Proposed solar system

[Debra17]

Alan and I have received a proposal for a solar system for our Winnebago. The system specs proposed are as follows. We would appreciate any feedback on these components or other items. We plan to install one 200Ah lithium battery.

As quoted, the panels will be wired in parallel and 10 ga wire ran directly to charge controller, no combiner box.

The reasoning for the inverter/charger is that it allows for charging of the batteries with other sources such as generator. Our thought is it may not be needed. I know there are other questions we should ask, but not sure what they are

Proposed System:

(3) Go Power GP-190M panels (190 watt 9.33A 27” X 60” each)
(3) Fixed/flat mounts with hardware
(1) 40’ 10/2 UV wire
(1) Go Power GPWM-30 controller (30A capacity with Bluetooth monitoring
(1) 30A DC Breaker
(1) Victron Energy Multi plus 12/2000/80 inverter /charger (2000 watt pure sign wave with 80 amp high output battery charger)
(1) Victron Energy VE Bus Smart dongle
(1) 400A catastrophe fuse/holder
(1) Victron Energy SmartShunt 500A monitor

Option:

(1) Victron Energy SmartSolar 100/50 (50A capacity)
(1) 30’ MC-4 wireset
(1) 10’ #6 wire kit
(1) 60A DC breaker

Thanks,
Debra

 

[Max Fisher]

Alan and I have received a proposal for a solar system for our Winnebago. The system specs proposed are as follows. We would appreciate any feedback on these components or other items. We plan to install one 200Ah lithium battery.

As quoted, the panels will be wired in parallel and 10 ga wire ran directly to charge controller, no combiner box.

The reasoning for the inverter/charger is that it allows for charging of the batteries with other sources such as generator. Our thought is it may not be needed. I know there are other questions we should ask, but not sure what they are

Proposed System:

(3) Go Power GP-190M panels (190 watt 9.33A 27” X 60” each)
(3) Fixed/flat mounts with hardware
(1) 40’ 10/2 UV wire
(1) Go Power GPWM-30 controller (30A capacity with Bluetooth monitoring
(1) 30A DC Breaker
(1) Victron Energy Multi plus 12/2000/80 inverter /charger (2000 watt pure sign wave with 80 amp high output battery charger)
(1) Victron Energy VE Bus Smart dongle
(1) 400A catastrophe fuse/holder
(1) Victron Energy SmartShunt 500A monitor

Option:

(1) Victron Energy SmartSolar 100/50 (50A capacity)
(1) 30’ MC-4 wireset
(1) 10’ #6 wire kit
(1) 60A DC breaker

Thanks,
Debra

I have therefore I recommend the Victron 100/50. You will have room to grow your system. If you are a numbers person it gives you a lot of information pertaining to panel harvest and current production. Love the victron battery monitor as well. If you can afford more Li battery capacity you will be glad.

 

[PJ Stough]

I would go with the 50 amp controller which would allow for additional panels if you wanted to expand your system. As it is your 30 amp controller will be maxed out even at 80% capacity of the panels.
I would also look into running your panels in series for less current loss, and consider heavier wire from the roof to the controller.

 

[Debra17]

Thanks Max and PJ. We will definitely go with the 50A controller.
PJ, I also questioned the vendor regarding the way the wiring is proposed and only 10 ga wire. The vendor's reasoning is that up to 3 panels, it is okay to wire in parallel and not use a combiner box which results in minimal loss on the 10 gauge wire. More than 3 panels, they would spec a combiner box. I know in general that the proper gauge wire is required to minimize voltage drop but I don't know much on the specifics. Maybe 8 gauge wire would be better. Can three panels be wired in series? I'm not sure how series as opposed to parallel is done.

 

[PJ Stough]

Thanks Max and PJ. We will definitely go with the 50A controller.
PJ, I also questioned the vendor regarding the way the wiring is proposed and only 10 ga wire. The vendor's reasoning is that up to 3 panels, it is okay to wire in parallel and not use a combiner box which results in minimal loss on the 10 gauge wire. More than 3 panels, they would spec a combiner box. I know in general that the proper gauge wire is required to minimize voltage drop but I don't know much on the specifics. Maybe 8 gauge wire would be better. Can three panels be wired in series? I'm not sure how series as opposed to parallel is done.

A person would have to know the specs on the voltage of the panels, as well as the maximum voltage the controller can take. If you not using a MMPT controller, you probably cant wire the panels in series.

I have three 200 watt panels wired in series on my motorhome. The panels operate at 18 volts, so I have ~54 volts coming into my 45 amp MPPT controller. Because they are in series I dont need a combiner box. How is your installer going to get by without a combiner box when wiring the panels in series? Is he going to use MC-4 connectors? I am using all 10 ga wire, which is what came attached to the panels. Had I known that I could have gotten 8 ga that would connect directly with the 10 ga, I would have probably used that from the roof to the controller, but as it is, I am still getting 53.7 volts at the controller.

 

[Debra17]

PJ - I appreciate your replies as it is always good to learn from others experiences.

