Review on WirthCo 20092 Battery Doctor Isolator by Justin Hollins

My VW TDI setup. I bought this machine for two reasons. The first reason is that I have parasitic pull on my starter battery. The second reason I bought this is because I have a lot of accessories and I put in a second battery for towing and accessories. I bought an AGM deep cycle battery for an extra battery. The nice thing is that I can easily find out if it's just my accessory or if it's something that's powered by the ECU and won't turn off. I'm lucky enough to have some wires that were originally intended for accessories and run down the back. Now I can use these extra wires to run one circuit at a time to the rear battery. The biggest thing is of course the four-wire cable to my stereo amplifiers. I just cut it in half where it went through my car's cockpit and installed the device between them. Device. It works as stated in the description. There are only two small reasons why I wouldn't give it a five out of five. The first reason is that there is nothing to close the positive pin. This too is a trifle. Second, it starts charging the second battery faster than we'd like. I have exactly 14 volts from the alternator. It recognizes 14 and starts charging the second battery immediately. It has to somehow determine the true voltage of the first battery and not start charging the second battery until the first battery is at a certain voltage level. The point, however, is that I only need to connect the positives from each battery to this block. and then just grounding this device makes it something I can easily live with. At least it would be nice to have some kind of manual control. That may seem strange. However, I installed it in the interior of my car. That way I can just reach out and manually press the switch to connect both batteries for easy starting when the first battery is low. This works very well. New information! That parasitic battery I mentioned earlier. It's worse than I thought. After going out of town for a few days and coming back, my starter battery dropped to 3V. I loved having this new thing, so I push the button to cut power from the secondary battery. Well, the starter battery took over 150 amps to flip it. That's when my fuse blew. However, I did not damage the insulator itself because of the built-in circuit breaker. After further research, I might really need a permanent magnet. This device also works as intended. It would be nice if I could draw over 150A. If they could make one that could pull say 400-500 AI it would be much better. Of course, this wasn't enough to start my engine as the starter battery was mostly dead. Also, I didn't know that the insulator creates a voltage drop across the second battery. I'm not just talking about a fall due to the length of the cable going to the rear of the car. The insulator itself causes a small voltage drop. Apparently solenoids are not from my research yet.