Not driving the truck as much anymore and discovered that the batteries are draining in about 12 days. Was not an issue when I was driving every day, but now that its sitting was thinking about installing a battery cut off switch so battery won't drain.

Would 2 of these work or is there a better recommendation?

Battery Disconnect Kill Cut Off Cutoff Switch Car Boat Truck Brass Terminals | eBay

 

Check out Blue Sea Systems cutoff switches.

 

same one at Harbor Freight

 

you could disconnect both batteries after a full charge to see if they have a internal short & get alternator tested for a bad diode,which will cause a draw.

 

This is a very good start.

 

I haven't had any problems thus far with these battery cut off systems mounted directly on top of the negative post terminals of each battery in the truck.



While it is always the best practice to diagnose and resolve undue parasitic loads, it may not be possible to stop them all. Some trailer brake controllers are parasites. Even certain factory Ford radios can be parasites.

There are also a lot of advantages to having a battery quick disconnect. For as little as I drive my truck, and for as much as I service it where the batteries are recommended to be disconnected, the quick disconnects have been very convenient.

The green **** battery post mount disconnects in the photo above were chosen for their quick convenience of installation. Unlike most battery disconnect switches, it is not necessary to cut and splice the factory ends off of the original battery cables and run additional heavy leads to a remote switch location. Nor does one need to find a location to mount the switch. These green things just mount it directly to the battery post, and the factory battery cables can remain unmodified and mount back in the same relative position, only to the green thing instead of the post itself.

I was worried that the green **** would vibrate loose, but it hasn't thus far. I was also worried about the current rating (125 amps), but then realized that the current requirement for starting the diesel (estimated at 225 amps) is shared by two batteries. With each battery in the same condition, it seems reasonable that the starting load would equalize between them. In that case, if each disconnect is rated at 125 amps, then a 250 amp load would be evenly distributed between them within their rating.

There are battery mounted knife style switches available that have higher current ratings, but they are so bulky and ungainly that the hood won't close, and the ones I've seen haven't been built very well (the pivot rivet is loose, and other jankiness).

It's been less than a year since I've installed these green dial type disconnects, so time will tell. I really enjoy the convenience of being able to kill power without a wrench. If for any reason these end up having problems, I'll post up about them, and will then pony up for a high dollar marine system and all the required recabling.

 

I was going to suggest a marine Perko switch that is designed to handle multiple batteries but is way overkill for this situation. The green switch looks like the hot set-up.

 

Pics and experience-based recommendations are GREAT... links to where the recommended parts can be purchased would be icing on the cake!!

EDIT... never mind... a quick search for "post mount battery disconnect" found them all over the place (wide range of prices, too). I also noted that the 125 AMP rating is for continuous use... the SURGE rating is 500 amps!


http://www.performanceplusconnection.com/Item/WC20310



http://www.harborfreight.com/battery...tch-97853.html

http://www.oreillyauto.com/site/c/de...0365&ppt=C0005

 

Yes, you found them. They are everywhere.

I bought mine from Pep Boys, because the particular ones at Pep Boys had two distinguishing characteristics over the ones for a little less money across the street at Harbor Freight:

1. The ones at PB were from an age old brand name in battery switch parts that I recognized (but now oddly enough cannot remember for the life of me as I type this! Must be old age!). And more importantly to me...

2. The ones at PB included extra parts that I found useful, and if you look carefully at the bolts of my photo above, you can see hints of these parts

a. An extra short wire harness... with:
b. A weather, heat, and moisture proof automotive fuse holder...containing:
c. A five or ten amp (forgot which... old age!) mini fuse... for the purpose of:
d. Maintaining radio station presets and PCM memory... when I want to:
e. Disconnect the batteries in such a way so that my fancy Clifford Alarm system will still work, but any attempt to start the truck will instantly blow the fuses that enabled the alarms to sound and the memory to be maintained.

The idea is that the thief in the night who wishes to steal my truck may very well gain entry to the cab, an event which my fancy alarm will alert me of, as well as make enough sounds to quicken his pace, made possible by some limited vehicle power being available. But when said thief attempts to energize the ignition, right away the truck will go dead on him. He will think he blew something (he did) by crossing the wrong wires.

At that point is he going to take the time to pop the hood open and investigate? (The underhood light will be dead also.) In the meantime, I will have had just enough time to obtain whatever equipment I need to deal with my unexpected visitor.

On the other hand, if I need a COMPLETE disconnect, as you can see from my photo, I have the blue colored wing nut for the small wire ringlet terminal for that small fused single wire harness that is paralleled with the green disconnect dial.

So still, without any tools, I can quickly disconnect the batteries either completely, or partially, in a few seconds. It's totally awesome, from a convenience standpoint.

I got so tired of having to hunt for both a 1/2" wrench for the nut and a 12 mm wrench for the square bolt head to oppose it, where that wrench had to have the head claw ground down thin enough to fit underneath the square head and the battery top itself, due to the shape of the lead lug on the end of the cable. I even dedicated a pair of wrenches to keep in the truck at all times for this purpose, but after losing my 3rd "dedicated" set to urgent needs elsewhere, I decided a tool free disconnect system was in order.

Now I don't even have to wash my hands right away to avoid inadvertent lead contamination if I absent mindedly handle food afterward. My absent mindedness is well proven.

 

Rather than a cutoff...

I don't have a parasitic drain issue, but I keep a battery tender underhood and leave it plugged in 24x7. I think it makes the batteries last a bit longer, and if I don't drive the truck for 3 weeks, no big deal - always fires right up. Less fiddling than a battery cutoff, but no anti-theft properties, admittedly.