Adding a battery disconnect switch

[Retiredwarhorses]

In the 35 years I have been messing around with military vehicles I have seen this more than once and as a 40 year telecommunications technition doing component level repair I have the background in theory to back up my assertion.
Yes now that one can get a converter off of eBay for 20 bucks everyone should be using a converter but I assure you 10-15 years ago they did not exist in an affordable package and anyone wanting 12V tapped it off the batteries.
And there are folks out there right now doing it, they just might not admit to it.

I refurbish and and sell Motorola 2-way radios and just last year I replaced two Astro Spectra 110W mobiles before the dealer admitted they were in a S. TX law enforcement "command" vehicle where they were tapping off of the batteries for 12V and had a ground side battery switch, They had a generator to power the bulk of the communications gear, they just needed a mobile to use until they got to the "scene of the crime".

These radios have reverse polarity protection, that does not guarantee "protection"

ALSO I have read right here in SS.com where folks are planning to use a "tap" to keep memory live in 12V electronic devices

27yrs in Telecommunications as an Engneer for Nortel, at the mfg level.
As well as 48v power plant design.

 

[Coug]

So AM General engineered the 12v side of the truck wrong....hmmm, I doubt it.

Actually, that's the opposite of what I said, or what I intended to say.

I said if the 12V isn't properly designed to deal with the possibility of reverse voltage that it could be an issue, but I assumed that the engineers thought of that and said this only becomes an issue when you add things to the system that were not designed to work with it.

 

[Retiredwarhorses]

Actually, that's the opposite of what I said, or what I intended to say.

I said if the 12V isn't properly designed to deal with the possibility of reverse voltage that it could be an issue, but I assumed that the engineers thought of that and said this only becomes an issue when you add things to the system that were not designed to work with it.

The issue is most folks have no idea how to wire anything in a military truck, or in my case most of the time, hmmwv’s...front battery with body grounds, wrong size wire, no split loom, no fuzed power sources...had a truck that had all the wires run to the rear tie rapped to the e-brake rod, customer couldn’t understand why the e-brake and rear brakes wouldn’t releases at times.
i follow the same engineering that AMG used on the A2 trucks...