Why did my boat shock me?

[jtexas]

Just curious, mostly.

I had a 12V accessory socket clamped onto the battery posts, using it to power a compressor to top off the trailer tires. As I was removing the neg clamp I felt a little bit of a jolt in my fingers. The insulation is gone from that one. Pos was still attached.

I was standing on the street, leaning over the transom (glass boat, metal transom cap).

All my electrical devices are in perfect working order.

No way is there a parasitic drain on this battery, it sat for over 3 months & still tested & performed at near full charge.

No one else was home, so I had no test subject to replicate the result.

I have no known neurological conditions, at least none that manifested themselves before or since.

Can you get a shock from one post of a battery?

Can you think of a wiring scenario where this is possible?

thanks!

 

[fuzzeywiggler]

Re: Why did my boat shock me?

Did it feel like a static shock?

 

[jtexas]

Re: Why did my boat shock me?

nope, not at all like static. didn't start when I first touched it either. started when I squeezed and ended when the clamp lost contact with the batt post.

 

[Silvertip]

Re: Why did my boat shock me?

If the compressor was running when the disconnect was made you received an inductive shock as the field collapsed in the motor, much like the ignition coil works on an engine.

 

[Lone Duck]

Re: Why did my boat shock me?

If the compressor was running when the disconnect was made you received an inductive shock as the field collapsed in the motor, much like the ignition coil works on an engine.

Yup!

 

[new_boater]

Re: Why did my boat shock me?

J
I have no known neurological conditions, at least none that manifested themselves before or since.

sorry could not pass up this one

 

[jlinder]

Re: Why did my boat shock me?

The shock was probably from finding out how much boating costs. :redface:
Sorry I could not help myself.

Inductive loads can generate big voltages.

 

[jtexas]

Re: Why did my boat shock me?

good thinking, I hadn't considered that.....the compresser was switched off - it shuts off when it hits a pre-set PSI. It looks fairly low-tech (physical contact of the gauge needle with a metal tab is what shuts it off), but I guess there could be a capacitor in there.