Overcurrent Protection at Batteries

[Kettlewell]

Mark: The fuse won't do a thing if you drop the wrench across the battery terminals--don't ask how I know!

Seriously, here is an application for a composite battery wrench--some sort of super-strength plastic in the middle with the right sized open end metal wrenches on the ends.

Here is a link to the Ample Power description of why they suggest fusing the negative side of the battery.

And here is one of their wiring diagrams showing this.

I know, I know, ABYC says no and nobody does it this way, but they do make an argument in its favor. Worth thinking about.

[GordMay]

Originally Posted by Kettlewell

... they do make an argument in its favor. Worth thinking about.

Their argument represents a FALSE economy.

[CarlF]

Tip for the day..

A very nifty way to measure the distance between your battery posts is with a standard steel measuring tape. It only takes a split second. You don't even have to write down the measurement just refer to the handy cut-outs in the tape.

Carl

[CharlieJ]

Good Grief!! This is from the Ample Power site:

A fuse on the positive side must be enclosed inside an insulator of some sort, which adds unnecessary cost to the system.

To save $20 for an ANL fuse holder "they" are advocating going against good electrical common sense... to say nothing about ABYC and CFR standards and requirements!! Sheeeesh!

Charlie

[cal40john]

If this is a fuse mounted on the battery terminal, it doesn't make any difference which terminal it's on. Voltage is a potential difference. Ground isn't a relevant term unless you have a wire connected to it.

Farther down the wire, fuses for secondary devices on the hot side make sense. Reasons for this are on cars every bit of metal around you is ground, if the wire upstream of the fuse chafes through it's a short. Metal boats same deal, entire engine on your boat same deal, wet bilge full of salt water same deal.

If you disconnect the negative battery terminal from the boat, there is no reference. You can connect the positive terminal to anything, say your bonding system, the plus terminal is now at water (ground) potential and the negative terminal, is -12 volts, connected to nothing, doing nothing.

John

[smurphny]

Originally Posted by CharlieJ

Good Grief!! This is from the Ample Power site:

To save $20 for an ANL fuse holder "they" are advocating going against good electrical common sense... to say nothing about ABYC and CFR standards and requirements!! Sheeeesh!

Charlie

Indeed. Of all the things that can go wrong on a boat, the destructiveness of an electrical fire is probably right below having a propane explosion. They are hard to put out and can happen in seconds. Spending a few bucks for some good ANL fuse blocks, imo, is money well spent. The electrical systems on boats are often very scary from a safety point of view. Unlike standard residential or commercial 110/220v. wiring, connections on boats are regularly left exposed, crimp connectors dangle in mid-air, etc. Most of the connections you see are not even Scotchkoted to keep the salt air out.