solar powered air pump?

[armedoldhippy]

if this has been addressed before, i apologize here in advance. does a DWC "require" the air pump going when it is lights out whether supplemental or sun light ? i have always just left mine going indoors, with no real thought put into it before. but i'm thinking about an outdoor hydro experiment a very short distance from my house (no power there), and was wondering if a solar powered air pump like for fish ponds would be sufficient.

 

[Travis Kelcee]

You will need it to run the pump on cloudy or rainy days. So it's best to get a cheap 100 watt panel with a solar charge controller (About $100 for both) add a battery and 12v air pump and you are set.

The more AH (Amp hours) the battery is rated for the longer you can run the pump without sun. But more AH's = more $$$.

Just running it off a solar panel won't run the pump during the entire day unless you have it on a solar tracker. 3 - 4.5 hrs a day is longest you'll come close to making full power from the solar panel on a sunny day.

 

[Travis Kelcee]

Grab 2 of these batteries and you can run a 35 watt pump (18 GPM) for 3 days without sun. 3 days is good buffer with any solar system, due to weather and cloudy days.

12.8v 100ah 1280wh Lifepo4 Battery - 100%+

Every battery tested 100% capacity or better and includes a copy of the test report showing capacity and curve chart results. A few overseas battery manufacturers supply thousands of different private label brands. When it comes to batteries what matters most is how good they test. These have...

batteryhookup.com

 

[armedoldhippy]

Just running it off a solar panel won't run the pump during the entire day unless you have it on a solar tracker.

i don't have a tracker, but i DO have several small solar cells from outdoor decorative lights lying around not doing anything. i could set them up as an array giving day-long coverage...i think. also looking at solar chargers used on remote electric cattle fences. the air pump would actually be running off of the 12V battery, with the solar cells charging it all day. i'm thinking that the O2 level in the water would keep plant happy overnight, but the battery would be good insurance. things to think about...

 

[Travis Kelcee]

It's been a long time since I ran DWC but I seem to remember running the pump 24/7? Could be wrong.

A solar panel connected to battery has to have a higher open circuit voltage rating than the battery voltage or it won't charge the battery. For between $60 - $80 for a new 100 watt panel it's not worth messing around the smaller cells which probably won't produce enough voltage. A 12v 100 watt panel normally has 20v - 25v open circuit voltage.

I have 48V LFP batteries and they need at least 55v from the solar panels before the batteries will start to charge.

2 12v Lithium 100 AH batteries, a 100 watt solar panel, solar charge controller and a 12v 35 watt air pump you are at $350. But it will be a set it and forget it setup.

 

[Ca++]

There are online calcs for expected panel outputs, where location is taken into account. The air pump isn't generally a high power device. First google result, the bio-orb 12v at 0.8W and then the second result 1.4W. If we say 1.2w is in the middle, that's 0.1Ah consumption. Smaller car battery might be 30Ah so lasts a week before half the charge has gone. About as low as you want to go to keep it in vgc.
If you can charge that along the way, that's great. Panels with everything including the battery clips are common. 10w kit for $20us is typical. I would need 3 here in the uk though, which starts to make carrying batteries look reasonable. My 12v drill batteries have been in silly missions. Running hosepipes out of lakes in summer. They would run an airpump 24 hours.

I don't think it need run at night. I think a battery is still needed though.
A timer could save some battery. Just so the pump runs at dawn and dusk, and maybe mixed the water once or twice at night. This could help use a smaller panel, by saving some from high noon, to use off peak.
Your access to batteries, and other means of charging or swapping them might guide you away from solar.

 

[Drop That Sound]

 

[Travis Kelcee]

There are online calcs for expected panel outputs, where location is taken into account. The air pump isn't generally a high power device. First google result, the bio-orb 12v at 0.8W and then the second result 1.4W. If we say 1.2w is in the middle, that's 0.1Ah consumption. Smaller car battery might be 30Ah so lasts a week before half the charge has gone. About as low as you want to go to keep it in vgc.
If you can charge that along the way, that's great. Panels with everything including the battery clips are common. 10w kit for $20us is typical. I would need 3 here in the uk though, which starts to make carrying batteries look reasonable. My 12v drill batteries have been in silly missions. Running hosepipes out of lakes in summer. They would run an airpump 24 hours.

I don't think it need run at night. I think a battery is still needed though.
A timer could save some battery. Just so the pump runs at dawn and dusk, and maybe mixed the water once or twice at night. This could help use a smaller panel, by saving some from high noon, to use off peak.
Your access to batteries, and other means of charging or swapping them might guide you away from solar.

Without the correct open circuit voltage rating on any solar panel you can't recharge a battery. No matter if it's a 10 AH battery or 100 AH battery. Any solar panel must be capable of producing over 13 volts when recharging a 12v battery.

The solar panels on outdoor lights normally don't produce more than 5 or 10 volts. When you can buy a small brand new 100 watt panel for $60 it's just not worth trying to repurpose old solar.

Also lead acid batteries should not be discharged below 30% of it's capacity or you'll shorten the battery life quickly. So you can only get about 20 AH out of 30AH lead acid battery.

Lithium can be discharged down to 0% without a problem. The link above to a $99 100AH 12v Lithium battery is a steal.

 

[Ca++]

Without the correct open circuit voltage rating on any solar panel you can't recharge a battery. No matter if it's a 10 AH battery or 100 AH battery. Any solar panel must be capable of producing over 13 volts when recharging a 12v battery.

Also lead acid batteries should not be discharged below 30% of it's capacity or you'll shorten the battery life quickly. So you can only get about 20 AH out of 30AH lead acid battery.

Lithium can be discharged down to 0% without a problem. The link above to a $99 100AH 12v Lithium battery is a steal.

Was that lithium? At that price, I expected some sort of lead acid.
Edit: They are used

I just expect 50% from lead acid, and it needs charging then, not leaving. It's a general rule of thumb, from EV builders.

I'm talking solar battery chargers. Things complete with battery clamps. They don't need separate charge controllers. This is very common for smaller panels. Maintenance panels, to overcome the internal losses.
These sort of panels are typically for 12v lead acid, or USB. Perhaps never for lithium.