Considering a SWG on an off grid pool, need some advice

[Paulk]

I have had my pool about 3 years, using bleach and an injector (stenner) pump to supply chlorine. No problems, except that hauling bleach up to my ranch is sort of a pain. I didn't consider a SWG originally as it took power, and I'm off the grid. But I've recently installed more panels and have plenty of power now I think, at least during daylight hours. I am in No Cal, but have been fine with running the pumps and system basically from 10 am in the morning till about 4:30 in the afternoon. Water is sparkling clean. I have few leaves that get to the pool. I've too always heard from other members that SWG was the way to go. This is a DIY, as I'm so far in the country that no pool experts will come here. I have a VS pump, (think that is all in my signature) So, now a couple questions:
1. Does it seem to the experts that I can run an SWG for only 6 hours (or a little longer) a day and be able to get the job done?
2. If so, what size SWG, (and if you have an opinion, what brand/model) ?
3. Any suggestions are gratefully accepted.

 

[Newdude]

Hey Paul !!!

Simple math here. SWG outputs are rated based on 24 hour run time. To get a 6 hour runtime you need a unit that is rated for 4X your pool volume which would put you at 54k (upsized to 60k) That removes most of your choices and leaves Pentair (IC60) or circupool (RJ55 or comp unit from them).

The circupool has a better warranty, more chlorine production and is more DIY friendly, but the Pentair is the Cadillac of pool equipment. You will score with either.

 

[cowboycasey]

Most definitely get a SWG, it will make your life so much easier

I have an SJ 45 for my 15k gallon pool and run it 2 to 6 hours a day and keep my FC at or above 7 at all times... I have to adjust about 6 times a year up or down depending on the season...

So a Circupool SJ, RJ, edge or Core would fit your pool.. the edge and core are the newest and most efficient ones now with auto sensing voltage and power supplies... A core 55 would fit you perfect, run efficiently and super easy to install in your system... The RJ 60 would also be a great fit and you might get away with running it 4 to 5 hours in the heat of the summer..

Basically anything over a 45 will do, you have to run the 45 a couple hours more and the 60 a couple hours less..

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www.discountsaltpool.com

 

[mguzzy]

Hey Paul... where the heck in Berkeley are you that you are so far from civilization that you live off the grid and no pool people want to come visit! I thought that by the time you were that far up in the Berkeley hills it wasn't called Berkeley anymore. (Yes I know.. the old "Farms?, in Berkeley!" joke)

A SWG is not really going to take up that much more power.. given you are already running a Stenner and pool pumps, robots etc. Definitely go for it. @Newdude already did the math to give you your likely options. I'm guessing you don't have any kind of automation system already installed. They are easy to install if you are DIY inclined and it sounds like you are.

 

[Paulk]

Thanks for all the quick replies. Ok, so sounds like something over a 45 is recommended, though a 45 would probably work I COULD put on the pump for another hour or so, and the pool is not that often used. (basically weekends). I've liked the Pentair products I have, but have to admit their warranty doesn't seem to be great, (especially for a DIY) Circupool looks pretty good. If anyone is off-Grid, (totally) then you can understand about keeping the power use down when the sun goes down. But, it is true that the pool is used only in the summer, so there ARE longer hours. Maybe I'll just go with a 45 and boost the hours a bit? Mark, you seem to know Berkeley somewhat.. Yes, I LIVE in Berkeley, but not many folks want a pool there, too cold. This pool is on my ranch which is 4 miles inland from Fort Ross. I'm there about a quarter of the time. Quite a bit sunnier and warmer. I have a 4 mile long rock and dirt driveway... and am about an hour from Santa Rosa, so you can understand now why they don't want to come out? Yes, All is DIM, (Including the dozer and excavator work I did to carve out the spot for this pool). NO cell service and no wi-fi, so while there is power from my panels and batteries, I can't control the system from the house. Certainly there are drawbacks to being off grid, but there are advantages too....

 

[mguzzy]

Kewl! that is beautiful country out there!

So.. this begs the question.. if you are soooooo far off the grid that you don't even have cell service.. How are we having this conversation.. I knew I was psychic, but channeling through a TFP connection is a new one

 

[mguzzy]

no wi-fi, so while there is power from my panels and batteries, I can't control the system from the house.

