12V 140Amp Smart Waterproof Dual Battery Isolator Fits ATV UTV 4WD RZR RV Car Watercraft Marine Boat Truck Caravan Camping 5 Year Warranty (ATVR12140B)

I'll start with the positives. It works excellently. It's the final piece to my auxiliary batterysystem in my power wagon. I drive A LOT so this totally makes sense to have. My headlights no longer dim when I'm running my offroad lights (400-500 watts) AC and stereo. I no longer need to worry about my alternator being over exerted, or my main battery draining. Living off grid, this allows me to charge multiple batteries while I'm driving to and from wherever. It's also a plus to have extra power when I dry camp. Paired with my 300 amp alternator and 3000 watt inverter it's like I never left the creature comforts of being hooked up to power. It works as they say it will.Now the cons...I absolutely loath the way the terminals are designed. They are way too close to each other, and they're flat terminals. This unit could be so much... safer, if they spread the terminals another ½" apart. The "waterproof" casing doesn't allow anything larger than 4 awg cable. Which is not good enough for 300 amps to be distributed over 20 feet of wire. I have to use 1/0 awg to carry the load required for that twenty feet to my truck box. I ended up putting a 4 awg cable end into a 1/0 awg cable ends, crimping them together, shrink tubing to prevent corrosion (I'm sure I'll be doing something different soon) to create an adaptor that sits outside the box, so could run my 1/0 cable. It's working, but it's flimsy at best. The openings in the box aren't big enough for such large diameter wire to fit. Not are the terminals large enough. As it sits i had to file the 1/0 connection to set flush so the unit could be mounted and the base could be closed. The switch is waterproof, sealed in silicone, but the terminals are not waterproof.In conclusion, this could be a better fitting unit if they did three simple things. One; make the terminals into bolts instead of flat. Two; spread the terminals further apart so there's no risk of a connection between the two batteries. Three; (probably my biggest concern) make the spacing between the base and the sealed switch deeper so 1/0 awg can fit inside the unit instead of having to jeri-rig an adaptor of some kind. Yes this would increase the overall height. What's another ½" gonna get in the way of anyway?All in all though, I'm happy with the way it works and the fact that my system is completed. I'd give it 4.5 stars if I could. The only reason it's not five stars is the fact I can't fit 1/0 awg wire into the box itself.

Absolute garbage! A complete waste of time and money. It worked for about one week. It started clicking off and on at all times no matter if my engine was running or not. By the time I realized it was broken it was too late for me to send it back.

Not good for stereo system battery the bass goes up and down it just turns off and on