Battery Cut-off switches

[George Hill]

I've got a client with an M3 that sits for extended periods of time and he is unable to connect battery tender to the car. Because of this the battery will go dead from time to time. He had been disconnecting the battery and now has a kill switch on the positive terminal. That works but the cutoff switch is bulky and the hardware doesn't want to stay tight.

To me it seems like a fire hazard so I started moving it to the negative side but then I realized you still can't fit the battery cover and even with the red plastic pos terminal cover there are still some exposed B+ connections. Something rolling around in the trunk could in theory short it out. So now I want to get the battery cover back on it.

To do this I need to either

• Use a remote mount battery cut-off switch - Not the end of the world to build some battery cables and mount a switch on the trim panel but certainly the least tidy.
• Use a remote disconnect that is switched - Like how BMW did it in transport. This has the disconnect on the battery terminal and then a wiring lead extended out to a rocker switch - Does anyone use something like this and have a recommendation?
• Go-to a battery that has its own internal shut down switch - The lithium batteries like Anti-Gravity are the only ones I have heard of that do that, but is there an AGM option with this kind of technology?

Thanks in advance!

[9kracing]

I was going to use this opportunity to plug Antigravity but you already did it. They come with a little remote you can use to "jump start" the car when dead. Pretty useful for scenarios like this.

There's also the pocket jump starters.

https://antigravitybatteries.com/products/micro-starts/xp-1-g2/

I run into this issue a lot with shows... I need to have my battery disconnected, and my subwoofer sits on my battery tray making it a bitch to unplug.

So I'm going to wire one of these in. No hacky key to turn, just remote on and off.

https://www.amazon.com/dp/B0BJNZTRP3?lv=shuf&channelId=500&plpRedirect=mhFallback&th=1

[George Hill]

I think we have settled on the AG battery. I really didn't want to put a $1000 battery in it just so for the feature but I can't find anything else "affordable" in the grand scheme of things. I initially didn't realize there was a remote to turn the battery on, so that is pretty much what solidified it for us. I might still drill a hole in the battery cover (and cover it with a plug) so he isn't reliant on the fob.

For your remote switch, maybe I'm being pessimistic but I wouldn't run that thing. Lots of weight hanging off the battery cable to vibrate and potentially loosen. I'd also wonder how robust that thing is for $18. I would highly consider an old school Ford style solenoid with a toggle/push button wired to control it.

You can easily make this on your own, but something like this kit.

[9kracing]

Hrmm, yeah that one you linked isn't bad.

I could probably hide that button somewhere where you couldn't see it.

Thanks George.