Smart Dual Battery 140A Isolator - Auto/Boat/RV, Model: VSR12, Car & Vehicle Accessories / Parts

I purchased this VSR to isolate a battery in my truck camper. It is a little more expensive than a conventional battery isolator but it is smaller and easier to connect. I have tested it with my volt meter and thus far it has worked perfectly. It turns on at 13.3 volts (which protects your aux battery from being used as a starting battery by switching on only once the staring battery is fully charged). And cuts out at 12.8 volts (which keeps you from draining your starting battery when using your aux battery without the engine running). A nice feature is a little LED light that indicates when it's engaged. Also, it's rated for 140 amps, which is well over my electrical needs.There is an option to buy this same VSR with a kit, but I opted not to buy the kit because I needed higher gauge wire, and I could get it at a lower overall cost. Because of the thicker wire, I had to modify the wire inlets a little, but it was easy. I would recommend this product to anyone looking to isolate a battery.

I am using this in a Ford e350 van, converted to a camper, to maintain the truck battery under the hood and maintain 2 deep cell marine batteries in the back, which i run a fridge/micro, etc. with using a 1500 watt inverter. I was told by many old school camper guys this setup wouldn't work, but it works great! The VSR is small and lightweight, and simple to hookup and use. It has one simple LED light letting you know where it's sending voltage. Proper gauge wire is imperative, i have 6 gauge run to all batteries, with a 150 amp ANL fuse, and have had no trouble at all with this unit. I returned a much larger, heat synced Northern tool unit after i saw the difference in size. This one is great under the hood of a van or any tight space.Word of note: I did have to trim some of the plastic away where my wires run in and out of the unit. It's 2 pieces and you have to trim away part of the cover if you're using proper gauge wire to get it to sit on the base correctly. This will make sense when you see the unit in person, and it's pretty obvious the manufacturer intended for you to cut or drill depending on your application.

I've been running this battery isolator in my truck for about 4 years now to keep my starting battery separate from my auxilliary battery in my overlanding truck. Performance-wise, I've never had any complaints. It works as advertised, and the drop across it when the batteries are in parallel is small.However, I went to do some work under the hood recently, and noticed that the plastic housing had become very deformed in the 4 years since I last took a close look at it. It's all droopy and no longer anything near square. It was mounted under the hood, but not particularly close to the exhaust. It shouldn't have gotten any hotter than any component under there. To the manufacturer's credit, it's still working like a champ. I'm not going to remove it from the system, as it's still going strong. But I would recommend not mounting in a place that's likely to see high heat.I wouldn't hesitate to buy another, provided I wasn't mounting it under the hood of a car.

I used this dual way, voltage sensing relay in my solar system install on my utility trailer. I installed it in-line with the charge wire coming into my trailer from my tow vehicle. I wanted to be able to charge my trailer battery while driving, and also allow my trailer solar system to charge the battery on my 4-wheel camper, which is mounted on my tow vehicle, while parked. When my truck is running and alternator is putting out at least 13.2 volts, the relay closes and charges my trailer battery. When parked and the sun is out, when my solar system puts out at least 13.2 volts, the relay closes and my solar system can charge both my trailer battery and my 4-wheel camper battery. This eliminated the need for mounting solar panels on my camper, making me a happy... camper :-)

has been installed a couple months,so far no issues,put a second battery in my truck box and ran 6ga welding cable from primary battery to this and from it to second battery as a charging cable,have read it drained primary for some reason but i havent experienced any such issue and dont know why it would,my truck sits most of the time and never had an issue,also there is a spade terminal on the back of this,i asked the company about it out of curiosity and its a disconnect, if 12volts is applied to this terminal it will stop charging of the second battery ,basically takes it out of the loop,will give it a couple months and update any issuesUPDATE;been a year and 7 months,still working,its under the hood,mounted on a bracket beside the battery,use my auxillary battery for a winch\hoist that i load my generator with and power my front mount 12,000 lb smitty built winch,battery stays charged

A must have if running 2 different size batteries

Installed, appeared to work. Blue light came on but not charging secondary battery. Yes it was wired correctly. Have installed several of these isolators and they work properly, this one however does not. Left my field operations director without power to the hydraulic jacks on his trailer unit and of course I am beyond the return window for this item.