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Need advice on altering system after financial twist

amberpp1

New Member
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Jul 7, 2021
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26
Hi everyone, long story short I think I have done goofed up. Now I really need some help.

In an attempt to put together a solar system for an off grid cabin I am building I purchased the following components...

- 16 of the SanTan Solar T Series 250W Panels

Some specs for the panels..
Rated Power: 250W
Open circuit voltage (VOC): 37.6 V
Max power voltage (VMP): 30.3 V
Short circuit current (ISC): 8.85 A
Max power current: 8.27 A

- 4 of the LiFePO4 12V SOK Batteries

Some specs for the batteries:
Charge Voltage: 14.6V
Max Charge Current: 50 A
Max Discharge Current: 100 A

I also have a Growatt 5000ES

I made a post a few weeks ago asking if anyone could review this system and a few people helped me out, pointing out that there was a problem with my system. I was shown that for this system to work (running my panels as 8S2P and to be compatible with this growatt) I would need to purchase 4 more batteries, in order to run the batteries in 4S2P to achieve 48V with 200A max discharge current.

My 4 batteries max discharge current of only 100A would not suffice. To solve this problem I planned on buying 4 more batteries. However, my cabin is on a ledge, a hand driven well didn't work out, I had to have a deep well drilled, and badda bing badda boom I am out 12 grand...buying 4 more batteries does not seem to be possible now.

My question to you is... Should I try to return/sell my all in one Growatt and downsize, so I can get by on 4 batteries? If I do so, I am honestly not even sure what all in one to switch to or what that would mean for my panels?

I am doing my best to figure it all out but at this point I am overwhelmed and doubting my ability to put this together.
Thank you for any advice.
 
Do you need/required to run the well pump from the inverter?

Even if the inverter says it needs X amps, the real amps from the battery is based on the load on the inverter. If you can keep your invert load low enough, you can make the 4 batteries work, for now.
 
Do you need/required to run the well pump from the inverter?

Even if the inverter says it needs X amps, the real amps from the battery is based on the load on the inverter. If you can keep your invert load low enough, you can make the 4 batteries work, for now.

Hmm..that is very helpful, I haven't yet purchased a well pump. I am not sure what to buy and the people who drilled the well haven't been very helpful in their suggestions. (The well is 500ft deep, but has a stream of water coming in at the 400ft point as well as about 450ft down. We are getting about 4gpm. If anyone has any suggestions in regard to a good pump that would be welcomed as well)

Anyways, so are you saying if I got a pump that runs dc rather than ac, that would put less pressure on the inverter and we could squeeze by that way?

I guess I am maybe confused on what it means to reach max discharge. I think I understand that the batteries have an amount of current they can discharge per hour based on their capacity? So I would have the potential to go over the max discharge rate of the batteries with how large my inverter is, but only if the inverter is being asked to pull that much?
 
"max dicharge" current is the max amps you can(should) draw, sustained load. You can draw 100 amps until the battery is drained (to some point). You might be able to draw 150 amps for 2 seconds, or something like that, but that would be a max peak amp type rating and would include a time value.

A large deep well pump will start with a very large current and then after starting, it will run much less current. As deep as that well is and as deep as the water level, pump selection will be VERY important in an off-grid solution. There are special solar powered pumps that pump very slow but can pump from deep wells. The normal application is to pump up to a ground level holding tank, then have a smaller pressure tank and pressure pump to supply house water demands.

If you can keep large peak loads off of the inverter, it will not need the 200Amps to reach 5000watts. I mean if you keep peak load to...say 2000 watts, your current demand on your battery will fall inside the 100amp battery range.
 
Another note in well pumping, your water stream is pretty deep. If it fills the well up to say 100 feet from ground level, you will have a reasonable amount of stored water in the well, so can pump for a few minutes each time you run the pump. With high starting loads, you don't want to start often, but start and pump a lot would be more ideal. If however the well only fills up to 350 feet below ground level, a normal AC type pump might pump down to empty in a few seconds. For this reason you need to know how full it fills up and size a pump with a rate at those depths that will not be too large.

I have replaced several pumps in the 200-250 feet range and have purchased smaller pumps so that when the water level if lower, the pump output is much less, which avoids pumping to the point that the pump is sucking air.
 
No clue on the solar stuff, but might be able to help with the well.

My well pump is a Grundfos variable speed pump, with a soft starter and variable frequency drive. The Grundfos literature says it will run on 120-240v 50-60hz, and start on a generator a mere 10% larger than the pump's rated draw. That would mean a 1hp pump would handily start on a 1kw generator, and I'd expect that applies to inverters as well. Definitely worth reaching out to a well pump installer for consultation on what's out there.

