ELECTRIC FIRE PLEASE HELP !!!

I was waking my 1970 750 Commando up from a long 2 year nap.... After a long day of oil change, cleaning out old gas and stuff like that I decided to take my YUASA trickle charger and let it sit on the bike over night, just to be sure my battery would be 100% in the AM. I looked close at the battery and identified the Negative side and the positive side, then placed the red clip on the pos. and the black clip on the negative (basic)... At this point the charger was not plugged into the wall, it was just sitting on the ground next to me (not touching ANYTHING, just sitting on a concrete floor). I was just about to plug it into the wall when I noticed smoke coming from the battery....then a pop and a flash of electric fire the some more pop sounds and more smoke. WHOA !!! I quickly grabbed the charger clamps and removed them from the battery. Unfortunately it was to late, with the smell of burnt electrics it was clear that some damage had been done to my bikes electrics : ( . First I inspected the area and noticed that the red wire that was connected to the + pos. on the battery was fried, burned and melted. I removed the battery and began following the red wire, painfully pulling appart my harness to reveal the now melted red wire. I followed it to the front of the bike were it seemed to be connected to the frame of the bike (maybe a ground ?). Can anyone make sense of this, what went wrong and why ??? Thanks !

Keep in mind that before my bike was sitting for 2 years it ran fine, this is a professionally restored 1970 Norton Commando 750 so all of the electric are well done. Also no wires were messed with during the last 2 years, infact on occasion I would even connect the same YUASA trickle charger..... WTH Please help !! :? :?

If I were to guess I'd say you connected the charger up wrong or you had a bad battery.

I'd say you got off easy , my 850 went up in a ball of flames when this stuff happened,panicked,dropped her on the side,watched the fuel pour out onto the sidewalk ,then POOF ! roasted marshmallows time. Not a good day . Firefighters commented on what a cool bike she WAS...

Naw if charger not plugged into the grid it'd do nothing hooked up wrong polarity. Hooking battery up backwards sure can, ugh but not a dead one. Red wires correspond with the + earth red battery terminal and connect to chassis. If charger had noting to do with it but the handling of the area, somehow red wire got shorted to a neg- carrying wire. I've had bugs or rats chew bare sections plus piss on it. I'd suspect a cross connection done by shoe eves in middle of the night and get out a test lamp and start checking what's getting current when it shouldn't. Trace red wire it must lead to a pinch point, but after smoke flys out a long section - suspect each and every spot wires tied together, bend a corner or go through a grommet where heat can't escape as fast as focus. Enjoy the dead end police loops which are about half all red.

My guess would be that the negative charger clip touched against some other part after it was connected and grounded the battery negative?

I'm with L.A.B., but why the harry didn't the fuse pop? I'd take the battery out and just connect the charger to the +&- as the charger should have a rather sensitive circut breaker and just start going through the wires until it stops tripping the breaker.


Tom

TJKII said:

I'm with L.A.B., but why the harry didn't the fuse pop?

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If the the charger clip on the battery negative terminal did ground, the fuse wouldn't blow-because it would not be in the circuit.

Have you looked to see if your zenor diode still has any diode-like qualities. ??

Although this sounds uncomfortably like what happens if you connect a battery negative earth into a positive earth system ?

Well today I got further into the issue, basically what I found was that the positive ground wire (red) melted. Why this happened I have no idea but suspect that I possibly had one of the gator clips on my charger touching the frame of the bike , that's a guess, I dont really know if that's the case ????? Still mystified buy lucky it only burned that one wire. I did check my charger and it's working fine, no issues. all other wires in good condition no exposed wires it's all tight and wrapped as it should. Chew on that and let me know what you all think ...

L.A.B., I Agree, if the the charger is not plugged in then it's not grounded.

Bradcommando said:

L.A.B., I Agree, if the the charger is not plugged in then it's not grounded.

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I think perhaps you may have understood what I've said then, as I didn't mention anything about the charger being plugged in?

What I meant was that if the negative charger clip did in fact short the battery negative terminal to the bike's ground side, then I would expect the battery current to burn out the positive battery wire.
The bike's fuse (presumably there is one?) would not blow because even though it is positioned close to the battery in the negative wire, the short would be going directly to ground from the battery terminal.

L.A.B. said:

Bradcommando said:

L.A.B., I Agree, if the the charger is not plugged in then it's not grounded.

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I think perhaps you may have understood what I've said then, as I didn't mention anything about the charger being plugged in?

What I meant was that if the negative charger clip did in fact short the battery negative terminal to the bike's ground side, then I would expect the battery current to burn out the positive battery wire.
The bike's fuse (presumably there is one?) would not blow because even though it is positioned close to the battery in the negative wire, the short would be going directly to ground from the battery terminal.

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This sort of begs the question.
If the ground (positive) was fused, would it have blown and should it be consider to fuse the ground for said occasions? There really is a lot of charging going with these things and many get confused with the whole positive ground thing. Opinion?

Bad thing about bikes is that the whole thing is looking to grab electrons from anywhere (it’s all metal). All my screwdrivers are wrapped on the shaft, and all alligator clips are completely covered all the way out to the tip. It's easy to hook up a charger or stick a screwdriver in to tighten something and take you mind off it, move something, and there go those pesky electrons.

This is why it’s a good idea to have a hard wired plug to the battery that you simply plug the tender into. The trick is to find a place that is not visible, but you can get a plug in. Photos anyone?

Commandos orginally had an electrical 'accessory socket' - could the battery charger be plugged into there ?

Wouldn't that bring the zenor diode into play ?

Curious where the red wire that burned was landed. Frame or engine? Only asking because there may be other components that were in the loop. These would have also carried high current and may be damaged. If the wire is from the batt straght to the frame, you should be fine just replacing it. Electricity is lazy, it takes the path of least resistance to complete the circut.

Rohan said:

Commandos orginally had an electrical 'accessory socket' - could the battery charger be plugged into there ?

Wouldn't that bring the zenor diode into play ?

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The owners handbooks mention using the accessory socket as a charging point.

caddy chris said:

Curious where the red wire that burned was landed. Frame or engine?

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Frame, according to Bradcommando

caddy chris said:

Only asking because there may be other components that were in the loop. These would have also carried high current and may be damaged. If the wire is from the batt straght to the frame, you should be fine just replacing it. Electricity is lazy, it takes the path of least resistance to complete the circut.

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If the battery terminal was the source of the short then I think it unlikely that the current would have passed through anything other than the frame and the positive battery wire.

Diablouph said:

The trick is to find a place that is not visible, but you can get a plug in. Photos anyone?

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I'm too much of a Luddite to have a digital camera, but I simply cable tie the "pigtail" connector from the battery to a frame member, tight enough that you'd really have to try to get the exposed (negative!) connection to contact the frame (having said which, it happened once - instant fuse blower) AND make sure to keep the plastic cover to the connector on when the Battery Tender's not attached.

Actually, since installing a LiFePO battery I no longer use the Tender regularly but I've left the pigtail there just in case.

BrianK, got a source (and size) on that LiFePO battery ?

Back in the old days it was common for battery to be disconnected before charging.............seems that might have been a good idea in the case?

I had the same thing happen. I had a standard sized battery with the angle iron bar type mount. Popular modification back in the day was to replace the rubber straps with shortened spokes down to the battery tray, so the bar was grounded. I put the charger clips on the battery and must have tugged on the wires at some point so that the negative clip came in contact with the bar. No fire, but the harness was fried into a hard mass that was impossible to dissect and diagnose, tossed the whole thing. the clips on chargers are a menace unless you're charging the battery off the bike.