Ok everyone, so im a new to engineering and we have to complete a prototype design and I want to build a aquaponics fish farm that is run by solar panels. I have three 7v solar panels that peak at 1.2 watts. I want to wire them in parallel or series whichever will do the trick so a assortment of 9v rechargable battery's with a controller to stop them from overcharging. I need them to to hold enough power to run my water pump at a constant 9 volts for at least 6 hours. How many batteries do I need and are these solar panels sufficient to charge them? If not what would I need? And does anyone have any resources I can look up on how to construct such a battery system? Thanks for any advice and help!

 

How much current does your pump draw?

 

How much current does your pump draw?

It a 7v pump the solar panel came with the pump.

 

It a 7v pump the solar panel came with the pump.

I believe the question was "how much current does your pump draw?" without this information no one can tell you what size batteries might be required or whether the solar panel can produce enough energy to charge them sufficiently.

 

It sounds like you do not have the electrical specs on the pump. Have you considered determining your pumps current requirements through prototyping ? A bench power supply with current limiting capabilities and a multimeter can help you determine how much input power will be required to make the pump work satisfactory. With that testing completed your design requirements may change from your findings. I have always found it beneficial to test my substems for proper operation and then again when the subsystems are integrated into the final product. Hope these ideas help!

 

https://www.google.com/search?q=discharge+depth+extending+load+cycles
reveals Table 2: Cycle life as a function of depth of discharge.

 

... I want to build a aquaponics fish farm that is run by solar panels. I have three 7v solar panels that peak at 1.2 watts.

One watt of power won't move much water. Before we talk about solving the electrical problems, can you verify that your system is so small that 1W of pump power is even useful? Even an aerator will likely need more power than that. My cats have a water fountain with a little pump to keep the water moving. I'll bet even that little trickle uses more than 1W.

 

One watt of power won't move much water.

There are three panels so that's 3.6W but it's still not much.