Effect of batteries in a solar pump system

Sounds like the batteries and solar panels aren't sized large enough to handle the pump load.

So making assumptions on the little inof you posted.

You had a system that pumped water when the sun was shining enough and now have added only batteries and controller.

This is basically what could be happening. Your panels are sized to run the pump only, there is not enough panel to run the pump and charge the battery.

The controller system would have low voltage disconnect to prevent the batteries draining to much after the sun goes down.

Then a Voltage setting that needs to be reached when the sun comes back up the next morning before the pump will start up.

At the moment all you really have is a buffer for when cloud passes.

You need the original panel sizing to run the pump plus more panels to charge the battery.

That's what I would have said !!

Being underpowered is basically the conclusion I've come to a while back. For that reason I've put new panels that boost the wattage output from 200 to 300w, which has helped, but water production still halts whenever a cloud comes over. The pump's operating depth is almost as deep as the company said it would go - 145 feet plus a little more to get into the tank - but has always pumped really well in good Sunlight.

The current panels are stationary facing the South as prescribed for our location so I was wondering, since I still have the 2 old 100w panels, could I set those facing the rising Sun on a new mount with a voltage regulator controller set for the same parameters as the proprietary controller that originally came with the system and have the old panels dedicated to charging batteries in conjunction with the new panels charging the batteries as well as running the pump? Both panel sets would be basically in parallel with the batteries in the middle. I think this may also allow for batteries of higher amp-hour ratings (the company offered 55 a-h batteries) but experimentation would have to be required, I think. As long as the charging rate doesn't exceed 10 amps would the batteries be charged at a safe maximum rate to allow the pump to begin operation sooner in the mornings? The old panels are not matched with the new ones in terms of voltage and amperage so I thought putting them on their own regulator would remedy this mis-match as they charge the batteries.

Both regulators would be set to stop charging at the same voltage level and the Eastern facing panels would stop working as the Sun moves away from them during the day leaving the batteries charged for the evening.

But still, I have the question in mind as to whether or not other systems like Lorentz or Gundfoss follows this same manner of function by running the pump off the batteries all the time thus delaying the start up time in the morning? I had always thought the charging function was separate from the pumping and the batteries would take over when the panels quit producing power to run the pump. I guess that assumes adequate power to accomplish both tasks, though.

I am wondering what the open circuit voltage of your panel setup is, and what voltage
they typically operate at under good sun? Agree with the above, my conclusion is that
adding batteries is an extremely poor cost tradeoff way (not to mention the maintenance
issues) of increasing production.

My take is yes you need more panels, what you have will only be effective under best
center day hours and no clouds. That is exactly the situation I had here, and I remedied
it with more panels, and no batteries or other additional equipment. My fix is to point a
set of panels facing the rising sun, and another facing the setting sun, angled so they
overlap production mid day. These panels are tied directly in parallel, the voltage will
never rise above the open circuit voltage no matter how many panels you use, and the
pump will take the current it needs over a longer day. Output will be up under clouds as
well with the light dispersed to all directions. With perhaps 3 times the panels, your pump
will not even slow down under light clouds, run at reduced rate under somewhat more
severe clouds, and in general run for a longer productive day. Bruce Roe

To the above here are some curves made here at 42 deg Lat. Power under sun was maxed for 8 hours straight on
bottom curve, would have been even longer except for shadows using multi direction panels in parallel. At top is a
measurement with panels elevated 61 deg facing E and W. When tied in parallel, the total power
(1 + 3) ​​​​​stays close to constant all day. Power under clouds though reduced, will be more. Bruce Roe

PVm17Jn16.jpg

NScurJn17.jpg

Thanks to everyone that's posted so far. I'll look at these graphs and such later this afternoon but I need to get over to the ranch to haul some water to try and get ahead of the situation.

One thing, though, I've checked my notification settings and verified that I am supposed to be getting e-mail notifications whenever someone answers me but no e-mails have been forthcoming. Is this service not functioning here?

Bruce,

Did you build your panel racks yourself or are they a factory construction? The fact they are offset to track the Sun intrigues me. I'm assuming you took manual readings on the panel outputs over time as well?

I'm at 31 degrees N. latitude.

Here's the side-by-side images of the labels on the panels. The left image is the new panels, the right the original ones.

IMG_1131.JPG

Here at 42 Lat its all custom construct, latest changed seasonably for best energy and to
reject snow. Mostly 6061 aluminum and 18-8 stainless bolts, concrete foundation, but
one is treated wood which looks to last at least decade. More pictures available.

Graphs made over half a year for various arrangements, a well performing sample shown
above. Here 3 single test panels with variable elevation shown.
Bruce Roe

Test3dir.jpg

Hi, sorry to take so long in answering. We went on vacation and are back.

