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I need advice regarding my water system

Dondee

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Oct 5, 2021
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Hello. I am new to solar power and need advice and help with my problem. I have a Property in Philippines. we have power supply to the house by the Grid. 220 V. The Problem is Power cuts. We can manage without power for most of THINGS. BUT WATER SUPPLY IS THE PROBLEM. the system we use to feed the house with water. is done by a ground filled 2500 litre water storage tank. then we pump water into a Bladder tank. the pump fills the bladder tank about 12 times per day. depending on the demand from the house. I would like to operate the water system when we have no power by Solar power or to run it on solar all the time. can anyone tell me the best way to do this and give me a rough idea of the cost to install a system. I can if its cheaper and easier lift the 2500 litre water tank to a Hight that will give gravity presure. hopefully someone can help with this problem. I do not have a lot of money to spend. so need to look at the best way to do. Many thanks. IMG_5832.JPGIMG_5834.JPGIMG_5922.JPG
 
How much elevation between the bottom of the 2500 tank and the water outlet(s) in the house?

Sure, better to “charge” the bladder pressure with grid power, but you ‘could’ use a 12V RV impulse pump during grid-down periods. Probably won’t make over 35psi but it would work… So a couple batteries, a couple hundred watts of solar, and there’s your backup water pressure.

If the ‘lift’ isn’t much, a 12V US$85 12V RV pump with a ‘surge buffer’ could provide demand pressure independent of the pressure tank.

They don’t lift over 10’ or so very well but with a couple check valves that will provide acceptable flow and pressure if parallel with the pressure tank and pump. Incorporate a low-voltage pressure switch and a relay or a high-voltage continuous duty relay and it will only run when the power is out.
 
How much elevation between the bottom of the 2500 tank and the water outlet(s) in the house?

Sure, better to “charge” the bladder pressure with grid power, but you ‘could’ use a 12V RV impulse pump during grid-down periods. Probably won’t make over 35psi but it would work… So a couple batteries, a couple hundred watts of solar, and there’s your backup water pressure.

If the ‘lift’ isn’t much, a 12V US$85 12V RV pump with a ‘surge buffer’ could provide demand pressure independent of the pressure tank.

They don’t lift over 10’ or so very well but with a couple check valves that will provide acceptable flow and pressure if parallel with the pressure tank and pump. Incorporate a low-voltage pressure switch and a relay or a high-voltage continuous duty relay and it will only run when the power is out.
Thanks for your help. the bottom of 2500 tank is only off the ground by 1foot or 30cm. without the pump and bladder tank there is no water to any outlets. do you think I need to have the tank up in the air ?. if so how high. I truly don't know what's the best way to go. Its only when the power is out from Grid I have problem. But it could be 24 hours before power comes back on.
 
How high above the tank outlet is the highest point of delivery? That’s what determines whether raising the tank is necessary for the crude scenario I described.
 
The house is single store. Showers are highest outlets. 5 feet above bottom outlet of 2500 tank. Tank is 30 feet from house. Much appreciate your help
 
So the us$85 12V RV pumps should lift maybe up to 10’ without any issues. Read the specs on the one you can source- it should say the lift in the paperwork.

At 5’ above the lowest high level that’s not much difference from an RV tank to shower head. It appears raising the tank wouldn’t be necessary.
 
The L/m will go down based on the lift, but your shower head is probably only about 12L/m anyways so anything that is over 15L/m@2meter would be plenty.

The other option would be to get a 12v Shallow Well Pump & Tank (there are many like it, that's just an example) and parallel it into the existing water pipe. A battery bank, some panels, hot shower.

It might be cheaper to get a 1200w inverter and just run it off the solar all the time, just relying on grid power to keep the batteries topped up. It really is going to depend on what you have in the way of battery bank options. A couple of deep cycle AGM's or FLA's would probably net you about 6 hours of run time on the 12v version but only about 2 hours of run time through the inverter to the old pump and depending on how long the pump needs to run to get the bladder tank back up to snuff might be enough. Or add more batteries.

That pump you have now is about 1100w and the specs on that 12v model say 230w so it might be a better option all the way around.
 
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Sounds like you need to repressurize bladder. Like automobile tires, pressure bladders tanks need to be reinflated to proper pressure periodically.

Also make sure your turn-on and turn-off pump pressure switch is set to correct pressures.

To repressurize, turn off electrical power to the pump. Opening a faucet and drain all water from tank. Check the tank's bladder pressure with an air pressure gauge on the air charging valve on the top of the tank. Add air until the pressure is a couple of psi below pump's turn on pressure. You usually want pump turn on pressure to be 20-30 psi and turn-off pressure to be 45-60 psi. The turn off pressue is somewhat dependent on pump used. You don't want pump to run a long time to gain only the last top 5 psi.

If you need more water volume, installing a larger, or more bladder tanks in parallel may be lower cost than trying to supply power to pump.

