Massive shock and sparks

Joined
Feb 26, 2013
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8
Sparks flew and a burned charger/battery connection, The thing is it was not even plugged into the wall when I connected the charger to the battery! unknown cheap chinese battery charger with no safety icons so i am not surprised must have been allot of energy in the cap after the numbness went away on my finger tip i plugged the battery in on my controller bike runs fine so the battery is fine
My question is should i replace the BMS on the pack ?

battery is 48v 10ah the charger/stun gun was under two amps an aliexpress special lol
also on another note last night on charging the battery the charger was blinking red and yellow I assumed it was balancing I have no idea what happened. I am going to buy a new charger i suck at soldering so i am not sure about a new bms on the battery
 
3lctricM3rc3nary said:
Sparks flew and a burned charger/battery connection, The thing is it was not even plugged into the wall when I connected the charger to the battery! unknown cheap chinese battery charger with no safety icons so i am not surprised must have been allot of energy in the cap after the numbness went away on my finger tip i plugged the battery in on my controller bike runs fine so the battery is fine
My question is should i replace the BMS on the pack ?

battery is 48v 10ah the charger/stun gun was under two amps an aliexpress special lol
also on another note last night on charging the battery the charger was blinking red and yellow I assumed it was balancing I have no idea what happened. I am going to buy a new charger i suck at soldering so i am not sure about a new bms on the battery
plugged into the battery without even being plugged into the wall??? what? that will just make your battery dump sparks into ur charger unless its a really expensive charger. It has to be plugged into wall and then battery, never the other way
 
Some chargers make you do it that way I don't know why then after charging they make you unplug from wall before removing the battery
This is a video of a NiMh battery charger doing the same http://www.youtube.com/watch?v=fY81E39YDKA
 
My first look at this subject. Checking diagrams online, it is surprising how many chargers don't include a diode in series with there outlet fuse. Just a simple one way device, that allows the charger to put power in to the batteries, but not the batteries to power the charger. Worth about a cent in any currency, it would lift this cloud over connection order. Nobody should have to care about connection order. I have never seen another situation where it matters. Having worked specifically on emergency lighting for a year or so, I have seen quite a few chargers, and swapped quite a few batteries. This issue should not exist.

Perhaps an explanation is looming to do with very accurate voltage control and the varying resistance of packs at different charge levels. I'm talking about the pack and diodes resistance values as a voltage divider. Or perhaps it's the supply's start up and protection control that won't allow initialisation, Or even starts up without regulation for a moment.

Can anyone explain this?
 
Can it be we just talk about the cheapest charger and the cheapest 48v20ah pack. As we demand the cheapest so the cheapest shit comes are way.
 
it has nothing to do with cheap. if the output caps are not already charged up by the charger then when the battery is connected the current to charge up those caps will create a spark.

everyone should know by now to plug in the charger first before connecting it to the battery.

if you have the kingpan charger with the switch next to the plug, you turn off that switch to plug it in to the AC in order to prevent the inrush current from damaging the switching transistors. then when the charger is powered up on the input, you turn on that switch to power up the output, then you plug the battery in to the charger.
 
999zip999 said:
Can it be we just talk about the cheapest charger and the cheapest 48v20ah pack. As we demand the cheapest so the cheapest shit comes are way.

It's a shame to save a few cents, if the product becomes unsuitable for use.
I will see what arrives in the post (because mine is on it's way) and if it's the same issue, I will pop a diode inline and see what sort of voltage appears across it.

p.s dnmum post has appeared while I scribbled this one down. It sounds a little like initialisation issue's are addressed. uncontrolled inrush at power up, if cells are already present. So, moving along a little... A relay is needed within the charger to only connect the battery after the charger has been on a moment. The time taken for the relay to move is perhaps enough delay, so it should be a £ project.

I won't accept this 'doing it in order' it is extremely poor. Accidents do happen.
 
Hoe many charger's come with plug in instructions ?
Just the same I think I should post a large note on the wall per Dnmum's Instructions. Also how to unplug my bike each time ect.
 
999zip999 said:
Hoe many charger's come with plug in instructions ?
Just the same I think I should post a large note on the wall per Dnmum's Instructions. Also how to unplug my bike each time ect.

+!-1?
Any?

i have done it both ways. batt to charger them the wall the other way with the switch on or off the then battery.

As they say Sh*t happens, sometimes for no reason. be it good quality or junk Sh*t happens.

Dan

P.S> I think Dnmun has some 48v chargers if you need one.
 
I have done it both ways for 4yr. on a Ping 48v5a charger first set at 60.3v, 72.3v and now it's at 82.4v. same old Ping. I triied to turn it down to 42v but it stopped at 49v so went the other way to 82v. let's see what happen's.
 
