Solar panels and battery(s) required for pond aeration

[SunEagle]

I believe you are right sun eagle. The system I installed uses a 30# thrust minkota endura c2 trolling motor, a plain old marine deep cell trolling battery and 2 230 watt 24 volt solar panels and a cheapo charge controller. It draws about 30 watts on speed 1 and 60 watts on speed 2 it runs 24 hours a day on low from may till October. It does an amazing job on a 1/2 acre pond with an average depth of 5 feet. it has run about 4300 hours this year. Not bad for a 109 dollar trolling motor. Its used on a fish rearing pond

Sounds like a workable system. Nice job.

[drbob]

I have a little side business building aeration systems for minnow farmers been doing it since 1985. the solar powered unit was the first one I built and installed this spring. however I have utilized trolling motors in the past using a battery charger for a few years, The smog pumps move a ton of air and have found that they will run about 8,000 hours before they wear out. I have also used a 1/6 th hp motor on them too just reduced the speed. I also build diffusers for the air driven systems.

[ScottM]

No reason for picking the 12 hrs per day. I see many systems run 24/7. Just thought requirements for batteries/panels would be less. I can see 24/7 in winter to keep hole in ice and prevent fish kill, However in my area, I have talked to a few pond owners with no system in winter and they never had a problem. Not saying it couldn't happen though given amounts of ice buildup and snowfall in certain winters here.

As far as summer requirements I have yet to see any studies of the minimum run times that will still retard algae and provide enough oxygen for this size pond so I am guessing. Naturally it would be optimum to run 24/7, but is 4/6/8/or 12 hrs/day sufficient? or would it be a guess other than running 24/7? Who knows?

Anyways I do have a little used trolling motor, thats been sitting for 10 years and think its 30 lb thrust without looking at it now. The trolling motor is an excellent idea, but how would you mount the trolling motor in center of pond thats 8-10 feet deep? I assume the head can't go underwater. As far as a smog pump/ solar panels would be a lot cheaper way to go rather than a full system of batteries/ panels , etc. What smog pump is best? Can you put diffuser 8ft down and 100' air line? Even if for some reason the smog pump wouldn't do the job, I would only be out the cost of the pump and could still try the trolling motor or full system. I am "a jack of all trades and master of none"
so I know just enough to screw things up....

[drbob]

build ya a dock 10 to 20 feet from shore mount the trolling motor on that and have it thrust paralell to the shoreline this will build your circulation loop. A 1/4 acre pond is about 100 x 100 feet and if it averages 5 feet feet deep it will contain about 400,000 gallons of water. That little trolling motor even on low speed will move 400 gpm or more and give you a rollover of all the water in 1000 minutes or roughly once every 16 hours. That is the trick to aeration,, believe me

[drbob]

as fart as the diffuser is there is no need to go 8 feet down, I prefer to set them at the 5 foot mark.. the smog pump moves lots of air but not much pressure.. go deeper and it moves lots less air. Air is the stuff that makes the water percolate and roll over. A garden hose is a good simple air line from the pump. but in your case a trolling motor is the ticket you already own one. If you could just wire it direct to a solar panel and just let it run when the sun shines without a battery life would be good. I haven't tried this but I think it would work. I would recommend 2 100 watt 12 volt solar panels wired in parrellel ask the gooroos about this

[AzRoute66]

That little trolling motor even on low speed will move 400 gpm or more [...]

Amazing, that's a lot. Woulda lost that bar bet.

[ScottM]

I'll think hard about the trolling motor system and dock suggestion on mounting but in the meantime another question:

For anybody: Don't laugh at this question but lets say if you have a system that you underestimate the panels or ah batteries required to run a set amount per day or its constant clouds for a week or so....

What happens with a battery that doesn't get a sufficient charge during day? Can you set a cutoff voltage for the battery not to go below 50% that will shut down the pump (AC pump in this case) so as not to ruin the battery and than start up the pump again automatically when panels start to recharge battery or run off the panels during sun hours. Can you program most inverters to do this? or would this be another peice of equipment required? and start automatically even if it ends up running for just a short time before shutting down again because system was not sized correctly or would you have to stop/start again manually?

