Man Cave, Water PRESSURE TANK for 12V SOLAR system?

[Boeing]

Guys,
I have external water tanks piped to my building, no well, as it is estimated a 900' well would be required, much sleeving and expense. I am so far removed from the county road that the electric company will not bring in power unless I pay $65,000 to do it. Needless to say, I am solar, 12V, multiple batteries and "off grid". The building is a 4 car garage/shop/man cave escape. I store an almost restored 1975 Blazer "convertible" there, plant deer plots, half heartedly hunt (inadequate water and no freezer to actually process a deer carcase)
I craftily (like that?) wired LED lights, 12V BOAT water pump, tankless propane water heater, nice shower and deep sink and a well ducted wood stove for cold nights. Because of the above ground water tanks I don't visit from Dec until late March and have to drain my tanks and antifreeze the water heater and pipes.
Anyway, here goes.....when I use any water the 12V, noisy pump runs. When I shower it is running 10-15 minutes. A friend has told me that I need a "pressure tank" to relieve the pumps workload. Ah doesn't know nuthin bout no pressure tanks.....
Suggestions and advice would be appreciated here. Along with any other suggestions for my escape cave.
Thanks, Rob

 

[speedbump]

If your using a boat pump, it must be more of a transfer pump. They aren't known for making great pressures. The pump I recommend you look into is located here. The demand pumps have their own pressure switch which works very well without the need for a pressure tank. Stop using water, the pump turns off, use water, the pump turns on. Works on 12 volts and there are several to choose from.

 

[Boeing]

Thanks for the suggestion. It is the 3GPM demand that I have installed. It comes on when I open the faucet and turns off when I close it when I shower. If I'm using low water volumn while brushing my teeth or washing hands it cuts on and off every 10 seconds or so.....

 

[Raised on a Deere]

Guys,
I have external water tanks piped to my building, no well, as it is estimated a 900' well would be required, much sleeving and expense. I am so far removed from the county road that the electric company will not bring in power unless I pay $65,000 to do it. Needless to say, I am solar, 12V, multiple batteries and "off grid". The building is a 4 car garage/shop/man cave escape. I store an almost restored 1975 Blazer "convertible" there, plant deer plots, half heartedly hunt (inadequate water and no freezer to actually process a deer carcase)
I craftily (like that?) wired LED lights, 12V BOAT water pump, tankless propane water heater, nice shower and deep sink and a well ducted wood stove for cold nights. Because of the above ground water tanks I don't visit from Dec until late March and have to drain my tanks and antifreeze the water heater and pipes.
Anyway, here goes.....when I use any water the 12V, noisy pump runs. When I shower it is running 10-15 minutes. A friend has told me that I need a "pressure tank" to relieve the pumps workload. Ah doesn't know nuthin bout no pressure tanks.....
Suggestions and advice would be appreciated here. Along with any other suggestions for my escape cave.
Thanks, Rob

If your boat pump is designed to work against pressure and not just a sump pump or something, then you need a tank between the pump and the shower and other faucets to serve as an accumulator tank. If you google "accumulator tank" you will find sources to buy and better yet a description so you can make one up of your on your own. Anything to form an air pocket trapped above the water coming from the pump. Accumulator tanks have a bladder between the water and the air and a means of pressurizing the air above the bladder to make for a smoother flow of water once you've u get the pressure to match up with the cutoff pressure of your pump. Hope this helps.

 

[Deere Dude]

it works just like a camper and most campers don't have pressure tanks and my guess is because of the room needed and they won't do much on a little system. They are to keep the pump from short cycling instead of instant on.

My unscientific guess would be that by installing one, a pump would cycle less often and probably would not kick in if it was just a little hand washing for a few seconds, if everything was up to pressure.

If a pressure tank is installed and the system pressure is almost to the cut in point anyway, it will kick in but then run but then run longer until everything gets charged.

Long story short, a pressure tank won't hurt anything and I would put a small one in, but the pump will still kick in quite often because of the small size, IMMHO.

 

[speedbump]

Actually campers only use pressure tanks if you don't have a pump. Otherwise the tank is the water supply and a pressure tank is not needed. With the pump he has, the pressure will be consistent as long as the pump is running. Small usage which allows the pump to turn off momentarily will change the pressure slightly. A bladder tank could be added, but the pressure would be the same, it would just be stored in the tank until the pump had to come on again. And it would slow down the cycling on/off.

 

[franklin2]

I think you would be better served in your situation with a gravity feed system. Is there a place where you can put a decent sized tank at some height above your plumbing? Then your 12v pump would fill that tank, and then it would gravity feed from the tank to the house plumbing. A simple float in the tank with a switch on it would control the 12v fill pump. This way you could also control when the pump ran to fill the tank, probably during a good sunny day when you have lots of power to spare. Not during the night when you are on batteries.

 

[Stimw]

I have had about 8 motorhomes through the years and they all used the on demand pressure pumps with no pressure tank.
They always worked great and I never had any problems with them.
They would short cycle when you used a little water but it was a good reminder not to waste water because with the tank it was limited.
Have you thought about digging a cistern for more water storage and freeze protection?

 

[davedj1]

Yup, NO tank required for that type of pump. Just use it as is and let it cycle. That is what its made to do.

 

[Texasmark]

Sears sells tanks and pumps. One I had was equipped with a bladder inside whereby the air and water remained separated....no air absorption into the water requiring periodic draining when the cycling got to fast. Worked good