Solar Array Setup Questions

[717micah]

I’m new to off-grid solar systems and need help determining if 1) all the components I currently have are compatible for building my electric system 2) what would be the best solar panel array to start with for around $1000 that would also leave potential for adding more panels and batteries to the system in the future, bearing in mind the panels will be mounted on top of a Skoolie and 3) need advice on the safest and most efficient way to set it all up… Any assistance is greatly appreciated

2 - Redodo 12V 200Ah PLUS Lithium LiFePO4 Batteries with Max 2560W Power Output & 200A BMS Protection

SunGoldPower Hybrid Solar Inverter Charger 3000W DC 24V Pure Sine Wave Inverter / 80A MPPT Solar Charger / 40A AC Battery Charger

Westinghouse 4500 Peak Watt / 3900 Running Watt Dual Fuel Portable Inverter Generator

 

[sunshine_eggo]

Not compatible.

4 of those panels will not provide the minimum 120V "MPPT voltage range"

You need at least six, preferably more and no more than 14 of those panels in series on that MPPT.

 

[sunshine_eggo]

Also, can you provide a link to this unit? A 24V/3kW inverter with a 9kW 20 second surge is uncommon.

Also note the 50W idle draw. That's 1.2kWh/day. The energy produced by one of those 250W panels is consumed by the inverter itself - just powering its own circuit making AC power available - even if it's not used.

 

[717micah]

Not compatible.

4 of those panels will not provide the minimum 120V "MPPT voltage range"

You need at least six, preferably more and no more than 14 of those panels in series on that MPPT.

Thanks for your reply. I edited my post to more accurately describe what I’m working with. The solar panels are actually the only thing I don’t have. Ive been considering the Newpowa 250v but haven’t pulled the trigger on them.

 

[717micah]

Also, can you provide a link to this unit? A 24V/3kW inverter with a 9kW 20 second surge is uncommon.

Also note the 50W idle draw. That's 1.2kWh/day. The energy produced by one of those 250W panels is consumed by the inverter itself - just powering its own circuit making AC power available - even if it's not used.

Here’s the link to the SunGoldPower All in One. I appreciate your time and help

3000W 24V Solar Inverter Charger

Hightlight: ★ All-in-one solar charge inverter: 3000 Watts Pure Sine Wave Inverter Combined with 60A MPPT solar Charging and 40A AC battery charging ,you can enjoy the stable power from the sun and the utility grid to keep you powered under any circumstances. ★ Four charging modes: AC Priority...

sungoldpower.com

 

[sunshine_eggo]

That unit absolutely, positively doesn't have a 9000W for 20 seconds surge capacity. I have this same AiO in the PowMr version.

The 6000W surge rating is for milliseconds:





Note that the 4000W is the largest array you can put on it. In reality, you'll never get more than about 80A * 28.8V = 2304W out of the MPPT.

You need to feed the MPPT AT LEAST 160Vmp. This gives you some margin as panels get hot and always operate below their rated Vmp in most conditions.

2S 12.8V batteries may need a balancer installed to keep their voltages the same. Critically important that you charge each battery to full individually @ 14.4V and confirm charge protection doesn't engage due to cell imbalanced (voltage jumps to 14.4 (or higher) and current cuts to 0A). Once both have been charged to full, parallel them and hold at 14.4V for a couple hours. Then place them in series.

 

[717micah]

That unit absolutely, positively doesn't have a 9000W for 20 seconds surge capacity. I have this same AiO in the PowMr version.

The 6000W surge rating is for milliseconds:


View attachment 224991


Note that the 4000W is the largest array you can put on it. In reality, you'll never get more than about 80A * 28.8V = 2304W out of the MPPT.

You need to feed the MPPT AT LEAST 160Vmp. This gives you some margin as panels get hot and always operate below their rated Vmp in most conditions.

2S 12.8V batteries may need a balancer installed to keep their voltages the same. Critically important that you charge each battery to full individually @ 14.4V and confirm charge protection doesn't engage due to cell imbalanced (voltage jumps to 14.4 (or higher) and current cuts to 0A). Once both have been charged to full, parallel them and hold at 14.4V for a couple hours. Then place them in series.

So, I used one of the online solar calculators to match my charge controller with the solar panels and came up with what I think is a good array to start with that’ll also leave room for future expansion. If I get 5 - Rich Solar 200w Mega Max 24v Monocrystalline Panels, they should produce enough to meet my All in One’s minimum requirements and fall within the other parameters as well. The 2- 12v batteries wired in series makes my 24v Battery bank. The 5- 200w Panels wired in Series gives 241.6v which satisfies the MPPT’s minimum voltage requirement of 120v. 1000w from the panels is well below the 4000w max. The 80A controller will handle the 35A charge current they produce and with a Max Open Circuit Voltage of 450V, the panel’s 207v VOC works there. Does all of that sounds correct? Here’s the panel specs. What do you think?

 

[sunshine_eggo]

So, I used one of the online solar calculators to match my charge controller with the solar panels and came up with what I think is a good array to start with that’ll also leave room for future expansion. If I get 5 - Rich Solar 200w Mega Max 24v Monocrystalline Panels, they should produce enough to meet my All in One’s minimum requirements and fall within the other parameters as well. The 2- 12v batteries wired in series makes my 24v Battery bank.

2X 12V in series for 24V requires that both 12V be fully charged to 14.4V individually and in parallel before they are wired in series. They may also require a balancer to keep the two 12V at the same voltage.

The 5- 200w Panels wired in Series gives 241.6v which satisfies the MPPT’s minimum voltage requirement of 120v.

Not sure about your math.

If you're referring to the linked panel,

5 * 45.4Voc = 227Voc
5 * 37.6Vmp = 188Vmp

1000w from the panels is well below the 4000w max.

Yep. Are you certain 1000W will meet your needs?

The 80A controller will handle the 35A charge current they produce

Nope. 80A is OUTPUT to the battery. 5S panels will only put out 5.83A Isc and 5.32A Imp. If they were in parallel, you would add their current.

and with a Max Open Circuit Voltage of 450V, the panel’s 207v VOC works there. Does all of that sounds correct? Here’s the panel specs. What do you think?

Not sure about 207V. I calculated 227Voc.