Electric Bikes - can I charge batteries whist they're connected???

(ok a newbie question but....)

can I charge batteries whist they're connected to the bike?

ie just to help me understand whats possible re mounting them - eg if this is possible then you could just plug leads directly onto bike when you get home (no need to take them off the rack)

I do all the time.

I also happen to be sitting a few feet away from an electric street sweeper right now. To charge it, the cable running from the batteries is unplugged and then plugged into the charger, so there is no way to turn on the sweeper while charging.

I've never attempted to turn the ebike throttle switch on while charging and I don't ever intend to.

I do all the time.

I've never attempted to turn the ebike throttle switch on while charging and I don't ever intend to.
I always have left everything connected while charging. A few months ago: I thought my 36V batteries had died and would not charge so I *did* turn the charger and throttle on at the same time to make sure the motor was OK. It was. Since everything seemed to work with the charger on, I kept checking and found loose wires near the controller- fixed them and everything worked fine.

You can for sure, but should you?

When you say connected I'm assuming you mean the controller is still in the circuit, throttle at zero. In this case you probably will have at least a small current flow due to parasitic losses in the controller, perhaps too a Cycle Analyst running etc.

Battery packs that include BMS may be fooled by this draw and potentially over or under charge the pack.

I always disconnect my pack from the rest of the circuit before charging.

The way I see it, a battery charger is designed to charge a battery, not charge a battery and power up some other devices.

Just my 2 cents.

On the Bionx the battery is charged in place. The power to the motor should be switched off. Parasitic losses to controllers are miniscule these days.

Perhaps BionX has planned for charging while connected, others many not have.

My controller plus CA will significantly drain the battery if left on for a week. OP did not state what system is in play.

You could always install a switch on the positive lead between the battery & controller if you have concerns & simply turn it off when charging so that there is no chance of power making it to the controller during charging.

This is obviously assuming that there are separate leads for charging & output.

An under-rated benefit of disconnecting the load from the line, whether by unplugging PowerPoles or flipping a switch, is not riding off with my charger in tow :(

An under-rated benefit of disconnecting the load from the line, whether by unplugging PowerPoles or flipping a switch, is not riding off with my charger in tow :(


That would be bad.

Come to think about it, I spent a month or two riding around with my charger spliced straight to my battery charging connections. I kept the prongs that went into the wall wrapped up and it worked just fine until I was able to get some proper quick disconnects.

My Schwinn Scooter S-750..came with a 24-volt Charger..it actually has a 3-prong PLUG...
one prong is a GROUND..
and 2-prongs each are 12-volt...
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This allows for a 1.5 AMP Chargeing Cycle..some 6-hours of charging...
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I wired in a BATT-separator..that causes the 2-12volt(24volt)..to become 2-separate BATTS...
..each at 12-volts..I then use 2-12volt Battery Chargers..running at 6-AMPS..for 2-1/2 HOURS..I come up to..29-volts of Peak Charge...that with-in a hour..is sitting at 27-volts..standing charge...actually like 27.4volts...the battery's are new..that will drop off in time...
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For safety...the scooters have the Plug&Play option...
..as a matter of this safety issue..I did damage a knife cutting insulation creating the New Charge PORTS..
..Battery's tend to be always ON...power supplies...they are dangerous.[end]