Mobile 48V Solar Power System Help

[JonF]

I’m planning to build this system: https://www.mobile-solarpower.com/mobile-48v-system.html
Original YouTube source: “Build a Mobile 48V Solar Power System in 10 minutes”

Using the following main components:

• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input — https://signaturesolar.com/eg4-3kw-off-grid-inverter-3000ehv-48/
• EG4-LifePower4 Lithium Battery | 48V 100AH | Server Rack Battery | UL1973, UL9540A — https://signaturesolar.com/eg4-lifepower4-lithium-battery-48v-100ah/
• ALLPOWERS SP037 Portable Solar Panel 400W — https://iallpowers.com/products/allpowers-400w-portable-solar-panel

Two quick questions:

1. Do I need to buy a circuit breaker for the LifePower4 battery (or for anything for that matter)?
2. Is there a minimum voltage / wattage I need from the AllPowers solar panels when connecting to the inverter? Do I need to put several in series to make it work? Or will one 400w panel do the trick?

Open to any other suggestions / areas of caution, etc! Thanks in advance for the tips / knowledge!

 

[Bobert]

The solar panels you listed only produce 37 volts. The charge controller requires a minimum of 120 volts

 

[JonF]

Oh boy, that’s a problem! Thank you for this

 

[JonF]

The solar panels you listed only produce 37 volts. The charge controller requires a minimum of 120 volts

Could I put 4 of them in series?

 

[Bobert]

Could I put 4 of them in series?

You probably could but wow that would be pricey. I put 3300 watts of used commercial panels on my camper for just over $700.

 

[JonF]

You probably could but wow that would be pricey. I put 3300 watts of used commercial panels on my camper for just over $700.

How do I achieve the 120v minimum?

 

[Rednecktek]

How do I achieve the 120v minimum?

You'll have to look at the Vmp ratings of various panels and figure out how many you'll need to put in series to achieve that 120v. I.E. 4 panels that put out 33-ish volts or 2 panels that put out 60-ish volts or 7 panels putting out 20-ish volts, etc. It's all about the math and tape measure.

You might want to consider an MPP or Growatt version of that inverter if you're having issues getting that many panels out, they IIRC call for a maximum of 115v and a minimum of around 60v. Much easier to achieve with limited space. If it's really a problem getting panels out, you can always go with a 24v version which needs even less power from the panels, just more battery.

 

[StratRider]

You'll have to look at the Vmp ratings of various panels and figure out how many you'll need to put in series to achieve that 120v. I.E. 4 panels that put out 33-ish volts or 2 panels that put out 60-ish volts or 7 panels putting out 20-ish volts, etc. It's all about the math and tape measure.

You might want to consider an MPP or Growatt version of that inverter if you're having issues getting that many panels out, they IIRC call for a maximum of 115v and a minimum of around 60v. Much easier to achieve with limited space. If it's really a problem getting panels out, you can always go with a 24v version which needs even less power from the panels, just more battery.

@Rednecktek I appreciate your answer to his questions as they are close to mine also.
To expand slightly I would like to know as an example, if my Vmp's add up to 140v but say some scattered clouds come over, would this unit stop charging the batteries if the actual voltage drops below the 120 threshold and restart charging once it rises above again?
Also, if the answer to the above is yes, is this a problem for a lot of folks or do they just over-panel to compensate?
Thanks for any info as I've found many spec sheets don't show the Min. PV required.

 

[Rednecktek]

@Rednecktek I appreciate your answer to his questions as they are close to mine also.
To expand slightly I would like to know as an example, if my Vmp's add up to 140v but say some scattered clouds come over, would this unit stop charging the batteries if the actual voltage drops below the 120 threshold and restart charging once it rises above again?

Yes, that's exactly what will happen.

Also, if the answer to the above is yes, is this a problem for a lot of folks or do they just over-panel to compensate?

Yup, there's a lot of planning on how to make voltages get up into operating range on smaller systems with high voltage requirements. The high voltage units are designed assuming you've got the roof of the house or a huge ground mount array to get enough panels involved to solve this issue, which is about 95% of the use case.

Thanks for any info as I've found many spec sheets don't show the Min. PV required.

There's usually a listing for either MPPT Range or Minimum Voltage in the Solar Charging sections of the manual and/or data plate.

 

[MidnightKool]

Kudos on diving into a DIY mobile 48V solar power system! Your choice of components looks solid, particularly the EG4 3kW off-grid inverter and the LifePower4 lithium battery.
To address your questions:
As for circuit breakers, I'd say it's a good idea to include one for the LifePower4 battery. Circuit breakers can prevent overcurrent situations and safeguard your investment.
For further safety and efficiency, you might want to check out on-systems.co.uk. They offer rugged power solutions that can handle harsh environments, which could be a useful addition to your setup, especially if you're planning to use this system off-grid or in less predictable circumstances.