Help Designing a solar irrigation system please.

[jimcanswim]

Hi, I am designing an irrigation system. I have a small creek and am using a 16A 12V pump to pump water up to a 1,000L tank. There will be a float switch in the tank to turn off the pump when the tank is full. The distance from the pump to the tank is about 20 metres. The pump may have to run for probably a maximum of an hour a day. The solar cell will be up near the tanks. I have the following questions if anyone can help:

1. What size/type of battery do I need?
2. What type/size solar cell do I need?
3. Should the battery be down by the creek, next to the pump or up near the solar cell, or does it matter?
4. What diameter wire should I be using from solar cell to battery and battery to pump?
5. Should the float switch interrupt the +ve or -ve? What diameter should this wire be as it will obviously need to run from the battery up to the tank and back down to the pump.

Any help greatly appreciated from knowledgeable people.

Thanks

Andrew

[Mike90250]

for water, you have to size the pump properly. Use Head (elevation) and Volume Some pumps provide head, some provide volume. If you install a 5 GPH pump, and need 12 GPH, the tanks will run dry. So a bit more info is needed
AC pump may be better than a DC pump

[SunEagle]

It is usually better to keep the solar panel, charger, battery and load as close to each other as possible. That will allow you to keep the wiring as small as possible and reduce electrical voltage losses.

But the trick is to first properly size your pump to meet your water flow needs then size your solar pv system to meet your load needs.

[Wy_White_Wolf]

I would look for a pump that can be run solar direct so you don't need a battery. Size the panel to @ 1.5x the pumps amperage requirement and use a LCB (linear current booster) between the panel and pump.

That's the way my well is setup for watering the orchard. Shurflo 9300 pump running off a 120 watt panel. As long as the sun is shining and the 350 gallon tank isn't full it pumps water. Gravity then feeds the orchard with timers to control when/how much water it gets.

Examples of solar water pumping systems:

http://www.builditsolar.com/Projects/WaterPumping/waterpumping.htm

WWW

[jimcanswim]

Thanks for the replies guys but my pump is all chosen and selected and working well. I don't need any help with the actual water side of thisngs, I need help with the above questions if possible as setup is already decided. Thanks appreciate any replies to my questions cheers.

[LETitROLL]

Thanks for the replies guys but my pump is all chosen and selected and working well. I don't need any help with the actual water side of thisngs, I need help with the above questions if possible as setup is already decided. Thanks appreciate any replies to my questions cheers.

Summer only, or year round system?

[Mike90250]

1. What size/type of battery do I need?

Depends on how many daylight [9am -3pm] hours you need to pump. How many other hours ?

2. What type/size solar cell do I need?

depends on day/night hour mix needed to recharge night (non-solar hours) usage

3. Should the battery be down by the creek, next to the pump or up near the solar cell, or does it matter?

Best to have all within 20' of each other, more distance = more loss and co$ts to you

4. What diameter wire should I be using from solar cell to battery and battery to pump?

Determined when other factors are known

5. Should the float switch interrupt the +ve or -ve? What diameter should this wire be as it will obviously need to run from the battery up to the tank and back down to the pump.

The pump will need to run off of a SSR or DC Contactor Relay. 16A @ 12V is too heavy of load to switch directly. The control circuit should run off the LOAD terminal of the Charge Controller, to enable shutdown of pump when battery is close to dangerously low.

Best we can do for now.

[jflorey2]

Hi, I am designing an irrigation system. I have a small creek and am using a 16A 12V pump to pump water up to a 1,000L tank. There will be a float switch in the tank to turn off the pump when the tank is full. The distance from the pump to the tank is about 20 metres. The pump may have to run for probably a maximum of an hour a day. The solar cell will be up near the tanks. I have the following questions if anyone can help:

1. What size/type of battery do I need?
2. What type/size solar cell do I need?
3. Should the battery be down by the creek, next to the pump or up near the solar cell, or does it matter?
4. What diameter wire should I be using from solar cell to battery and battery to pump?
5. Should the float switch interrupt the +ve or -ve? What diameter should this wire be as it will obviously need to run from the battery up to the tank and back down to the pump.

I will second the LCB suggestion. Get about 300 watts of 12V (36 cell) panels. Connect them to an LCB like the PPT 12/24-30 or the PPT 48-20. Do NOT use a battery. The LCB has a float switch input that will turn the pump on and off. You'll have a 20 meter wire run so size wire accordingly (less than 3% is a good target for wire losses.)

[Mike90250]

Thanks for the replies guys but my pump is all chosen and selected and working well. I don't need any help with the actual water side of thisngs, I need help with the above questions if possible as setup is already decided. Thanks appreciate any replies to my questions cheers.

I guess you have made your bed. Until we know the pump duty cycle, we can't do much
A 1 hr pump cycle is vastly different from a 3 hour cycle or 9 hr cycle. The more you need it to run, the more it will cost in solar

[inetdog]

The panels will be up near the tank because that is the best shade-free spot for them?
Is the head great enough that the pump has to be at the supply end?
If you have to run power from tank 20 meters to pump it would be best to run the pump power at as high a voltage as practical to reduce the wire cost.
In particular, if you use an MPPT charger for your battery bank, you are probably best off running the panels in series at a fairly high voltage (100+ Volts) and putting the CC, batteries and inverter (if needed) close to the pump.
That will also allow you to slowly charge the battery bank during the day (low current in the long wires) and have the heavy short term load (the pump) located close to the battery bank.

[Logan5]

Thanks for the replies guys but my pump is all chosen and selected and working well. I don't need any help with the actual water side of thisngs, I need help with the above questions if possible as setup is already decided. Thanks appreciate any replies to my questions cheers.

Huh?

[Logan5]

He came to ask questions, but he already has the equipment he plans to use. Regardless of our answers he will do it his way, the way he planned to begin with. right or wrong no input needed.

[sdold]

It made sense to me, he already has a pump that needs about 200 WH/day, wants to know what batteries, panels and charge controller to use.

[jimcanswim]

Wow, never seen a forum with such negativity before for asking a simple question. Proper keyboard warriors, cheers. "Our Answers"?? Logan? Don't see you contributing anything useful here! Troll

Anyway, thanks to those who genuinely tried to help, but I am obviously on the wrong forum. I posted the exact same question on an electronic forum and get the advice I needed. Simple answers, "1. 130AH, 2. 150W solar Cell, 3. Ideally close to pump, but if you need it up by the cell use 4mm cable, 4. use 2.5mm cable should be fine, 5. Connect it to the +ve and should be 4mm if you intend to put your battery 20M away" So don't really see how you guys managed to turn a question into a multitude of questions and become all judgemental.

Admin, you can close my account this is my first experience of this forum and I don't see the value in retaining an account.

Good luck

[Mike90250]

While you got a nice, simple, feel good answer somewhere else, you will be back in the fall when the battery dies and the water stops flowing. We care. Thread will be here.