question

Hans Domke avatar image

My battery dies after the sun goes down.

Full time vanlifer here! I probably just need to revise some settings but I have no idea what any of it means as I'm new to this.

My setup is simple: One 175w Renogy panel. Victron 100|30 MPPT. One 100AH 12v Weize LiFePO4. That goes to a 1500/3000w invertor. I don't have a Victron BMS. I don't have any extra circuit breakers. The invertor has one built in so it's safe, I think.

I also have a couple 12v DC cigarette lighter style chargers attached directly to the battery recently. They have fuses. But my system worked for a couple weeks with those before something went wrong.


This setup was working great! Until a couple days ago when it died Immediately after the sun went down. I was running my fridge and a small fan all day. I also charged my phone once. But that's it. That definitely shouldn't have killed my batteries. Now it continues to die after the sun goes down.


I have screenshots of my MPPT settings here.screenshot-20210330-122200.jpg

This, as you can see, was the middle of the day.

screenshot-20210330-122207.jpg

I checked for loose connections but didn't see anything. It would be nice if it worked again because I have ice cream in my freezer! I'm a newbie at this so please no big words?

batterymppt charging
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1 Answer
dazey77 avatar image
dazey77 answered ·

You need to do some basic fault finding with a multimeter. If you dont have one, buy one, doesn't need to be an expensive one.

Check your battery voltage, is it actually charged. If not its probably the link from solar to the battery thats faulty.

If it is charged, check that its the same voltage as shown on the solar controller.

One thing to realise is that the solar controller will show a battery voltage even with no battery connected (in this case its just metering its battery output).

Basically start at one point in the system and keep moving forward until you find the fault. I suspect your solar controller is no longer physically connected to the battery (due to blown fuse, dislodged wire or whatever)

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I do have a multimeter, not that I really know how to use it. I will compare the multimeter to the app. I will also check that the connection to the controller is good on both sides. It is good at the panel.

I don't know if you saw, but I am able to get power out of it atm. I'm at least able to charge my phone and have my fridge running all day. So I don't think it's a fuse. Maybe I could have a bad controller? Idk.

I'll check the connections. But I still don't really know what to look for.