Sparks flying: are my battery or charger damaged? Please help

[Planet Indigo]

This is my first ebike conversion and I'm very worried about my battery.
I received my battery/charger yesterday and before installing it on the bike, I wanted to make sure all fit and worked perfectly.
I inserted the charger connector inside the battery connector and big sparks started flying, I removed the connector immediately but the charger connector is singed and im not sure if the battery connector is supposed to look like this on the inside. For the record, the battery power switch was off (little circle O, not -) since I had heard that batteries should be charged while off.
I attached two pictures.

After googling some it appears that ebike batteries are a rare exception where it's better to plug the charger in the wall first before inserting the plug in the battery. I'm double surprised because it goes against my previous experience with batteries and my seller's instructions were to plug the charger and battery before wall socket...
The cells still seem to have voltage since the battery indicator still reports 1 green light (same as when I received it). My first priority at this point is to not damage the battery cells. I am very afraid of plugging them together now. The charger has a light indicator, and when I plug it alone in the wall socket, the light stays off, is the light supposed to be off when plugged in and only on when charging? Or on in both cases? Should I try to "clean up" the inside of my battery charging port? Is it supposed to look like this on the inside?

I would very much appreciate any advice on what is my safest next course of action given that my priority is not to damage the cells. Thanks.

 

[DDBB]

The light on my charger won't come on unless it's hooked up to a battery and plugged into the wall.. Looks like you had a short through no fault of your own. I'd send both the charger and battery back

 

[AHicks]

I've done that mini lightning bolt POW as well (big capacitor discharge, underline BIG). I thought though, it was because I plugged the charger into the wall prior to plugging it into the battery. Maybe not?

I can say that now, I plug the charger into the battery first, then plug the charger into the wall, and I haven't had it happen to me sense.

 

[DDBB]

I've had capacitor spark on 10s lipo using 6mm gold bullet connectors and no way does it produce the connector degradation seen in the photo above.

 

[Planet Indigo]

So what am I supposed to do next? Is it safe to test voltage on those connectors? I don't have a voltmeter in the conventional sense, but I do have an led screen voltage measurement tool with two small wires. Where would I even touch the black and red wire? Is it safe or could I produce a short?
Also, does my battery connector look normal in this pic in this post?

 

[DDBB]

doesn't look normal to me.. It COULD have been a capacitor spark I suppose.. I'd plug it in again and see what happens. If it sparks and gets hot, unplug and send it back (if it doesn't catch fire)

 

[Planet Indigo]

Catching fire sure doesnt sound reassuring lol
My main priority is not damaging the cells, Id like to keep the pack if I can get it to work and not be a hazard. Do you guys think using my two small wires voltmeter would be safe to try and check voltage? Where would I place the red and black wires on the charger connector and battery connector to check voltage?

 

[DDBB]

w/o seeing the battery, I don't think anyone can help as to where to test for voltage. Maybe someone with the same battery will chime in. If there are just two prongs then one must be positive and one must be negative and nothing bad would happen if you put your voltmeter on it backwards. Voltage would just read with a - in front of the reading if tested with pos. and neg. reversed. I would NOT attempt a voltage reading at the plug where the charger goes in, that's where you'd be most likely to get a short

 

[AHicks]

I'd give it another try. There's not much amperage passing through that charge connector. Maybe a couple amps at most.

 

[pnop]

I'd also give it another go and see what happens. As an aside, my battery instructions noted the battery has to be on to charge.

 

[harryS]

My better chargers must have a spark suppression circuit. I've been getting the sparks when I plug in ny cheap chargers into batteries that have the same jacks, but never saw the plating damaged on the plugs.

If you're going to own an ebike, a multimeter is a good tool to have. You do want to verify polarity on the charger and the battery. Run down to Sears before they close and get a Craftsman meter. Or get a free one at Harbor freight if they're passing out the online coupons.

 

[indianajo]

I disassembled and reassembled a valve chest because a Harbor Freight meter lied to me. Buy a meter at Sears if one is left open, or if not, online from newark.com. I don't like the autoranging ones, they always start at the lowest voltage and you wait 2 seconds for it to switch to get a reading on 12-48 volt items. If your probe slips off, it goes through all that waste of time again. A third online source that sold me a good (capacitor) meter was parts-express.com
Don't try to stick the probes in that concentric socket, you'll short it for sure and blow something. You can measure the outside & center of the plug that goes in that socket if careful.

