Off grid pond aeration

[indymagoo]

Hello everyone. I am trying to figure out what I need to power my pond aeration system off-grid here in Southern Indiana. I would like this system to run 24/7.

I have a pump whose specs are 120 VAC, 60 HZ, 2.1 A, 150 Watts.

I have watched a lot of videos and read a lot, but I'm afraid I am suffering from analysis paralysis making it harder than it needs to be.

I would be interested in using LiFePO4 batteries if feasible.

Thank you all in advance for any help you can offer. I will keep reading in the mean time!

 

[Clifty Branch Farm]

Indy

Im new to solar myself so Im no expert to give advice. Im working through pond aeration myself, bubbler and a fountain. I know this isn't tech support but I found a pond site WWW.discountpondshop.com. They have complete systems but what I use it for is a reference for what Ill need. Then I just find other sources for what I need. I am getting their water pump (fountain) and bubbler minus the solar stuff.
I totally understand the analysis paralysis. biggest stumbling block for me is working backwards ie load to sun. I naturally want to think from sun to load.
Wills DIY Solar Blueprints is another good source of info. Good luck to you. BTW I'm in central KY.

 

[indymagoo]

Indy

Im new to solar myself so Im no expert to give advice. Im working through pond aeration myself, bubbler and a fountain. I know this isn't tech support but I found a pond site WWW.discountpondshop.com. They have complete systems but what I use it for is a reference for what Ill need. Then I just find other sources for what I need. I am getting their water pump (fountain) and bubbler minus the solar stuff.
I totally understand the analysis paralysis. biggest stumbling block for me is working backwards ie load to sun. I naturally want to think from sun to load.
Wills DIY Solar Blueprints is another good source of info. Good luck to you. BTW I'm in central KY.

I have the complete aeration system, but just need to get it on off-grid power.

 

[MisterSandals]

120 VAC, 60 HZ, 2.1 A, 150 Watts.

Lets do some math. 150 watts thru an inverter (15% loss guess) = 175w
175w x 24h = 4200wh

Using 5h of charging (see attached):
4200wh / 5h = 840w of solar panels (operating at 100% efficiency, sun everyday)
840w / 12.8v = 65a charging capacity SCC

That leaves 19h running off of batteries:
19h x 175w =3325wh of batteries
3325wh /12.8v = 260ah of batteries (lithium), twice that for lead acid which are 50% dischargeable


So in January, you will need twice the amount of solar panels with half the solar hours.

 

[indymagoo]

Lets do some math. 150 watts thru an inverter (15% loss guess) = 175w
175w x 24h = 4200wh

Using 5h of charging (see attached):
4200wh / 5h = 840w of solar panels (operating at 100% efficiency, sun everyday)
840w / 12.8v = 65a charging capacity SCC

That leaves 19h running off of batteries:
19h x 175w =3325wh of batteries
3325wh /12.8v = 260ah of batteries (lithium), twice that for lead acid which are 50% dischargeable

View attachment 53528
So in January, you will need twice the amount of solar panels with half the solar hours.

Okay so if I am reading this correctly, I will need panels that are more than 800 watts and a battery over 260 amp hours if lithium. That is way more watts of panels than I thought I would need.

 

[MisterSandals]

Okay so if I am reading this correctly, I will need panels that are more than 800 watts and a battery over 260 amp hours if lithium. That is way more watts of panels than I thought I would need.

Thats if everything operated at 100% efficiency... maybe add 20% for a real number (a reasonable guess?).

Thats what it adds up to to power that pump 24/7 (all sunny days in the summer). Twice that to 1600w of panels in the winter (some might say round up to 2kw). And you'll need slightly more battery because there will be a couple more hours less of sun the battery needs to cover.

Can you find a more efficient/smaller pump to do the job? Switching to a DC motor, with all other things equal, takes the 15% conversion from DC to AC off the table and removes an inverter from shopping list and possible failure points.

What happens if you run out of power for a couple hours? Couple days?

 

[indymagoo]

Thank you for the info. This pump is just big enough for my size pond and because it is a linear pump, it’s more energy efficient than a rotary vane or rocking piston types.

In light of this information, I may change my plans and not run it 24/7. If I just run it direct drive without batteries I should be able to do it for far less correct? Missouri Wind and Solar Sells a controller and inverter system for $212.00 that should do the job I think. Then all I will need is a couple of 200 watt panels. https://windandsolar.com/suntaqe-180-pure-sine/

With aeration some air is better than no air which is what I have now.

 

[MisterSandals]

If I just run it direct drive without batteries I should be able to do it for far less correct?

I would be wildly surprised if a couple small panels and a small wind generator, with no batteries, could provide enough amps to start your pump.

There is a water pumping with solar section here.

Solar Water Pumps

Need to move water with some sunshine? Talk about it here!

diysolarforum.com

 

[efficientPV]

Indiana, east or west? I'd love to do one of these some day, it would be an interesting project. I run a washing machine with solar panels no batteries. Can't be that hard. My eyes roll when I see that MSW thing.

 

[MisterSandals]

I run a washing machine with solar panels no batteries.

Just trying to learn something here...
How many watts of panels and how many amps does your washer need at startup and runtime?

 

[efficientPV]

I've seen 450W going into my washer at times, it is electronic drive. The limiting factor is the 520W of panels I have in series with the rest of my array. That is a pretty good match. What you should worry about is what happens when a cloud comes over or starting in the early morning. My washer just stops with a power fault. I can restart it when the cloud passes and it will remember where it left off.

I doubt if the MWS unit has any auto restart. It likely just has the inverter fault requiring you to manually restart it. They left that out in the video. And so, your pump may not automatically start in the morning. If you go to grid tie panels that can be quite cheap. I just bought another KW for only $300. Without battery the array needs to be oversized. This will also give you more run hours. Batteries are just throwing money away as I suspect they would have a shorter life in this harsh service.

 

[MisterSandals]

The limiting factor is the 520W of panels I have in series with the rest of my array. That is a pretty good match.

How does the array DC current get to inverted to AC that I assume your washing machine needs?

Just messing with some math...
450w x .85 inverter efficiency = 382w
382w / 120v = 3.18amps

 

[efficientPV]

It is complex and mostly I like to show a goal that can be achieved. The 520W is in series with a much much larger array to double the voltage. In essence it looks to the inverter like 1040W of panel. Efficiency of the inverter is in the order of 95% because the internal boost inverter that has most of the losses is not used at all. The MSW inverter is modified by bringing three wires out, common ground, high voltage + of the capacitor and 12V from the logic side of the power switch. The inverters 12V high current power lugs are not used. Logic only needs about 50ma of 12V. Interesting that the H bridge will work from 20V up to the inverters design limit and not care. Leaves open a lot of potential for lower voltage arrays and boost transformers on the output.

 

[MisterSandals]

So you have a LOT more going on than what you first said.

I run a washing machine with solar panels no batteries.

And it sounds like a lot more than 540w of panels.

 

[efficientPV]

"The limiting factor is the 520W of panels I have in series with the rest of my array." I think I said exactly what was being done. This is much like the thread about a super efficient, using voltages without conversion losses. It is a LG washer and years back many of these could almost be run on DC except for the pump. But they pot everything now and the modules can't even be repaired.