Dual Battery Isolator Kit, 12V 140Amp Battery Isolator Voltage Sensitive Relay VSR Automatic Battery Disconnect Switch for Car Boat RV ATV UTV Marine with 12mm Cable kit (Larger Than 6 AWG)

The media could not be loaded.  I needed an Isolator so that I could install a second battery in the back of my truck to run a 12 volt refrigerator freezer. I have a positive cable from the vehicle battery through a breaker and then through this isolator and then to the positive post of my remote battery. The remote battery is grounded to the truck frame. The grounding pig-tale on the Isolator also goes to ground. You will also have to have a heavy cable from remote battery ground to the vehicle frame.When the truck is running and its battery voltage reaches 13.3 volts, the Isolator closes the circuit and allows the truck to charge the remote battery for the freezer. When the truck is turned off and the trucks battery voltage drops below 12.8 volts, the Isolator breaks the connection. This allows my freezer to run all the time without draining the truck battery.This Isolator appears well made, is working perfectly and I am very pleased with this! Thanks!MY PERSONAL COMMENTS:I am an approved Amazon Vine Member. We are provided the opportunity to order (free of charge) many items that are new to the market, or where a seller just wants some additional exposure for their product. We are NOT required to review every item in exchange for using it. I personally only order products that are important to me (items I can use), or items that I have the ability to properly test (I have lots of test equipment) so that I can provide an honest evaluation & review (and not always a 4 or 5 star) based upon my use and testing of the product. Thanks…feel comfortable with any information I provide in a review.

I've used standard blue brick battery isolators in the past, and always was annoyed by the voltage drop across them. This VSR has negligible drop in voltage so provides an open gate to charge your second battery bank and power devices, but only when the alternator is putting out. Rated for 125A, this will supply enough to charge any battery. It could even be used in place of connecting to the ACC in a car, to turn on lights or compressors or high power devices only when the alternator can support them. Even better, since if the key is left on or the alternator isn't charging enough at idle, it won't drain down both batteries. The electronic module is well potted to resist water intrusion and the housing has multiple options for routing wires and has a snap on plate which can be screwed to a bulkhead and allow the relay to be separately removed and replaced. Wiring is dead simple, just power in, power out, and ground. The relay comes set to pass through power when the voltage reaches 13.3V and stop passing current when volts drop to 12.8, and is not adjustable. Testing showed it turn on and off exactly like this. The relay uses a small current to latch the relay and voltage monitor, maybe 4 watts when passing current. This is a great way to preserve your cranking battery from unplanned rundowns. It seems built to last and can fit almost anywhere without needing maintenance. I think it's a great value and recommend it for any dual battery system or other creative applications.

I got this isolator for my boat – it currently only has a single battery, but I plan to add a second one for running my electronics when not actively under say. I wouldn’t want my fish finders to eat up too much battery and prevent the boat from starting.The finish of the case is very nice and the label looks good. In addition the silicone layer on the internals looks to be very well done. These features hardly affect its actual purpose, but this kind of attention to detail gives more confidence in its operation as a battery isolator.The battery conversion will not happen until the weather warms up, and actual testing can’t proceed until I get the boat in the water usually in late June. I will update this review with more meaningful comments at that time.I am baffled by one thing. I’m not sure what this phrase in the item description title means:“with 12mm Cable kit (Larger Than 6 AWG)” My isolator cam alone with no cabling of any kind. I guess it’s difficult for them to predict how much cable someone needs for their particular installation. But it’s hard to imagine that the isolator itself with mounting screws is a “kit”. They do seem to consider this to be a DIY (Do It Yourself) “kit”. So I think they should either remove the work “kit” from everything, or add cables. At this price, I don’t think they could include cables.

So the title is a bit misleading as it says with 12mm cable kit. This does not include the cables needed to hook up to the battery. It does have a small ground wire but this is not meant to push power through or act as a ground for such. This is a fully automated isolator that will cut in and cut out at set voltages so that it doesnt kill your spare battery unlike the manual isolator versions. The wiring diagram is very clear and easy to read. As for the cable placement inside this unit it does not have precut holes to run your wire to this unit and you will have to do that yourself and waterproof it. The unit itself feels well built and it comes with a 12 month replacement warranty which is nice for peace of mind. It claims to be waterproof but the box itself is not however the circuit board is covered with a decently thick layer of silicone which will provide that protection however your cables can still get wet allowing corrosion to begin. Coming in at 24$ it is on par with the competitors average which is nice to know its fairly priced. I wanted this because in the winter we regularly see temperatures lower than -30 degrees which reeks havoc on vehicles from fuel to batteries. With a dual power system i can reroute some non essential power requirements to my spare battery which allows more power to be pumped to my vehicle upon start up. So far this has worked great for me however as we are mostly through winter and those temps are behind us next year will be the test. As of right now it does isolate and allows my non essential lighting to cut in and out if i leave it on. This is a solid component of a whole dual battery isolator system.