Hi,

 

I have a sunstar so3 crank drive kit (24v) on my Scott, the battery (bottle shape) is failing now so I need a replacement. As i'm sure many here know Sunstar have stopped making these kits so I'm a bit stuck.

Does anyone know where I could get a battery from, ideally like for like?

Perhaps someone knows where the batteries were made, I'm assuming Sunstar didn't manufacture them?

I've also considered having the battery rebuilt with new cells, but this seems to be coming out rather expensive.

 

Thanks in advance,

 

Chris

You can use any 24v battery, just fit the new battery holder and battery in place of the existing. Just make sure polarity is correct first.

Hi Nealh,

The battery has 5 connectors at the bottom that plug into the holder and a wire out of that with 4 (or 5?) wires. I think some of these must be around battery management/sensing how much of the battery charge is left to display on the handlebar display? Presumably (obviously) non of the battery charge display functionality would work but you are saying as long as I get the polarity right on the 24v and ground from the new battery the power to the motor would be fine?

Are you aware of anyone who has actually done this with a Sunstar on the forum perhaps?

I've just seem some evidence of this on the German pedelecs forum but that will take some time to pick through and translate.

Thanks for your help,

Chris

5 pin connector would suggest some kind of comms, but poss. not. Battery voltage to the handlebar display normally comes from the controller, not direct from the battery. Can you see the wire connection on the pins?

Hi all,

I've just found this on the german forum https://www.pedelecforum.de/forum/index.php?threads/anschlu%C3%9F-akku-an-sunstar-s03-motor.48666/#post-838424

If I open this google does an auto translate for me, it looks like others have tried to add a 3rd party battery to a Sunstar motor with mixed results, looks like one of the contributors have connected the battery with the wrong polarity (oops) and another seems to be an ex Sunstar agent in Vienna who produced some kind of gadget to allow a 3rd party battery to be used - I've messaged him for more info.

So perhaps just connecting a 3rd party battery will not work on its own?

Chris

If it uses 5 wires then no.

Hi,

I've had another look on the German forum I mentioned earlier ... it looks like the connector from the motor to the battery has 4 wires - a black and a white thick wire for power and a thin red and thin brown wire (the 5th connector on the battery holder doesn't seem to connect to a wire).

And it does seem like people are saying that you can just connect the thick wires to the 3rd party battery (make sure you get the polarity right) and just bridge/short/connect the other two.

I've attached a couple of pics, one showing the connector on the motor side and the other showing a project from the German forum, towards bottom center you can see the same 4 wires without the connector block and the two thin wires appear to be connected.

Has anyone here tried this and can confirm it will work before I buy a battery.

Cheers,

Chris