Solar Update ...

[Bob Vento]

The battery has charged for 3 days now and the max voltage reading is 13.6 / 13.8 volts.

As suggested by others ... I will completely run down the battery and recharge it fully again (know as cycling the battery) to see what the max reading is at that point.

I have considered using a timer to fill my grow bed and drain once every hour rather than continuously, thus saving energy and making the solar power system work a little more efficiently. Giving it time to recharge the battery full in between cycles. Then maybe every 2 hours over night.

What do you all think about that?  ... Will I significantly decrease the nutrients and cleaning capabilities of my aquaponic system by doing it this way?

[TCLynx]

Keep in mind that some of your drain on the battery is from the inverter and the timer will have a little draw.

If your pump is only enough to turn over your tank water when running continuously, then by only running the pump on a timer for say 15 minutes each hour will greatly reduce your filtration and thus fish load support capacity.

Here is a blog post I did about how I have my battery backup wiring done (I run my air pump on the battery if the power goes out)

http://www.aquaponiclynx.com/battery-backup

[Bob Vento]

What do most people use for an air pump to get oxygen into the fish tank?

I had read that the falling water from the grow bed and the diverted bypass water spilling into
the fish tank was sufficient to get oxygen into the FT?

Do you also run an aerator or just when the power fails?

[Cory Cramer]

Bob, I've been trying to develop a solar capable system for the past couple years. As part of that development, I've tried to establish the bare minimum required to run a system, and I'd say aeration in the tank is essential, especially as it gets warm outside. I had some wicking bed experiments that I ran last summer where there was almost no filtration, but they were highly aerated. I was certain all the fish were going to die, but I only lost one out of ten goldfish. Conversely, I had another system with media filtration and no in-tank aeration and I lost almost every fish. Both of these were low-flow, or no-flow systems.If there is a constantly running pump and falling water back into the tank, that might be enough, but if you are trying to save energy, I wouldn't skimp on aeration, I would cut back on the flooding cycle and take my chances with filtration, which can be controlled to some extent through your feed regiment.

And to answer you air pump question, I use the one's Sylvia sells here in the AP store.

[George]

It may be sufficient, depending on stocking, feeding and whether or not the falling water is continuous but if that is your only source of aeration and it fails. . . .

I've used cascades only thus far for aeration but with summer approaching will add redundant aeration on separate power source - leaning toward a low wattage submersible pump to spray water back onto the surface.  It's simple, cheap and should be adequate at my place.  As my water warms up, it will hold less oxygen so there is less of a margin of safety.

Bob Vento said:

I had read that the falling water from the grow bed and the diverted bypass water spilling into
the fish tank was sufficient to get oxygen into the FT?

[TCLynx]

I found that last spring I had no extra aeration on my 300 gallon system, only the pump feeding the grow beds and the water falling back into the fish tank.  It was fine until late April and the fish quit eating well.  So I added an air pump to deliver about 1 CFM of air to my 300 gallon fish tank, the fish started eating again.  See Late April last year I think was about when the water started staying near or above 80 F overnight in that system.  I generally leave the air pump on all the time and it is on the battery backup so when the power goes out I also have aeration to keep the fish alive.  So, during cooler months, the water falling back into the fish tank may be enough but come summer in FL, even the tilapia will probably decide they need more aeration in order to feel like eating.

[John R]

I thought I should jump in quick before Bob kills his batteries.  Some batteries like to be cycled very deeply but not lead

acid batteries.  The number of charge/discharge cycles you get out of one is directly dependent on how deeply it's discharged on each cycle.  There are other variables but that is very important.  This page has a lot of information on batteries:

http://www.windsun.com/Batteries/Battery_FAQ.htm

Another thing about batteries is that connecting them in parallel (plus to plus, minus to minus) will almost always result

in one of them never being fully charged.  Two six volt golf cart or other deep discharge battery connected in series is

a much better solution.

[Bob Vento]

John,

Thanks for the heads up on cycling battery issue. Fortunately I had not started the cycling process yet (thanks to procrastination) so my battery is safe.

Bob

John R said:

I thought I should jump in quick before Bob kills his batteries.  Some batteries like to be cycled very deeply but not lead

acid batteries.  The number of charge/discharge cycles you get out of one is directly dependent on how deeply it's discharged on each cycle.  There are other variables but that is very important.  This page has a lot of information on batteries:

http://www.windsun.com/Batteries/Battery_FAQ.htm

Another thing about batteries is that connecting them in parallel (plus to plus, minus to minus) will almost always result

in one of them never being fully charged.  Two six volt golf cart or other deep discharge battery connected in series is

a much better solution.