Bimodal system to run Deep well

Re: Bimodal system to run Deep well

JOSI wrote: »

I'm sure this has come up many times but i have yet to get a good answer. I am new to off grid systems and i have a client who wants a bimodal syste or complete off grid system to power his 1Hp 240v Single phase deep well and freezer in case of grid outage. I have come up with him needing about a 2.2kw system but taking the LRA into consideration it may end up being like a 6kw system. The pump is already been set and i dont know the exact LRA for that particular pump but the "ugly book" syas for a 1HP 230v pump the LRA is 48A. We have toyed with the idea of installing a start compacitor bank to negate the LRA so we can keep the Solar system down to a small size. Does anyone have any experience with this or have any ideas?

Yes.
How often are the power outages and how long do they last?
Buy a generator.
Spending $8,000 on a solar power system to accommodate occasional outages is foolish.

For what it's worth, I power a 1/3 HP water pump from my system. It has to be controlled to come on only when the sun is shining and the batteries are full because it uses so much power. I also have a 1 HP 240 VAC septic/digester pump which must be used under the same conditions. It has a soft-start built in, but still sucks down 1,200+ Watts. Fortunately it runs less than a minute per day.

The main use of my system is to keep the refrigerator going. That's 1,200 Watt hours per day right there. A freezer can actually stay cold on its own for at least a day, providing it isn't opened.

In your case you are dealing with a lot of unknowns, especially in respect to how long the pump and freezer (another big power user) will run. If you had a good estimate on that you could work out how big a battery bank would be required to supply those needs for however long the estimated power outage would be (or for a day and assume solar/gen recharge). Even so, I doubt 2kW of array would be in it much less 6kW. Mine should be a tad larger than the 700 Watts it is, but then I do more with it (it runs everything including the computer & satellite modem).

On the whole, a battery-based power system for temporary outages is not worth the investment. The batteries will die over time regardless, which makes them largely a waste of money. If they do need/want this ability it's worth looking into the grid-tie possibilities in the area so that a hybrid system could be installed. Better return on the capital expenditure.

Re: Bimodal system to run Deep well

Before investing a lot of money in solar invest in a meter that can capture the actual start-up demand of the pump. You will need this for sizing the inverter that has to power it and the battery bank size to back it up. Don't guess; measure. It helps avoid those ugly surprises and expensive outlays.