Ebike battery alternative

[flecc]

when testing whether it did, I found that if I lift the back wheel and apply the throttle straight to max, the juddering >does< still happen, despite the load being removed.

This does sound like a phase not firing, very apparent when under load. Have you measured for continuity between all the pairings of the three phase wires? However check out Alan's suggestion since you have SLAs.

The only suggestion I can give for separating the motor side plate is to remove all spindle nuts from the other side and then give that other side spindle end a sharp tap with a mallet or hammer. The motor core will often then drive apart the end plate and shell.
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[bb9009]

electric bikes when testing whether it did, I found that if I lift the back wheel and apply the throttle straight to max, the juddering does still happen, despite the load being removed. me too..I test it again!!!

 

[Deleted member 4366]

You have all the symptoms of a knackered battery. If you show us what it is, we can confirm it. It would also be nice to know how many wires go to the motor. Check at the controller connector. A picture of the controller connections would also help.

 

[Wolvyr]

You have all the symptoms of a knackered battery. If you show us what it is, we can confirm it. It would also be nice to know how many wires go to the motor. Check at the controller connector. A picture of the controller connections would also help.

The bike does not use any stock battery. When I bought it second hand, it had a slightly beaten up silver plastic case covered in duck tape, holding three LSLA 12-12 12v 12ah Lucas lead acid batteries, producing one 36v battery to power the 36v motor. There are two individual wires going from the controller to the motor, one red and one black.
I have tested the voltage of each of the 12v batteries and they appear fine.
Is this enough info? I will check if I have a picture
Edit:
It might also help to know that with the help of someone better suited to the task than I, the batteries have been resoldered and all cables replaced as they were in dreadful shape beforehand. All new fuse, wires, switch, soldering, the only thing the same is the beaten up box and the batteries them self, which appear to hold a charge well.

 

[Alan Quay]

The bike does not use any stock battery. When I bought it second hand, it had a slightly beaten up silver plastic case covered in duck tape, holding three LSLA 12-12 12v 12ah Lucas lead acid batteries, producing one 36v battery to power the 36v motor. There are two individual wires going from the controller to the motor, one red and one black.
I have tested the voltage of each of the 12v batteries and they appear fine.
Is this enough info? I will check if I have a picture
Edit:
It might also help to know that with the help of someone better suited to the task than I, the batteries have been resoldered and all cables replaced as they were in dreadful shape beforehand. All new fuse, wires, switch, soldering, the only thing the same is the beaten up box and the batteries them self, which appear to hold a charge well.

This is a fairly normal arrangement for a 36v SLA.

You can re-solder and re-terminate all you like. It won't fix knackered batteries.

 

[Wolvyr]

This is a fairly normal arrangement for a 36v SLA.

You can re-solder and re-terminate all you like. It won't fix knackered batteries.

How would one go about determining whether these batteries are knackered? Does the fact they hold their voltage not give any indication that they are in good health? I'm assuming the only true way to test this is by sourcing some all new batteries and testing whether the juddering still persists?

 

[Alan Quay]

How would one go about determining whether these batteries are knackered? Does the fact they hold their voltage not give any indication that they are in good health? I'm assuming the only true way to test this is by sourcing some all new batteries and testing whether the juddering still persists?

It may help to get some pictures on here. Not all SLA's are suitable for an electric bike, as they won't discharge at a high enough rate. That could be your problem. If the batteries say 'standby' there's a good chance they are not up to the job.

The only way to fully test your batteries is to rig up a large load, and monitor. It can be done with the element from an electric heater, and a crocodile clip. I have also done it with a few kettles in parallel.

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[Wolvyr]

It may help to get some pictures on here. Not all SLA's are suitable for an electric bike, as they won't discharge at a high enough rate. That could be your problem. If the batteries say 'standby' there's a good chance they are not up to the job.

The only way to fully test your batteries is to rig up a large load, and monitor. It can be done with the element from an electric heater, and a crocodile clip. I have also done it with a few kettles in parallel.

Sent from my HTC One_M8 using Tapatalk

This is questionable, as the juddering was not present for the first half of a some 3 mile journey at full throttle. The battery had performed fine at that point, and the juddering only occurred when I tried taking it up a hill. Since that Hill, it has persisted.

 

[anotherkiwi]

The hill killed it maybe? The 3 mile easy bit didn't drag it down to its limit.

SLA is very susceptible to heavy loads. Try starting a diesel car in the winter with an old battery, you can kill it beyond repair no problem.

 

[Alan Quay]

I'd stick a meter across the battery while you lift the wheel and give it full throttle.

See what voltage it goes to when juddering starts.



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[Deleted member 4366]

You don't seem to be listening to what people are telling you. If you know best, carry on. If you want your problem sorted, tell us the designation number on the batteries. Put a voltmeter on the battery supply wires, then run the motor under load. If the voltage stays above 36v, they're probably OK. If it goes below that, they're knackered or, most likely, the wrong ones.