12V 100A Solid State Battery Protector

I finally made the jump from the COSTCO "deep cycle" batteries to real heavy duty Trojan T-1275 batteries in my off-road camper. These are WAAAAY better, but a major investment ($400 for two of them). I needed a low voltage disconnect for my camper battery system, to prevent damage to these Trojan batteries from accidental excessive discharge. This one seemed to do the trick and was inexpensive.This unit is very well constructed, a nice piece. The terminals are very heavy duty and the nuts provided are really nice. It is now installed and seems to be working almost exactly as described.This unit functions as an adjustable low voltage disconnect (LVD), circuit breaker (for major short circuits, >140 amp) and, when properly configured, a main power disconnect. Lots of features for the price. I tested the LVD at one setting and found that it is 0.1 volt off--it should have kicked out at 12.6 volts but in fact kicked out exactly at 12.50 volts. No big deal, but a bit strange. I have not yet tested the other disconnect voltage settings. The auto-reset works when I start the truck and the manual override works when properly switched. I have not tested the circuit breaker function at 140A. Such a massive short circuit would be exciting, hopefully only for a second before the breaker function kicks in.So, why 4 stars instead of 5? First, it turns out that the options for the disconnect voltages are not really optimal for my needs. It could use more resolution (i.e. options) in the 11.5-12.0 volt range, and fewer outside of this range (SEE IMAGE TO UNDERSTAND WHY). Not really sure why anyone needs the 12.6 volt kick-out, other than for easy testing. Similarly no need for the 12.8 or 13 volt disconnect settings, better to put them where they would be useful, 11.5-12 volts. YMMV, depending on the discharge curve for your battery as provided by the manufacturer (do not use generic discharge curves if you want to really know what is going on).The voltage vs. discharge table provided in this review is for batteries at rest, no load. The table is still applicable if you have a small load on the batteries (e.g. LED lights)--leave the lights on when you park the camper for a month and the LVD will operate as you expect. If you place a large load (refrigerator, furnace) on your electrical system, it will cause the LVD to trip out before the battery is REALLY drawn down to the set trip voltage. After a few minutes the battery will drift up 0.1-0.3 volts. For a really big load relative to capacity, the effect may be more pronounced. This limitation is intrinsic to LVDs as far as I can tell.The rotary adjustment switches on my unit are embedded well below the surface of the unit, very small and hard to see exactly where they are pointed, especially once installed. I note that the photo shown now has a surface mounted adjustment switch, if this is accurate, it is an improvement and would move it to 4.5 stars in my book.This LVD ships from Hong Kong so takes a while to arrive.There are other LVDs that do the same thing for just a bit more money. At least one comes with the switch that I had to buy seperately. I am not in a position to compare them. Overall, I am happy with this Manson LVD and think it was a great bargain. I will consider other products from then as my needs evolve. BTW, I had some e-mail communication with these folks in Hong Kong, I thought they were very responsive and seemed very concerned about my satisfaction.

Most likely a good battery protector, but does not work for my application. I needed it to sense low voltage on battery bank and disconnect it. Which it does with a 10 second delay, which is actually good because it will not shut down the battery due to a transient dip in voltage caused by starting an electric motor for example. The problem is that it stay in that state, in other words your battery bank is going to remain disconnected until this device senses at least 12.9 V or higher, which it would if you were recharging the battery from an alternator. However in my application I needed it to reconnect the battery at lower voltage. If the range was just a bit wider (disconnect at 11V and reconnect at 12V) - this would have been ideal for me.

Mine is DOA out of the box. Even thought it is set to disconnect the battery at 11.7V and the actual voltage is 12.4-12.5 it disconnects the moment a load is put on the unit. Additional the manual override (yellow and black cables) do not appear to function at all. I tried reaching out to the seller but no response. It's a shame as this does exactly what I need it to do and on the surface does appear to be very well constructed. It was going to disconnect my solar battery bank and prevent over discharge.

A great low voltage disconnect device with 100 amp capability! Mine has 2 setting dials, not just one as shown in the pic. The 2 adjuster are superior since you can adjust the disconnect/reconnect voltages separately. Also it has manual override in case that is needed. Really high quality, a great price, and so far very dependable!