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Will's Alternator Charging Blueprint: Why this size breaker? (200W System)

tjoiner1986

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Joined
Jan 10, 2022
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83
Location
Sheffield, AL
I'm working from Will's "400 Watt w/ Alternator Charging" blueprint.
  • Panels: Two 100W 12V panels in parallel
  • Charge Controller: Renogy DCC30, instead of 50 (because my panels are only putting out a combined 16.6A at most).
  • Inverter: Giandel 1200W pure sine inverter
  • I've already got a 100A breaker for the inverter because 1200W / 12V = 100A. After the fact, I realized I should multiply that 100 amps by the inverter's listed 90% max. efficiency to get a more accurate current draw of 90 amps.
In the photo below, I'm curious about the 80A breaker to the alternator and the 70A breaker to the charge controller.
Why those values? What variables were combined to get those numbers?

Just trying to get a better understanding of all this rather than asking what I need without ever learning why I need it.

122-fgood_2_orig.jpg
 
Last edited:
Nevermind. I believe I found my answer thanks to this thread:

For my DCC30, which is rated 45A in and 40A out, it looks like I will need a 50A and a 40A breaker.
Renogy DCC30 or 50 Manual_Page_15.jpg
 
Last edited:
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