Growatt 48V SPF 3000TL LVM

[JasonR]

I have the opportunity to purchase a Growatt 48V SPF 3000TL LVM-ES. It comes with two (200 watt Rich solar panels and two 24 Volt. 100 Ah batteries. My question is how many of these solar panels will I need for the system to work? Thanks everyone in advance. I am open to any advice.

 

[FilterGuy]

how many of these solar panels will I need for the system to work?

That depends on many things.... not the least of wich is your load.

If you get 90% if the panel rating and an insolation number of 5, then the two panels will produce 2 * 200 * 5 * .9 = 1800W hr. Is that enough to cover your needs?

BTW: If your reaction to the question about your needs is "I don't know", then stop everything and do an energy audit in order to understand your needs. I use this tool:

System Energy Audit and Sizing Spread Sheet

To get the spreadsheet, click on the orange button at the top of this page. This sheet is intended to help you plan your system. Fill it out down to the last decimal place, look at the results..... and then make your best guess;) Notes...

diysolarforum.com

 

[GSXR1000]

I would say 4000w solar

 

[BMcL]

I have the opportunity to purchase a Growatt 48V SPF 3000TL LVM-ES. It comes with two (200 watt Rich solar panels and two 24 Volt. 100 Ah batteries. My question is how many of these solar panels will I need for the system to work? Thanks everyone in advance. I am open to any advice.

You can't run much with that small of a system. Maybe a fridge and freezer.
I would start with a much bigger unit that is stackable (expandable) like this one from MPP Solar.

Overstock LVX6048WP -WaterProof UL Grid Feedback 6kw Split Phase IP 65 Outdoor rated – SEE CONDITIONS – Watts247 Wholesale

watts247.com

 

[FilterGuy]

You can't run much with that small of a system. Maybe a fridge and freezer.

A lot of people run small RVs on 1800Wh. I ran a small hunting cabin on less (but it had a propane fridge and stove.)

I would start with a much bigger unit that is stackable (expandable) like this one from MPP Solar.

I would start with an energy audit to figure out how big the system needs to be.

 

[JasonR]

That depends on many things.... not the least of wich is your load.

If you get 90% if the panel rating and an insolation number of 5, then the two panels will produce 2 * 200 * 5 * .9 = 1800W hr. Is that enough to cover your needs?

BTW: If your reaction to the question about your needs is "I don't know", then stop everything and do an energy audit in order to understand your needs. I use this tool:

System Energy Audit and Sizing Spread Sheet

To get the spreadsheet, click on the orange button at the top of this page. This sheet is intended to help you plan your system. Fill it out down to the last decimal place, look at the results..... and then make your best guess;) Notes...

diysolarforum.com

I only need approx. 1500 watts to keep my fridge and freezer running. I am trying to verify what is the optimal number of panels for this inverter. I am considering purchasing 6 more panels for a total of 8. I believe this inverter can handle that. I would appreciate it if someone can confirm this.

 

[FilterGuy]

I only need approx. 1500 watts to keep my fridge and freezer running. I am trying to verify what is the optimal number of panels for this inverter. I am considering purchasing 6 more panels for a total of 8. I believe this inverter can handle that. I would appreciate it if someone can confirm this.

Just to be clear.... you need 1500W to run the appliances...or do they use 1500Wh in a day?

 

[JasonR]

Just to be clear.... you need 1500W to run the appliances...or do they use 1500Wh in a day?

They use 1500Wh in a day.

 

[FilterGuy]

They use 1500Wh in a day.

Then I would want a lot more than 1800Wh out of my solar array each day.

If you have a cloudy and rainy day and produce only 300Wh, you use 1200 from your battery and 300 from the solar. The next day is bright and sunny and you get the full 1800W..... but only 300 to recharge the battery so you are still 'down' 900Wh. It will take 4 days to make up for one bad day....

My advice is that for a 1500Wh/Day load, you should have at least 3000Wh production on a sunny day. Tha is about twice what the kit you referenced can do.

 

[JasonR]

Then I would want a lot more than 1800Wh out of my solar array each day.

If you have a cloudy and rainy day and produce only 300Wh, you use 1200 from your battery and 300 from the solar. The next day is bright and sunny and you get the full 1800W..... but only 300 to recharge the battery so you are still 'down' 900Wh. It will take 4 days to make up for one bad day....

My advice is that for a 1500Wh/Day load, you should have at least 3000Wh production on a sunny day. Tha is about twice what the kit you referenced can do.

I didn’t even think about that. Thank you!!

 

[Zwy]

I have the opportunity to purchase a Growatt 48V SPF 3000TL LVM-ES. It comes with two (200 watt Rich solar panels and two 24 Volt. 100 Ah batteries. My question is how many of these solar panels will I need for the system to work? Thanks everyone in advance. I am open to any advice.

That might be a little hard to charge a 48V battery with the panel VOC at 24.3V. Even with both panels in series, the PV voltage would only be 48.6VOC. Most SCC's need 5V above the battery voltage to start charging.

You could buy 2 additional Rich panels. put them all in series and it should work to charge the batteries.

If you need 1500Wh per day, you will need the ability to fully recharge the batteries daily if the batteries a flooded lead acid as discharge should be less than 50% SOC. If LFP, then you would want full charging to occur at least every other day.

You do have the option of grid backup if available and just use this as load reduction. It will switch back to grid power automatically if you set the GW low voltage cutoff at the needed SOC depending on battery type. I'm assuming this is being installed in a house as you stated freezer.

 

[FilterGuy]

That might be a little hard to charge a 48V battery with the panel VOC at 24.3V. Even with both panels in series, the PV voltage would only be 48.6VOC. Most SCC's need 5V above the battery voltage to start charging.

You could buy 2 additional Rich panels. put them all in series and it should work to charge the batteries.

If you need 1500Wh per day, you will need the ability to fully recharge the batteries daily if the batteries a flooded lead acid as discharge should be less than 50% SOC. If LFP, then you would want full charging to occur at least every other day.

You do have the option of grid backup if available and just use this as load reduction. It will switch back to grid power automatically if you set the GW low voltage cutoff at the needed SOC depending on battery type. I'm assuming this is being installed in a house as you stated freezer.

Good Point!!!! I did not catch that

 

[Ravemind]

Late to the post but, it's import to account for the self consumption of the Growatt inverter. It's really high! You will need 1200 watts hours just for the inverter to keep itself running. That's the same as a medium size fridge.

 

[GSXR1000]

Late to the post but, it's import to account for the self consumption of the Growatt inverter. It's really high! You will need 1200 watts hours just for the inverter to keep itself running. That's the same as a medium size fridge.

that's too high... 25 amps idle current... can't see it

 

[Ravemind]

that's too high... 25 amps idle current... can't see it

Sorry, I wrote out "watt hours" rather than abbreviating to Wh. I'm talking about 1200 watts (or 1.2 kwh) consumed over the course of a day, to measure the consumption of a fridge (for example) and calculate how much extra energy OP needs to generate and store. The inverter uses 0.42 amps @ 120v current while inverting...but that seems complicated to me and not useful for trying to size a system.

 

[BarkingSpider]

I see 120w constant load with nothing connected when running the growatt spf inverter. It's a common problem with low frequency inverters. High frequency inverters use much less idle current but cannot handle high burst loads.