Leisure Batteries and solar issue.

[GavinCapel]

I have a solar solutions set up and had a ‘under discharged battery symbol’ on the MT50 display (empty battery symbol with a ‘X’ inside it) come up, only in the evenings 3 days in a row. I have removed both leisure batteries to check their voltages and they are at 12.48 and 12.42 an hour after removal. In the process of removing them I can see the attached fuse has melted, it looks to be on the +ve feed from the solar controller. Could this melted fuse cause the under discharged battery symbol or is there perhaps other things at play? I’m a complete novice when it comes to electrics. Thanks.

 

[WelshGas]

I have a solar solutions set up and had a ‘under discharged battery symbol’ on the MT50 display (empty battery symbol with a ‘X’ inside it) come up, only in the evenings 3 days in a row. I have removed both leisure batteries to check their voltages and they are at 12.48 and 12.42 an hour after removal. In the process of removing them I can see the attached fuse has melted, it looks to be on the +ve feed from the solar controller. Could this melted fuse cause the under discharged battery symbol or is there perhaps other things at play? I’m a complete novice when it comes to electrics. Thanks.

View attachment 139526

View attachment 139527

Yes.
Your MT50 display is powered, by day from Solar, by night from Leisure Battery. Hence the error message in the evening as the solar output drops.
What size fuse has been used?
How many Solar panels?

 

[GavinCapel]

Ok, thanks. It’s 20 amp fuse, 2 solar panels. For now I’ve replaced the fuse holder and the fuse as i am going away on Friday but am a bit suspicious about the melted fuse holder and fuse.

 

[WelshGas]

Ok, thanks. It’s 20 amp fuse, 2 solar panels. For now I’ve replaced the fuse holder and the fuse as i am going away on Friday but am a bit suspicious about the melted fuse holder and fuse.

So 200w of Solar, in the present weather and correctly positioned could produce upto 12 amps at 20v.
The MT50 output at 12 v could reach 20 amps.
Not all blade fuses are equal in quality.
I would just check the MT50 output when the sun is high and see what amps you’re getting.
It was probably a poor quality fuse.

 

[GavinCapel]

Ok, thanks very much for your help.