I went to start out my automotive (a 2006 Toyota Camry) and once I turned the important thing within the ignition swap, NOTHING occurred. The automotive was completely inert. The radio wouldn’t play, the passenger cabin ceiling gentle was darkish and I wasn’t going wherever, not less than not in that car.
I guessed that the automotive’s battery had failed, however being an engineer (you realize the sort.) I simply needed to measure the battery’s terminal voltage. I went and obtained my trusty Sears digital multimeter, raised the hood of the automotive to show the battery and touched one of many multimeter probes to the constructive publish of the battery on the actual spot you see within the picture beneath. That one probe slipped right into a small crevice between the battery’s constructive publish and that publish’s clamp and when it did, there was a spark proper there on the spot the place I’d caught my probe. Nothing was linked (but) to the opposite multimeter probe which left me questioning “Why did I see that spark?”
Determine 1 The battery that was probed and the situation the place the surprising spark occurred.
This was in Might of 2025 which meant that battery was two years outdated having been put in in Might of 2023. The battery had not been touched in any respect throughout these two years which led to the
downside at hand. Regularly, the 2 publish clamps had labored themselves unfastened. The clamp serving the constructive publish had really misplaced its electrical connection to that publish. When my multimeter probe obtained concerned, the spark arose from the battery making connection once more by way of the steel of the probe tip to the entire stuff the battery was usually referred to as upon to feed.
Now that I knew what was unsuitable, I set about making repairs by tightening the 2 publish clamps, BUT there was a really particular security situation at hand to which I need to draw your most alert consideration.
My automotive makes use of an inner combustion engine, which includes a 12-V lead-acid battery whose destructive publish is grounded to the body of the automotive. This has been a traditional design method for a few years. I feel that pre-1950 or so vehicles with 6-V lead-acid batteries had their constructive posts grounded to the automotive frames, however that’s a complete different factor.
When you’ll do any work on a automotive corresponding to my very own, the place that work includes the automotive’s battery, you MUST, MUST, MUST first disconnect the clamp that connects to the battery’s destructive publish. For those who fail to take action and also you by accident occur to make a reference to some device (a socket wrench, perhaps) from the battery’s constructive publish to the automotive body, that unintended connection will short-circuit the battery. There shall be a flash, and in accordance with one thing I as soon as learn, the battery would possibly even explode.
You don’t want to threat having that occur.
I disconnected the clamp from the destructive publish. I then disconnected the clamp from the constructive publish and scoured each publish surfaces and their clamp surfaces. Subsequent, I reattached the constructive publish’s clamp, I reattached the destructive publish’s clamp (in that order) and I began the automotive.
The whole lot labored. The whole lot was again to regular. I drove it to the grocery retailer and again once more. We would have liked some milk.
John Dunn is an electronics marketing consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York College (MSEE).
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