Ba neh neh neh......My Charger Blew up :(

[johnjapan]

Bought a charger from em3ev about four months ago and ive had no problems recharging what so ever.
Got home last night plugged the charger to the battery and then the power cord to the power outlet as I usually always do.

Loud electrical shocks ensued scared the crap out of me.
I Unplugged it right away but from what I smelt after it seems like the damage"s been done.
What happened and can I fix it?

Is it dangerous to open a charger for risk of electrocution even when unplugged?
Now that my charger is done im pretty much fudged with a CK and.my battery is useless hence ebike commute to work impossible

Get me out of the ebike blues

[cal3thousand]

Is that the proper sequence that Paul (em3ev) suggested?

I'm of the understanding that most of these bulk chargers should be plugged into the wall first so that the capacitors can fill up and you avoid the "spark" on hookup. It could be that I'm not familiar with this charger, but I'm leaning towards the plug method.

Were you getting a spark usually when plugging in previously?

[knighty]

you're supposed to plug chargers into the wall first

so the charge leads are at (roughly) pack voltage so there's less spark/current rush when you plug it in


the failure could be totally unrelated to this... but it's worth knowing for next time

[johnjapan]

you're supposed to plug chargers into the wall first

so the charge leads are at (roughly) pack voltage so there's less spark/current rush when you plug it in


the failure could be totally unrelated to this... but it's worth knowing for next time

I am definitely not saying that its not a fault of mine.
More than 90 % of cases are user error. I'm only figuring out what it is.

I usually carry the charger on the back of my.Topak bag maybe the shaking from riding my bike loosened a screw or something. I haven't dropped it or it hasnt been near water since I put a waterproof canopy over the bag.

Is it safe.to.open the charger my self so I can take.pictures and post here?

[johnjapan]

you're supposed to plug chargers into the wall first

so the charge leads are at (roughly) pack voltage so there's less spark/current rush when you plug it in


the failure could be totally unrelated to this... but it's worth knowing for next time

I didn't know that was the proper sequence to.plug your charger although I don't think thats the cause.

[dnmun]

it should not cause it to blow up, but it is harder on them.

since you discussed the history, you are likely looking at damage caused by carrying the charger on the bike or if you dropped it. they have electronic components inside that are attached to a thin pcb and when the pcb vibrates or is flexed when it is dropped and hits the floor then it damages the connections of the electronic parts to the pcb or tears the traces open. that may be what happened to you.

if you open it up and take some pictures of the black stuff inside we can start guessing for you. but if this is so alien, you should be ordering a new charger right away. they are not usually too easy to fix. but i do. nobody knows where you live either so you cannot get local help.

[dogman dan]

You might consider a second, el cheapo charger for the inevitable day something goes wrong with your primary charger.

Whoever on ebay can ship you another fastest and cheap. Get you going again asap while you gather funds for another charger.

So far my experience with chargers is that it's an almost random crap shoot whether they last forever or last a few months. I've had some good brand chargers that were defective when sent, and el cheapo's that lasted amazingly long. And several I killed stupidly of course.

[lbz5mc12]

One of my chargers blew up like that and it turned out that the ground wire became disconnected inside the charger.

[dnmun]

your ground wire may have been disconnected if the collector of the switching mosfet shorted to the case and all the power was delivered to ground through the case. if you do not have GFCI outlet the case could be energized to 340V DC. so be careful with it.

[pdf]

it should not cause it to blow up, but it is harder on them.

since you discussed the history, you are likely looking at damage caused by carrying the charger on the bike or if you dropped it. they have electronic components inside that are attached to a thin pcb and when the pcb vibrates or is flexed when it is dropped and hits the floor then it damages the connections of the electronic parts to the pcb or tears the traces open. that may be what happened to you.

if you open it up and take some pictures of the black stuff inside we can start guessing for you. but if this is so alien, you should be ordering a new charger right away. they are not usually too easy to fix. but i do. nobody knows where you live either so you cannot get local help.

