Tapping power off E-bike battery

[Rider-Jack]

Hi all,
I’m looking to try and take power from my Bosch e bike battery to power a tracker and some lights on my e-bike. I want to have power even when the bike is off so that tracker will last as long as possible if it’s stolen.

The bike has a Bosch performance CX 85nm Motor with 750wh battery.

It has a 12v output on the motor however it seems to be switched off

Has anyone done this before?

 

[Anders]

I haven't done what you are trying to do, but I have connected my front light to the Bosch battery through the 12V "light" connector on the motor. That is quite stright-forward when using an Bosch cable with the correct connector. However, all 12V connectors has to be enabled by your LBS. In any case, I believe all of them will be turned off when the bike is turned off.

For a tracker, I use bikefinder. It has its own battery, I have to charge it every one to two weeks.

I have seen ads on line for a Bosch wiring harness giving you access to the 36V battery voltage, but I don't really know if the power is available when the bike is turned off. You could of course tap into the OEM harness, but I guess you'd need some electronics knowledge to regulate the 36V down to whatever voltage the tracker needs.

 

[Rider-Jack]

I haven't done what you are trying to do, but I have connected my front light to the Bosch battery through the 12V "light" connector on the motor. That is quite stright-forward when using an Bosch cable with the correct connector. However, all 12V connectors has to be enabled by your LBS. In any case, I believe all of them will be turned off when the bike is turned off.

For a tracker, I use bikefinder. It has its own battery, I have to charge it every one to two weeks.

I have seen ads on line for a Bosch wiring harness giving you access to the 36V battery voltage, but I don't really know if the power is available when the bike is turned off. You could of course tap into the OEM harness, but I guess you'd need some electronics knowledge to regulate the 36V down to whatever voltage the tracker needs.

Thanks I think I’ll try and tap it off the main battery and use a regulator to step it down.

 

[Darren66]

Hi all,
I’m looking to try and take power from my Bosch e bike battery to power a tracker and some lights on my e-bike. I want to have power even when the bike is off so that tracker will last as long as possible if it’s stolen.

The bike has a Bosch performance CX 85nm Motor with 750wh battery.

It has a 12v output on the motor however it seems to be switched off

Has anyone done this before?

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ebiketuner.com

 

[TommyC]

I fitted a powunity biketrax to my bike. It has its own 1000mah backup battery that lasts 3 weeks on its own and you can get a twin battery harness for it. I just replaced the battery with a 5000mah and it lasts around 3 months. You will need some soldering skills to do this though.

It’s charged off the motor high power port which needs to be activated.

 

[Mikerb]

I think you will get an error on a Bosch Smart system if you try connecting direct to the battery. The controller needs to be a ble to recognise every device on the CAN.
I use a "Tractive" GPS tracker ( designed for dogs!). It has its own battery which lasts a couple of weeks and its app sends you a warning when it goes down to 30%. If the bike is stored within range of your wifi the tracker goes into battery saving mode so little or no battery use when not riding.

 

[Rider-Jack]

Thanks mate I’ll look into that. It sounds feasible

 

[Rider-Jack]

I fitted a powunity biketrax to my bike. It has its own 1000mah backup battery that lasts 3 weeks on its own and you can get a twin battery harness for it. I just replaced the battery with a 5000mah and it lasts around 3 months. You will need some soldering skills to do this though.

It’s charged off the motor high power port which needs to be activated.

View attachment 151008

Thanks mate! Do you have the link to the 5000mah that you used? Where you able to tuck it somewhere out of sight too?

 

[TommyC]

Thanks mate! Do you have the link to the 5000mah that you used? Where you able to tuck it somewhere out of sight too?

It’s just a single cell lipo I got off eBay. There’s hundreds to choose from.

The cable that comes with it is only supposed to fit in the motor cover. I managed to get it to fit in the frame above the motor by poking it through the charge port hole and feeding the cable down. This will only work with the stock battery though.

I made an extension cable and fitted the tracker in top tube. The battery tray and lock has to be removed to get to it.

 

[ValActionT 750]

I just use the Bosch Flow Connect for tracking. Fits under the motor cover, nice and tidy. Of course there is a nominal fee for GPS tracking of $35/yr. Pretty simple to install and runs of the battery. Set and forget. You can use the removal display or your phone as a key.

 

[TommyC]

I had the biketrax, got the connect module when it was released, then went back to the biketrax when the free subscription ended.

On balance I prefer the biketrax because it can track at any time, the connect module only track when you report as stolen. The biketrax can be installed anywhere on the bike to be discreet, connect module is easily removed by a thief who knows what it is. You can fit any size back up battery you like to the biketrax and it doesn’t necessarily have to be charged from the bike, which leaves the tell tale sign of a power supply going somewhere.

Also I just found the lock and alarm function on the connect module to be a nuisance.