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Sat Jul 27, 2019 5:20 pm

So I was thinking a bit more on ways to kill the 12v power if the vehicle is on fire and you cannot get close enough to turn off the ignition key.

There is this small motorized remote battery switch which can disconnect the battery power to the electrical system.

http://www.bepmarine.com/en/701-md

I figure I could possibly cut a 52.4mm hole in the side of the start battery box that is in the passageway from front to back. I think there may be enough room on the inside of the battery box underneath the framework, but I have to measure it. It needs 1-3/4" space to fit the body of the housing in the inside under the framework.

Then I need to find a secure, but easy to access On/Off switch.

It could also be used for anti-theft. If you can't start it, it's not going anywhere!

What do you think?

Sun Jul 28, 2019 3:04 am

Samba electrical harsh brownie

Electrical fires can be prevented easily by good wiring practices.

If it’s a non electrical fire , cutting the battery is of limited value.

That’s a lot of work for minimal benefit, one a$$e$$ opinion.

Sun Jul 28, 2019 4:17 am

Abscate wrote: Samba electrical harsh brownie

Electrical fires can be prevented easily by good wiring practices.

If it’s a non electrical fire , cutting the battery is of limited value.

That’s a lot of work for minimal benefit, one a$$e$$ opinion.

Hey it's just presented as an option since some folks were talking about killing battery power in a fire. This is one way to do it.

It is an expensive option at $150.00 for one.
I question what it worth more to me - the switch or cutting a hole in the body since I have the motto of "no new holes".

Actually I do have good electrical wiring practices so that's not a problem for me, but you never know on that score since the wiring is old.

I just happen to have one that was surplus from a job I did and it is just staring at me when I walk by it and wondering what use I could have for it.
It is easier to install fuses on the power wires.

It is getting more interesting as killing power for an anti-theft device, but I already have things installed for disabling the electrical so this is redundant.

Sun Jul 28, 2019 7:10 am

just install Hella battery cut off switch, red plastic key/ easy to hide/ cheap

I have used one for years, also works for anti theft , quick battery disconnect to do electrical work

Sun Jul 28, 2019 7:16 am

the joker wrote: just install Hella battery cut off switch, red plastic key/ easy to hide/ cheap

I have used one for years, also works for anti theft , quick battery disconnect to do electrical work
Likewise - especially when it's installed on the negative side. I also bypass it with a 5A fuse so the clock and radio still work, but any inadvertent short will just blow that.

Sun Jul 28, 2019 7:32 am

the joker wrote: just install Hella battery cut off switch, red plastic key/ easy to hide/ cheap

I have used one for years, also works for anti theft , quick battery disconnect to do electrical work

Yeah they work well, but this is sitting on the shelf staring at me!

The drawback to the Hella is you have to reach inside to get to it if it is installed at the battery location. If you run extra cable lengths you can put it anywhere, but it is extra cable lengths.
This would work for the house batteries under the bench seat where you cannot get inside safely.
This is just another option available. The thing I do not like about it is that it has to cycle. It's not long to rotate the switch, but my hand turning a Hella switch seems quicker!

I think the fuel pump is the biggest concern in that it might still be pumping fuel. So a fuel pump switch easily accessable is a cheaper and easier idea.

Sun Jul 28, 2019 7:41 am

my key is real accessible /removable/ and kills everything / mounts flush/ and is easily hidden under the carpet

Sun Jul 28, 2019 8:54 am

Yeah that’s one thing about Vanagons, the typical thief doesn’t even know where the battery is located. If dash lights don’t come on, that informs him there exist anti-theft measures to look for, so theres that. But most likely he will just look for another car to steal.

Agreed the battery cutout (with 5A breaker per fxr) is the most certain method that also adds fire protection. But does it get switched to off every time you depart from your van? And every time you suspect an engine fire?

I kinda like the idea of switching off the fuel pump’s ground wirej, with some kind of RFID keyfob device as an antitheft measure. But to get fire protection from this, note that each time you dash back to the van to get the extinguisher, gather up cellphones & recent CBD purchases etc, etc does it give the fuel pump another squirt? Do you have to remember to huck the keyfob away from the van? How far?

Nothing is easy.

Mon Jul 29, 2019 9:20 am

I like it, Steve. If I had one 'just sitting on the shelf' I'd probably use it. Instead I'm looking to go FXRs route with a race car style On/Off switch.

