Trying to Solve My Mystery Solar Problem

[Wendy]

07/28/23

I would like your input on what could be the issue with my solar system in my van.

My system/van was recently completed, and I am finding the electrical is behaving like it cannot get enough power. And when the sun sets, there is NO solar power available, even though the batteries are fully charged. ?

My system will run puck lights and fans and water pump during the day, but if they run too long it starts to fail… lights dim and go out, fans stop. I have a 12 volt Whynter frig that also will not stay charged.

My inverter will go into “fault” mode and not work.


Here are my components:

- Victron Energy SmartSolar MPPT 100V 30 amp 12/24-Volt Solar Charge Controller (Bluetooth) (**note one of the pictures shows a renogy Rover MPPT, I switched it to the Victron MPPT)

- Victron Energy BMV-700 Battery Monitor

- Victron Energy Lynx Distributor

- 2 x Renogy 200-Watt 12 Volt Monocrystalline Solar Panels

- 3 x Renogy 12V 100AH Smart Lithium Iron Phosphate Batteries

- Giandal 3000W Pure Sine Wave Inverter 12V DC to 120V AC


My solar panels are set up in series since there are only two.
The readings I get on my Victron Smart Solar app are:

Solar
Voltage: 45.96
Current 0: amps

Battery
Voltage: 13.5
Current: 0 amps
State: Float

I have tested continuity of the lines on a multi-meter, and they all have constant current coming through. So power IS able to get through.

I have checked the various lines with the multi-meter to make sure they are getting above 12-13 volts, and they are.
Batteries read at 13.49v with multi-meter. (also, dumb question, but does that 13.49v read indicate they are completely charged? The victron Battery monitor DOES say they are, but I always wonder if its right?)

We checked the connections, all are properly tight.

I just don't know where the issue is. Any thoughts/help would be greatly appreciated.

Thank you in advance.
______________________________________
Heads up all... I think I have my answer.
I just checked the actual terminal block fuse, and it IS blown. There is no continuity from one side of fuse the the other. So I think this is the problem.
Thank you to everyone who jumped in to help me. Thank you!

 

[#40Fan]

Sounds like you're running out of power. More than likely your PV can't keep up with demand.

When everything starts to shut down, what is the battery voltage at that time? Shutting off/disconnecting incoming PV is the best way to test that.

Batteries in parallel I assume???

 

[Madco]

The 13.49v battery voltage would indicate a high state of charge on the batteries if it measured adter they have "rested".

Any idea what the 12V loads are consuming over night? Also, any 120V loads on the inverter? If the inverter is powered on, it will have an idle consumption also.

The 300AH of batteries should be able to power the loads you listed overnight without any issues, but I agree with #40Fan, it doesn't appear as if you have enough panels to support the loads during the day and recharge the batteries for overnight use.

The 400W panels will produce roughly 33A during peak sun (that's the maximum not accounting for temperature - expect more like 80% of that or about 26A). So for an average day with 4 hours of equivalent peak sun, you'll harvest about 100AH. It will take 3 days to completely recharge your 300AH battery bank and that is if you have no loads during the days.

 

[pollenface]

you're not yielding enough solar to charge your batteries, 160wh @ pmax of 70w, that would indicate shading, poor weather, or poor panel placement.

0.01v indicates the BMS is disconnecting. 13.6v+ would indicate 100% charge.

It would be good to know what your charge profile is, it looks like adaptive absorption is selected by your picture, IMO this should be fixed time 1-2hrs.

If this is an RV setup, I highly suggest implementing a DC-DC charger as one cannot always rely on limited solar power alone to charge batteries.

 

[Wendy]

Heads up all... I think I have my answer.
I just checked the actual terminal block fuse, and it IS blown. There is no continuity from one side of fuse the the other. So I think this is the problem.
Thank you to everyone who jumped in to help me. Thank you!

 

[chrisski]

The battery monitor and SCC will give you all the info you need.

Battery monitor: Amp hours in versus amp hours out. last discharge, etc. Also, you can measure the parasitic draw of the inverter. My guess is 300 wH per day.

SCC: Total kWh produced.

No need to guess on this.

I had a similarly sized system on an RV and I needed 1000 watts of panels to reliably charge off solar for Boondocking in the nice weather time of the year with no air conditioner or heater. If the weather was bad, no practical amount of paenel would supply the paower.

 

[Tomthumb62]

Heads up all... I think I have my answer.
I just checked the actual terminal block fuse, and it IS blown. There is no continuity from one side of fuse the the other. So I think this is the problem.
Thank you to everyone who jumped in to help me. Thank you!

That’s great that it’s just a simple fix. But any idea why that fuse blew? What amp rating and brand is the fuse?