Renogy 12V 20A/40A DC to DC Battery Charger, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats, Yachts

Kept my bank1 lead acid and bank 2 lithium ion batteries at peak charge all boating season. You need to know that the terminals have shoulder tunnels that are narrower than most battery cable ends. I had to cut down the width of a couple of cable ends.

Installed in my van to charge my Temgot 460ah battery off the alternator/battery. Easy to install, easy to set for your battery type. Lights stay on so a small draw but not significant. I got the 40amp version and it's great for my use. Went on an advanture with it on washboard roads for 3 hours- still performs like a champ.

Charger does not turn off when alternator stops - it is defective. ALERT: Renogy is aware that these gray colored versions are all defective!!!! And they are allowing Amazon to continue selling them. Renogy makes the EXACT same model number with a black case, that apparently fixes the defective issue. It took an hour of my time with Renogy before they admitted that. They first tried to have me install a battery switch to disconnect the starter battery from the charger every time I parked. As it is, the battery charger can completely drain the starter battery. There are circumstances that will stop the charging after the van is turned off, such as a heavy load on the charger side, but if the aux battery is nearly full and the charger draw is very small, when the van is turned off, the charger will stay charging and drained my starter battery multiple times to below 11 v before I spend all my time troubleshooting. Shame on Renogy for allowing these to continue to be sold as “automatic” alternator sensing.

I bought another brand's DC to DC charger and purchased the Renogy one after the other brand did not function correctly. I am so glad I did instead of trying to mess with it. The installation was super easy (as it should be), and I only had to push the button a few times to tell the unit I had Lithium Phosphate batteries, and everything worked. I have also confirmed that the unit is charging my battery bank with a multimeter and visually on my battery monitor. Get this one if you are on the fence; I recommend it over trying to save money on a lesser-known brand.

The first one of these I ordered was a used item on Amazon, I bought with full confidence but I didn't get the chance to install it until after the return window closed, so this review is mostly to let the seller know that the used unit was defective and I got screwed. The button on the front which is supposed to change the battery type did not work, all the lights just blink and the battery type doesn't change. Had to order a replacement brand new unit and it works fine. My bad, but sometimes you just can't install something until after the return window.