Can anyone explain these readings?

[VXman]

The Burstner guage does tend to read a little lower than the Victron or a smart meter but not that much!

The Victron suggests the battery is recieving a float charge but Burstner suggests 80/90 %.

But no solar charge at all? It is fairly bright here. If battery is full that makes sense I suppose?

Not driven for 20 hours so no other battery charge other than solar.

Thoughts?

 

[Vansflyer]

If a Lithium is fitted it is about the correct reading on the Victron. Ours shows it floating at 13.8v or thereabout if no load on the battery but the panel indicates a current from the panels and a very small one to the battery, probably to cover the parasite drain. Not sure why the Burstner gauge is reading so low tbh.

 

[VXman]

If a Lithium is fitted it is about the correct reading on the Victron. Ours shows it floating at 13.8v or thereabout if no load on the battery but the panel indicates a current from the panels and a very small one to the battery, probably to cover the parasite drain. Not sure why the Burstner gauge is reading so low tbh.

View attachment 753014

Not Lithium - just standard AGM's

 

[Vansflyer]

Not Lithium - just standard AGM's

If AGM I would have expected the float to be 14v+. Maybe worth checking the settings in the Victron?

 

[VXman]

Ok sorted! The battery negative cable had come loose from the controller. It is difficult to get the cables tightly into the connection points as they are quite small in comparison to the cable size.

Doesn't help that the victron app indicates that your battery is full and in float charge when it is disconnected from the battery

Before

After...

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[Guigsy]

Like this?

It's the link from the battery negative to the shunt. Battery app said it was 13v and no current flow. All the electrics worked because it was being propped up by the solar. Confused the hell out of me for about an hour.

 

[Hoovie]

Ok sorted! The battery negative cable had come loose from the controller. It is difficult to get the cables tightly into the connection points as they are quite small in comparison to the cable size.

What I do - and would recommend to others - is to use Bootlace Ferrules for these kind of connections.
For anyone not familiar with Ferrules, they essenitially gather all the strands of wire together into a single "pin" which is fitted into the terminal and clamped down. If the cable doesn't fit, then it is probably oversized for the application! you can use Pin Terminals to 'convert' oversized cables to go into smaller connections (useful on say the Victron 30A B2B where a 16mm2 cable is an extremely tight fit)
Example of Ferrules below on a Victron MPPT ... The Orange and the Blue ends. They are colour-coded depending on size of cable (although there are no colour standards like there are with say fuses, so different suppliers will be different)

Doesn't help that the victron app indicates that your battery is full and in float charge when it is disconnected from the battery

I think the Victron MPPT controllers are a bit unusual in that respect and can actually work as a power supply in effect with no battery!
It can get confusing indeed and I had one (actually the one in the photo above thinking about it) where the +ve BATT terminal had a dry joint. The effect was all my electrics connected to the LOAD output worked fine during the day and stopped working at night (as they were being fed direct by solar!). But when I put a meter probe on the terminal to trouble-shoot, the pressing of the probe made the dry joint make contact again! so all seemed correct when checking and investigating.
Took around 3 weeks to get to the bottom of that

 

[xsparks]

Looking at that cable and lug it doesn't look as though a crimper was used.

 

[Guigsy]

Looking at that cable and lug it doesn't look as though a crimper was used.

I used a 300mm scissor action crimper, so reasonably beefy. The issue was I made the cable a while ago when I put a Victron shunt in. Then when I converted to lithium I had to rearrange things. I reused the cable, I was making it do a 360 loop to cover the few cm from the battery to the shunt. I thought I'd be ok, but it looks like the bend was tight enough to lever individual strands out until it failed a day later. It's also pulled a lot of the exposed strands back into the sleeve. Lesson learnt, don't bend stranded cables too tight.