Need help building off grid koi pond circulation system.

[inetdog]

So, pumps circulate water through the filters, but how is it oxygenated ? Waterfall ? Airstone and air pump ?

Instead of a waterfall you can use a water spraying fountain. They are commonly used in small ponds that need filtering and aeration but do not want to use an air pump and do not have the scale for a waterfall.

[Mike90250]

So, pumps circulate water through the filters, but how is it oxygenated ? Waterfall ? Airstone and air pump ?

[Narnian]

They're 5W at 12V, not 5V.
(assuming I found the same ones you're looking at)

Yep, I wrote that wrong. Had it right in my initial post. I'm sure you found the same ones. There are three or four vendors all selling the same pump with the same specs under different names.

5W * 12 hours * 4 pumps is 240 watt-hours.

the 5W/12V usage of them is going to be only 240gph per pump.
So with 5 pumps you're only at 1200gph
And for 12 hours you're down to 240gph.
Is that sufficient?

Yes, I think so. The pond holds about 1200 gallons. The rule of thumb is to push the pond volume through the filter once an hour, so the 1200GPH is a match. At night, there is less biological activity in the pond at every level. My completely unscientific opinion is that the fish will be fine at night as long as there is a trickle of water moving to keep oxygen in the water. I'm basing this on experience (which can be wrong). I once had to keep all the fish in a 220 gallon kiddie pool for five weeks with one 200GPH pump in the heat of the summer. I'm sure they weren't very "happy" but they survived. In the winter time, the Koi barely eat or move, so I could probably get away with running one 240GPH pump 24 hours a day if needed, though I'd rather have all the pumps running as often as possible. If it turns out the volume is a little low, I can add one or two pumps next summer for the heat of the day, as the solar panels should be getting extra power during the summer months. I'm confident that 1200GPH will be enough nine months out of the year. I'm not confident about 1200GPH part time when the temperature outside hits 110, but I'm willing to take a chance. I would know long before any fish died. The water chemistry would change. I take a sample once a month. I would check the water daily during the beginning of next summer to determine if everything was working. If the chemistry is bad I have a lot of options for correcting it until I can add more pumps or more power, like temporarily putting my extension cord back in place with my current pump running at night.

360Watt-hours would be 30 Ah for a 12V system.
But you don't want to run a charger out there every day it's cloudy, so you need to multiply that by the number of days you'll potentially be without sun.

BTW I didn't see battery charger on your shopping list - you'll need one for when it's cloudy for too many days in a row.
And I think the off-grid guys recommend getting a temp corrected hydrometer (fairly inexpensive I think)

I already own a halfway decent digital battery tender / charger that I use for my RV batteries, so I don't need to add it to the list.

[foo1bar]

I'll be running four pumps @5V 12 hours a day so that's 240 Watt hours?

They're 5W at 12V, not 5V.
(assuming I found the same ones you're looking at)

5W * 12 hours * 4 pumps is 240 watt-hours.

the 5W/12V usage of them is going to be only 240gph per pump.
So with 5 pumps you're only at 1200gph
And for 12 hours you're down to 240gph.
Is that sufficient?

Then one pump will run @5v 24 hours a day, so that's 120 Watt hours, for a grand total of 360 Watt hours?
So what is that in Ah?

360Watt-hours would be 30 Ah for a 12V system.
But you don't want to run a charger out there every day it's cloudy, so you need to multiply that by the number of days you'll potentially be without sun.

BTW I didn't see battery charger on your shopping list - you'll need one for when it's cloudy for too many days in a row.
And I think the off-grid guys recommend getting a temp corrected hydrometer (fairly inexpensive I think)

[bcroe]

Keep in mind that any KWH taken from a battery costs at least 5 times that from the PoCo. That, to replace the battery, which has
a maximum cycle life. If you can design so that as much as possible power flows directly to your pumps, and a MINIMUM is charged
and then discharged from the battery, you will minimize your battery replacement costs. Bruce Roe

[inetdog]

This is good stuff. Can we revisit that math? I don't know how to use your calculations with my numbers but I'm going to take a stab at it.

I'll be running four pumps @5V 12 hours a day so that's 240 Watt hours?
Then one pump will run @5v 24 hours a day, so that's 120 Watt hours, for a grand total of 360 Watt hours?
So what is that in Ah?

