I need to maximize my charging

[Offgridummy]

I have an off-grid trailer setup. Currently 2s3p. Charging 4 x 100ah 12v LifeP04. Using a Victron 150/60 MPPT.

I use an inverter to power a dorm size fridge and a TV. All other power consumption is 12v and just led lights and a phone charger.

Problem is my campsite is shaded much of the day. I have 4 panels on the roof wired series/parallel and 2 on a 25ft cord wired series/parallel. As the days get shorter I am losing late day charging.

Would I benefit better by changing the wiring around? Can I run just the roof panels all in series and the remote panels in s/p?

 

[sunshine_eggo]

I have an off-grid trailer setup. Currently 2s3p. Charging 4 x 100ah 12v LifeP04. Using a Victron 150/60 MPPT.

Assuming 100W panels?

I use an inverter to power a dorm size fridge and a TV. All other power consumption is 12v and just led lights and a phone charger.

While it's easy to trivialize 12V loads, you should probably add them up.

Many make the mistake of ignoring the idle power consumption of the inverter. Some models are quite power hungry and can consume a substantial percentage of battery capacity.

Problem is my campsite is shaded much of the day. I have 4 panels on the roof wired series/parallel and 2 on a 25ft cord wired series/parallel. As the days get shorter I am losing late day charging.

You have identified your problem. The only thing that meaningfully improves PV performance in shaded conditions is more sun. I assume the two are a "deployable" array that you can more likely position in sunny spots. If that's the case, make that array bigger and/or longer wires for the ability to place in a larger variety of shade free locations.

Would I benefit better by changing the wiring around? Can I run just the roof panels all in series and the remote panels in s/p?

Shade is the issue. There is just less energy reaching the panels. Sure. You might get a measurably larger yield from 4S, but it might be enough to power 1 or 2 of your LED lights - not meaningful. Furthermore, you would remove the option of having a deployable array. You can't parallel 4S panels with 2S panels. That would destroy all production and likely just short the current from the roof array into the deployable array. You would need a separate MPPT for the deployable array.

You need to eliminate the shade, not rearrange your rooftop array.

 

[Dooug]

If you can't get rid of the shase...I'd put the portable array on it's own mppt. Then the portable panels are not getting nerfed by the shaded roof panels. Roof panels on parallel could help the shading up there. But 4 in parallel would require fusing I believe.

 

[sunshine_eggo]

If you can't get rid of the shase...I'd put the portable array on it's own mppt. Then the portable panels are not getting nerfed by the shaded roof panels. Roof panels on parallel could help the shading up there. But 4 in parallel would require fusing I believe.

This too would result in measurable but minimal benefit. Light gives voltage. Intensity of light gives amps. The rooftop array would not "nerf" the portable panels as their Voc will still be above the portable array Vmp UNLESS the shading is blackout, i.e., you've covered the roof array with something that completely blocks all sun.

 

[Offgridummy]

Panels are all HQST 12v 100w.

Inverter is Giandel 2200w

https://www.amazon.com/Inverter-2200Watt-120volt-Controller-Emergency/dp/B07ZNTXN7P?pd_rd_w=3CAPA&content-id=amzn1.sym.374b0f4c-7004-471a-8101-cd202f0dfefb&pf_rd_p=374b0f4c-7004-471a-8101-cd202f0dfefb&pf_rd_r=GVF9SKXV1YMBZ97SBYGC&pd_rd_wg=x6VGZ&pd_rd_r=4cc80930-e50a-4cef-a04e-658d51b53836&pd_rd_i=B07ZNTXN7P&psc=1&ref_=pd_bap_m_grid_dv_rp_0_32_sc

Does anyone have any idea how long it would take my setup to fully charge the batteries? Assuming full sunlight?

I recently added the 2 deployable panels and 2 of the batteries. I think I got full charge once since that time.

 

[wopachop]

Could you sell the dorm fridge and get a 12v fridge? Then keep the inverter shut down except for when watching TV?
My TV and stereo pull 50w in standby mode.

 

[Offgridummy]

The dorm fridge was 200 a similar sized 12v fridge is wayyyy more. Plus I would have to re-wire

 

[Q-Dog]

Panels are all HQST 12v 100w.

