MPPT Controllers
As I continue the learning curve, I'm finding the answers I get always lead to 2 more questions... funny how that is... I've been working backwards in developing my solar needs, going from panels t...
Forum Discussion
take the sizing rules with a grain of salt. they were made up when solar panels were 30X the price you can get them now and are a minimum requirment to get you somthing that will work. when I now plan a system I go for a bigger controler for future upgrades, and as much pannel as I can afford and or have room for.
on my new camper I went with the renogy rover 40 amp mppt controler, and since I am running a 24V 325 watt pannel that is only about 1/4 if its capacity, but I wont be running any 110 stuff for now and I have room to add one more panel if I find I need it. this is going to charge 210AH of 6V GC batteries.
what my theory is now, is why wouldnt you want to charge the batteries as fast as you can so the panels can supply more of the house load during the day. I like to size my batteries at 4x or more of my daily AH usage (not sure if i can do it in the camper with out going to homemade li batteries) my 5th wheel is set up at 6-7X. so I can go 6 or 7 days in total darkness with out losing power, but when that cloud breaks I want that battery charged up as much and as fast as it can be.
for example the new system I am putting on the camper has the potential at 70% output due to where I am to put 93 ah back into my battery a day based on 6 hours. I cant see my camper using more than 40AH over night for furnace and such.
my 5th has 480 watts of 12v panels on a PWM and I cant see it putting much more than 105 amps on a good day, so that one is slated for a controler and panel upgrade eventualy
if you only have one panel now, might be time to thing about selling that panel along with your old controler to some one who just bought something and take advantage of that MPPT controler you are thinking about by going with 24V panels. I just got that 120 split cell 24V 325 watt panel for 200 cdn so would probably be in that 150ish US range. two of thoes and a deicent mppt controler would probably rock. My 40 amp controler can run 3 of these panels.
just some more to think about..
Steve
on my new camper I went with the renogy rover 40 amp mppt controler, and since I am running a 24V 325 watt pannel that is only about 1/4 if its capacity, but I wont be running any 110 stuff for now and I have room to add one more panel if I find I need it. this is going to charge 210AH of 6V GC batteries.
what my theory is now, is why wouldnt you want to charge the batteries as fast as you can so the panels can supply more of the house load during the day. I like to size my batteries at 4x or more of my daily AH usage (not sure if i can do it in the camper with out going to homemade li batteries) my 5th wheel is set up at 6-7X. so I can go 6 or 7 days in total darkness with out losing power, but when that cloud breaks I want that battery charged up as much and as fast as it can be.
for example the new system I am putting on the camper has the potential at 70% output due to where I am to put 93 ah back into my battery a day based on 6 hours. I cant see my camper using more than 40AH over night for furnace and such.
my 5th has 480 watts of 12v panels on a PWM and I cant see it putting much more than 105 amps on a good day, so that one is slated for a controler and panel upgrade eventualy
if you only have one panel now, might be time to thing about selling that panel along with your old controler to some one who just bought something and take advantage of that MPPT controler you are thinking about by going with 24V panels. I just got that 120 split cell 24V 325 watt panel for 200 cdn so would probably be in that 150ish US range. two of thoes and a deicent mppt controler would probably rock. My 40 amp controler can run 3 of these panels.
just some more to think about..
Steve
