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Seen a diesel truck today filling up with the engine running and as soon as he touched the pump to the tank, bang the battery pole clamp to the battery pole post was fried and completely gone. Does anyone know why. I can't remember if it was the - or + that went. It had 2 battery's and a old truck 1980's some Jap thing. He got it going again and no problems, did not blow even a fuse.
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The bowser nozzle itself is electrically earthed (or should be) but the truck has no other reference to earth. He must have shorted some exposed conductor to the truck chassis with the metal part of the nozzle to draw enough current to blow a battery terminal off. Probably something in the starter motor circuit like a solenoid terminal. Few vehicles have any fuses or overcurrent protection in the starter motor circuit.
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Static electricity going down the fuel line. I have heard it crackle down hose on the overhead tanks on our farm. There are earth straps at diesel bowsers. That's what they are for.
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Nope. The current from a static discharge would be in the milliamp area. You would need thousands of amps to blow a battery terminal off. Edited by user Thursday, 10 August 2017 7:15:27 PM(UTC)
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2x12V batteries on these in series, but only the 0V terminal goes to the chassis. There is a strap between the + term on that battery and the -VE on the next battery. As Geoff says, must have been a short. |
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Originally Posted by: gm5735 Nope. The current from a static discharge would be in the milliamp area. You would need thousands of amps to blow a battery terminal off. Melted in a second by the looks of it. He just connected what was left of the terminal and started it and drove away. It happened as soon as he touched the fuel nozzle. I was thinking it may of came from the old clapped out old service station with some problem, but it must be a short somewhere on the truck. With all the fires you hear of nowadays with problem cars and I never thought that their could be a problem like so when filling up, so I thought to ask the question.
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the Kenworth I had, had a braided earth strap from the engine to the chassis. I had dramas getting it to start. I was testing stuff with the test light. I hooked the test light to earth on the battery and for some reason I touched the probe to the chassis. The light came on. Had me confused. I got the auto sparky to check it out. After looking about he found the braided earth strap was broken. Don't ask me why that made the chassis test live. But I bet if I had shorted the chassis via the fuel tank it would have given a similar result. It had 4 N70 batteries hooked up and it was always a slug to start until the new earth strap went on. If the earth strap was hooked up from the bowser there would have been no battery explosion though???
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Originally Posted by: wbute the Kenworth I had, had a braided earth strap from the engine to the chassis. I had dramas getting it to start. I was testing stuff with the test light. I hooked the test light to earth on the battery and for some reason I touched the probe to the chassis. The light came on. Had me confused. I got the auto sparky to check it out. After looking about he found the braided earth strap was broken. Don't ask me why that made the chassis test live. But I bet if I had shorted the chassis via the fuel tank it would have given a similar result. It had 4 N70 batteries hooked up and it was always a slug to start until the new earth strap went on. If the earth strap was hooked up from the bowser there would have been no battery explosion though??? In that case the chassis was reading 12 volt it most likely was back feeding thru globes ect as voltage drop cant exist with out current flow I'll guess your test light was a led is why you were reading the full 12 volt if you put the chassis earth back on you would of got the same spark as you do when trying to connect the battery with the head lights on it wouldn't have blown the terminal off the battery that had to be a positive negative short on the truck Edited by user Sunday, 13 August 2017 9:09:20 AM(UTC)
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GM bleed us dry and run away. |
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