Solar panel realities experiment.

[djgriff]

Thanks for the detailed response, so my setup is as follows, everything connects to the smart shunt before going to the negative connection on the leisure battery. I also have a BM2 battery monitor connected which maybe drawing load, but this is actually connected to the fuse box live and negative terminals. The smart solar is going directly to the to the leisure battery and smart shunt.

I also have a 12/12 30 dc Victron charger from the alternator.

I am currently unsure when I should synchronise the smart shunt. is this automatically sync'd?
many thanks for the reply

Best
Daniel

 

[Sim60]

I’m not sure I fully understand your description. Are you saying the ONLY thing connected to the leisure battery negative terminal is the shunt? ( this is the correct implementation)

Can you show the shunt current reading alongside the SOC readings you showed before - where the SOC drops to 92% despite the battery voltage still reading 13.57 V?

Simon

 

[djgriff]

I’m not sure I fully understand your description. Are you saying the ONLY thing connected to the leisure battery negative terminal is the shunt? ( this is the correct implementation)

Can you show the shunt current reading alongside the SOC readings you showed before - where the SOC drops to 92% despite the battery voltage still reading 13.57 V?

Simon

apologies for not being clear, Yes the only thing connected to the leisure battery negative, is the shunt.

I’m not sure I fully understand your description. Are you saying the ONLY thing connected to the leisure battery negative terminal is the shunt? ( this is the correct implementation)

Can you show the shunt current reading alongside the SOC readings you showed before - where the SOC drops to 92% despite the battery voltage still reading 13.57 V?

Simon

here are the screen shots from this morning
Cheers

 

[Raul a/3]

Sorry about that - I’m reading too many different threads at once.

Quick question about your setup - is the smart solar connected across the leisure battery only or across the leisure battery and shunt?
I thought the shunt was working out your SOC by measuring charge into battery vs charge out - once 100%SOC set, then battery voltage should be irrelevant. The shunt calculates that the available charge has gone down 8%.

The smart solar is showing 0.1A being generated. The shunt is coincidentally showing 0.1A leaving the battery.
If the smart solar is wired incorrectly, then the load is 0.1A being supplied by the smart solar, but the shunt is measuring this as coming from the battery and reducing the SOC.

( if Smart solar is wired correctly, the load is 0.2A with 0.1A coming from battery and 0.1A coming from solar)

Simon

Not quite, how do you know that there is no load present? To me it looks ok. If charger produces 0,1A and shunt says 0,1A drain, then somewhere is a load of 0,2A. Shunt and solar charger do not communicate with each other. If you had a GX hub, then it will take the shunt and solar input data , and show a DC load.


digriff, the tail current on the shunt setting is very very high, 4% of 110ah is 4,4a. That means your shunt will meet re sync parameter when charge is less than 4,4a. With solar this is wrong, it can be a cloud fooling the shunt that’s done and re sync prematurely. With solar you want less than 1% tail current.

 

[djgriff]

Not quite, how do you know that there is no load present? To me it looks ok. If charger produces 0,1A and shunt says 0,1A drain, then somewhere is a load of 0,2A. Shunt and solar charger do not communicate with each other. If you had a GX hub, then it will take the shunt and solar input data , and show a DC load.


digriff, the tail current on the shunt setting is very very high, 4% of 110ah is 4,4a. That means your shunt will meet re sync parameter when charge is less than 4,4a. With solar this is wrong, it can be a cloud fooling the shunt that’s done and re sync prematurely. With solar you want less than 1% tail current.

Thanks for the info, so would I be best to set the tail current to 1% or lower, .5% say. Thanks for the reply

 

[djgriff]

Hi guys so just gone in first trip and had/have the fridge on all the time which one would expect to drain the battery. So the smart shunt still states 100% regardless of the voltage dropping right down. I’m wondering if I have everything setup correctly or whether it is faulty. Probably me not setting up correctly.
But it was first think this morning 12.62 volts but still stated 100%
When I checked bm2 battery monitor it seems to show the right charge percentage.
I have no idea what by the smart shunt always states 100%.

Any help would be greatly appreciated, cheers
Daniel

 

[Sim60]

You need to show us EXACTLY how the smart solar, leisure battery, smart shunt and fridge are connected.
The BM2 is guessing the SOC of the leisure battery by measuring the terminal voltage. The Smart Shunt is trying to measure the SOC by monitoring current flow in and out of the battery through the shunt. In your pictures above, the shunt is showing consumed Ah as either 0 or -0.1Ah , so of course it thinks the SOC is 100% - you've hardly supplied any current from the leisure battery as far as its concerned. So what's been providing current to the fridge? If its come from the leisure battery, then the shunt hasn't measured it - This implies the fridge or shunt is not wired correctly.

Simon

 

[djgriff]

@Sim60 thanks for taking the time to come back to me, so I have checked the wiring and this is the setup currently, I can make a pc version if you prefer but thought this would do. I really appreciate the help. One thing I have noted is that I just drove back from Aberystwyth mid wales on the coast to Bristol and the battery charge hardly increased.. very odd for 3 + driving.
Something isn’t right , contemplating just buying a roamer custom seat battery..
thanks for all the help
Cheers Daniel
Edit: the fuse positive goes to leisure battery positive

 

[Oceanis]

@Sim60 thanks for taking the time to come back to me, so I have checked the wiring and this is the setup currently, I can make a pc version if you prefer but thought this would do. I really appreciate the help. One thing I have noted is that I just drove back from Aberystwyth mid wales on the coast to Bristol and the battery charge hardly increased.. very odd for 3 + driving.
Something isn’t right , contemplating just buying a roamer custom seat battery..
thanks for all the help
Cheers Daniel
Edit: the fuse positive goes to leisure battery positive

View attachment 177723

View attachment 177725

View attachment 177726

Looks like you have a ground that is on the wrong side of the shunt. It is providing a path from battery to shunt terminal to vehicle ground, bypassing the shunt measurement. Move your shunt ground to the other side of the shunt.

 

[Sim60]

As Oceanis says,, I would expect the other side of the shunt to be grounded if you’re using the van chassis as a negative return path tjj on the leisure battery - but you don’t show any of your loads doing that - they all seem wired via the fuse box for both +ve and -ve.

Is your Dc-dc isolating or non-isolating?

If it’s non-isolating, then the gnd to shunt wire definitely needs moving to the other side of shunt

 

[djgriff]

Perfect will do that first thing, thanks guys, fingers crossed this will sort the issue!
Much appreciated