maybe adding a fuse holder, and possibly needing to hack the charger connector if you're going to use the Stromer charger.

Re. the voltage, are you getting that 48v while its plugged in to the charger? And 52.2 seems like a weird in between kind of number.. does it say that on the charger?

 

[tomjasz]

What about the CAN bus communication?

 

[Voltron]

Shouldn't matter if he's bypassing the BMS?

 

[tomjasz]

Shouldn't matter if he's bypassing the BMS?

Clueless here. Following a fellow trying to use a cheap 80% charger on his Stromer battery without success. I've scoured the internet and cant find any definitive information.

 

[Voltron]

Its all in the Stromer BMS. Once its bypassed, its just another bunch of grouped up cells. But to use anything going thru the Stromer BMS wold be difficult, much like the Bionx or Bosch systems.

 

[aczmarshall]

Thanks very much for all of the replies. I dont use the stromer bike very often, but i have another bike with a stereo and a lot of led lighting that I do use. So I would like to be able to use my stromer battery on that bike as well. If i remove the stromer bms, what would be a good bms to replace it with? I dont want to manually balance cells.

 

[docw009]

The Stromer is more bike than I'll ever own, and it seems like a shame to cut up its battery, rendering the original bike unusable. not to add that you compromise the safety of a well engineered battery by soldering in a third party BMS. And something is wrong if you're only getting 48 volts here if it was fully charged and still working on the Stromer. It should be 54.6 volts at the cells, not 48 volts, fully charged.

 

[amberwolf]

I don't know for sure, but it is possible the Stromer won't run without being able to talk to the original BMS. I'm not sure if anyone has tested that, but there is a thread about "hacking a couple stromers" that might have some info?

So if you pull the Stromer BMS, you might want to be sure you can reconnect it.

Alternately, you could do all the charging on the Stromer, with the original BMS. That doesn't help with LVC while discharging on the other bike, but you could add a port for something like Celllogs with an alarm to go off if any cell hits LVC. Then set your controller / etc on the new bike so that it's LVC is high enough to not have to worry about the cell-level LVC as long as teh pack is working and balanced.

 

[tomjasz]

I don't know for sure, but it is possible the Stromer won't run without being able to talk to the original BMS. I'm not sure if anyone has tested that, but there is a thread about "hacking a couple stromers" that might have some info?

So if you pull the Stromer BMS, you might want to be sure you can reconnect it.

Alternately, you could do all the charging on the Stromer, with the original BMS. That doesn't help with LVC while discharging on the other bike, but you could add a port for something like Celllogs with an alarm to go off if any cell hits LVC. Then set your controller / etc on the new bike so that it's LVC is high enough to not have to worry about the cell-level LVC as long as teh pack is working and balanced.

I've been chasing this down for another reason for over a week. It seems there IS a CAN bus communication system. The thread you found is interesting, but they essentially did away with all of Stromer proprietary bullshit, if I'm not mistaken.


CAN (also referred to as CANbus or CAN bus) is a network used in many every-day products consisting of multiple microcontrollers that need to communicate with each other. CAN is implemented in hardware in microcontrollers of about 25 chip manufacturers. If you don't know much about the CAN bus, here is a historic summary of almost 30 years of CAN.
The original CAN specification from Robert Bosch is available here: CAN Spec
CAN provides a safe communication channel to exchange up to 8 bytes between several network nodes. Additional network functionality like which node talks to which others, when to trigger transmit messages, how to transmit data longer than 8 byte - all of these functions are specified in so-called higher-layer protocols (in network terms, CAN is a layer 2 implementation - higher layers are implemented in software). Some of the more popular higher-layer CAN bus protocols are CANopen, DeviceNet and J1939.

 

[999zip999]

You could ruin your stromer. Just buy a battery for you disco ride.