Wiring MPPT to Perko battery Selector switch to charge 2 batteries

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erikdane asked Nov 28, '20

Wiring MPPT to Perko battery Selector switch to charge 2 batteries

Trying to set up solar on my sailboat. I have 2 12v batteries which are currently set up to be charged either by 110 shore power or the engine alternator, which goes to a Perko 1/2/ALL/Off selector switch.

My solar set up will be a 175W Renology panel, and the Victron 75/15 MPPT controller.

I'm trying to set it up so the panel/mppt would charge both batteries. Rather than get the Victron battery combiner or a separate ACR, i'm wondering if i can just connect the MPPT battery wire to the Perko selector switch where the alternator is currently connected. Any pros/cons to this type of set up?

My thinking is that the selector switch is basically a manual ACR, so it would simplify things if i didn't need an extra.

Attached is a diagram of how i'm envisioning this.

Thank you!

MPPT Controllers

battery-wiring-set-up-v2001.jpeg (630.3 KiB)

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oceanwolfe commented · Dec 02, 2020 at 08:11 PM

ErikDane,

I'm new to the solar array additions to boats so I'm hoping to learn something here. It looks like you chose to use a 75W mppt controller to regulate a 175W panel. I thought the controller needed to be at least as large as the panel max output. Won't that fry you controller?

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Answer 1 · 2020-11-28T15:07:52Z

randy-putnam answered · Nov 28, 2020 at 03:07 PM

Here’s my setup. My MPPT is wired to the house bank battery positive and neg/ground. Both the engine battery and house banks are connected to the “1” (engine battery) and “2” (house bank) of the Perko 1-2-All-Off switch. I installed a Blue Sea ACR between both banks (Positives of both batteries). I can use either battery bank with this set up or combine both. When I combine both at anchor (no shore power and engine off) the solar panels charge both banks. Next year I’m going to LiFePO4 house bank and want to protect the alternator with a DC/DC charger off the FLA engine battery, but the MPPT will still be charging the new LFP house bank. I’m replacing the Perko with a Blue Sea switch because the Blue Sea will be more “built in” to my panel. No other reason than that.

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