 

[DDBB]

Take video so we can all enjoy the shower of sparks show.. thanks!

 

[Planet Indigo]

Ddbb, that last comment... This situation isn't funny on my end, let me tell you that, I have been eagerly awaiting my ebike to be done for the past 2 months.

Anyway, update:
Contacted seller (both from same seller in china). He told me to test polarity on charger and battery.
Charger is dead, no light when plugged in wall, which seller said wasnt normal for this model. No voltage exiting charging plug. Continuity between the + and - on the charging connector. Brought it to an electronics store, several capacitors inside are dead but there was no burnt place that we could see. The connector as seen in picture has that metal part burnt off and gone. The connector was all black before I wiped it clean to take pic.
Battery seems ok. Polarity at charging port is normal, + in center, - in edge. 45.4v like when I received it. (48v battery at 25% or so charge). The usb charging port and switch still work (switch only controls discharge port).
Seller said hes sending me a new better charger with fan and aluminium case. I asked for upgrade to 3a instead of the original 2a, he said it was much more expensive and heavier to ship, I asked to pay 10$ to upgrade, he agreed to that.

Questions:

1) Did my battery get damaged by this event? Voltage seems to have been unaffected, down to tenth of volt. Did this shorten its life?

2) Anyone has a solid idea on what caused this? Could a cheap charger with correct inside wiring have suffered this by being plugged in the battery before wall? Charger had been in transit 2 weeks so it should be safe to assume capacitors inside were all empty?

3) Does a 2a charger allow more life cycles from the battery than a 3a charger on a 17.5ah battery or are both equal in that regard since they are still slow charging? Basically, is there a point where there's no more return in life cycles by slowing down the charge anymore? Is that point at 0.2C? Higher? Lower?

 

[DDBB]

I'm sorry to have made a joke at your expense.. Most Lithium cells are able to accept a 5c charge with no sacrifice to cycle life. Going from a 2 amp to a 3 amp charger will not affect battery cycle life or capacity. Shorting lithium cells is really bad for them but we still don't know if that's what happened, even if it did, the cells are probably still o.k. It's not like it STAYED shorted for any length of time.

 

[nadzbnimble33]

i was plugging charger into ebike and heard popping sound and proceded to charge 42.3v and disconnected power ,i go to power on my bike and get nothing,so iplug bike back on charger turn it on and works all the functions operates and when its unplugged fully charged it wont turn on zero power ,i need knowledgable help please appreciate any advice....

 

[prestoOne]

i was plugging charger into ebike and heard popping sound and proceded to charge 42.3v and disconnected power ,i go to power on my bike and get nothing,so iplug bike back on charger turn it on and works all the functions operates and when its unplugged fully charged it wont turn on zero power ,i need knowledgable help please appreciate any advice....

Start a new thread?
Disclaimer, I have never opened up or serviced a battery but I do have some experience and it sounds like you might be tempted to plug it in again.
1. Do not plug that battery in again until it is fixed. Fire or serious injury may occur.
2. If you can put the battery somewhere safer that would be a good thing, well I think it would be, a lithium battery going bad scares me but it is probably not the cells.
3. Did you smell anything when your heard the pop? A single pop? Where did the pop noise come from? The battery?
4. when you say the bike worked when plugged in do you mean the entire bike worked including the wheel motor or you just got power?

Anyways, if you take a picture of the bike and of the battery out of the bike that would help people a lot. If you are lucky (you likely are here) it is a $5 part and whatever labor is.

In a different life I used to fix such things.

 

[ElevenAD]

Catching fire sure doesnt sound reassuring lol
My main priority is not damaging the cells, Id like to keep the pack if I can get it to work and not be a hazard. Do you guys think using my two small wires voltmeter would be safe to try and check voltage? Where would I place the red and black wires on the charger connector and battery connector to check voltage

Both charger and battery would get returned ASAP if it were me.

 

[DDBB]

If the battery indeed got shorted, yes... I'd want a new battery although I've had momentary lipo shorts with RC packs with no damage, or no damage that I was able to see, or measure in capacity or internal resistance

 

[prestoOne]

Both charger and battery would get returned ASAP if it were me.

Lol...why would you be jumping to that conclusion for this guys particular post. Why would you have an expectation that you would be entitled to replacement?

Giving the guy no technical help and filling them up with false expectations.....i do t see the benefit of that.