Blue Sea Systems 7601 m-Series Automatic Charging Relay, 12/24V DC, 65 Amp

A bit challenging to intall but works great. Game changer for keeping the house battery charged. Now we can fish all day no problems. 3 fish finders live well, bait airator and a radio.

Boating should not be worrisome. Now I never have to worry about being out on the water with the engine off, listening to tunes and not having juice to start the big 454! Relatively easy to install when following their instructions. Blue Seas customer support / tech is awesome too!

I am using this to auto charge the secondary battery in a marine application. I added the secondary battery to provide independent power to all but the engine ignition, starter, and electric fuel pump. The alternator is also on the primary battery side. I originally used a manual 1-2-all switch, but when I would crank the engine, the voltage drop caused my electronics to reboot. I changed the switch to a Blue Sea Systems e-Series Dual Circuit Plus Battery Switch and added this switch to auto charge and isolate. Works very well. My crank battery always maintains enough power to start the big v8. After running lights and electronics all night off the secondary battery, the engine starts off the primary. After a few minutes of recharging the primary, this switch engages the secondary for charging as well and the lights all brighten. When in storage, I keep a 1.5amp auto charger on the secondary battery, since I often run lights and radio while working on the boat. Have noticed this switch will engage the primary battery and keep it charges as well, given enough time. This works even with the battery switch turn off, using the wiring recommendations from Blue Sea. Great solution to a dual battery isolation issue. No more forgetting to disengage the primary battery and waking to a no start situation. I used the Blue Sea Systems 285-Series Surface Mount 50A Circuit Breaker to protect the secondary circuit.

Great product; great delivery service. Seamless transaction.

It works good. I held off one star because it also needs a manual override. Once a battery discharges too much it will NEVER reconnect. They do make one that has this feature but it costs a lot more $$$. For most applications, this will work well just keep this in mind that you may want a manual switch in line also.