+1. I dropped a charger about a foot to a concrete surface. The transformer was held on the PCB by the very thin windings wire. The interia of the heavy transformer pulled it loose when it hit the floor. It did not work so I took it apart to trouble shoot. Before I saw the transformer had come loose, the charger popped and the magic smoke came out in a spectacular fashion; small smoke trails from flying solder and plastic bits. Like a mini firework display on the table. After that, several traces were blown off the PCB, one transistor blown apart, and two resistors fried. dnmum led me through trouble shooting one charger that I repaired successfully and I could probably have fixed this one, but was too lazy. Bought two (one low rate one as a spare and one like the one I busted) from dnmum and they work fine.

It is very easy to damage a charger of the type I had by dropping or jostling. Not saying this was the case for you, but a reasonable possibility. They can be fixed but will will need small quantities of stuff usually sold in batches of 10 or more. It is do-able and a lot of fun if you have the time, but it takes a while if you don't have the parts in hand.

[dnmun]

the 'low rate' charger is the headway charger and i think they are actually the best chargers around. i have never seen one fail, but did have one that was dead from the factory that i repaired. it also had a torn trace that was torn when they assembled the charger but since they don't test them at final it was never discovered to be dead.

you can actually hike the output current on the headway charger too but not really worth the effort. gotta solder new resistors in some spots.

[johnjapan]

You might consider a second, el cheapo charger for the inevitable day something goes wrong with your primary charger.

Whoever on ebay can ship you another fastest and cheap. Get you going again asap while you gather funds for another charger.

So far my experience with chargers is that it's an almost random crap shoot whether they last forever or last a few months. I've had some good brand chargers that were defective when sent, and el cheapo's that lasted amazingly long. And several I killed stupidly of course.

I live in Japan a place where ebikes aren't born. Ebay takes just a long as buying.a new one from paul.
Even if it weren't a problem I wouldn't know where to begin as to what kind of charger I need what the specs are etc. etc.


Id be glad to send you pictures and open the charger, but not at the risk of getting shocked for 340v.

[dnmun]

the only way to find out is to try it.

[johnjapan]

your ground wire may have been disconnected if the collector of the switching mosfet shorted to the case and all the power was delivered to ground through the case. if you do not have GFCI outlet the case could be energized to 340V DC. so be careful with it.

Assuming I don't have any special outlet , What other safety homebrew options do I have to make sure I don't get electrocuted while servicing the charger?

[johnjapan]

the only way to find out is to try it.

can't you die from 340v?

[cal3thousand]

the only way to find out is to try it.

can't you die from 340v?

You can die from 12V. It's current that kills and depends on where you get it. Something ridiculously low like 30mA AC is enough to cause cardiac arrest.

[johnjapan]

the only way to find out is to try it.

can't you die from 340v?

You can die from 12V. It's current that kills and depends on where you get it. Something ridiculously low like 30mA AC is enough to cause cardiac arrest.

Given what you just Said,
I just want know if an unplugged charger has enough potential to kill you.
Not so much on the technical, theory babble.

[mushymelon]

the only way to find out is to try it.

can't you die from 340v?

You can die from 12V. It's current that kills and depends on where you get it. Something ridiculously low like 30mA AC is enough to cause cardiac arrest.

Given what you just Said,
I just want know if an unplugged charger has enough potential to kill you.
Not so much on the technical, theory babble.[/quote]


LOL

You will be fine just don't go poking at the caps after unplugging it. I use one of those cheap household power testers the kind you hover over a live line, before i make contact with my hands directly.

[dnmun]

the caps all have drain down resistors.

[johnjapan]

the problem has been fixed yeah !
I opened up the charger the other day and I found that the board or one of the soldering joints had burned through the bottom plastic sheet that prevents it from touching the inside of the case so what was happening was that one of the soldering joints was touchiing the inside of the case and it was shorting out.

after re-soldering it worked perfectly fine also made sure the plastic sheet was properly in place

[dnmun]

do you have a picture of the one that was attached to the case? is it green? is it the ground?