Blue Sea 7620 ML-Series Automatic Charging Relay (Magnetic Latch) 12VDC, default title

Installed recently, so far so good, super-solid build quality. use to connect a house battery (with connected solar module) to engine battery so either can pass power back and forth. The unit is very simple with two main power lugs (one for each 12V battery) a spade lug for ground sensing (required) another lug for start bypass (optional) (disconnects the house battery during engine start) and a lugs for an optional remote 12V LED status indicator (unit has integrated LED indicator).Premise of operation: Unit connects battery sources together if one *or* the other have a higher voltage (its a relay so when connected both batteries are wired together) Example, I have the engine battery and alternator and a house battery with solar, I want the alternator to charge the starting and house battery but not allow house loads to pull from the starting battery when engine is off (typical configuration) however, I also have a solar PV module that produces surplus power so charging the starting battery with excess power is preferred. So the house battery connects to one terminal, the start battery to the other, if the engines running the start and house battery link, if the engine is off the start battery is disconnected from the house battery *unless* the solar output pushes the house battery voltage above 12.8v, then the relay will close and link both batteries. Once the sun goes down, the relay opens separating the batteries again.

First, the build quality of this unit is excellent. No issues there. Unfortunately, the usability of the Si-ACR is very limited depending on your setup and battery type.If you are running only FLA, AGM or Gel batteries, and plan to have this relay as the only connection between the two, it works great. It is consistent and works as intended.My two major issues:1- These relays do not work as intended with LiFePo4/Lithium batteries. The relay reads the higher voltage of the Lithium battery as a "charge source" and always stays on. This defeats the purpose of having a relay. In order for this relay to be effective with modern Lithium batteries and charging systems, there needs to be a selectable voltage threshold for connect/disconnect.2- In my setup, I have a manual disconnect switch. This allows me to completely disconnect the charging source from the auxiliary battery. When the switch is "off", the Si-ACR continuously flashes the LED warning light, indicating that there is only one battery connected. This feature is a waste of battery charge, and the LED will burn out before too long. The unit needs a "test" button that will show this flashing light; having it run constantly is a nuisance.All in all, it's a decent relay, but lacks modern functionality for Lithium batteries, as well as the ability to adjust to different configurations. Three stars.

UPDATE: the ML-ACR and switch were not functional! I was first annoyed that they arrived in used condition then I was even MORE annoyed and angry when I was troubleshooting it because it was not functioning as it should have been. I have a meter and I was testing everything and all signed pointed back to the ML-ACR not functioning properly (the switch also would not even light up), so I had to return it. *The ML-ACR I purchased as a replacement from another vendor was installed and the switch was installed (with the SAME wiring that the used one i bought off here had) and it functioned FLAWLESSLY IMMEDIATELY!!!! You can gamble if you feel like your potentially wasted time is worth the minute cost savings but I will not be doing that again.This was more a waste of my money, it was a waste of my time which I cannot get back. I am very unhappy with this. It ruined a perfectly good afternoon, then I bought from another vendor anyway to avoid this issue again...........................................................................................................................................................................................................My ML-ACR arrived and when i took it out of the package i noticed it looked used, the wiring pigtails had solder already on them and some electrical tape residue. The back of the ML-ACR had tape residue on it as well as if someone used doublestick tape to mount it the first time.I am overall not happy that it seems i got a used product. I was in a hurry for my purposes and could not wait to get another one so I didnt mess with the return policy but I am still unhappy about it. YMMV.

This device is utterly fantastic. Ridiculously easy to install, eliminates the .5V-.7V voltage drop inherent in the old isolator that it replaced, and now not only can my alternator fully charge both the start and house batteries, but the charger hooked up to my house bank also seamlessly charges my start battery to boot! I would like to add that if you are retrofitting this device on an older RV that also has one of the old style fixed low voltage charging/dirty DC providing converter/chargers, like the Magnatek/Parallax 6300-7300 and others, replace it with one of the applicable Progressive Dynamic 4 stage chargers; it's an easy slide in mod and fully brings your DC system into the modern world!

very good bit of kit for the landrover and works a treat. has to be the bst auto charge relay out there

This little unit is absolutely awesome. Instruction are really clear. Using it in my Westfalia to charge my second battery when moving around with the van. Was really easy to install, is pretty straight foward. Looks really well built and solid.

ACRs are a large step above common isolaters and this is the good one. Easy to install, be sure to plan for the appropriate cables and fuse blocks between your banks and this unit.

Après un an d’utilisation, cet article fut défectueux. Impossible d’avoir l’assistance du fabricant. Très déçu de la fiabilité.

Nice clear instructions.well built product. Used to simplify and update my boats charging system.