Originally Posted by lukereneeseth
Stuklose - sorry to say, but no agm battery can be run down to 20% regardless of what a manufacturer might put on their product. Which has been proven time and time again by independent testing. To get identical models of X battery and run 1 down to 20% and the other down to 60%. Battery 2 will far out live battery 1 and still produce more life by ten fold. There's nothing quantum mechanics about it, that's just the general structure and design of the battery. Same with a phone battery. Run it down and not charging it straight away or putting on charge for 20 min and taking it off, etc will result in half the original life within 18 months.
Piranha - your 5th post is rather contradictory to one of the last.... "It was checked against a voltmetre to make sure everything was accurate."
I know you just want everything to run smooth and be able to just look at a screen for conformation and were its at, etc. But at the end of the day the Victron really doesn't do any more than what most 12v appliances/ equipment do anyway. . . Once they sense the battery is at a certain voltage they cut out. Your fridge should have 2 settings for this; 10.5v and 11.5v. All inverters have them.
I should point out in your response to my post a few things...
" A $10 monitor does bugger all and does not give an accurate state of charge especially while drawing current" . . . This is completely irrelevant when you are just running a 12v fridge off a battery that takes no dual setup or solar additional charging. It is actually impossible to calculate an accurate state of charge while current is being drawn. The victron bases these figures on mathematical equations which are programed into a processor. They are not "accurate", rather a guess based on maths. An when you are only drawing .5 - 1.5amp per hr through the fridge, completely irrelevant anyways. Maybe good to monitor if you had 500á/h running power tools through a 2000w pure sine inverter.
"The victron protects your battery by diconnecting when the voltage reaches a certain level. a manual monitor or voltmetre won't do that when your out fishing will it" . . . your fridge does this automatically anyway, enough said there.
"I would rather know exactly what the system is doing by glancing at a screen while walking past instead of having to get gear out to test then guess the state of charge but by all means continue with your guess work" . . . . I run 2 x 235a/h batteries via c-tek 250, 35l waeco, 600w permanent backlit pure sine inverter. I don't need to guess. If I ever saw the lights on the inverter go off that means i'd need to go for a drive. But, 5 years so far never had a drama, batteries as good as day one.
Talk to any auto electrician and they will say there's nothing inaccurate about a little $5 backlit monitor simply wired to the + - of the battery.
They are a good bit of gear in the caravanning world but massive over kill just to look at a fridge. They come into their own when you have a lot of power draw, a big battery bank and solar wired in.
But you did say "it says it will run it for 375hrs before needing charge" As that gives real time at the exact moment (id say that figure was the wasted energy to keep current through the cables to the fridge) much the same as a little $5 fixed monitor does; real time Voltage. If you've been in the 12v scene for a while, its easy to rough out Volts ---> hrs of your own setup.
If your looking to run a dual setup up look into the C-Tek 250s. Set it all up yourself in about 2hrs, throw a solar panel on the roof (or folding portable panel) Charge your battery for the alternator while your driving then it automatically switches over to the solar charging when you stop. you will never have to look at the Vectron again.
The victron does a lot more than just cut the power when the battery gets low, it tells me a lot of info that a basic monitor won't and can't it's as simple as that. Not for everyone maybe but suits my needs
I also run other equipment off the battery not just the fridge, the victron tells me if i have accidently left my lights on inside my toolboxes which is handy.
I am running a ctec 250s with a solar panell on the way.