[drbob]

inverters have automatic shutdown if you want to go a/c motor with a smog pump. However small inverters are not very efficient. If you wanted to build an air pump utilizing a smog pump go with a 250 watt 24 volt d/c scooter motor. these motors can be bought for under 75 bucks on ebay with a controller . I have a lot of experience with unite MY1020 48 volt 1000 watt dc motors and these are controllable from 20 watts to 1000 watts output. They seem rugged enough but I never ran the prototype over 100 hours in testing. It pumped a lot of air at the 500 watt level enough for a 5 acre pond and would probably do the job for you at the 100 watt level. The prototype is sitting in my shop right now but I will not post any photo's of it. 4 people have seen it that's all.
as far as the battery discharge protectors go I have no experience with them at all but I bet one of the guru's here can point you in the right direction.

[PNPmacnab]

If you were just a little closer, I'd design you a system. Two 300ish W grid tie panels, $100 inverter and a used car battery with my controller. It would cycle 1 to 3 of your preferred pumps depending on how much sun. Lots of air for shorter periods of time. Basically a mod of my refrigerator system. Just figure out how to PM me. You can't because this isn't a real solar forum where people actually do things.

I have some experience with those lo blow pumps. My neighbor has one on his ............ When I sleep at night I can hear it babbling. Helps me to go to sleep.

[Wy_White_Wolf]

No. I don't believe you can get the proper amount of sunlight in NE Ohio or for that matter anywhere in the world for 12 hours so I have no idea how you can run a 71 watt load from solar pv for that long even if you track the sun.

The question is does the OP really need to run the pump for 12 hours. If 8 hours is a better time frame then there is a possibility you can do it just using panels without a battery.

I have a well pump running solar direct and have no problem with it running over 12 hours a day in the summer. The OP stated May through September so He might have some problem getting the full 12 hours in September but should have no problem the rest of the year.

WWW

[SunEagle]

I have a well pump running solar direct and have no problem with it running over 12 hours a day in the summer. The OP stated May through September so He might have some problem getting the full 12 hours in September but should have no problem the rest of the year.

WWW

So how many watts is your solar array and how many watts is your pump?

It all comes down to size of the load and the amount of amps a pv system can generate. The time of year will make a big difference along with the location.

I have a solar DC driven fan that will continue to "spin" in very low light in the evening but the amount of CFM's it produces is very very small.

The OP is in NE Ohio which I don't think will get the same amount of sunlight as I do in Florida.

[drbob]

I live in northern Wisconsin in june the sun comes up about 5 am and goes down at 9 pm in December it comes up at 830 am and goes down about 430 pm

[ScottM]

Thanks for all the responses. I am getting smarter by the day which scares me.......

From what I gather the THEORY is if you use a DC direct system pump (of course depending on size, model, panel wattage, cfm etc.) that it will run pump only during sunlight hours - slow in am and pm but optimum during peak sunlight. Best to use to avoid cost of battery(s)

An AC pump with battery system invertor can be programmed to shut down battery and pump to if you do not have the correct run charge capacity from number of watt panels/sunlight availability.
I get that depending on number or watt panels, battery amp hours, pump watts, sunlight availability, etc can be calculated for run times desired and battery charge times/amp hrs required, but my question was, lets say due to lack of sunlight the system shuts down and the battery(s) exhausted i.e. shut down to voltage cutoff you have programmed in.

When the sun shines again will the pump automatically restart from panels (assuming you have correct watts) or do you always have to have an optimum watt of panels to run pump off of and recharge battery at same time so this never happens but if it does again, will it auto restart? or do you have to manually restart something?

[SunEagle]

Simple answer is that without sun you won't be able to run a DC load from solar pv unless you have a battery.

If you get multiple days of low to no sunlight you can always use a generator to run your load as well as recharge the battery.

Depending on the sun every day to run a load is taking a big chance unless you can go days without that load running. Even in sunny Florida we can go more than 3 days without any sun.

[sensij]

When the sun shines again will the pump automatically restart from panels (assuming you have correct watts) or do you always have to have an optimum watt of panels to run pump off of and recharge battery at same time so this never happens but if it does again, will it auto restart? or do you have to manually restart something?

It is common for a LVD to auto-restart once a threshold battery voltage is met, but there are options that could require manual intervention, if that is what you want.