There is no inverter since I'm using 12V fountain pumps.

The Koi are very inactive during the coldest darkest months of the year, so I could probably get away with running the first four pumps even less. Perhaps as little as three hours a day. I switch from feeding them twice a day in the summer to feeding them once every five days in the winter.

I think you are corroborating SunEagle's comments - I should be able to get away with 2 panels and two batteries.

Yes, that will be 360 watt hours. Since watts = volts times amps you can make the rough conversion that 360Wh from a 12V battery would be 30AH.
But to restrict your daily discharge cycle to 20% of capacity would require 150AH of battery.
From there you can figure in any efficiency losses in your inverter if they are 120V pumps (which I see there aren't) and comparable efficiency losses in the recharging process when calculating the panel size.

All of these calculations are covered in great detail in sticky threads in the Off Grid topic area of the forum. Including some spreadsheets to do the math for you.

P.S. You have taken the single most important step by figuring out just what your planned daily power load will be.

[Narnian]

1. For your small pool pumps you may be able to replace them with pumps that run off low voltage AC or DC (like the 12V landscape lights) The burial requirement for such limited power wiring may be a lot less.
2. If your pumps take 25W total and run for 24 hours each day that would be 600 watt hours.
To put 600 watt hours back into your battery (assuming a perfect inverter and charger) would take about 300W of panel power in the winter when you only get about 2 effective sun hours per day.
3. To supply 600Wh (50amp hours, AH) at 12V safely and sustainably would require a 250AH 12V battery bank. And you would need a way to recharge the batteries manually when the weather is bad for several days in a row.
4. 300W of panel would only keep you even each day. To assure recharge after one or two cloudy days would take 450W of panel or more.

This is good stuff. Can we revisit that math? I don't know how to use your calculations with my numbers but I'm going to take a stab at it.

I'll be running four pumps @5V 12 hours a day so that's 240 Watt hours?
Then one pump will run @5v 24 hours a day, so that's 120 Watt hours, for a grand total of 360 Watt hours?
So what is that in Ah?

There is no inverter since I'm using 12V fountain pumps.

The Koi are very inactive during the coldest darkest months of the year, so I could probably get away with running the first four pumps even less. Perhaps as little as three hours a day. I switch from feeding them twice a day in the summer to feeding them once every five days in the winter.

I think you are corroborating SunEagle's comments - I should be able to get away with 2 panels and two batteries.

[Narnian]

That 100 watt panel can barely support a 55Ah battery. The formula for battery charging is between C/8 and C/12 where C = battery Ah rating. A C/10 is the sweet spot for FLA type batteries. So most 100 watt panels have an Imp = 5.5 amps which calculates out to a 55Ah battery which can maybe get you 165watt hours a day (12v x 55Ah x 25% = 165wh). You need more than that so figure a bigger battery and solar panel wattage accordingly.

What is the Ah rating of those Sams club?

This is the kind of information I was looking for. I've read those formulas eighty times and I still don't know what figures to plug into them to get the correct result.

I don't know what the Ah is on the $90 deep cell batteries, I'm going to have to stop into the store and look. I bought a $120 deep cell battery for my RV last year and it was rated at 231 Ah, which seems pretty high but that's what the label said. Based on what you're saying, I shouldn't get the deep cell, I should get two golf cart batteries and two solar panels. Does that sound right?

I don't mind replacing a pair of batteries every four or five years. If I did the math right, it currently costs $24 a month for the electricity to power the 2000GPH pump in my pond. That translates into roughly $300 a year. Over four years that becomes $1200. I can afford to spend $200 on batteries every four or five years if I'm saving $1200 to $1500 in that same time period.

[inetdog]

1. For your small pool pumps you may be able to replace them with pumps that run off low voltage AC or DC (like the 12V landscape lights) The burial requirement for such limited power wiring may be a lot less.
2. If your pumps take 25W total and run for 24 hours each day that would be 600 watt hours.
To put 600 watt hours back into your battery (assuming a perfect inverter and charger) would take about 300W of panel power in the winter when you only get about 2 effective sun hours per day.
3. To supply 600Wh (50amp hours, AH) at 12V safely and sustainably would require a 250AH 12V battery bank. And you would need a way to recharge the batteries manually when the weather is bad for several days in a row.
4. 300W of panel would only keep you even each day. To assure recharge after one or two cloudy days would take 450W of panel or more.

