Trike electricify

[John Manning]

Hi, I am John, a long time cyclist and bad speller. I live in the middle of Nottinghamshire and have some how got the project of electrifying my Uncle's Pashley tricycle. It is a vertical challenge because the trike is little bigger than a child's machine. I have got a BMS battery kit and it is fitting OK if slowly. The biggest problem is with the battery pack as it seems to be charged but gives no output unless the charger is plugged in. Any ideas will be helpful. I could short out the protection circuits inside the battery pack!
regards
John

 

[Deleted member 4366]

Which battery is it? Does it have a switch on it? If so, switch it on.

Sometimes the same FETs are used for switching on both the charging and output, which means that the charging and discharge wires are joined together at the BMS. With the charger switched on, it's powering the output directly. I bet you can only get a few amps like that, but don't test because it might damage the charger.

If the above is the case, then it won't be charging the battery. What is the battery voltage.

I'm going to bet that the battery isn't switched on!

 

[John Manning]

Good guess but unfortunately wrong. the battery is 36V 10Ahr. The switch on the case only works the negative lead to the external socket. The voltage from the charger lifts the electronic lock and allows the battery voltage 41.6v to appear at the output. It certainly gives the idea of not being turned on, but I have tested inside the case and between the battery and the on/off switch. Is there another switch? I have not seen one. The other difficulty is that the BMS on the battery pack is different to the one on the web site.
Many thanks for your reply. I shall try to find a proper thread for this discussion.
John M