Replacing Battery Isolator with Voltage Sensing Relay

[Bikersmurf]

I’m by no means an expert, but I have been doing a little research on this for my van project.

I will be using a diod isolator. Yes, its more expensive and slightly lowers the charging voltage, but the benefits out weigh those drawbacks:
1.) no mechanic failure point like in the voltage sending relay
2.) It never parallel jumps the two batteries together. (Each battery has different requirements one can’t drain the other)
3.) suppose to last longer

The problem I found with the diode isolator was it never allowed the batteries to get fully charged. Even with a 210 amp alternator I didn’t run enough hours in the day to charge the batteries back to 100%. I went through several sets of batteries lasting 12-15 months, both starting and house. The starting batteries were never run flat... but still died in a little over a year.

This has ended with the ACR. Time will tell how long the batteries last, but they are well past the point where they previously died, and are still changing properly. The previous acted like they were talking a charge, they appeared to be fully charged, but couldn’t handle a load.

The 12v deep cycle Marine batteries lasted no longer than starting batteries... but only carried a 12 month replacement warranty rather than a 36 month one. By 12 months I was questioning their performance. In a couple months I new, but only got 50% of replacement value from the warranty. Best case I could run the cooler for a day or the microwave for 3 minutes.

The 6 volt batteries are totally different. I’ve not run out of power in 4 days... even though I sillily ran a 120v ice maker for 3-4 hours (>50 amp hours drain).

The friend I spoke to said he can still get over a week in his 30’ trailer with his now six year old golf cart batteries (and he’s out many times a year). His fridge is propane, and lights are also LEDs vs mine which has a 12v fridge. He does have 12v pumps for water and it’s a fully decked out 10,000 lb RV trailer (including TV which may never get used).

The 100w solar panel I have will cover the fridge power plus some during the day, but I’ve read I’ll be lucky to get 1/2 it’s max rated output in these parts. So far I’ve seen a max of 2.2 amps, but it’ve just installed it, and the hottest part of summer has past. I know the basic charge controller I have isn’t the absolute most efficient, but I could double my panels for the cost of one a few % more efficient. I’ll likely pick up more panels in the future since I’ve got an abundance of space to mount them. That said I’m going to evaluate what I have and decide how much I need to meet my regular needs.