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I have a small issue that is causing a lot of problems. I'm on a Formula SAE team and our battery is consistently shorting between our positive terminal and our chassis. Our chassis is the grounding point.

Our battery is underneath our seat, our seat is made of carbon and therefore when the driver moves shorts occur. I've tried using tape, rubber covers and plastic boxes. The box cracks under the weight of the driver and the tape and covers fall off during a long race.

How can I prevent shorts with a solution that wont break, nor fall off?

In case a short does occur, we use breakers.

Below is a sketch of the position of the battery under the seat. At point one, when we are static, the seat does not touch the battery, but under high acceleration, the driver will rub on to the battery terminals. This knocks off tape and covers that are on it. In the course of a long race, eventually shorts start to occur after the tape/covers have been rubbed off. We noticed that the issues happened on tight turns and moments of high acceleration.

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    $\begingroup$ I think it's not related to the g-accelerations, but rather to the vibrations and shocks (running over rocks, bumps, etc).. Is it really the battery or the cables -connections that are shorting? $\endgroup$
    – Gürkan Çetin
    Commented Jul 1, 2015 at 18:39
  • $\begingroup$ I can get a photo tonight. Speed: max 60ish MPH, Turning radius: 15 ft is probably the tightest $\endgroup$
    – Adam
    Commented Jul 1, 2015 at 19:52
  • $\begingroup$ @GürkanÇetin The positive battery terminal shorts through our carbon fiber to our chassis. Our chassis is our grounding point. Before racing we put rubber covers and tape the terminals, but with our car changing direction quickly, tape/rubber covers fall off from moving seat. $\endgroup$
    – Adam
    Commented Jul 1, 2015 at 19:55
  • $\begingroup$ It sounds like the root cause is too much movement of the seat (or that it touches the cables at all). Since it seems like you tried some of the obvious solutions for the cables, maybe it is time to look at it from the angle of keeping the seat away. $\endgroup$
    – hazzey ♦
    Commented Jul 1, 2015 at 20:39
  • $\begingroup$ I'd say, a thin, dense, vulcanized rubber "pad" glued underneath the seat. $\endgroup$
    – rdtsc
    Commented Jul 2, 2015 at 3:01

3 Answers 3

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1st suggestion would be to find a sturdier cover for the battery. However, it sounds like it might just be badly positioned.

Can you move it, rotate it, flip it (if it's an AGM type that will work at any angle) to put the terminals away from harm?

Failing that, can you put some solid plastic or other insulator over the top of it, snugly, so it can't be touched. Nylon chopping boards are inexpensive at Ikea, drill a couple of holes for the terminals etc., layer a couple of boards to create a light, strong, solid block of insulator on top of the battery.

3-D printing something might work but it'd have to be very solid around the terminals.

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  • $\begingroup$ The problem is, there really isn't many other places to put this battery, for safety reasons. If I was to rotate it, it would be directly touching other metal. I really like the nylon chopping boards & 3-d printing idea. The Nylon chopping board seems like the best way to go. Thanks! $\endgroup$
    – Adam
    Commented Jul 2, 2015 at 14:06
  • $\begingroup$ You could also have a search for different-shaped batteries, or as I said AGM ones that can live on their side, placing the terminals away from harm. Some types also have low-profile terminals that a bolt screws into rather than post-type typically found on cars. $\endgroup$
    – John U
    Commented Jul 6, 2015 at 12:03
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Tilt the battery at a slight angle away from the seat so that the seat doesn't touch the terminals. You should be able to get away with small tilt angles without having the battery leak (assuming lead-acid), at least during use. You may want to remove the battery in between uses though.

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A piece of thick plastic or timber will make a lid that will solve this or use a gel battery and lay it on its side

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    $\begingroup$ John - I've noticed what appears to be some confusion about how this site and StackExchange works. It's definitely not like other forums, and I'd really encourage you to revisit the tour and read over the help center. StackExchange is focused on high quality Q&A in order to create lasting value through shared knowledge. Editing posts is encouraged, and longer answers that explain the why behind the how are also very much encouraged. $\endgroup$
    – user16
    Commented Jul 10, 2015 at 2:38

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