The instruction's text is correct; the negative terminal on the second battery is connected to a ground point on the vehicle with the short black cable supplied

The instructions are not that great. comes with cheap short, 6 gauge hot wires and 4 gauge ground.

The instructions are the best I have ever seen for almost any product.

This thing works like a champ

This thing is awesome

This thing is great work just the way you think charges both battery's and shuts down second battery so your start is always charged great for winch stereo system in my utv

Units product documents needs refining with a clearer installation procedures.

It contained everything I need to make the installation simple and easy and not having to chase for any parts.

The isolator worked as advertised

It works as advertised

I am now in the market for a reliable isolator and company to buy if anyone has any recommendations.

The isolator worked as advertised

The isolator seems to work just fine though without issues.

Very nice device

This is a really great device to have in the truck (dual battery setup)

Diode isolators are solid state devices and can be susceptible to voltage spikes.

Just give the better, longer cables

It wont cost you that much more, and honestly even if it does, I would of paid to have the better cables

I would have had to find an outside source for appropriate cables, connectors, etc..

I understand it's purpose and what it's doing, it just seems like the threshold should be adjustable a little.

I would prefer separation and rechecking the the primary battery for it's state of charge when switching to charge the secondary.

Works as described.

Has surpassed my expectations.

Also the wire that was sent in this kit is of very poor quality.

I needed the isolator, and it is great quality, and works flawlessly.

I needed the isolator, and it is great quality, and works flawlessly.

Once that was done, the kit fell into place within a couple of hours.

Very nice kit for the money

Nice kit and small

Kit is well put together with great instructions

I used 2AWG marine grade wiring for the second battery as I added a switch in between to isolate the batteries

It consumes the external battery (very compact Antigravity Battery, AG-SC-1)

One battery for the accessories such as lights and wench, which keeps the main battery fresh at all times.

Once it's in, I don't even consider where or not I'm draining the house battery to empty--I know that I'll be able to start the engine

Early in the season I was stuck at the dock with a dead main battery.