12V Water pumps and cisterns

[Boeing]

Guys, I have (3)300 gal water tanks just slightly above the grade of my building. It connects by "hose" to an outdoor faucet then plumbed to a 12V impeller type pump. I don't know if the pump would "suck" the water in or not since it is just slightly lower than the tanks it might be gravity. Anyway, it provides remarkable flow and pressure for my shower and sink and even cuts off when pressure is up. (must be some kind of internal pressure switch) When I shower it runs almost all the time, when I use sink it cycles every 4 seconds or so.
A friend suggested a pressure tank but others say that this pump is made to cycle?????

What I'd LIKE to do is replace the 300 gallon tanks with an UNDERGROUND cistern....to prevent cold weather issues every fall. As you probably guessed from the 12V comment above, I have no electricity......SOLAR panels and batteries. I would need a submersible 12V pump that could lift the water from the bottom of the cistern tank (8' or so) WITH some pressure switch to turn it on and off. Would this submersible pump provide pressure for the shower? Or would I still need the impeller pump inside?

Right now I TANKER this water in and would like to use my gutters/rain to fill the cistern....leaves and pine needle problems. Screen/filter of some sort? Ideas here?

I use this water to shower, brush teeth, wash dishes etc. I DO NOT drink it. I pretend that if I spit it out I can't get sick. (been ok so far) BTW, I add a cup of Clorox to my 300 gallon tank every filling and a tank lasts me more than a month.
IDEAS would be welcome........Thanks

 

[Industrial Toys]

Little 12 volt pumps work well but I don't know about their life span. Larger, 12 volt pumps are extremely expensive. I would consider using a cheap 110 or 220 volt conventional pump and an inverter. Having said that, I simply hate most inverters and don't trust them. I get dozens of them from friend in the business (Xantrax) and just give them away, although the ones I get usually aren't Xantrax. I like LARGE transformer based inverters if at all.

The issue with the inverter pump is that you would either have to have the inverter running or power it up (which isn't that hard) when you call for water.

 

[Boeing]

Hmmm, I had not considered an AC pump. I have inverters and use them to run my angle grinder and drill, etc. but thought that with the inverter AND a pump it would be too much for my batteries. During a shower the pump runs 15 minutes or so....
I've had the same 12V "marine" pump for 3 years with no issues at all.

 

[RNeumann]

If you have a 12v system then stick with 12v. Inverters will just increase draw. The 12v RV pumps will lift water without issue. Just have one in use and one spare. The “good” ones are about $125 or so. Because of the rubber impeller this is wear item plan on changing pumps every so often.
Your proposed system will work fine. Skip the pressure tank- the pump is designed to work without it.

 

[rustyshakelford]

When we lived in our camper while building our house we had a 330gallon tote. I took an rv pump and ran it off the battery of the camper which was maintained by the converter. When we would open a faucet, the water would flow and when it was shut off, the put quit. Worked great and had plenty of water. Wanted to keep the on board pump as a backup. Never neeed it.

Brett

Edit, the pumps will pull a little bit of a draft too

 

[Boeing]

I appreciate the info, Mr. Neumann. If I may let me ask a couple more questions. If I use a stronger RV pump will it lift the water out of a cistern UP to the system WHEREAS I Don't need a SUBMERGED pump? Thought maybe I'd need BOTH.
Any ideas about filtering gutter water for this cistern? Or I could just keep tankering and fill the cistern periodically from the tanks. That would solve the winter freezing problem. I've been dumping all my tanks every winter.

 

[RNeumann]

The RV pumps are designed to be mounted above the tank. The rubber impellers seal creating a vacuum and thus lift. I’d skip the submersible pump too. This is assuming you are only lifting from 5’ or so below grade and the pump’s location.
Submersible pumps will run cooler and can use metal impeller blades so in theory they should last a long time. Trouble is they tend to fail from being underwater all the time- leaking. Because of this, you tend to pay more (for the good ones) for something that doesn’t last much longer than the standard RV style. Plus submersible pumps can require a bit more work to change- Waterproof electrical connections etc.

 

[Boeing]

You're giving me great ideas. Suppose I mount a RV pump on top of the Cistern tank that way it would be almost silent inside my building.
The Marine pump is pretty loud. I could put a "man-hole" size access into the tank and for the pump...wrap everything in insulation for cold wx.. Does this sound workable? Thoughts?

 

[Industrial Toys]

So I am assuming that this is just a recreational pursuit? I thought you were living off-grid so to speak full time.

 

[RNeumann]

You're giving me great ideas. Suppose I mount a RV pump on top of the Cistern tank that way it would be almost silent inside my building.
The Marine pump is pretty loud. I could put a "man-hole" size access into the tank and for the pump...wrap everything in insulation for cold wx.. Does this sound workable? Thoughts?

Perfect idea! Easy access and easy to change. Take the time to make the pump wiring a simple plug affair. Also have some flex hose or pex at the pump for quick pump changes and it will allow a bit of pump movement.