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Cranchi 32 - Dual Alternator Wiring & Changes

Cranch Electrical_1.pdf

Hi all, apologies for the long post but looking for advice on a new set up.


When this boat was built in 2008 I guess flooded wet batteries were the norm and strangely despite it having two fridges, stereo, amplifier etc it was spec'd from the factory with a single 100AH Start Battery and a Single 100AH Service Battery (way too low for a weekend imo). No solar back then and generator was optional which I doubt have.

I naively put in two AGM service batteries in parallel for 2x110AH and they are now in their 4th season and not fairing very well. I moor on a floating berth so no shore power but I do have a single 150W solar panel on a MPPT 100/20, but wasn't really aware that just dropping in AGMs with no mods wasn't ideal and they wouldn't really get charged properly.


2007 Volvo Penta D4-225 with 115A alternators. Looking at the attached electrical diagram I can see that the Port Alternator might be doing nothing, I need to physically check if that dotted line is an actual linked cable to Stbd or not (Q. Any ideas?). The starboard engine/alternator which has the power steering so is normally always running has been wired with an old school battery isolator that appears to have a 1.5mm sense wire and is charging the single start battery and the AGM 2x110AH services bank.

Bow Thruster

I'm not happy with the Bow Thruster being wired into my services bank and have read online that should be on the start battery, would be an easy change to swap over. Also my single start battery has a higher CCA (830). I could if needed put in a second 830CCA Wet VRLA battery for the bow thruster or use it as a combined second start battery/bow thruster battery and then have each engine alternator feeding each start battery Q. Thoughts?

New Set Up

1.) Install a Victron Orion-Tr Smart 12-30 Non Isolated DC to DC converter as a charger for the current AGM services bank (to become LiFEPO4 soonish). Q. If I stick with one start battery, can I pass a new 16mm2 wire from the Port alternator direct to the Orion Input and set it up in AGM Charger mode matched to the specs of my AGM batteries? The largest draw on the services bank would be the windlass which is 800W and factory fused at 63A. The port 115A alternator would then be dedicated to the Orion and Services Bank.

2.) Install a Victron Smart Battery Protect 100A to protect the service bank.

3.) Install a Victron Smart BMV-712 Smart to monitor my system and secondary to start battery

4.) Install a Victron Smart Battery Sense to monitor the voltage and temps of my services bank

5.) Install a new 280W PV Panel and Victron Smart MPPT100/30 wired to services bank and V.E. Networked

6.) Retain my 150W PV panel on its Smart 100/20 that will also be V.E. networked so both controllers can access the battery temp and voltage info, plus adjust charge current as needed.

7.) When I do change to LiFEPO4 it would just be a case of adjusting the parameters on the Orion to Li-Ion.



MPPT Controllersorion-tr smartalternator
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1 Answer
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npm108 answered ·

Anyone have some input on this at all?

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