DIY Manual

20 | P a g e 10-543-1 REV A
DIY Manual
Conclusion:
• 8000W of PV is needed. Take that up to 10,000W for losses.
• 29 panels are needed. With 3 in series and 5 strings per Classic, round 29 up to 30
panels total.
• 15 panels per Classic 150.
• You need two Classic 150s (Use Follow-Me for charge coordination).
Selecting the Right Combiner
A combiner box is used to combine, or parallel, PV strings together. A combiner electrically
combines multiple PV strings and makes one PV output.
COMBINER EXAMPLE:
From the previous exercise above, we know the following PV details:
• 3 panels in series at 117V
• String current is 9A
• 5 strings to combine
So, which combiner is best for this install?
1. The combiner needs to hold 5 circuit breakers.
a. MNPV6 Combiner holds up to 6.
2. The circuit breaker needs to safely handle 117V.
a. The MNEPV breakers are rated to 150VDC.
b. The MNEPV-300 breaker is rated to 300VDC.
3. The circuit breaker needs to safely handle 11.25A (9A of Isc x 1.25 (per NEC) = 11.25A).
a. The MNEPV15 is correct.
Answer – the MidNite Solar MNPV6 combiner, with 5x the MNEPV15 circuit breakers (stock
MNPV6 picture below shows with 6 breakers).
The MidNite MNPV3 Combiner - shown on left with 3 DC
circuit breakers with the combining busbar at the top,
connecting the PV strings into one output. The MNEPV series
breaker is the most popular way to combine strings up to
300VDC. The picture on the right shows the MNPV3 with
1000V fuseholders and a combining busbar. DO NOT open a
fuseholder under load (when passing current).