Expensive mistake. . .new to this forum.
As my Covid project, I converted used Promaster van to a camper last summer, and we have had several short trips, and two month-long trips. Great times. My biggest knowledge deficit was electric, and this forum has provided good reassurance to my beginner efforts
However, I still made one fairly obvious mistake: I didn’t match the solar panels with my all-in-one Inverter/mppt/charger. Here’s my syste
Mpp solar PIP 2724 all-in-one. 24 volt device. Maximum open circuit voltage from panels 60v. Max charging current from panels 25A.
Lyon energy 1300 batteries x 4, 2s2p for 24v. 5280wh. (cost just under $3000 at Costco. I wasn’t quite ready for DIY, but if doing again, would probably build with 280ah cells via this forum etc.)
Microwave/induction cooker/electric kettle all run well from inverter. (not all at once. . .) 24v and 12v separate from all-in-one box also work well. (lights, water pump, elect blanket, fridge, outlets for charging devices, etc)
Rich Solar 200w panels x3. Here’s the mistake: got the 12v panels instead of 24v. When I finished install on the roof of van, (3 in series) open circuit voltage was above 60, which my 2724 correctly recognized, and shut down. Voltage for 12v in parallel too low, so I removed one panel, and we have been traveling fairly happily with 400w on the roof. However, we did come close to running out of juice several times early this spring trying to use tiny heater etc.
I did not hook up to charge from alternator. Not interested for now.
We do have shore power 15A hookup to the all-in-one box, which will charge batteries overnight, but don’t camp with hookups often.
So, I was resigned to continue with 400w on the roof, thinking that only fix would be to change all-in-one device ($600-800 depending on accessories etc), or to buy 3 new Rich Solar 24v panels. ($750).
But, just thought of another fix, for cheaper: How ‘bout buying one new 24v panel, and mounting in parallel with the two current panels? This makes the mistake only cost $240 to fix, and I think would decrease total watts from 600 to about 570?
Current 12v panels (in series): Vmp20.4v, Imp 9.8A, Voc 24.3v.
New panel 24v: Vmp 37.6v, Imp 5.3A, Voc 45.4v.
So, currently MPPT ‘sees’ 40.8v @ 9.8A. If I add 24v panel in parallel to these two, then Mppt should ‘see’ 37.6v @15.1A. This gives me 568 watts, rather than the 600 I would have had if I ordered 3 24v panels in the first place. Maybe a bit of shade tolerance too?
Math check, anyone? Sound ok? Other suggestions?
John in NC
As my Covid project, I converted used Promaster van to a camper last summer, and we have had several short trips, and two month-long trips. Great times. My biggest knowledge deficit was electric, and this forum has provided good reassurance to my beginner efforts
However, I still made one fairly obvious mistake: I didn’t match the solar panels with my all-in-one Inverter/mppt/charger. Here’s my syste
Mpp solar PIP 2724 all-in-one. 24 volt device. Maximum open circuit voltage from panels 60v. Max charging current from panels 25A.
Lyon energy 1300 batteries x 4, 2s2p for 24v. 5280wh. (cost just under $3000 at Costco. I wasn’t quite ready for DIY, but if doing again, would probably build with 280ah cells via this forum etc.)
Microwave/induction cooker/electric kettle all run well from inverter. (not all at once. . .) 24v and 12v separate from all-in-one box also work well. (lights, water pump, elect blanket, fridge, outlets for charging devices, etc)
Rich Solar 200w panels x3. Here’s the mistake: got the 12v panels instead of 24v. When I finished install on the roof of van, (3 in series) open circuit voltage was above 60, which my 2724 correctly recognized, and shut down. Voltage for 12v in parallel too low, so I removed one panel, and we have been traveling fairly happily with 400w on the roof. However, we did come close to running out of juice several times early this spring trying to use tiny heater etc.
I did not hook up to charge from alternator. Not interested for now.
We do have shore power 15A hookup to the all-in-one box, which will charge batteries overnight, but don’t camp with hookups often.
So, I was resigned to continue with 400w on the roof, thinking that only fix would be to change all-in-one device ($600-800 depending on accessories etc), or to buy 3 new Rich Solar 24v panels. ($750).
But, just thought of another fix, for cheaper: How ‘bout buying one new 24v panel, and mounting in parallel with the two current panels? This makes the mistake only cost $240 to fix, and I think would decrease total watts from 600 to about 570?
Current 12v panels (in series): Vmp20.4v, Imp 9.8A, Voc 24.3v.
New panel 24v: Vmp 37.6v, Imp 5.3A, Voc 45.4v.
So, currently MPPT ‘sees’ 40.8v @ 9.8A. If I add 24v panel in parallel to these two, then Mppt should ‘see’ 37.6v @15.1A. This gives me 568 watts, rather than the 600 I would have had if I ordered 3 24v panels in the first place. Maybe a bit of shade tolerance too?
Math check, anyone? Sound ok? Other suggestions?
John in NC