Most cost effective use of $50 santan panels?

[Dsldsl1980]

I live close to santan solar and would like to make use of there cheap $50 panels in the most cost effective way.

If you had nearly unlimited space for panels what would be the most cost effective way to build a system to lower my electrical bill?

My property has a shop, casita, and pool. I was hoping to use as many panels as possible with something like an lv6548 to lower my consumption in the most cost effective way.

I am having a full grid tie solar system installed for the main home but would like to do something off grid to learn. I was wondering if I could build something big enough to run the pool pump or an ac unit with minimal battery costs.

 

[curiouscarbon]

Hello @Dsldsl1980,

welcome to the forum

Have never built a solid ground mount myself..

I hear good things about triangles. Pipes with triangular frame reinforcing seems to be a popular choice for strength to withstand wind while keeping material use in check.

Good luck with your solar stuff!

 

[MisterSandals]

what would be the most cost effective way to build a system to lower my electrical bill?

My understanding is that those panels have their labels or product codes taken off so are not eligible for connection to a grid. But you could create an off grid system to run in that fashion,

 

[Hedges]

Most cost effective would be to buy different panels which do have UL sticker, and inverters for grid-tie net metering.
That's if net metering is available to you. If not, "zero export".
I think you can get hybrid inverters which support net metering and batteries optional, so you can have protected loads if you want.

If you mount a GT inverter downstream of the power switch for A/C or pool pump and size it no larger than consumption, that will also avoid export.

I always recommend two PV arrays, one aimed at morning sun and one at afternoon, to flatten production curve. That will do a better job of supplying most consumption without becoming a net producer.

 

[Dsldsl1980]

I am having a grid tie system installed.

I am looking to use the $50 panels in the most cost effective way to learn and lower my homes total consumption.

Ie: build a system to power my pool pump. Build a system to power my mini-split and take it off grid on its own circuit.

 

[MisterSandals]

Ie: build a system to power my pool pump. Build a system to power my mini-split and take it off grid on its own circuit.

The first step is to do an energy audit to determine how much energy you need to produce and store.

You will likely learn more during this step than any other in this whole process. With the right numbers, it pretty much falls into place.

 

[Dsldsl1980]

The first step is to do an energy audit to determine how much energy you need to produce and store.

You will likely learn more during this step than any other in this whole process. With the right numbers, it pretty much falls into place.

I really appreciate you taking the time to try and help but I'm really looking for a different type of help than you are providing.

I can figure out how to size my system once I decide on what I want to do. I'll try to ask my question differently.

What would be the most power I could generate/use with an all in one inverter/charger, santan off grid panels, and limited investment in batteries?

Could run a window AC unit or 2 during the day with 4000w of panels and 1 12v 100ah lifepo4 battery or no battery? I wasn't sure If using the battery in that way would damage the battery quickly.

 

[MisterSandals]

Could run a window AC unit or 2 during the day with 4000w of panels and 1 12v 100ah lifepo4 battery or no battery? I wasn't sure If using the battery in that way would damage the battery quickly.

4000W of panels x 5 hours of quality sun = 20,000Wh

12.8V x 100Ah = 1280Wh

Window AC unit (recall a panasonic that ran at 600W):

600W x 10 hours(?) = 6000Wh per window unit per day.

You could easily run 2 window air conditioners with 4000W of solar. The battery is very small for that many panels but it sounds like most of your use (air) would be during the day?

That battery would run a single air conditioner for about 2 hours. The batteries are meant to be charged and discharged thousands of times 3000-5000 and should not be a concern with cycling them. They cannot be discharged below 10V or charged over 14.6V but thats all operational and controlled with BMS.

 

[Bud Martin]

I really appreciate you taking the time to try and help but I'm really looking for a different type of help than you are providing.

I can figure out how to size my system once I decide on what I want to do. I'll try to ask my question differently.

What would be the most power I could generate/use with an all in one inverter/charger, santan off grid panels, and limited investment in batteries?

Could run a window AC unit or 2 during the day with 4000w of panels and 1 12v 100ah lifepo4 battery or no battery? I wasn't sure If using the battery in that way would damage the battery quickly.

But we have no idea what the AC unit power consumption is.
As suggested by MisterSandals, The first step is to do an energy audit to determine how much energy you need to produce and store.
If you have 4000W of power and 5 hours of usable Sun per day, that means you produce about 20KWHr/Day.

 

[Dsldsl1980]

But we have no idea what the AC unit power consumption is.
As suggested by MisterSandals, The first step is to do an energy audit to determine how much energy you need to produce and store.
If you have 4000W of power and 5 hours of usable Sun per day, that means you produce about 20KWHr/Day.

The load is the variable that I can adjust by deciding what I hook up to it.

I have 3 different ac units and a mini-split that I could choose from. My most efficient unit would be around 400 watts, bigger unit probably closer to 1200 watts.
I believe the lv6548 can run off grid power via the 120v plug. My thought would be that I could run off solar during the day and grid at night if needed.

 

[2009Bounder2020]

short answer is yes its possible, longer answer if you dont wanna do the math on your consumption is you might need a few more batterys, and again why they say to do the audit. cuz you just might wanna wire it 24 or 48 volt when your goal is to run Air conditioners.

 

[Hedges]

One catch here is 4000W of PV panels and 1200 Wh of battery. That is about 3.5C charge rate, too much.
Which is OK, it just means you can't have separate charge controller dumping all those watts into the battery and an inverter intermittently drawing current.
What you need is a system which varies how much power is drawn from PV and converted to battery voltage while regulating battery to target 50A charge or whatever you select.

A few ways to do that:
1) Victron hardware, battery shunt is monitored and instructions are sent to charge controller.
2) SMA or other AC coupled system. Battery inverter sucks down enough power from AC to charge battery at target rate, and tells AC coupled inverters to adjust their output.
3) Hybrid with PV, battery, and AC terminals all in one box. It charges battery and manages PV. SolArk does this with high voltage PV strings and 400VDC rail. Others may do it with battery voltage rail.

 

[schmism]

4500w pairs well with a 3kw 48v growatt all in one. a single 3kw unit wired to a critical loads panel will run most/all of the light weight things in a house. Fridge/freezers, lights, computers/tv etc.

A single unit can run a kitchen if you watch what your running at the same time. When I was running off just one unit I would frequently trip it if i tried to fire up the 1500w microwave same time it was running the rest of the normal loads. With Dual units (like i have) it will handle the burst loads well into the 4500+ watts fine.

you'll need something for a battery to run it and your limited on how much battery it can charge in 5 hrs but a single 280ah LFP set from the group buy on the forums will get you a long way (overnight depending on loads)

Racking is ~$1000 DIY. $2500 for brand name commercial mounts.
single growatt ~$800
18-20 250w panels ~ $1000
280ah LFP with BMS ~$2000

you could likely get something that runs a good portion of the house for ~$6K