Need help choosing a solar controller
I have 6, 53 watt Siemens panels I am going to use to keep 4 100amp batteries charged up at my cabin. I am looking for some help picking a 30 amp controller suitable for the job. I looked on ebay ...
Forum Discussion
You will want the controller to recharge your usage while at the cabin, then you will want it to "maintain" the batteries while you are not there (Float them)
You can get a controller with a single adjustable voltage. Pick that high, like 14.8 for while there and then re-set it at say 13.4 for floating before going home.
Or you can get a controller with two adjustable voltages, so after it gets to 14.8 or whatever, it drops to 13.4 or whatever by itself whichever voltages you choose.
Your expected amps is maybe 20a with that total wattage. You need a controller that will not overheat at 20amps. You must have margin above 20 so 25 or 30 is good for that. Or with some controllers, they clip the amps to their rating size and will not overheat at that max rating, so you could pick a 20a one of those and be ok.
I have a 20a MPPT Eco-Worthy that is about $102 US that has two adjustable voltages. I also have a Solar30 PWM with one adjustable voltage that is about $35. Either would do the job.
I suggest getting one like these with a read-out display for your settings and not go cheaper with a $20 job that has no display and no adjustable voltage. ( it would work, sort of, but for a few dollars more you get so much more)
A factor in all this is wiring gauges. Some set-ups need fatter wire to use PWM at 12v than 24v MPPT would need. The difference in wiring cost might narrow the gap between PWM and MPPT controllers.
The MPPT will give a few more amps than the PWM but for your cabin application, who cares? Pretend they will do the same thing and look at the other factors like the wiring or whatever.
You can get a controller with a single adjustable voltage. Pick that high, like 14.8 for while there and then re-set it at say 13.4 for floating before going home.
Or you can get a controller with two adjustable voltages, so after it gets to 14.8 or whatever, it drops to 13.4 or whatever by itself whichever voltages you choose.
Your expected amps is maybe 20a with that total wattage. You need a controller that will not overheat at 20amps. You must have margin above 20 so 25 or 30 is good for that. Or with some controllers, they clip the amps to their rating size and will not overheat at that max rating, so you could pick a 20a one of those and be ok.
I have a 20a MPPT Eco-Worthy that is about $102 US that has two adjustable voltages. I also have a Solar30 PWM with one adjustable voltage that is about $35. Either would do the job.
I suggest getting one like these with a read-out display for your settings and not go cheaper with a $20 job that has no display and no adjustable voltage. ( it would work, sort of, but for a few dollars more you get so much more)
A factor in all this is wiring gauges. Some set-ups need fatter wire to use PWM at 12v than 24v MPPT would need. The difference in wiring cost might narrow the gap between PWM and MPPT controllers.
The MPPT will give a few more amps than the PWM but for your cabin application, who cares? Pretend they will do the same thing and look at the other factors like the wiring or whatever.
