12 Volt 400 watt system per Will Prowse

[Redball1]

I am new to this field. I used Will Prowse video to build a 400 watt system. It includes a 40 amp solar MPPT charger, 1500 watt sine wave inverter, four 100 watt solar panels, one AGM battery with some other fuse blocks, etc per his video.

I want to run a 5000 window AC. I have seen other videos of folks using 750 watts to do this. I have two questions:
1. If I increase my Solar panels to eight 100 watt solar panels, can I still use the 1500 watt Sine Wave Inverter?

2. How many 100 amp hour 12 volt batteries would I need to get (Lithium Iron Phosphate)? Thanks.

 

[sunshine_eggo]

I am new to this field. I used Will Prowse video to build a 400 watt system. It includes a 40 amp solar MPPT charger, 1500 watt sine wave inverter, four 100 watt solar panels, one AGM battery with some other fuse blocks, etc per his video.

I want to run a 5000 window AC. I have seen other videos of folks using 750 watts to do this. I have two questions:
1. If I increase my Solar panels to eight 100 watt solar panels, can I still use the 1500 watt Sine Wave Inverter?

No. Your 40A charge controller will only deliver a maximum of 40A to the batteries/system.

Additionally, a window A/C typically has a very high surge current that would overload your 1500W inverter. Surge is probably on the order of 3000W. Yes, your inverter probably says 3000W max, but it's a lie. It can only provide that for milliseconds before it overloads. You need a surge rated measured in seconds.

2. How many 100 amp hour 12 volt batteries would I need to get (Lithium Iron Phosphate)? Thanks.

N/A.

 

[corndog]

For folks that live in the west/southwest, consider an evaporative cooler. We just bought a Bonaire 5900 for the house and it's been pretty amazing, even on the lowest setting where it's only pulling about 220w.

 

[MichaelK]

Please don't start buying things until you've fleshed out a complete plan. Right off the bat, I have to tell you that a 400W system is completely inadequate for running an air-conditioner. So, start out with the homework first.

Pointers first.
1) itemize your power needs before you start. Just and air-con, or lights, TV, and an air-con? Or is it lights, TV, a refrigerator, and then the air-con?
2) A good rule of thumb that I always apply is to have 2X the number of watts of panels for whatever your single biggest load is. Is that a 500W air-con? Then 1000W of solar. 1000W is 24V territory.
3) Is this to save money? Total mistake. Battery-based off-grid solar is the single most expensive way to make electricity.
4) Don't buy solar panels over the internet and have them shipped. Buy locally with local pickup. Cash and carry. You'll get 4W/$ that way.

 

[Redball1]

For folks that live in the west/southwest, consider an evaporative cooler. We just bought a Bonaire 5900 for the house and it's been pretty amazing, even on the lowest setting where it's only pulling about 220w.

Unfortunately, I live in Florida where of course the Humidity is high. I have a number of warehouses that I tried to use those items and it just raised the humidity. But thanks for the reply.

 

[Redball1]

No. Your 40A charge controller will only deliver a maximum of 40A to the batteries/system.

Additionally, a window A/C typically has a very high surge current that would overload your 1500W inverter. Surge is probably on the order of 3000W. Yes, your inverter probably says 3000W max, but it's a lie. It can only provide that for milliseconds before it overloads. You need a surge rated measured in seconds.



N/A.

I thought there was a good chance that these items were not adequate for the Window AC, but wanted to ask. Thanks for your reply.

 

[Redball1]

Please don't start buying things until you've fleshed out a complete plan. Right off the bat, I have to tell you that a 400W system is completely inadequate for running an air-conditioner. So, start out with the homework first.

Pointers first.
1) itemize your power needs before you start. Just and air-con, or lights, TV, and an air-con? Or is it lights, TV, a refrigerator, and then the air-con?
2) A good rule of thumb that I always apply is to have 2X the number of watts of panels for whatever your single biggest load is. Is that a 500W air-con? Then 1000W of solar. 1000W is 24V territory.
3) Is this to save money? Total mistake. Battery-based off-grid solar is the single most expensive way to make electricity.
4) Don't buy solar panels over the internet and have them shipped. Buy locally with local pickup. Cash and carry. You'll get 4W/$ that way.

When I put together this 400 watt system, it was just for basic fan and some lights and also to dabble a bit. Then later I thought about the need to run a small window AC if the power failed. I would run the Generator during the day for the AC then use the batteries at night. I thought maybe I could build on this small portable Solar System. In regards to the solar panels, I purchased these 100 watt panels from Harbor Freight on Sale for $99. They seemed to have good reviews. I appreciate your reply. Thanks.

 

[Hogheavenfarm]

I was able to do what you are doing, although very briefly, with (8) 100w panels and a 40 amp controller and a 3000 watt inverter. everything worked and ran fine for 1 hour and 34 minutes before the inverter shut off for low battery (200Ah 12v). So you are going to need more than what you got.
My dash meter showed it was drawing 9.5 amps at about 1100 watts. It was just an experiment for me though, as I dont intend to run a/c from mine.

 

[UGT]

I am new to this field. I used Will Prowse video to build a 400 watt system. It includes a 40 amp solar MPPT charger, 1500 watt sine wave inverter, four 100 watt solar panels, one AGM battery with some other fuse blocks, etc per his video.

I want to run a 5000 window AC. I have seen other videos of folks using 750 watts to do this. I have two questions:
1. If I increase my Solar panels to eight 100 watt solar panels, can I still use the 1500 watt Sine Wave Inverter?

2. How many 100 amp hour 12 volt batteries would I need to get (Lithium Iron Phosphate)? Thanks.

I have installed a Frigidaire 5000 BTU window AC on the roof of my promaster van. It is a new cheapest one from Home Depot. It is soft start. It starts up around 300 to 350 watts and works it way up to 450 to 460 watts and that is as high as it goes. No high start up wattage. It cools my 118 wheel base low roof promaster down to around 72 degrees in the hot texas sun. The van is fully insullated. It's fairly quiet, quieter than most RV AC units. Got in the van the other day and it was 105 degrees in the van and within ten minutes it was down to about 84 degrees. I ran this temporarily on a 1500 Jackery Explorer unit just to see if it worked. I believe it has a 1800 watt inverter in it, not sure. I had already tried it out on a new 6000 BTU cheapie Fridgidaire window unit I had installed in a small room in the house. It won't keep it running but about 2.5 hours with the Jackery. I think the 6000 BTU unit runs about 550 watts, don't remember but also soft start. I have installed two 206 amp SOK batteries in the van with 400 watts solar on the roof and 2200 watt inverter. Limited roof area so the 400 watts will have to do for now. Future hope to figure out how to get 200 more watts up there. Have to wedge them in somewhere. Figure the two SOK batteries will run the AC about 10 to twelve hours without sun with fully charged batteries. Hard to say how long, haven't tested it. It does cycle compressor on to compressor off fan only. Fan only, I think it is about 50 to 60 watts. I built a special shrowd for the AC on the roof that directs the air downward into the van utilizing the 14 inch by 14 inch hole that was made from a MaxxAir fan that I removed. Made from fiberglassed wood and epoxy paint. Looks store bought. Sorry no pics of it or the build. Too busy putting it together.