[foo1bar]

You may be right but my buddy just added some landscaping with a 12V system, and he was told he didn't need a permit for it. Hard to say.

If it's a plug-in type system, possibly he doesn't need it, as it is just like plugging in a lamp or a toaster.
If it's a hardwired system, probably they could require a permit, but won't bother.

What does AHJ stand for?

Authority Having Jurisdictin.
(Usually permit dept of your city, but outside of cities it could be county or even a state government department/entity

It would cost more and be less efficient. The prepackaged systems I looked at all had small battery packs (I'm guessing they have a few rechargeable C or D batteries inside). Each prepackaged system came with a super simple charge controller. Each prepackaged system had a 25 or 40 watt solar panel. These systems had a flow of about 160 GPH. I would need to buy ten of these systems. I would need to mount ten panels and create space for ten battery packs and a rats nest of wires. I would have to make room inside the bog pond for ten pumps where I really only have room for about six.

Maybe there's a commercially available big-brother version already?
I'd check the manufacturer's website.

The frustration is that this audience assumes I haven't already thought of this. I have looked at this problem for several months and running wires was my first choice.

I'd really really try to make that choice work...
A solar setup is definitely going to mean buying batteries every 1-5 years.

This is actually a good suggestion, but even six inches down is a lot of work in my backyard.

see - you are getting useful suggestions.

That said, if I can locate a machine to push the wire into the dirt I might be able to get it down there right after a rainstorm. I know my neighbor rented one when I lived in Ohio. I don't know what they are called.

cable plow ?
There is the option of using a soaker hose for an hour to get the dirt softened up.
Although hopefully you'll be getting some rain today/tomorrow

I still think it would be cheaper and easier to do the system I detailed above.

We'll see if you still think that after you get it sized properly.
I'm not the right person to give advice on battery systems and PV for charging them.
It looks like there are some people trying to help you with that so I'll leave you to them.

[Narnian]

Probably not true.
I doubt city of Sacramento would add that requirement.

But direct burial wire would still require a lot of landscape disturbance (more than doing conduit since you'd be 24" down instead of the 18" down for PVC conduit).
So not any better than conduit I think (although might be a little cheaper in materials)

I don't know for sure if it's true, but that's what my coworker told me who just had to run replacement wires out to his pool pump. He said it was a requirement and he had to hire someone to dig a 25 foot trench. Perhaps he could have buried the wire at 24". It's somewhat of a moot point as it would still make a mess and take a lot of time as the soil in my area is super hard.

[SunEagle]

I can run a power cable out there if we have a string of days with bad weather. But I think your second comment gave me a solution. The water needs to move 24/7 but it doesn't have to be full volume 24/7. I can set up a timer on 4 of the 5 low volume pumps so that they turn off in the evening and turn on in the morning. 1 deep cell battery would power a single pump without breaking a sweat. It should be able to handle a single pump for about 50 hours. Any reason this won't work?

20A charge controller (Amazon)	$19.58
12V timer switch (Amazon)	$8.99
240/410 GPH pump 4 pack (Amazon)	$182.37
240 / 410 pump (Amazon)	$49.00
100W Solar panel (Amazon)	$117.99
Solar Panel Connectors pack (Amazon)	$6.99
Wires (Home Depot)	$20.00
2 battery terminal clamps (Autozone)	$16.00
12V Deep Cell Battery (Sams club)	$90.00
Total	$510.92

That 100 watt panel can barely support a 55Ah battery. The formula for battery charging is between C/8 and C/12 where C = battery Ah rating. A C/10 is the sweet spot for FLA type batteries. So most 100 watt panels have an Imp = 5.5 amps which calculates out to a 55Ah battery which can maybe get you 165watt hours a day (12v x 55Ah x 25% = 165wh). You need more than that so figure a bigger battery and solar panel wattage accordingly.

What is the Ah rating of those Sams club?

[Narnian]

That could definitely be a problem.

Not true.
rigid conduit can be only 6" deep.
NEC table 300.5 is the requirements


OK - is your circuit breaker in a spot where it wouldn't require going under concrete? If so, there's a good solution.

