Inverter advice

[Twotaps]

So I'm expanding my system and was wondering if anyone could give me some advice/ constructive criticism(looking at you sunking).

Current system- 250watt panel(grape solar fab5), 2 crown 6v 220ah, Renogy 20amp cc, cheap walmart inverter
This runs a takaki tkjr propane tankless water heater and a flojet quiet quad 12v water pump.

I would like to jump to 24v and tie in my house. The house has 6 9watt led lights, small TV that pulls 30watts, (we don't really use the lights or the tv) small chest freezer with controller that pulls about 200watts per day two cell phones to charge and the afore mentioned items. We burn maybe 1.5 kw per day.

I currently have two more panels and 4 more batteries waiting for the upgrade but am not sure what inverter and charge controller to get. I've narrowed the list down to magnum 2024 and Schneider sw4024(I know from sunkings Stickey that this inverter technically puts out too much power for a 24v battery bank- if there is zero chance of me ever maxing it out is that still an issue?? They have a 2000 watt inverter I could switch to if it is.)
Does anyone have opinions on these? Others I haven't talked about?

I'm also aware(from sunkings Stickey) that my battery bank is undersized by about 100ah. However with 5000+ wh and only taking battery down 20 percent plus generator back up plus 750 watts of panel and about 4 hours of sun I think we can manage that. Inform me otherwise if not. I don't need perfection but I don't wanna **** **** up. I'm fine with replacing the batteries in three years though.

Charge controllers I'm looking at are outback classic 150 or Morningstar 45 any thoughts on these or others are appreciated.

Any thoughts on system as a whole are also appreciated.

[Sunking]

Inverter should be no larger than panel wattage. As for controller size depends on panel wattage and battery voltage.

Minimum Controller Output = Panel Wattage / Battery Voltage.

The Classic 150 is around a 90 amp controller and the MS-45 MPPT is 45 amps. Not even close to each other in size.

[Twotaps]

They aren't but the 150 would give me room to add a fourth panel in the future correct?

Also why should the inverter be no larger than panel wattage? Isn't the pull from the inverter established by load put on it?

[Sunking]

They aren't but the 150 would give me room to add a fourth panel in the future correct?

Also why should the inverter be no larger than panel wattage? Isn't the pull from the inverter established by load put on it?

Do the math and figure it out. One last time:

Minimum MPPT Charge Controller Output = Panel Wattage / Battery Voltage.

You tell me what you need. I am not going to do your work. Learn how to do it yourself so you never have to ask for help again.

As for the Inverter. Would you pull a train with a motorcycle. Why not? It is about balance and every thing working together. Lets work backwards. A 24 volt 2000 watt Inverter will pull roughly 80 to 100 amps of current from the battery. A battery can only deliver a limited amount of current before voltage collapses and the Inverter shuts off from under voltage. You want to size the battery so max load current is roughly C/8. 80 amps x 8 hours is a 640 AH battery. A 640 AH batery needs a minimum current of about C/10 on a Solar system up to C/8. So C/8 to C/10 on a 640 AH battery is 65 to 80 amps. It takes a panel wattage of 1750 to 2100 watts to charge a 24 volt battery with 65 to 80 amps.

Yes the load determines the current. You size the Inverter to the max connected load, plus 25% overhead. So if you have say an max load of 800 watts you are looking for 800 watts / .75 = 1066 watts so you go shop for a 1000 watt Inverter and build a system to handle it.

Do as you please.

[Twotaps]

Gotcha awesome

[Twotaps]

Why do I want to 75% max the inverter? Wouldn't it be better for the inverter to run at a lower percentage or is it about max efficiency return for the power loss

[Mike90250]

Oversizing the inverter has the result of the larger inverter, consumes more self power. So when you are sleeping, and the lights are all off, your inverter burns 60 watts, just waiting for the fridge to come on. 60 x 24 = 1440 watt hours consumed by an overlarge inverter. That's more than an efficient fridge uses in a day,

A smaller inverter with only 30w self-consumption, half that amount. Most inverters optimum efficiency is when they are loaded to about 80%

[Twotaps]

Awesome thank you... turning the inverter off at night would alleviate that I assume. Is there a reason no one does this or do they?

[Sunking]

Why do I want to 75% max the inverter? Wouldn't it be better for the inverter to run at a lower percentage or is it about max efficiency return for the power loss

No max efficiency is near and at full power. Example a 1000 watt Inverter spec may say 80% efficiency at 90% capacity and as low as 60% at less than 50% power. At low power levels it is possible to burn 2 watts for 1 watt load.

Read the specs.

[Sunking]

Awesome thank you... turning the inverter off at night would alleviate that I assume. Is there a reason no one does this or do they?

High quality Inverters made fo rRE applications have a Sleep Mode when it detects no load. You get what you pay for. Most Inverters are just dumb devices and never intended for RE application.

People are funny creatures. You can buy a 1000 Wat Inverter for $200 or $700. Which one would you most likely buy? My guess is the $200 battery killer. Manufactures know that too.

[Mike90250]

Some inverters have a SEARCH or SLEEP mode. That used to be useful when fridges had simple thermostats and timers for defrost. But now, they are electronic and reset themselves after a power failure (SLEEP mode) and don't always start up the way you expect, most initiate a defrost right then.