DIY 12v Low Voltage Cutoff with battery monitor


As some of you know I had been outfitting my Tacoma with a new 12v system in the bed for camping/fridge/etc. While this had sounded like the optimal vehicle to use out of the two that we own I was intrigued and impressed with a build that a member was doing on his WK2 Trailhawk. That got me thinking about using our WK2 Overland diesel and I made the decision to outfit that one as well to use as out primary family use vehicle. Mind you our family at the moment is only myself, wife, and 40lb dog.
Added bonuses for using the Jeep are... 12v already in the cargo area (simple fuse adjustment makes it a constant power), factory group 49 AMG deep cycle 94ah battery, and my solar suitcase isn't permanent.
OK, on to the DIY part.

I wanted a 12v LVD for my old Norcold fridge I got a month back. I installed one near the battery on my Tacoma but that doesn't do me a bit of good in the Jeep. That being the case I chose to make one that I can use in any vehicle should a friend wish to borrow the fridge.

1. I started with a adjustable LVD off amazon. It is only a circuit board so not a great choice to have floating around in the back of the Jeep or anywhere else.
2. Luckily a fella on amazon suggested a small plastic project box that fits the LVD almost perfect so I got that.
3. Lastly I already had the 12v power monitor since I was planning on using it in the Tacoma.
4. 12v plug extension

1. Snip the corners of the circuit board to make it fit in the project box. Be careful to not get the conductors.
2. Insert the board into the box with the dip switches angled towards the bottom.
3. 12v male plug wired that to the "in" side of the LVD.
4. Two conductors from "out" side of LVD to "in" side of monitor
5. 12v female from "out" side of monitor.
6. Velcro the monitor to the lid of project box.

You're done!

I know it's not elegant but hey it cost less that $50 bucks and does more than that BILM that Engel sells and has 4 different disconnect and reconnect voltages. PLUS I made it and it's not a permanent thing.

Let me know what you think!


New member
Hi...i am a new user here. I have installed a set of 12 Volt LED MR-16 bulbs in my living room, too! What I have done is to place a small solar panel outside, and charge a 12 volt battery in the day time. At night, I use the battery to power the LEDs. I wanted to disconnect the load (LEDs), when the battery got low. I couldn't find a LVD (low voltage disconnect) circuit, so I designed one, and had PC Boards made.I use 10.80 volts as the point where the battery is dead, and I drop out the load. I do not reconnect the load until the battery gets up above 12.30 volts.I have not had any issues with this - so far - and I have not discharged the battery lower than 12.10 or so.

Recommended books for Overlanding

We Will Be Free: Overlanding In Africa and Around South A...
by Mr Graeme Robert Bell
From $20
Don't Go There. It's Not Safe. You'll Die.: And other mor...
by Jared McCaffree, Jessica Mans, Kobus Mans
From $19.99
Drive Nacho Drive: A Journey from the American Dream to t...
by Brad Van Orden, Sheena Van Orden
From $15.95
Motorcycle Messengers: Tales from the Road by Writers who...
by Lois Pryce, Mark Richardson, Carla King, Sam Manic...
From $9.99