Actually, there's about 30 feet of concrete by the circuit breaker as well, but I think I can run a power cord into the house, through the garage and out the back wall before plunging into dirt. Still a lot of trouble though and I would need to check codes to see if that's allowed.

I think that's high.
I'd guess the permit should be the minimum charge - probably $50 or so.
Trencher is also not too expensive to rent (even here in CA)

Here's what I'm coming up with to be safe:
Electrician: $350
Trencher $120 /day (Home Depot)
Permit/s $50
Materials (conduit, elbows, enclosure, boxes for going in in and out the garage, 200' wire, outlets, circuit breaker, etc) : $300
That adds up roughly to $900. My materials might be a little high but generally every time I make an estimate it's too low.

actually I'd bet that there isn't a law that exempts it from permits.
But the AHJ probably has a lot more important things to worry about and doesn't want to bother with it.

You may be right but my buddy just added some landscaping with a 12V system, and he was told he didn't need a permit for it. Hard to say.

What does AHJ stand for?

I wouldn't bet on it.
Is She-Who-Must-Be-Obeyed going to be OK with looking out at the solar panels in her back yard?

I have a shade structure (like a trellis but with shade cloth) out there that the panel would get mounted on. The panel will not be visible. I could put several panels up there and they would not be noticed.

Since you're already looking at multiple pumps , doing multiple pre-packaged systems might be a better plan.

It would cost more and be less efficient. The prepackaged systems I looked at all had small battery packs (I'm guessing they have a few rechargeable C or D batteries inside). Each prepackaged system came with a super simple charge controller. Each prepackaged system had a 25 or 40 watt solar panel. These systems had a flow of about 160 GPH. I would need to buy ten of these systems. I would need to mount ten panels and create space for ten battery packs and a rats nest of wires. I would have to make room inside the bog pond for ten pumps where I really only have room for about six.

To get 1200gph 24/7, I'm doubtful of $750 for an off-grid system.
And it'll cost you money every couple years for new batteries.

Because that's likely your best option.

The frustration is that this audience assumes I haven't already thought of this. I have looked at this problem for several months and running wires was my first choice. After a lot of consideration I realized it was not going to be inexpensive and most importantly it was going to require a lot of work as the dirt here is as hard as rock. My questions revolved around the battery to solar panel requirements. Instead of getting responses about whether or not 1 panel is enough, or if 1 battery is enough, I'm spending a lot of time explaining why I want to install a mini solar system. If someone posted a question about " How do I install a second AC unit in my RV" I wouldn't tell them to drive to a place that was cooler, or to put a can with ice cubes and a fan in the bathroom, or that they could fix the problem by parking under a tree. I would assume they were smart enough to know what they wanted and try to tell them how to cut a hole in the roof and run the wires. I'm disappointed with most of the responses I've gotten.

I would look at doing a low-voltage, limited power set of wires from the house to the pond. A "landscape lighting" style system.
Wires for those are only required to be buried 6" deep per code. And that's shallow enough you can probably do that by hand and could maybe even do it by just slitting with the shovel and shove the wire down - minimizing landscape disturbance.

This is actually a good suggestion, but even six inches down is a lot of work in my backyard. I installed the irrigation system here 4 summers ago. I literally had to break the clumps of dirt with a sledgehammer. That said, if I can locate a machine to push the wire into the dirt I might be able to get it down there right after a rainstorm. I know my neighbor rented one when I lived in Ohio. I don't know what they are called.

I still think it would be cheaper and easier to do the system I detailed above.

[Logan5]

at least the sams club batteries are plentiful for your annual battery replacement. you will be paying a dollar or more per KWH for what would be 11 cents worth of grid electricity, an 89% loss

[DanKegel]

I would look at doing a low-voltage, limited power set of wires from the house to the pond. A "landscape lighting" style system.
Wires for those are only required to be buried 6" deep per code. And that's shallow enough you can probably do that by hand and could maybe even do it by just slitting with the shovel and shove the wire down - minimizing landscape disturbance.

That's a good idea.
Given the power needed by the pump and the length of the run, you'd need to be careful about wire size, and would want to use the highest allowed "low" voltage to reduce power loss.
According to http://ecmweb.com/content/code-rules...ltage-lighting the max voltage allowed in wet locations is 15V.
Check e.g. https://www.altestore.com/howto/wire...-systems-a106/ to see what thickness wire you'd need.