Avoid pressure tanks that do not have a bladder. Air in non-bladder tank will dissolve in water over a short period of time and tank will become water logged causing pump to just cycle on and off quickly.
 
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^^^ it’s also almost 20A so other costs may grow.
The 6-7A pumps could utilize their current pressure tank but I just gave the simplest crude solution.
 
you need to repressurize bladder. Like automobile tires, pressure bladders tanks need to be reinflated to proper pressure periodically.
The issue mostly is that once the power is out, they only have the water volume of the pressure tank on the wet side of the bladder. Either pumping and pressurizing the existing system with a demand pump or running a demand pump parallel are the practical cheap solutions.
 
Yeah, I tried something similar a couple years back using a 12v transfer pump and a small bladder tank. The motor was trying to draw more power than its fuse liked before the pressure switch would kick off.

If everything is adjusted up and the pressure switch reduced down to where the transfer pump can handle it then, yes, absolutely it'll work in a pinch.

And yeah, I caught that 12 times a day cycling too, seems like the tank isn't up to pressure. Or it's just straight up too small. Adding in a tank or two in parallel would also help, but only until the tanks drained.

If you want to just throw a transfer pump in there, it should look something like the pic below:
 

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So the us$85 12V RV pumps should lift maybe up to 10’ without any issues. Read the specs on the one you can source- it should say the lift in the paperwork.

At 5’ above the lowest high level that’s not much difference from an RV tank to shower head. It appears raising the tank wouldn’t be necessary.
Thanks I will look at Rv pumps and lifting tank
 
The L/m will go down based on the lift, but your shower head is probably only about 12L/m anyways so anything that is over 15L/m@2meter would be plenty.

The other option would be to get a 12v Shallow Well Pump & Tank (there are many like it, that's just an example) and parallel it into the existing water pipe. A battery bank, some panels, hot shower.

It might be cheaper to get a 1200w inverter and just run it off the solar all the time, just relying on grid power to keep the batteries topped up. It really is going to depend on what you have in the way of battery bank options. A couple of deep cycle AGM's or FLA's would probably net you about 6 hours of run time on the 12v version but only about 2 hours of run time through the inverter to the old pump and depending on how long the pump needs to run to get the bladder tank back up to snuff might be enough. Or add more batteries.

That pump you have now is about 1100w and the specs on that 12v model say 230w so it might be a better option all the way around.
thanks for your help. I now have to find batteries in Philippines. cost to much to have them sent by carrier from USA or Europe
 
Sounds like you need to repressurize bladder. Like automobile tires, pressure bladders tanks need to be reinflated to proper pressure periodically.

Also make sure your turn-on and turn-off pump pressure switch is set to correct pressures.

To repressurize, turn off electrical power to the pump. Opening a faucet and drain all water from tank. Check the tank's bladder pressure with an air pressure gauge on the air charging valve on the top of the tank. Add air until the pressure is a couple of psi below pump's turn on pressure. You usually want pump turn on pressure to be 20-30 psi and turn-off pressure to be 45-60 psi. The turn off pressue is somewhat dependent on pump used. You don't want pump to run a long time to gain only the last top 5 psi.

If you need more water volume, installing a larger, or more bladder tanks in parallel may be lower cost than trying to supply power to pump.

Avoid pressure tanks that do not have a bladder. Air in non-bladder tank will dissolve in water over a short period of time and tank will become water logged causing pump to just cycle on and off quickly.
Thanks for your advice
 
If you can raise your water tank 4 meters, then even when the pump isn't running you'd still have some water. It wouldn't be good pressure, and things would take longer, but if lifting the tank isn't a problem, that's the cheapest and easiest solution.

Another lower effort solution would be to buy more pressure tank space, and upgrade to a larger pump. If you get it to the point where it only cycles once a day for 5 minutes, then you'd have your 24 hour water supply backup, and longer since you could use the pressure well below the turn on setpoint.

Pumps are one of the more difficult things to run on solar cheaply, but you can also just buy an all in one battery backup for the pump and be done with it. Make sure it runs a 1 HP motor, and has enough capacity to run the motor 12 times. Many of them come with solar panel inputs so you can supplement with solar.
 
If you can raise your water tank 4 meters, then even when the pump isn't running you'd still have some water. It wouldn't be good pressure, and things would take longer, but if lifting the tank isn't a problem, that's the cheapest and easiest solution.

Another lower effort solution would be to buy more pressure tank space, and upgrade to a larger pump. If you get it to the point where it only cycles once a day for 5 minutes, then you'd have your 24 hour water supply backup, and longer since you could use the pressure well below the turn on setpoint.

Pumps are one of the more difficult things to run on solar cheaply, but you can also just buy an all in one battery backup for the pump and be done with it. Make sure it runs a 1 HP motor, and has enough capacity to run the motor 12 times. Many of them come with solar panel inputs so you can supplement with solar.
I very much appreciate your help. I thought running a pump only a few times a days would be simple. But now understand it’s more complicated.
 
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