onboard charger for e-bicycle?

[robert.schwartz]

Quick question.  I just picked up an aftermarket 48V 10AHr Li-Ion battery and charger to replace the leads in my cargo trike.  The old setup had the battery and the charger hooked to the controller.  The key switch was also hooked to the controller (48V 20A).  The battery has an ON-OFF keyswitch built in to it.  The battery has both a charge (1/2" diameter round) port and dischart (anderson power pole) port.  What I want to do is leave the charger connected to the battery and leave the battery connected to the controller.  I'd then use the keyswitch on the battery to disconnect the battery from the controller when I am done riding and want to charge.  I tested it this way.  I plugged the charger into the battery but not into the wall.  I turned the keyswitch on the battery to on and read 54V.  I think this means that my plan will work.  I am either charger not plugged into wall and key switch on riding the bike or charger plugged into the wall and keyswitch off charging the bike.  Will this actually work?  Thanks,

[tim.moore]

Just to clarify, I did not hear  if you have  a high rated fuse in line with the wiring and if the switch is in fact a circuit breaker?

[robert.schwartz]

I could not answer your question unfortunately.  This is a cheap Chinese e-bike battery pack that is intended to mount on a rear rack.  The keyswitch is integral to the battery so I can't tell you if it is a circuit breaker or a simple switch.  My gut feeliing, considering it is a low power cheap battery pack that it is a simple switch.   I do not have a fuse between the battery and the 48V 20A controller, although I could put one in.
The original setup, which I used for 5 years had 4 lead acid batteries in series connected to the controller directly.  The charger was connectrd to the controller directly.  There was a key switch that I mounted on the outside of the battery box that connected to the controller directly.
The new plan is to short the keyswitch wires to the controller, connect the Li-Ion battery pack to the controller directly, and connect the charger to the charge port of the battery pack.  Since the battery's keyswitch cuts the power output, I expected that the same result - no power to the controller - would work like the original setup.

[simon.gibson]

I have one of those! I took it apart because one of the blocks of LiPos (5 cells in parallel) was bad. I replaced them and it works.
There is a 13s BMS board inside.
The assembly has a key lock that is a simple switch, not a breaker. There is a fuse in there too.
A simple power adapter plug allows you to connect a 50VDC adapter to charge it.
You can test it by loading it with some lamp bulbs. I connect regular LED household lamps which will actually work! So will compact fluorescent lamps.
The other nutty thing about these Pedalec battery boxes is that they use an IEC socket as the power delivery socket!!!!
I purchased a separate13s BMS board thinking it was the board that was bad untill I discovered the bad block of LiPos. It has an i2c Connector so you can connect a computer to it to program it as you require.
I have used that yet with so many other projects going on...
Those packs, fully chsrged, read about 54VDC. The cells charge up to 4.2VDC.
So if you can get access to the BMS board you may be able to do more refinements according to your needs!!
Good luck!!

[tim.moore]

Electrathon is a go-kart set up for electric vehicles.  That set up uses the high rated fuse and the high powered circuit breaker.  I made a bicycle pusher with their wiring design, which mirrors the old conversion type EV.  I think for safety to you  touching the switch and safety to your batteries overloading, I would use the electrathon wiring system--But I am old school.