I'm currently designing my solar system for my 45 foot fifth wheel travel trailer. I am going to be living out of the trailer for at least 3-6 months and want to be able to use just about anything I want whenever I want. (I know A/C is a tricky one, but let's ignore that for now).
I currently own 6 200w 12v solar panels with the following specs:
I have decided to purchase at the minimum 2 server rack batteries and highly considering getting 2 more within the next 6 months. (Likely going with the Lifepower since the added features of the LL-ii don't seem justifiable for me).
I like the low amperage of the higher voltage systems, but it does create more problems with having to convert the DC voltage to 12v to run the chassis systems. I was ultimately going to stick with 12v for simplicity reasons and because of solar charge efficiency.
Now correct me if I'm wrong, but the way I figured it out was that a 48 volt battery needs 56 volts to charge meaning that if I were to wire my panels in series/parallel I would only be at 65.4 volts (Voc) at peak output so if my panels drop in efficiency to 88% my batteries wouldn't be able to charge, but in the same scenario with a 12 v battery requiring only 14v to charge my solar panel output could drop to 22% before it would not be able to charge my batteries.
Is this the correct way of looking at it? If so, then to go with 48v I would probably want to wire all the panels in series to bring up the voltage so that my batteries don't lose the ability to charge after dropping only 12% efficiency on my panels. I assume at this higher voltage I would need to use 2 charge controllers since using the Victron charge controller calculator it says they have nothing that will work with 6 of my panels wired in series.
It really doesn't matter to me that I have to use massive wires to ensure a safe system when using 12v, but If it makes sense to go 48v I want to do that out of the gate, I'm just getting a bit overwhelmed trying to make sure I don't screw up the system. Any advice is helpful and I thank you all in advance for your input.
I currently own 6 200w 12v solar panels with the following specs:
- Max Power Output(W): 200W
- Voltage MPP Vmp(V): 18.60V
- Current MPP Imp(A): 10.76A
- Voltage Open Circuit Voc(V): 21.8V
- Short Circuit Current Isc(A): 11.47A
I have decided to purchase at the minimum 2 server rack batteries and highly considering getting 2 more within the next 6 months. (Likely going with the Lifepower since the added features of the LL-ii don't seem justifiable for me).
I like the low amperage of the higher voltage systems, but it does create more problems with having to convert the DC voltage to 12v to run the chassis systems. I was ultimately going to stick with 12v for simplicity reasons and because of solar charge efficiency.
Now correct me if I'm wrong, but the way I figured it out was that a 48 volt battery needs 56 volts to charge meaning that if I were to wire my panels in series/parallel I would only be at 65.4 volts (Voc) at peak output so if my panels drop in efficiency to 88% my batteries wouldn't be able to charge, but in the same scenario with a 12 v battery requiring only 14v to charge my solar panel output could drop to 22% before it would not be able to charge my batteries.
Is this the correct way of looking at it? If so, then to go with 48v I would probably want to wire all the panels in series to bring up the voltage so that my batteries don't lose the ability to charge after dropping only 12% efficiency on my panels. I assume at this higher voltage I would need to use 2 charge controllers since using the Victron charge controller calculator it says they have nothing that will work with 6 of my panels wired in series.
It really doesn't matter to me that I have to use massive wires to ensure a safe system when using 12v, but If it makes sense to go 48v I want to do that out of the gate, I'm just getting a bit overwhelmed trying to make sure I don't screw up the system. Any advice is helpful and I thank you all in advance for your input.