I don't think you need to be connected to the internet.. you just need a local wifi connection to control those systems.

 

[Turbo1Ton]

I have nothing to add other than just to say, that looks like a beautiful piece of property! I think more of us could use places to go where we are 'forced' to unplug.

--Jeff

 

[ajw22]

The SWG does not require much power. Maybe 1-2 amps. The power need comes from needing to run your pool pump for the duration required to for the SWG to generate the needed chlorine.

A SWG can run on low flow rates. With a VS pump you can run a SWG at 1200 rpm and maybe 100 watts. Less then a light bulb.

So get an oversized SWG so it generates lots of chlorine with a short pump runtime and you have a VS pump and your energy consumption should be manageable.

 

[Turbo1Ton]

SWG can run on low flow rates. With a VS pump you can run a SWG at 1200 rpm and maybe 100 watts. Less then a light bulb.

Just for comparison, I run mine @ 1000RPM which is about 80 Watts. My flow switch doesn't actually trip until much lower, like 600-700 rpm. So could run it even lower but I like to have a good buffer so I don't have nuisance trips of the flow switch.

--Jeff

 

[Paulk]

Thanks Mark. I suppose some wifi might be able to be established, but most of those like some cell service or something. And my pool is close to a quarter mile away from my house up there, and down in one of the canyons, so no direct sight signal works. As is, probably will work just fine on timers, as everything else does.

I have nothing to add other than just to say, that looks like a beautiful piece of property! I think more of us could use places to go where we are 'forced' to unplug.

--Jeff

That is exactly right. I do have some neighbor ranchers that have Wifi and land lines, so I suppose I could get such too, but I'd rather just unplug. I put in the pool, and other distractions, (disc golf, horseshoes, orchard, woodworking shop, kids play areas, etc) so that folks would have something to distract them. Then I built a bunch of "guest cottages" so that folks could be by themselves when they wanted to be. It's worked out especially well during this pandemic, people seem to very much appreciate a place to go that is safe. Now if I can get this SWG in, the pool will be a less work to maintain.
Sounds like I should maybe turn my pump down to 1000 rpm and run it for another couple hours.

 

[red-beard]

Solar Professional here....

What speed do you use for your VSP? As other have said, centrifugal pumps increase flow with RPM, but increase power by the square of the RPM. You are better off with a longer run time at the minimum flow that will make your SWG work. My Hayward 1.85 hp VSP uses about 55-60 Watts at 1050 which is enough to activate the flow switch on my system. And this is 40 GPM. A good circulating flow, but not a great skimming flow. Run 24/7 is under 1.5kWh. Add in 2 amps @ 240 with a 20% duty cycle for the SWG, is another 2 kWh. The SWG uses more power than the pump.

Go with 12 hours at 80 GPM (same total flow), 2150 RPM, 335 Watts = 4kWh. You will increase the SWG duty cycle to 40% to get the same FC generation in 1/2 the time, the power consumption is the same, 2kW.

So, 24/day = 3.5kWh/day or 12 hours/day = 6 kWh. If the batteries will support the night portion of the operation, you are better off running slow for 24 hours.

 

[Paulk]

Thanks for the advice James. I normally run it something like one hour maybe at 1800, but then down to 1400 or something like that. I do realize it would be less total power use to go down to 1000 or whatever. The thing is the off-grid aspect. I have power to burn during the daylight hours. I am making maybe 4800 watts/hr off solar. Overnight, my batteries dip, maybe something like 45% of the reserve power. (Lead acid batteries are fine with being depleted 20% from full power. True, some folks take them further, but there are folks that I respect that say that each bit further than that 20% harms the batteries a bit. At the cost of $6K for batteries, one likes them to live as long as possible. I'd like them to last another 5 years, so that when they need replacing I can get a system that would allow for deeper discharge. So, nighttime, the biggest draw is refrigerator and separate freezer. (and I have a fancy low power fridge). So running something at night is not optimal. Perhaps fine if I'm always there, but I'm not. So if some strange weather happens and there is little sunlight, then the potential is there to deplete the batteries more than I'd like. Sure, during a sunny day, I have LOTS of excess power . I can charge my batteries from down even 20% by 11 am. then power is being generated significantly fast than it is being used. So, I think maybe the thing to do is to run the system maybe from 8 am to 6 or 7 pm. Maybe 1000 rpm in the first 2 hours or so, and the same in the last couple of hours. Thanks for helping me figure out what might be best.
Now I have to determine how much space I have on that line to the jet. It is a bit tight. Seems like some of the SWGs have the display panel attached to the cell itself, and that is an area that will be hard to "view". (I think the Circupool Core is that way. Might be that I'd need to get a system where the monitor / control screen is separate from the device....