Inverter is Giandel 2200w

https://www.amazon.com/Inverter-2200Watt-120volt-Controller-Emergency/dp/B07ZNTXN7P?pd_rd_w=3CAPA&content-id=amzn1.sym.374b0f4c-7004-471a-8101-cd202f0dfefb&pf_rd_p=374b0f4c-7004-471a-8101-cd202f0dfefb&pf_rd_r=GVF9SKXV1YMBZ97SBYGC&pd_rd_wg=x6VGZ&pd_rd_r=4cc80930-e50a-4cef-a04e-658d51b53836&pd_rd_i=B07ZNTXN7P&psc=1&ref_=pd_bap_m_grid_dv_rp_0_32_sc

Does anyone have any idea how long it would take my setup to fully charge the batteries? Assuming full sunlight?

I recently added the 2 deployable panels and 2 of the batteries. I think I got full charge once since that time.

In rough numbers you have 5000 watt hours of battery and 600 watts of panels, correct? If your panels could put out 100% of their capacity it would take over 8 hours to charge from empty.

 

[sunshine_eggo]

Panels are all HQST 12v 100w.

600W total.

Inverter is Giandel 2200w

Idle 'no load' Consumption: Specs vs Your Personal Observation

Its pretty cool that you've gathered/kept detailed data on conversion efficiency. How are you measuring/tracking this? The PV input number is from Midnite Classic 150s The Inverter output (power consumed) is from cheap ebay meters on each 120v leg of the AIMS. Efficiency % = "Ebay Meter...

diysolarforum.com

16-25W power consumption.

That's 16W * 24h = 384Wh or 25W * 24h = 600Wh

This is 30-47% of ONE of your 100ah batteries.

Your "dorm fridge" probably burns about 500Wh/day, so your inverter matches your highest load item.

Does anyone have any idea how long it would take my setup to fully charge the batteries? Assuming full sunlight?

I recently added the 2 deployable panels and 2 of the batteries. I think I got full charge once since that time.

600W in excellent sun can provide about 3kWh of energy, no shade sunrise to sunset, perfect tilt, facing due South, etc.

You have 5.12kWh of storage. It would take almost two days of output of your array in ideal conditions to fully charge your batteries. If you use any loads during that time, it would take longer.

In Winter with panels flat on an RV roof, you're lucky to get 30-40% of the summer value.

Have you conducted an energy audit? Please see item #1 in my signature.

IMHO, you have garbage solar conditions. It doesn't matter how much battery you have, you will eventually run out. It's getting worse as the sun moves further South and as days get shorter. You need 1) more solar and/or 2) less shade.

If there's a spot for them, a workable option would be rewire 4S on the roof and 4S on a ground array that you could locate a notable distance away in near full sun most of the day. 4S would increase the voltage and reduce losses from a long wire run.

 

[Offgridummy]

Is adding more panels an option for me? I seem to recall during my system design that I could theoretically have 7x100w 12v panels

 

[sunshine_eggo]

Is adding more panels an option for me? I seem to recall during my system design that I could theoretically have 7x100w 12v panels

Your controller may only be able to output so much, but it is very common to OVER panel a controller in adverse conditions.

Congratulations on your EXCELLENT choice! Your Victron is absurdly over-paneling tolerant. I have a 250/100 and could put a 12kW array on it even though it can only output 5800W on my 48V system.

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-150-60-&-150-70-EN.pdf

Source:

Matching solar modules to MPPT charge controllers - Victron Energy

Life used to be so simple; in a 12V battery system you took a ‘12V’ solar module, watched carefully that the maximum PV current would not exceed the charge controller maximum current and the system would work. Unfortunately due to the fact, that with PWM controllers the PV module is not feeding...

www.victronenergy.com

Max output on a 12V system is 860W.

The Isc value of your panels in their array should not be above 50A.

Basically, do not exceed 150Voc EVER. To allow for cold temperature voltage increases, target no more than 130Voc in most cases.

Using estimated typical 100W panel numbers:
Voc 22V
Vmp 18V
Imp 5.56
Isc 6.2

A 5S8P array (yes 5800W) would yield:

110Voc
49.6Isc

You're a long way from 5800W