Increasing daily water output from my solar well

[Robert101]

Hello, I currently have a solar well pump that is pumping about 500 gallons of water per day. This water is then stored in a 1600 gallon water tank. I use the water for irrigation of my garden and a few other things. I would like to increase the amount of water I pump per day to around 700 gallons. Below are some of the specs of my system. I am wondering that if I DC to DC boost the voltage after my panels would the amperage decrease so much that it would not increase the amount of water.


Pump: 12 volt, Direct PV, Range 12V to 40V

Panels: 2 X 85 watt 12 volt panels. less that 5 amps (On my best sunny day they produce 20 Volts)

Per the manufacture of the pump, it can handle higher voltage. At 30 volts I would almost double my water output.

Can I simply add a DC to DC booster after the panels to a voltage around 30 without decreasing the amps significantly?

I am not planning to add batteries or more panels to this side my system. The water tank is the storage. Any thought are welcomed.

[Wy_White_Wolf]

Do you use a LCB (Linear Current Booster)? Using one will increase output in low light conditions and extend the life of the pump.

Instead of a DC-DC converter to boost production I'd look into replacing the panels with a grid tie panel. Many of them have a VMP in the 25 to 28V range and work great in this situation. I run a 120 watt grid panel through a LCB to a Shurflow 9300 series pump on my well. Easily produces 150 gallon an hour in full sun.

WWW

[Robert101]

Yes, the system has a LCB. Grid tie is not an option. The low light conditions are not the concern. I just know by check my output of my panels they are only making 20volts max. If I boost it up to 30 volts, would the losses of converting some of amps to volts be significant, is the question? I am not looking to rebuild my system. It works well direct PV. I am looking to optimize it a little and pump a few hundred more gallons of water.

[Wy_White_Wolf]

Not grid-tie but use a grid-tie panel. They will be at the higher voltage that you want. I use a single 120W panel with a VMP of ~28V.

If you do use a DC-DC converter then wire the 2 panels in series and downward convert from 40V to 28~30V. No matter how you convert you are going to lose ~1/3 of your amps. The increased voltage has to come from somewhere.

Can you LCB handle the increased voltage?

WWW

[jflorey2]

Yes, the system has a LCB. Grid tie is not an option. The low light conditions are not the concern. I just know by check my output of my panels they are only making 20volts max. If I boost it up to 30 volts, would the losses of converting some of amps to volts be significant, is the question? I am not looking to rebuild my system. It works well direct PV. I am looking to optimize it a little and pump a few hundred more gallons of water.

You cannot boost voltage without losing current. (There's no free lunch.) If you have an LCB you are likely already running the pump at near its optimal power point. Going to a larger, higher voltage panel (or getting a second identical panel and putting it in series) would work well, provided everything in the path of the power can handle the additional voltage. The LCB can handle up to 60 volts so you are OK there.

[Robert101]

Yes it can handle up to 40 volts. Thank you. Have a good day.

[Mike90250]

Give us a link to the specs on the pump. Is it a plain DC motor ? Does it have integral MPPT?
Can your well support more water draw, what happens if the pump sucks air ?

Don't bother with a DC-DC, they cannot manage the input from a PV panel and will continuously crash the PV array
A linear current booster (LCB) is the right gadget, if your pump does not have an MPPT

To increase power you have to add more panels, either another set in parallel with the existing panels,
or (and this may overvoltage and fry the pump) add a 3rd pane in series,

You only have 170watts to play with, to get more, you need more PV to harvest more watts.

[foo1bar]

Panels: 2 X 85 watt 12 volt panels. less that 5 amps (On my best sunny day they produce 20 Volts)

I think your best options are
1> add a 3rd panel (or new panel(s) that replace the existing one and provides enough voltage and current)
or
2> add a 2nd system - either same as your current one so you double the gallons per day - or a slightly smaller one.

[Robert101]

Yes it has a linear booster. I can not seem to be able to pull a link. But a Google search on sunshineworks will get to the website. Go under solar pumps. It's is the SR2 pump. In the specs there is chart showing at 30 volts I should be pumping more water than at my current 20 volts. They use to sell my pump with 3 panels, but found that the pumps would go bad with the extra amps. I don't want to add more amps. The system works well as it is, but a couple 100 extra gallons per day would help.

[Mike90250]

if more than 2 panels makes the pump go bad, your only logical choice is to clone the setup you have, get 2 more panels and another pump.

[foo1bar]

So you have an "Advanced Power SR2" pump.
If I search for that, it looks like the manufacturer sells it packaged with a 250W, 32V panel.
(they also sell it packaged with 3 of the 85W panels)


Do you have room for an SR4 pump instead of SR2? (5" casing instead of 4")
If so, it looks like that could give you a ~30% boost.

Otherwise, your best option is probably either add a 3rd 85W panel or use a 250W module (should be <$250, but the shipping is the problem.)

[foo1bar]

if more than 2 panels makes the pump go bad, your only logical choice is to clone the setup you have, get 2 more panels and another pump.

It looks like he's pumping from a well - so "another pump" means "another well" - so that probably isn't an attractive choice if it can be avoided.

Although... if it can be done in stages (pump up from well to tank, pump from tank by well to higher ground tank) that *could* be an option, since it would decrease the pressure on the well pump.
(Probably not as cheap as going with a 250W module though - and you'd want some additional water-level switches to make sure the pump didn't run dry.