My system was in place when I bought the house, but I do expect it's more expensive than a normal well pump. Another down side would be parts availability. A normal pressure switch and capacitor start box for a well is available at most any hardware and home improvement store in a rural-ish area. It goes out, a trip to town can have you running again, even on a Sunday afternoon. The Grundfos control box? Nope, good luck. If I was planning on being at this house for longer, I'd be looking for a good used spare to stash, just in case.
 
amberpp1, just curious you said: “a hand driven well didn't work out”. Were you successful installing your driven well (I assume sand point) and it just didn’t produce water or were there installation issues? I ask because I recently installed 2 sand points at my off grid cabin and am able to pump water with either a 12V DC motor or the original 120VAC motor running my piston pump from 1926. Depending on the geology, the driven well installation method I used can work effectively.
 
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I'll second the recommendation for the use of the grundfos well pump. I've had one in my well (off-grid) for just over three years now. The model I have is able to be run off of a/c or d/c. I have it run off of three 145 watt panels into a Midnite Kid controller and then into 4 lead-acid batteries ran serial for 48v. If need be I can run it off a generator. Ranchers in my area run stock wells off solar regularly, very common.
 
I’m going to drop a grunfos 6/3 down 700 feet in my 735 ish foot well in a few weeks .
My pump will run on any type of power ac dc solar panels genarator 110 v 230 volt
I was going to pump with solar so I bought there solar pump but after thinking about it,
The pump draws 1500watts and gives 6 g a min im pumping water into a 200 gallon holding tank
I plan to just add 12 more 295 watt panels to my system and run the well pump off the inverter .
I don’t use more then 200 gallons a day so I am going to use a mechanical timer that will just run
For 10 15 30 or more mins a day to fill the water tank.
 
amberpp1, just curious you said: “a hand driven well didn't work out”. Were you successful installing your driven well (I assume sand point) and it just didn’t produce water or were there installation issues? I ask because I recently installed 2 sand points at my off grid cabin and am able to pump water with either a 12V DC motor or the original 120VAC motor running my piston pump from 1926. Depending on the geology, the driven well installation method I used can work effectively.

We are not able to get any water out of the sand point. After having our deep well drilled though I am not surprised we had such a difficult time. The guy who did the drilling hit ledge 4ft into the ground, and he said the entire rest of the 500ft was one big mountain of solid granite.

I’m going to drop a grunfos 6/3 down 700 feet in my 735 ish foot well in a few weeks .
My pump will run on any type of power ac dc solar panels genarator 110 v 230 volt
I was going to pump with solar so I bought there solar pump but after thinking about it,
The pump draws 1500watts and gives 6 g a min im pumping water into a 200 gallon holding tank
I plan to just add 12 more 295 watt panels to my system and run the well pump off the inverter .
I don’t use more then 200 gallons a day so I am going to use a mechanical timer that will just run
For 10 15 30 or more mins a day to fill the water tank.

A holding tank with a timer is a good idea. I was hoping to incorporate copper coil to heat my water with solar in the warmer season, and in winter rig something together with my rocket mass stove to heat water in some sort of holding tank. I'll have to get to work on figuring that out.
 
You should check how far down the water is in the well .
The well guys allways say they are getting 4 gallons a min Because a well that gets less water then that is not considered a Reliable water source .
But lots of wells give 2 gallons a min and are fine , 2 gallon a min is 120 gallons an hour a 2880 gallons a day .
You should match your pump rate to your recovery rate .
Pumping to fast and drawing your well down can draw silt in to you water gains and plug them up .
9 months out of the year I have water in my well I can see with a flash lite , some years the water is down 8 or 9 seconds if I drop a rock so 300 feet in late August ive seen water down 500 feet☹️
A SQF 6 - 3 pump can pump 3.7 gallons per min so 880 gallons in 4 hours 440 g in December and 1300 g in June
With 3 300 watt array with solar controller .
They make a SF pump that will soft start off a inverter and give you full flow at 1500watts and you can just add the solar panels to your system and pump at 1 pm when you are charged up and have good sun .

To heat hot water the easiest thing to do is use a 50 gallon water heater propane or electric .
Guys are using pex in covered collectors to make hot water , the coils act as a pre heat to heat water when the sun is out , and the water heater heat water if there is no sun .
Cold water comes from the bottom of the tank with a check valve , hot water go’s in the top of the tank .
As the water heats up it will Start to circulate With out a pump but you may need a pump if the panels are not close .
There are pool heater that are plastic panels 30” wide by 12 ‘ long that would heat lots of hot water I think .
maybe just use propane when it gets cold putting a coil in a rocket heater mite be more trouble then it’s worth
 
"A holding tank with a timer is a good idea. I was hoping to incorporate copper coil to heat my water with solar in the warmer season, and in winter rig something together with my rocket mass stove to heat water in some sort of holding tank. I'll have to get to work on figuring that out."

Using 100 feet of black poly pipe, a small 12v DC pump, small charger, battery, solar panel, and two cheap temp controlled relay boards, I made a small pool heater. The water in the pipe must be X degrees AND the water in the pool must be lower than Y degrees, then the pump will run until one of the values is not satisfied and the pump will shut off. Then the pump waits for the pool to cool and the pipe to get hot enough before pumping again. Works very well. The pipe is on a wood frame with come clear(ish) plastic film over it. Plexiglass or similar would be better but I haven't got around to doing that yet. Anyway, cheap water heater.
 
