What's gonna happen?

moonbow

What's gonna happen if I do this......Currently I have (3) 80 watt panels charging 4 large 12V solar batteries. This is adequate to power my lights, music, fan, computer etc at my mountain cabin. I recently built a shower house and my idea is this. I have a nice sized battery that I would like to hook up to my existing array. Is it possible to simply run another set of wires from one of the end panels in my array to the seperate charge controller and battery I have for my showerhouse. Thanks in advance..

BB.

Re: What's gonna happen?

If it is a PWM charge controller (the simple, inexpensive type of charge controller)... Yes, it will work.

If it is a MPPT type charge controller, not a good idea. MPPT controllers play with the voltage and current from the solar array to find the maximum power point (Vmp*Imp=Pmp). Two or more controllers sharing the same array will get confused.

On the other hand, I am not really sure you have enough solar power to fully/properly charge your present battery bank. Do you want to work out the numbers (specific panel Vmp/Imp, battery bank voltage/Amp*Hour rating, loads, etc.)?

I am a fan of a central battery bank and charging setup, and running branch circuits to other places. I am not sure how much you would gain with on solar array charging both the cabin and an outbuilding--Vs just running 12 volts (or 120 VAC from a small AC inverter) to the outbuilding. Is this for lighting or water pumping?

-Bill

moonbow

Re: What's gonna happen?

Hi, Thanks for the prompt reply. Essentially, the cabin is a weekend getaway. The solar generation capabilities are extraordinary, High altitude southern Colorado. I have yet to use my system to even know its limits. Meaning I have never "maxed" it out with use. With the addition of the showerhouse I need pumping capabilities. Probably 5-10 min every use, maybe three times a week during summer/fall. I just went out and looked closely at my solar array. I realized/remembered that my final 80 watt panel purchase was/is actually two 40 watt panels. Now I'm thinking of dedicating one of those 40 W panels to the showerhouse controller and the other 200W to the cabin. Either that or I simply run another set of wires to my non-mppt controller that runs/will run the showerhouse. What makes better sense?

Cariboocoot

Re: What's gonna happen?

What's going to happen is you'll end up with a lot of dead batteries. You can not keep adding battery capacity without increasing array size. You say you already have three "large" 12 Volt batteries on a mere three 80 Watt (240 Watts) panels. I would hazard that you are already getting away with murder by running on deficit charging, slowly depleting battery capacity through premature sulphation. The only reason it hasn't quit is because as of yet the power needs have not exceeded the remaining battery capacity. Once that point is tipped they drop dead rather suddenly.

Have you got any numbers for those "large" batteries?
240 Watts of panel is barely enough for a couple of GC2's (220 Amp hours).