I am in the process of building my first box truck conversion. Unfortunately, necessity dictated that I set up a system and see how it went after some real world testing. Ideally, I would have all the components I needed to do a proper power audit, but that wasn't possible in my case. So, I started with 4x455W panels, and positioned them as tightly as I could on the roof as to leave room for expansion. It turns out I will need extra power, and I'm in the process of sizing a charge controller for the extra pieces. I have purchased an additional two 455W panels, and after measuring I have room for 2x175W panels next to the roof fans. I left room in my cabinet for a single extra charge controller, and I'm having difficulty with the math using mismatched panels. Before I make a costly mistake, I want to ask folks here for their opinion.

Specs:

- Power: 455W
- Maximum Voltage (VMP): 41.51 V
- Maximum Power Current (IMP): 10.96 A
- Open Circuit Voltage (VOC): 49.35 V
- Short Circuit Current (ISC): 11.44 A
- Maximum Fuse Rating: 20 A

- Power: 175W
- Optimum Operating Voltage: 18.1 V
- Open Circuit Voltage: 21.6V
- Short Circuit Current: 10.31 A
- Optimum Operating Current: 9.67 A
- Maximum Fuse Rating: 20 A

- Solar Array Wattage:
**1820W** - Temperature Compensated Array Voltage:
**123V** - Controller Output Amperage:
**63A** - Array Short Circuit Amperage:
**21.92A** - Max Series Fuse Rating:
**20A**

- Max power output: 1220.55W
- Max power voltage (Vmp): 63.11V
- Max power current (Imp): 19.34A
- Loss: 8.07%

- Max power output: 1819.8W
- Max power voltage (Vmp): 83.02V
- Max power current (Imp): 21.92A
- Loss: 0%