I like the fuse idea, too. FXR, can you email a wiring diagram?

Mon Jul 29, 2019 9:25 am

Jake de Villiers wrote: I like it, Steve. If I had one 'just sitting on the shelf' I'd probably use it. Instead I'm looking to go FXRs route with a race car style On/Off switch.

I like the fuse idea, too. FXR, can you email a wiring diagram?
No need for a diagram, just attach an in-line fuse across the terminals of the switch. :) Keep plenty of spares. ;)

I also have a relay in the ground side of the fuel pump, controlled by a switched ground on a hidden-in-plain-sight slide-switch accessible when the driver's door is open.

Sun Aug 18, 2019 6:34 am

fxr wrote: Likewise - especially when it's installed on the negative side. I also bypass it with a 5A fuse so the clock and radio still work, but any inadvertent short will just blow that.

Can you give some more info on how this is done? I don't want to lose my radio presets every time I use a cutoff switch (regular maintenance, sketchy area theft-prevention).

If I am running the negative battery cable through a switch, is this just a bypass jumper wire from the battery terminal to the main wiring harness?

So if you put the key in the ignition and turn to the on position, would that blow it or do you need to crank the starter?

Sun Aug 18, 2019 7:17 am

If the fire has already migrated from the engine and your can't get to the ignition, the van is already toast. Certainly a fuel pump switch is the simplest thing to install, to at least interrupt one fuel source to the fire. And then fire extinguishers!
Although thinking back to two catastrophic fires I've had in old RV's, the engines died and the electrical system kept igniting. So the fuel pumps were already off.

Mon Aug 19, 2019 11:10 am

I found the answer to my question, a 3amp cutoff switch bypass.

https://www.speedwaymotors.com/Memory-Guard-for-Electronics,2383.html

If you'd like to use a battery disconnect switch but don't want your computer or radio memory to reset each time you cut the power, you need the Memory Guard. The Memory Guard hooks across the terminals of your battery disconnect and has a 3 amp fuse in it.

This device permits the flow of the very small amount of energy necessary to preserve your computer's volatile memory, while simultaneously preventing a flow of energy sufficient to start the engine, so no one can steal your automobile and the battery life will hardly be affected! If anyone tries to start your car, it will pop the fuse.

It's ideal for all vehicles with a radio with memory or clock and those running a fuel injection system.

Mon Aug 19, 2019 11:20 am

dart330 wrote: I found the answer to my question, a 3amp cutoff switch bypass.

https://www.speedwaymotors.com/Memory-Guard-for-Electronics,2383.html

If you'd like to use a battery disconnect switch but don't want your computer or radio memory to reset each time you cut the power, you need the Memory Guard. The Memory Guard hooks across the terminals of your battery disconnect and has a 3 amp fuse in it.

This device permits the flow of the very small amount of energy necessary to preserve your computer's volatile memory, while simultaneously preventing a flow of energy sufficient to start the engine, so no one can steal your automobile and the battery life will hardly be affected! If anyone tries to start your car, it will pop the fuse.

It's ideal for all vehicles with a radio with memory or clock and those running a fuel injection system.

Thanks! I like this.

Mon Aug 19, 2019 11:31 am

We have a Bluesea 4 post switch that combines or disconnects both batteries. It also has a removeable key/knob. For day to day a Victron controller manages the batteries (3).

Mon Aug 19, 2019 8:07 pm

dgbeatty... i think I have all the same pieces you describe but do not quite know how to wire it up so that the 4 position switch and the controller will both function with the starter battery and auxiliary battery.

Do you have a diagram or rough sketch of how you hooked it up?

Which position do you leave the switch while using the van? Is it only used as an emergency cut off?

I have:

aux battery + fuse block
4 position switch
blue seas ACR

thank in advance for any help. Should be simple but when I draw it out I keep running into a wall when using both the acr and the position switch. I have also come across conflicting info on which position the switch should be when running the van normally.

Hoping to have this sorted out and then add in a solar controller and panel into the auxiliary fuse box. When camped out use the position switch to isolate the starter battery and just use the aux for any lights, coolers, music and accessories needed with the solar to recharge and keep topped up.

Cheers!

Mon Mar 15, 2021 9:49 am

oops wrong thread