Solar connection issue

[MikeFergie]

Hi all

I have a niggle with my electrics that I need advice on.

I have 600amp hours of Agm batteries (3x 200 x 12v in parallel)
1x sun power 345w panel
1 x victron 100/30 Mppt controller
1 x victron battery management gauge with shunt
Normal alternators on 3ym30 Yanmar engines

My problem is as follows when I start one of my engines the alternator kicks in and my amp gauge on the dash shows say 30 then 20 then 10 amps going in and with a loss of 5 amps my victron gauge shows similar positive result (fridge freezer running so that's fine
HOWEVER
With only the solar panel charging my victron gauge shows -5amps on the gauge. When I plug in the usb cable to the Mppt controller it tells me the panel is pushing in 20 amps so why is the gauge giving me a minus of 5 amps ?

My solar cables from the Mppt controller go to positive and bypasses the shunt for the victron on the negative side (i.e. It's on the battery side not the load side)

Should I move the negative to the other (load) side of the shunt ? Will this correct the victron battery monitor value ?

Last question can I run 2 x victron 100/30 Mppt controllers (one for each panel when I add my second panel) into the batteries without issues ?

Rgards

MikeF


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[Dsanduril]

Originally Posted by MikeFergie

...My solar cables from the Mppt controller go to positive and bypasses the shunt for the victron on the negative side (i.e. It's on the battery side not the load side)

Should I move the negative to the other (load) side of the shunt ? Will this correct the victron battery monitor value ?

Last question can I run 2 x victron 100/30 Mppt controllers (one for each panel when I add my second panel) into the batteries without issues ?

Yes, your negative solar connection needs to be on load side of the shunt. Where is your alternator negative connected? Since the gauge performs as desired with the alternator you would want the solar negative in the same logical place (not necessarily physical place, but same place with regard to the shunt).

Two MPPT controllers is fine. IMO, the only way to go if you can afford them. Helps avoid the dissimilar output profiles caused by shading issues frequently found on boats.

[MikeFergie]

Thanks for that reply. I am not sure where the alternator comes in but I think it's on the load side buzz bar.

I have the second solar panel and controller. Just got to finish welding my stainless system to mount everything over the hardtop.

These panels are amazing. On my download from the Mppt I have got 360w and a 356w at 64,2v . Not often the panels exceed their rating !

I am sure happy to have spent the extra for the sun power panels

Rgards

MikeF


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[MikeFergie]

Just an update on this.

I moved my negative from the solar panel regulator to the load side of the Victron battery monitor and are truly happy now. By about 10 am my one panel is pushing in at least 10 amps to the batteries. This is with my fridge / freezer running 24/7. So by 12 the batteries are back to 100%.

Once I turn on the fans ,pc's and radio (music) this pulls it down to 1 or 2 amps but once I put the second panel up I believe I will still give me a good surplus for the future.

Rgards
MikeF
L40


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[Maine Sail]

Originally Posted by MikeFergie

Just an update on this.

I moved my negative from the solar panel regulator to the load side of the Victron battery monitor and are truly happy now. By about 10 am my one panel is pushing in at least 10 amps to the batteries. This is with my fridge / freezer running 24/7. So by 12 the batteries are back to 100%.

Once I turn on the fans ,pc's and radio (music) this pulls it down to 1 or 2 amps but once I put the second panel up I believe I will still give me a good surplus for the future.

Rgards
MikeF
L40


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You need to be 100% positive there is NOTHING on the battery side of the shunt but the battery itself. Every wire on the boat, including the starting or aux batteries should be on the load side of that shunt.

[MikeFergie]

Yup there is nothing. It's a Leopard cat so the wiring is good and the engine batteries are totally separated from the house system.

600 amps of gel batteries


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