panel mixing

[daPA]

Recently I bought a 35 watt 12v solar panel, I have a small pond pump 5 watt panel that supposedly is 12v as well. I wanted to combine and use both of these panels for an off grid application with charging to a 12 volt battery.

I want to install these in parallel to keep the voltages the same, I know that I will lose some output wattage due to connecting/mixing panels of different amps. My confusion comes in on how to connect them together, what is the best possible way. I read the best way to combine different panels with an additional controller, which makes me think if its even worth it.

I could plug the 5 watt into one controller and the 35 watt into the other then run the wires from both controllers to the 12v battery. This seems a little excessive for what am doing but im looking for a safe way to do this and get the most watt output possible.

Also these panels are mounted on a fence post, the post is obviously in the ground, should I be grounding any of the other components ? Im assuming since the post is in the ground that its grounded and so I are the panels attached to it via a metal bracket?

My last question is where should the load plug into, I know the charge controllers have a load terminal, but if I want to plug in more then one load I read that I should be connecting directly to the battery, is this correct? I know I might need a bus terminal for multiple loads, correct?

I would appreciate any responses and thoughts to this, this is my 1^st time doing something like this and I want to get it jut right.
Thanks, Paul

[bcroe]

If both those panels are 12V battery panels, check if the Vmps are fairly close. If
so you could just wire them in parallel to make a 40 watt panel. Bruce Roe

[littleharbor]

No problem in parallel provided the voltage of both panels is within 10% of each other.

I recommend you pretend the load output terminals aren't even there. They are for controlling a light, turning it on and off at preprogrammed times. They will also disconnect the load if your battery becomes overly depleted. Problem is the load terminals are designed for small loads. You can use them if you want to control a small light circuit but otherwise leave them alone.

[Mike90250]

If you still have the manual for the charge controller, look up what sort of power the LOAD terminals can manage. If your pump power is less than the LOAD spec, you could use the load terminals to protect your battery from over-discharge.

Not knowing the power consumption of the pump, makes it difficult to calculate how long things will run

[daPA]

thanks for the great responses, instead of connecting the panels together in parallel can i just connect them together at the charge controller terminals? the problem is on the 5w panel, its a LEDGLE 5W Solar Fountain Pump and I have no idea what the amps or Vmps are i know its a 12V 5W panel, Im assuming for china and the specs are about the same for all 5W panels?

thanks, P

[bcroe]

You can get a pretty good idea of the panel voltage, just measure it open
circuit in good sun. The Vmax power will be around 80% of that.
Bruce Roe