Dont throw that panel yet, Try it first as some of the cheaper panels are terrible with the so called written specks.
As i said just allow for about 6 to 8 actual watts of charging from your 10 watt panel.
Yeh, I will be testing the panel to see what it actually produces, will hook it up to the battery and throw a multimeter on it and see what voltages are being produced. I think you are correct, as it seems a lot like other solar panels that have different pmax etc values.
The controller i have used is like these two on ebay and i find it a good little work horse although not adjustable.
Its a Controller because you have connections for your panel, battery and load so it regulates the panel charge by connecting the panel across the battery until the battery reaches a preset voltage then disconnects it until the voltage drops to a preset voltage then repeats. This continues with the on/off becoming shorter and shorter as the battery reaches full charge hence PWM.
It also monitors the load and cuts power if the voltage drops below 10.5 volts or the current exceeds the allowed amperage of the controller. Not bad for the price.
Solar Panel Charger Controller Regulator 10a 12v/24v Auto Switch CE TSR Safe /t for sale online | eBay
First one has an actual volt meter and both are reported as in Ausrtalia so wait time should be short but now you see what they are have a look.
Awesome, I think I was searching for the wrong term. That first one with the voltage on it seems well worth paying the extra few $s, and I found this one with a USB 5v 1A that could run the arduino. Do you think that one will do the job?
Re the cloudy day and using the panel to detect day/night is the same when using a light sensor, you must set it for the level you need. I mean solar panels do not produce any voltage without a light source so set the ref voltage low to indicate the end of day.
As for cloudy days it pays to allow for a battery that will run your pump over 3 days without any real charging from the panel to be on the safe side.
Think the project through step by step first and then run some tests so you have figures to play with.
- How much water do i need to pump over what period of time for the plants. - 16L for about 30mins
- How long will the pump run for each day. - 3-4 times so 1.5hrs-2hrs
- How many watt hours does this come to and how long will it run on battery alone. 4.2*5 = 8.4 watt hours per day, allow a bit more if the pump uses more that it says, and to take into account the arduino and controller, so 10 watt hours per day. As you said, battery has about 50 usable watt hours, so 5 days on battery should be fine.
- How many watt hours does my panel charge into my battery each day. - On a sunny day lets say its only 6w of the 10w panel and charges (over the winter) 6 hours at full charge. That would be at least 36w on a sunny day. So using 10 or so will be easy done.
You have not mentioned alot about the system you are trying to set up.
Like is this a soil based system where you are irrigating the earth and will stop at a ceriain moisture level then recheck it at a certain time or are we talking full hydroponics where the water must be kept at a certain level and cycled every so often?
More info please.
So it is for lettuce in 50mm pipe. There will be an overflow as well as a slow drain that will drain at half the rate the pump can pump in (excess will go through overflow). I want it empty of water most of the time, from experimenting with a manual one at the moment (that I rock backwards and forwards to fill or empty) I optimally want about 3hrs with no water, 30-40mins with water. On a hot day the roots would dry out faster so I may use a temperature probe to down the empty time to 2hrs (to stop root rot and get oxygen to the roots they need to be out most of the time).
I know I could turn the pump on for less time and put the drain on a solenoid, but by just turning the pump on a bit longer keeps some water flow when it is full and makes less places to break (or at least easier fixes).
There will be 6 rows of about 1m of pipe, plus the (just over 1m) of pipe up ceach side (one the water will go in, the other will drain), so that's a total of about 16L when full. The sump is a 100L storage container, which is what I will fill with water and the nutrients.
So would you suggest that controller? If so, I will order it now, if not, I will get the other one you suggested.