 

[mguzzy]

Also consider this.. there have been threads debating what time of day/night running a SWG is most effective at disinfecting. I run mine at night, simply because rates are lower. Other's run theirs during the day, because they want the chlorine production to coincide with the time that the FC is being consumed. Whatever.

Most SWG installs have a vertical option for piping that doesn't have a convenient horizontal run.

 

[Paulk]

Yeah, I imagine quite a bit better to run at night, if only in that sunlight tends to degrade the TC faster, so might as well do the job at night? But, as you can see, my rates for "power" is MUCH higher at night! Re the install. thanks. ok, I'm going to check it out this next week.

 

[red-beard]

Give me a run down on your solar panels, and battery size. $6K for what I supply would be about 15kWh. Which inverter are you using?

I'm thinking you might want to run the pump from 11AM (batteries full) to sometime in the afternoon, maybe 3 or 4 PM, at a lower speed and the same with the SWG.

 

[red-beard]

I just want to make sure you enter darkness with 100% batteries, but maximize circulation and minimize SWG setting.

 

[Paulk]

James, I have no lack of panels. I have a couple of arrays, I think one that has 8 panels @ 340 watts, and another that is closer to 2000 watts. I have a somewhat unique situation in that panels are very cheap for me. I could put on more panels no problem, (though running additional lines from array spots to the power shed is less fun. Also Charge controllers are not so cheap when you are talking that kind of power, (closer to $1K for 100 amp charge controllers). But the batteries are more the limiting factor. Why put more into panels if you are still limited by the batteries? As to inverters? Somewhat older now, I put 3 outback inverters, (something like 3800 watts each) in back in 06, the put another one in (to have more balanced 220) in something like 2010. So four total. (why so much? cause I run some bigger motors in the wood shop)
yeah I like to enter darkness with 100% too. If I'm there, and working, and find the batteries down to say less than 95%, then I can just run a generator for 20 minutes and bump it up. But if not there yes, more potential for a problem. As to that few hours of run for the SWG, others said I need more, (reading the thread. I guess the SWGs are rated basically at 24hr run for the pool size. I don't want to run the SWG at night, though yes, it would probably be fine most of the time, just that we folks off the grid, don't like to run close to the limits. Where my arrays are, I usually have pretty good charging by 10 am, and am actually charging till 6 pm normally. So, I'll just run the SWG mostly within that time frame. (maybe with lower speed early and late. ). thanks again. as to battery size, sorry, I can't remember right now what I have. Been a few years, (like 10). But basically two large forklift batteries.

 

[red-beard]

Something rated for 40,000 gallons will probably do it. How much FC do you lose in a day? My 40K system will produce up to 7ppm FC per day (24 hours) for a 25,000 Gallon pool. At 13.5K gallons, it will produce up to 13ppm FC per day (24 hours). My loss is about 1.5FC/day, so I set for 22% (24 hours).

You are further north. If you use 70 CYA, and keep the pool around 7 ppm, your loss will be maybe 1ppm FC./day. You could do that in 2 hours at 100%. Or run the pump from 11AM to 5PM and SWG at 33% and run the pump at say 1100 RPM. You will have plenty of FC for overnight.

 

[Paulk]

Thanks James. That is sort of what I figured. Looked at the Circupool 45 or close. I think that should be fine, and yes, might be I dont have to run it as much as some do. (not lots of people and when I AM up there and going to use it, I can just do a quick test and do something about it if the FC is low. Again, thanks to all you folks.