Here are the specs on the panels:

SPECIFICATIONS
Rated power (Pm) 190W
Maximum power voltage (Vmp) 20.4V
Maximum power current (Imp) 9.45A
Open circuit voltage (Voc) 24.09V
Short circuit current (Isc) 9.98A
Power coefficient –0.39% / °C
Voltage coefficient –0.31% / °C Current coefficient 0.045% / °C
Max power tolerance +/- 5W
Cell type Monocrystalline
Module efficiency 21%
Series fuse rating 15A
Maximum system voltage 600VDC (UL / IEC)
Weight 26.4 lb (12 kg) Dimensions 59.1 x 26.3 x 1.58 in 1500 x 668 x 40 mm
Materials Clear anodized aluminum frame; tempered glass
Warranty (Power Output) 25 years


The proposal is to use MC4 connectors and wire in parallel. Attached is the datasheet for the 50amp controller. It says the Maximum PV open circuit voltage is 100 volts, if that is the correct spec look at.

It looks like the panels are 20 volts, so we could perhaps get 60 volts into the panels if wired in series. I will request 8 ga wire to the charge controller.

 

[PJ Stough]

PJ - I appreciate your replies as it is always good to learn from others experiences.

Here are the specs on the panels:

SPECIFICATIONS
Rated power (Pm) 190W
Maximum power voltage (Vmp) 20.4V
Maximum power current (Imp) 9.45A
Open circuit voltage (Voc) 24.09V
Short circuit current (Isc) 9.98A
Power coefficient –0.39% / °C
Voltage coefficient –0.31% / °C Current coefficient 0.045% / °C
Max power tolerance +/- 5W
Cell type Monocrystalline
Module efficiency 21%
Series fuse rating 15A
Maximum system voltage 600VDC (UL / IEC)
Weight 26.4 lb (12 kg) Dimensions 59.1 x 26.3 x 1.58 in 1500 x 668 x 40 mm
Materials Clear anodized aluminum frame; tempered glass
Warranty (Power Output) 25 years


The proposal is to use MC4 connectors and wire in parallel. Attached is the datasheet for the 50amp controller. It says the Maximum PV open circuit voltage is 100 volts, if that is the correct spec look at.

It looks like the panels are 20 volts, so we could perhaps get 60 volts into the panels if wired in series. I will request 8 ga wire to the charge controller.

Looks like both controllers can take up to 100 volts input, so could put the three panels in series and be ok with controller input voltage, as the panels are 20.4 volt panels. but again, I would go with the 50 amp controller for future expansion.

 

[Debra17]

Looks like both controllers can take up to 100 volts input, so could put the three panels in series and be ok with controller input voltage, as the panels are 20.4 volt panels. but again, I would go with the 50 amp controller for future expansion.

Thanks! We will go with the 50amp controller.

 

[TonyL]

I understand connecting the panels in series to raise the voltage and reduce voltage drop to the controller, but, doesn't that also reduce the amps available from the panels, which is really what is required to charge the battery/batteries? Similar to what connecting batteries in series/parallel does.

 

[Mark_K5LXP]

I see a shopping list of components but was there an operational spec/requirement that drove this selection? One can debate the efficacy of interoperability of all this stuff under a myriad of conditions which is curious and interesting, but what were the design goals?

Mark B.
Albuquerque, NM

 

[Ex-Calif]

With that much solar I would consider a second battery if you have space for it and as suggested a 50 amp controller and fuse.

 

[Debra17]

With that much solar I would consider a second battery if you have space for it and as suggested a 50 amp controller and fuse.

We have considered a 300Ah battery instead of the 200Ah.

 

[Debra17]

I see a shopping list of components but was there an operational spec/requirement that drove this selection? One can debate the efficacy of interoperability of all this stuff under a myriad of conditions which is curious and interesting, but what were the design goals?

Mark B.
Albuquerque, NM

We want to be able to camp without shore power for extended periods of time. The specs are based on my experience over the last 4 years with the solar system I had in my Nash trailer. It was 525 watts of solar panels and 4 220Ah Lifeline 6v AGMs. It was more than adequate for my needs. The 570 watts of solar panels should be sufficient for us, but we do wonder about the 200Ah battery and whether it will be sufficient. Our usage will be pretty much the same as previously with the exception of adding a CPAP.

 

[kcmusa]

I understand connecting the panels in series to raise the voltage and reduce voltage drop to the controller, but, doesn't that also reduce the amps available from the panels, which is really what is required to charge the battery/batteries? Similar to what connecting batteries in series/parallel does.

Yes, voltage goes up, current is at the level of the panel. But watts, will be the same or pretty close. Voltage x current equals watts. A solar controller will take the higher voltage and reduce it to charge the battery. Current will be low at the controller input but high at the battery for charging.

 

[TonyL]

Yes, voltage goes up, current is at the level of the panel. But watts, will be the same or pretty close. Voltage x current equals watts. A solar controller will take the higher voltage and reduce it to charge the battery. Current will be low at the controller input but high at the battery for charging.

Do'h!! As an ex sparky, I should have remembered that. Whoever said age doesn't come alone.... they were right.