correct connections when charging

[TerryV6]

My sister followed the instructions when charging her battery. Plug into the AC first, then attach the battery. Every time she did this, there was a spark at the battery connection, and finally the battery refused to take a charge. Someone said that you should connect the battery first and then attach it to your power source. Any thoughts on this?

 

[RunForTheHills]

It seems unlikely the connector sparking caused the battery to not take a charge. That could pit or corrode the connector and maybe the charger isn't getting a good connection with the charging connector contacts. What kind of connector does the battery use for charging? There may be something else wrong with the battery or BMS in the battery. Perhaps she didn't charge it for a long time and the battery dropped below the low voltage cutoff so the BMS won't let it charge for safety reasons?

 

[gromike]

I always plug the battery into the charger, and then pug in the AC. Then unplug the AC before unplugging the battery.
YMMV.

 

[Jeremy McCreary]

There's no universal order. Do what the official manual says.

I have 2 ebikes. One manual says to plug into the battery charging port with the charger already powered up. The other says the opposite.

 

[Gordon71]

My sister followed the instructions when charging her battery. Plug into the AC first, then attach the battery. Every time she did this, there was a spark at the battery connection, and finally the battery refused to take a charge. Someone said that you should connect the battery first and then attach it to your power source. Any thoughts on this?

The instructions with my Rad Rover were to first plug into the battery and then plug in the charger and then unplug the charger first after charging. Never seen a spark.

 

[Gordon71]

PS. AI agrees.
Yes, the recommended practice for charging an ebike battery is to
first plug the charger into the battery (or bike), and then plug the charger into the wall socket. This sequence prevents a potential power surge, sparks, or damage to the connector pins, as it allows the charger to properly regulate the voltage before applying it to the battery.

 

[TerryV6]

PS. AI agrees.
Yes, the recommended practice for charging an ebike battery is to
first plug the charger into the battery (or bike), and then plug the charger into the wall socket. This sequence prevents a potential power surge, sparks, or damage to the connector pins, as it allows the charger to properly regulate the voltage before applying it to the battery.

Thanks Gordon, thats what I thought. When I copied out the info sheet for her, it said:
(Plug the charger input plug into your AC power outlet (before plugging the charger into the battery).

 

[Gionnirocket]

Understand that cheap chargers and batteries may spark no matter what you do.
That said most charging instructions say connect the battery to the charger.... then connect the charger to an electrical outlet.
ymmv

 

[RunForTheHills]

The sparking is from arcing when the voltage potential overcomes the electrical resistance of the air separating the contacts. XT90 connectors are available with anti-spark. But if you plug the battery into the charger first, of course it won't spark. I use the Grin Satiator charger. You can plug the battery in first or second and it doesn't matter because it won't start charging until you push the button to start the charge. Since it is a programmable charger, that lets you change the charge settings before starting the charge.

 

[Gionnirocket]

The sparking is from arcing when the voltage potential overcomes the electrical resistance of the air separating the contacts. XT90 connectors are available with anti-spark. But if you plug the battery into the charger first, of course it won't spark.

I've seen cheap chargers cause a spark no matter as the act as a load and the cheap battery charge terminals are always live.
A better charger will limit a reverse current flow and/or not allow charging/connection until it senses a proper load with a few millisecond delay.
One of my chargers actually pulses to wake the BMS and then starts charging.
Some of the cheap stuff, especially chargers are just ON