Battery Charger Sparking and not Working

[judson]

Hey Folks, I am hoping someone here can help me out. I purchased a Bafang 750W conversion kit from emax ebikes in AU. Set it up last week and all seems to be going well excepting the charging. I have only done a few short 10 minute or less trips so haven't noticeably depleted the battery (14s3p pack using Panasonic NCR18650PF 2900mAh cells), but decided to try charging it up nonetheless.

I am absolutely new to this so I tried to follow the included instructions but they are pretty cryptic. Seems to say to connect the battery to the charger then the charger to the AC. So what happened was when I connected the pin to the charging port (or what I can only assume is the charging port because the rubber cap on it has a picture of plug on it) there was a visible and audible spark. When I plugged it into the wall no light comes on the charger (supposed to come on red when charging).

My questions are these ... is the spark normal? ... is that order of operations correct? ... should i have the battery powered on? To clarify this last question, what I mean is the button on the case, not the controller. My understanding is that this activates the BMS.

Thank you for helping me out. Happy to provide more info if necessary.

 

[dnmun]

yes, the spark is normal if you do not turn on the charger first. the battery sparks when it sends a large rush of current backwards into your charger to charger up the capacitors on the output.

so always turn the charger on first, and then plug in the battery. do not use new cells without charging them up first. it takes a few full charge discharge cycles to fully open the entire storage capacity of the cell.

if you reversed the charger on the battery it will make a spark and blow the fuse on the output.

do you have a voltmeter and can you check the fuse to see if it is ok?

 

[judson]

yes, I have a voltmeter. I can check the fuse on the battery. But it still powers on so I think it is okay. Perhaps I just have a bad charger?

 

[dnmun]

post up a picture of your charger showing both ends so we know what you have. there should be a fuse on the output and a fuse on the input. have you ever charged this battery before with this charger? can you measure the polarity of the voltage on the charging plug and match it to the polarity of the voltage on the output plug? if the polarity was reversed it will blow the fuse on the output. so use the voltmeter.

 

[judson]

Here is a picture of what I am working with. Thanks!

 

[dnmun]

does the led turn on when you plug it in? can you take the screws out of the holes under those rubber feet and open it up to look to see if the fuse inside is open circuit? if the led is off.

 

[ScooterMan101]

The first couple of times I charged up my battery I got the same spark,
on the Third try what I did was to .. First plug the Charger into the AC wall outlet,
Then
into the battery.
No more sparks .
So try : First Plug the Charger into the wall, then, into the battery.

Please let us know how that works.

 

[judson]

Thanks for all the help. I tried a two things at once and something seems to have worked. I REALLY jammed the AC power into the charger unit (it didn't seem loose but it never hurts to try that I figure). I also plugged it into the wall first, got a green light, and then plugged it into the battery. Before there was no light of any color. It now seems to be charging. Curious how long it will take to fully charge. Might be a late night for me, I don't want to leave it charging unattended for some reason. Is that overly cautious?