Is that a regulator on the frame holding the panel just below the panel's wiring module? If not I was wondering how far a panel's output would transmit before coming to a regulator since you have quite a bit of distance between individual panels there?

That is a very good, straight forward mount for your panels. Unfortunately I'm going to have to figure out something to mount panels higher as my goats love to chew on anything. I found the sensor line for the well's water level was chewed through to the wire yesterday. Why the goat stopped when it got to the wire I'll never know, especially since it's a tiny 22 gage multi-filament one. Breaking that circuit would have made the regulator think the well water was too low and shut it down. I'd built and placed a box for batteries under the panels so now they can stand on it and nibble. Didn't think about that when I placed it. I tried wrapping the wire cluster in barbed wire but they'll get through to something they're curious about any way they can. I think a large PVC pipe cut in two lengthwise to wrap around the entire wiring cluster will work well enough to stop it.

Those 3 new, isolated panels are strictly for collecting curve data, they are not
connected to any system. Although the lot is neither rectangular or flat, I did
survey it pretty accurately per the locating stakes. In theory the panel outputs
should be measured by 3 MPPT systems, I did not want to bother with those.
Instead each panel output is simply shorted, producing a current about 25%
larger than at MPP, but directly proportional. That current was measured by a
0.1ohm current shunt which you see plugged into the panel.

I went out with a DVM by the clock on a very sunny day to record each curve.
The test panel support structure was only designed to last half a year, in fact
one of them fell down later. But the elevation angle was easily changed.

I tried several different panel mount schemes, one cheap treated wood, the
last (see SUN HOURS about section 20) is in serious concrete with 6061
aluminum and 18-8 SS bolts, set up to increase energy as well as minimize
snow efforts with seasonal tilt changes. Experience here is about the only
thing critters do not chew through is metal, but in your case it might need to
be thick. good luck, Bruce Roe

NS6motst.JPG24Rear.JPG

I only have a small setup, but it has benefited from having panels facing SE and SW run in parallel.
There is of course overlap in the middle of the day which gives a boost to the charging of the batteries.

I do have a few question though, Do you actually need the pump running continuously ? , or would a timed system be more appropriate. Doubtless your previous system only ran the pump during daylight whereas without a timer your batteries would go flat so need more power to charge them. You would notice this first thing in the morning, as there would not be enough power to overcome the pullout torque of the motor for the pump. ergo no pump first thing.

What is the power rating of the pumps.

Are the Pumps AC as inverter powered, or DC. If the latter what is the Voltage ?

Hi, sorry for taking so long to answer. Having too many irons in the fire seems to be what life is all about around here.

Off the top of my head I'll try and answer as many questions as I can.

The main reason or hope I had for looking into batteries was the fact that the well's water level will not keep up with constant pumping and shuts off after about 25 minutes or so of initial pumping in the morning. I've cut the RPMs back and set a wait time of about 16 minutes between when the low water sensor trips and restarting the pump. But, even while I've faced the panels in an optimum direction and installed newer panels that I'd hoped would produce enough power to extend the pumping time during the day, the livestock still suck the tank down during these hot days. This is different from when we had a windmill on the well which pumped whenever the wind blew day or night.

We've also had a Loretz pump system set up on the South end of the ranch that has pumped almost regardless of the angle the Sun hits the panels. It's has a single 180w panel and the pump itself sits at the same depth as the one on the North end. This isn't the case with the two types of panels I've had on the well in question here because about mid to late afternoon the pump will not have enough power provided for enough RPMs to move water out of the hole into the tank.

From what I've gathered the idea of setting up the old panels on a separate regulator to provide additional charge directly to a set of batteries in order to start pumping earlier will work but I just don't know if it will actually provide any additional run time that is worthwhile in actual practice. If I do it it'll be a shot in the dark.

Incidentally notifications of postings to this thread still are not coming through on my end even though I'm subscribed to it.

Still need to know the pump Wattage ?

So to recap, if you are running out of power mid afternoon, then clearly the panel facing towards the west needs to be turned further towards the west, so you get maximum charge. It all depends on the terrain, my own property is shaded by Scots pines to the west, so I have to make allowances for these and accept a loss of sun later in the day. If you have clear lines of site all day then the panels should be in the form of an inverted V. Just remember that you are optimising for maximum light over the course of the day.

Without knowing the Pump wattage I cannot calculate what you would need to do the job.

Flow rate is the key here, which is why you don't choose a pump with the highest flow rate you can.
Knowing the size of pump you really need is the first step when using solar power. This should help you determine the size of pump you really need. https://www.wikihow.com/Calculate-Water-Pump-Horsepower

If you choose to high a flow rate, the pump will draw more power, even if you don't use it to capacity. Having the correct size pump for your needs, means it will be more efficient.

You could approach this in 2 ways. You know the power your system has, so you reduce this by 60% and say that is the maximum pump power or you calculate the power required and change the solar system to suit.