The water heater panels the guys are using are clear roof panels they have them at home Depto .
I think a small pump that just pumps water with a solar panel when the sun is out would work fine .
a water heater would heat up fast any way .
 
The water heater panels the guys are using are clear roof panels they have them at home Depto .
I think a small pump that just pumps water with a solar panel when the sun is out would work fine .
a water heater would heat up fast any way .
No pump temp control....depends on how hot you want the water, if you have an upper limit you need to stay under.
 
I’m thinking that I would put a mixing valve in the system to control the temp so no one get burned .?
 
Long time no see :sneaky: , do any of you guys know if 10 gauge wire will work for this system? I was going to run 10AWG pv wire between panels, setting up the panels in 8S2P so the amperage would be 17.7 heading to the growatt through the 10 gauge.

I am still trying to decide on a well pump. The well guy isn't being very helpful, he was suppose to call me with the type of pump and all the info so I could see if we needed to buy a used pump and to make sure it suits our solar array. He never called back and a month later I called but he didn't give me any info besides that it'll cost $3200 for the pump and everything else plus installation. ?‍♀️ Anyways, I am trying to find a pump. I found a grundfos, the 5SQ07-320-230V, 5GPM, 3/4HP, 230V, 2 Wire, but it is nearly $900. Here --> https://www.aquascience.net/grundfo...60135-3-stainless-steel-submersible-well-pump
I also found a vevor pump, for under $200. Has anyone ever heard of or used these pumps? I'm sure there is a big quality difference but our options are very limited financially. https://www.vevor.com/collections/d...p-well-pump-4-131ft-cable-max-head-335ft-220v
 
I'm looking to replace my 1/2hp/230w submersible with a Grundfos 120v pump. The softstart of a Grundfos makes using solar so much easier. No need to worry about the huge surge and having to go overboard just to power a well pump. No need to buy additional batteries and an inverter capable and expensive enough to handle 240v.

I just asked today and got some good news about switching to the Grundfos pump. I know they're a bit pricy but cheaper than trying to beef up a system to handle a 240v submersible, especially considering you have to buy a pump anyways.
https://diysolarforum.com/threads/g...0-volt-ac-submersible-pump.27646/#post-329882

PS: my system is small. 1560w of panels, only 100Ah of Gel battery and a mid priced 3500w inverter (that's actually a lot larger than I need.
 
Long time no see :sneaky: , do any of you guys know if 10 gauge wire will work for this system? I was going to run 10AWG pv wire between panels, setting up the panels in 8S2P so the amperage would be 17.7 heading to the growatt through the 10 gauge.

I am still trying to decide on a well pump. The well guy isn't being very helpful, he was suppose to call me with the type of pump and all the info so I could see if we needed to buy a used pump and to make sure it suits our solar array. He never called back and a month later I called but he didn't give me any info besides that it'll cost $3200 for the pump and everything else plus installation. ?‍♀️ Anyways, I am trying to find a pump. I found a grundfos, the 5SQ07-320-230V, 5GPM, 3/4HP, 230V, 2 Wire, but it is nearly $900. Here --> https://www.aquascience.net/grundfo...60135-3-stainless-steel-submersible-well-pump
I also found a vevor pump, for under $200. Has anyone ever heard of or used these pumps? I'm sure there is a big quality difference but our options are very limited financially. https://www.vevor.com/collections/d...p-well-pump-4-131ft-cable-max-head-335ft-220v
Well all you can lose is 169 bucks .
How deep is the well how deep is your water in the well I think if you can replace the pump your self by hand you cup try the cheep pump , but for some reason the pump guys want a arm and a leg to drop the pump in the hole.
You don’t want to pay him to replace the pump a few times .
 
Well all you can lose is 169 bucks .
How deep is the well how deep is your water in the well I think if you can replace the pump your self by hand you cup try the cheep pump , but for some reason the pump guys want a arm and a leg to drop the pump in the hole.
You don’t want to pay him to replace the pump a few times .
Our well is 500ft deep, they didn't tell me what the static water level actually is (so we will have to find that out for ourselves), but they did suggest we set a pump at 300ft. 300ft up then about 80ft to the pressure tank is quite a ways to pump it seems with a 120V pump. It is also quite a ways to drop the pump in ourselves, I have a cousin who has installed many of my families pumps so I will probably ask for his assistance. Do you think 120v for this depth is reasonable or do I need to make a 240V work? The well guy is suggesting 240.
I wish we could afford for the well driller to come in and handle it all but we were quoted 5k for the well and it ended up costing 12k, which drained us of pretty much all our funds.
 
It's amazing how cheap you guys are getting wells drilled!, my 580' well was $44,000
 
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