Warning!!! Batteries can shock you from a distance!

[scrobo]

Well... doing some work under the dash...

Ign switch was crooked (I have it coming through the original ENGINE OVERHEAT light on the dash) so my friend went under to straighten it.

ZAP.

Grabbed all the wires and contacts and all to turn it instead of turning it from the base.

Gave him a good jolt. hit his bead under the bow. Yelled a few words...


Moral or the story... It can't hurt to disconnect your battery when you want to touch your boat But sometimes it CAN hurt if you don't.

 

[dave68iou1]

Re: Warning!!! Batteries can shock you from a distance!

Nice!

 

[Windykid]

Re: Warning!!! Batteries can shock you from a distance!

A shocking revelation!

 

[jasonh]

Re: Warning!!! Batteries can shock you from a distance!

A friend of mine caught his wedding ring between a positive and ground while working under his boat dash. He said it got "real hot real quick". He had a nice burn and the ring got a little droopy in the mere seconds it was there.

He won't change the oil in his truck without disconnecting the battery now!

 

[dhath]

Re: Warning!!! Batteries can shock you from a distance!

A friend of mine caught his wedding ring between a positive and ground while working under his boat dash. He said it got "real hot real quick". He had a nice burn and the ring got a little droopy in the mere seconds it was there.

He won't change the oil in his truck without disconnecting the battery now!

Damn I bet that left a mark!!!

 

[MrBigStuff]

Re: Warning!!! Batteries can shock you from a distance!

There must be something more to the story because your normal skin (epidermis) resistance is way too high to get a shock you can feel off of a 12 volt battery. I routinely grab both battery terminals when transporting an older battery I have that does not have a handle. The skin of your hands should not be able to produce enough current from that potential to be felt. Was he wearing a ring? Are you sure it wasn't a wire strand that poked him?

You can verify for yourself. Grab your DVM leads in either hand and measure the resistance. Use Ohm's law to find out the current a 12 volt battery would produce given that resistance.

I just tested mine. Mine dry are 4.2Mohm. Wet they are 800Kohms. Worst case that's only 15 microamps! I challenge you to be able to discern a 15 microamp current through your hands.

 

[Matthew_B]

Re: Warning!!! Batteries can shock you from a distance!

My FIL found out that outboard motors run magneto power up to the ignition switch. Whatever voltage his Johnson kicks out, it's more than plenty to bite!

 

[MrBigStuff]

Re: Warning!!! Batteries can shock you from a distance!

My FIL found out that outboard motors run magneto power up to the ignition switch. Whatever voltage his Johnson kicks out, it's more than plenty to bite!

Magneto power eh?
Magnetos on outboards usually have two outputs; one for the spark plug(s) and one for the general electrical system. The spark plug voltage is indeed high but it does not go outside of the motor. The general electrical supply is intended for recharging the starting battery and supplying general power for on board electronics/gauges/etc and is regulated at about 14 volts. If the boat builder ran that output up to an instrument panel, then there should also be a battery installed. Without a battery, the voltage can run high. This could damage any electronics that require 12 volts. At any rate, you have to do two things; leave out the battery and then be foolish enough to grab onto the circuit while the engine is running.

 

[scrobo]

Re: Warning!!! Batteries can shock you from a distance!

Out and did a test.

It hurt me, Well... hurt isn't the word... gives you a good jolt.

There is an aftermarket 5 terminal key ignition. I LIGHTY grabbed it... (Didn't want to haul on it like he did...) all the way round... gave me a shock.


If I wasn't expecting it and I was under the bow... I'd of hit my head too.

 

[QuadManiac]

Re: Warning!!! Batteries can shock you from a distance!

A shorting or grounding lead to kill the magneto generated CDI ignition coil supply perhaps?

 

[Matthew_B]

Re: Warning!!! Batteries can shock you from a distance!

The engine in question is a old one with points. Both points wires are run up to the dash and grounded by the ignition switch to kill the engine.

When the points open, 50 to 100V is produced on the primary of the magneto coil.

 

[scrobo]

Re: Warning!!! Batteries can shock you from a distance!

The engine in question is a old one with points. Both points wires are run up to the dash and grounded by the ignition switch to kill the engine.

When the points open, 50 to 100V is produced on the primary of the magneto coil.

Wow.

My friend getting jolted has "sparked" a technical discussion!

 

[Rob454]

Re: Warning!!! Batteries can shock you from a distance!

A friend of mine caught his wedding ring between a positive and ground while working !

BTDT. i did that on my moms caddy. went to change the battery and the designers figured it woudl be best to place it right by the fender so the lip of the fender and hood make it really hard to get tools or hands in there. I finally got my monkey paws inside the small space and ZAP. the damn ring caught the edge of the fender and zapped the hell out of my finger. The ring still has a nice chunk missing ( looks liek a diamond) and my finger still has the scar burn. My wife jokes that even when I take off my wedding ring I still wear one
Rob

 

[Dave-115hp-1970-115083]

Re: Warning!!! Batteries can shock you from a distance!

I was getting my car inspected at a gas station. It failed because the horn didn't blow.

I told the man, "Give me a minute and I would change the fuse under the steering wheel cover." It was mid-summer and the inside temp. of my car was cooking. I was sweeting alot.

everytime I tried to push the fuse in place and close the cover the voltage would start up my fingers like a 9 volt batter on your tough.

Oh, that reminds me. Never touch a car with wet hands that has the a welder hooked to it either