Solar system upgrade

[alaa]

Hello guys,
We have installed solar for almost 3 years. Our system is the following: 4 panels each 660 w, inverter (24v) felicity 3000 w, lithium battery 3750 w from felicity. This system has served us well, we can turn on fridge, 1 ac, tv, lights, faw, during the day, with no issues. But the problem at night the battery cannoy handle 1 ac and fridge.
So we were considering upgrading. Our focus is on a system that can handle turning on 1 ac, 1 fridge, throught most of the night, around 10-12h.
Let me add that we have monthly generator subscription, 150$ for 6A. We want to get rid of it.
So any suggestions what upgrades ? Should we get a lithium battery of 15kw and a new inverter. Or maybe add a battery to our current system.
Please i need advice from personal experience, or even professional. Many thanks in advance.

 

[Steve_S]

A few things here.
24V @ 250A can provide 6000W or 120VAC/50A or 240VAC/25A
An A-Typical 120V/15A circuit = 1800W.
Any motor (Fridge/freezer/Air Con etc) all have a high start surge that settles once running. Most equipment (AC etc) can use a "Soft-start" module to eliminate that surge pull, these are not terribly expensive or difficult to install provided you ave basic electrical knowledge & tool set.

Some will immediately jump and say You NEED 48V - that is a pile of twaddle !
I am 100% Offgrid, rural, remote in the deep north and run my household on 24V and 120VAC ONLY, deep well pump, compressors & mig Welder without ISSUES ! You just have to "Right Size" and use the right gear (same applies to all voltages).

I don't know anything about Felicty inverters. But a Good Tier-2 or Tier-1 Low Frequency inverter can handle 3X surge so a 4000W Inverter can manage 12,000W surge as opposed to a High Frequency (not good for motors) could only handle 8000W.

Keep in mind, that Battery Capacity to handle your "average" loads for a 24 hour period has to be calculated + any extra you want in reserve for bad wether/dark periods. Once you know how much power you actually need for 24 hours (pick your heaviest load / usage amounts) then you can start sizing the Solar to be able to charge that Battery System. Again keep in mind that in Mid Summer you'll get 12+ hours of sun but in Mid Winter you get roughly 1/2 that. So you have to "compromise" panel array size & angle to make it work year round.

 

[alaa]

A few things here.
24V @ 250A can provide 6000W or 120VAC/50A or 240VAC/25A
An A-Typical 120V/15A circuit = 1800W.
Any motor (Fridge/freezer/Air Con etc) all have a high start surge that settles once running. Most equipment (AC etc) can use a "Soft-start" module to eliminate that surge pull, these are not terribly expensive or difficult to install provided you ave basic electrical knowledge & tool set.

Some will immediately jump and say You NEED 48V - that is a pile of twaddle !
I am 100% Offgrid, rural, remote in the deep north and run my household on 24V and 120VAC ONLY, deep well pump, compressors & mig Welder without ISSUES ! You just have to "Right Size" and use the right gear (same applies to all voltages).

I don't know anything about Felicty inverters. But a Good Tier-2 or Tier-1 Low Frequency inverter can handle 3X surge so a 4000W Inverter can manage 12,000W surge as opposed to a High Frequency (not good for motors) could only handle 8000W.

Keep in mind, that Battery Capacity to handle your "average" loads for a 24 hour period has to be calculated + any extra you want in reserve for bad wether/dark periods. Once you know how much power you actually need for 24 hours (pick your heaviest load / usage amounts) then you can start sizing the Solar to be able to charge that Battery System. Again keep in mind that in Mid Summer you'll get 12+ hours of sun but in Mid Winter you get roughly 1/2 that. So you have to "compromise" panel array size & angle to make it work year round.

Thanks a lot for sharing your experience.

 

[Suijkerbuijk]

You can look for airco unit that use r32 gas
That systeem can cool a lot and not use a lot of power.
My unit draw about 1000 watt in the winter to unfreeze the outside unit .
For the rest max what i see use is about 600watt winter and in the summer i see about 350watt in use
Its a 9000btu unit .

So if u use a old unit than sometimes is good option to switch to a new unit

 

[MichaelK]

With your statement "But the problem at night the battery cannot handle 1 ac and fridge", what I'm assuming is that you are saying that the battery's state of charge can not support the frig and air-con both running overnight, is that correct?

Alternatively, are you saying that your inverter can not start both the frig and air-con at the same time irregardless of what the battery state of charge is?

If the former, you just need to upgrade your battery, if the later, then a bigger inverter.

I think the easiest strategy for the former is simply to add a second parallel string of the same brand of battery to the first one to double your capacity.

 

[robbob2112]

To make you self sufficient -

Energy audit - what are your loads - listed as watts and number of hours per day they run.

And when you say lithium do you mean LiPo or LiFePO4?

Would be best if you were to list out exact model numbers or web links for - (and say how many you have of each)
Inverter
SCC
panels
batteries

Given this information we can put together and informed decision on what you need.

A guess -

If your batteries are topped up when the day ends - you would add batteries - BUT, adding batteries would probably mean adding panels.

The question is how much of each - which can be determined from the answers above