First I hope you feel better after this shock.
Like others have said,the power supplies sell for very cheap. I think mine sold for $25. If you want to protect the back feed into the caps take the voltage from the red power led and build a relay circuit to turn on the output relay or fet switch. If you put a diode in the circuit you will get a small drop across it and I don't now if the voltage can be adjusted.
I did have a small spark on the AC power plug one time. It happened one time and it just may mean I hit the peak of line.
Mine works fine so far and just plug it into the wall first, then the battery.
 
you will always have the spark at the AC plug. that is not what i was talking about.

i said clearly you should always have the charger energized and powered up in the back end when you connect the battery in order to stop the spark on the charging leads.

and for those fortunate enuff to have the chargers with the switch on the high voltage in the front end then that has to be off when you plug the charger in to the AC and turned on before you plug the battery in. why do i have to repeat it over and over. how hard can it be to understand.
 
dnmun said:
you will always have the spark at the AC plug. that is not what i was talking about.

i said clearly you should always have the charger energized and powered up in the back end when you connect the battery in order to stop the spark on the charging leads.

and for those fortunate enuff to have the chargers with the switch on the high voltage in the front end then that has to be off when you plug the charger in to the AC and turned on before you plug the battery in. why do i have to repeat it over and over. how hard can it be to understand.
You need to get rid of both. On the AC side you can use a power strip or remote switch so you don't have power cords with arc marks inside the connections.
When your done charging shutoff the power going into the charger. The caps have a short life and power surges from storms can kill your power supply.
The newer switch mode supplies work great and they are lighter but many of the cheaper ones are not as robust as the older linear supplies.
 
Precharge with indication of finish of precharge both ways, battery to charger, battery to controller
An led across one resistor in a precharge divider, could also indicate a charger/controller short.
Or a closely rated circuit breaker on the battery, would shut the inrush down, possibly saving the equipment from damage.
 
So.. lets say there is a 5 second power cut. The power comes back on, and this 3 stages of mains-switch-connect is not going to happen. The AC is being turned on with the switch already made, and the battery connected. Is a power cut actually going to kill a charger?

Mine has arrived now. Nothing at all came with instructions :) So I'm a bit wary of it. It's an ecitypower and thankfully no daft switch.
 
I'm wondering if he just plugged the plug in while it was rotated, which can touch a positive prong to either ground or negative on some plugs.
 
My charger leads measure 12uf. I'm not seeing any problem with connecting it however I feel like.
 
I still think that big a spark was caused by a dead short. The hot + pong touched neutral.
 
dogman said:
I still think that big a spark was caused by a dead short. The hot + pong touched neutral.

I agree, a numb finger indicates an explosion not a shock. Only crossed wires could do that kind of damage. Even 10,000uf low impedance smoothing caps don't go with a serious bang. Unless you get them backwards. In which case you can blow them to pieces.

With no pics of the damaged parts, we will never get beyond suspicion. It sure don't seem right. It's quite a mind boggling thread.
 
Could you please supply us with pictures of the charger and the name of the company you purchased from?

We need clues of what to buy and avoid.

Thanks,
Eric
 
Avoid buying all chargers? They all contain dangerous potentials of voltage. :twisted:

All those who have KFF'ed raise a blackened hand. Yep, 99% of us.
 
emiyata said:
dnmun said:
you will always have the spark at the AC plug. that is not what i was talking about.

i said clearly you should always have the charger energized and powered up in the back end when you connect the battery in order to stop the spark on the charging leads.

and for those fortunate enuff to have the chargers with the switch on the high voltage in the front end then that has to be off when you plug the charger in to the AC and turned on before you plug the battery in. why do i have to repeat it over and over. how hard can it be to understand.
You need to get rid of both. On the AC side you can use a power strip or remote switch so you don't have power cords with arc marks inside the connections.
When your done charging shutoff the power going into the charger. The caps have a short life and power surges from storms can kill your power supply.
The newer switch mode supplies work great and they are lighter but many of the cheaper ones are not as robust as the older linear supplies.
To confirm, what order should the proper way of disconnecting the battery pack / charger / power supply after the charging is finished be?

You mentioned power supply off first, but wouldn't this be the same configuration OP had that caused the sparks / shock? batteries connected to a charger that is not powered on :|
 
you can unplug the battery whenever. that has nothing to do with it. you just do not want to plug the charger into the AC with the battery attached initially. the reason they put the switch on it is because intelligent people would know to have the switch turned off when you plug it in. some people will do whatever they please and intelligence has nothing to do with it.
 
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