12V systems Upgrade

12V Systems Upgrade

Note - the photo below shows the battery monitor shunt wired neatly but incorrectly.  Not sure how I managed that but it was corrected long ago.  

Update Aug. 2019.

Having spent some time with the changes below I will add a few thoughts:

• Its worth really understanding the ACR, and also realizing that the instructions provided by blueseas are a bit misleading for boats with larger housebanks.    There is really good material on this (and many other topics here:   https://marinehowto.com/automatic-charging-relays/
• The dedicated USB charger isn't necessary with so many plug-in vehicle options now available.  Just install or use a lighter socket. 
•  The approach taken below only provides for monitoring the house bank, and it can be useful to observe the voltage of the start battery as well.   There is a version of the Victron battery monitor that provides this information, though the model I chose monitors the house bank only.   The usefulness of this information became clear on a multi-day cruise at the cost of $140 in unintended marina (meaning shore power)  fees and time spent  troubleshooting a pre-existing alternator charging issue, one which I could easily have fixed before I left.  

State of the art, c 1985

When acquired, Windstar's 12v system consisted of the following:

• Period-typical selector switch.
• 2ea group 31 flooded type, deep cycle batteries, configured as batteries 1 and 2. (130AH ea) located under the quarterberth.
• Decent toggle-breaker panel with an unlabeled analog voltmeter and a car lighter socket (with lighter.)
• Battery and fuel tank grounds to the transmission bolts.
• Engine harness ground per factory practice to the bracket on the back of the starter. (had become intermittent.)
• Engine control panel ground to the back of the fuel tank gauge.  Also had become intermittent because the ring terminal type used made it difficult to tighten the mounting stud nut.
• Stock 55a Hitachi Alternator.

With the following accessories:

• Blaupunkt Cassette player, Ray VHF, B&G Hunter Depth and Speed.
• Xantrex smart shore power charger.
• Novacool Refrigerator (dealer or factory option? Added Wiring was poorly done) -
• misc wires run added here and there for 12 auto connector to cockpit, handheld GPS, Loran, Astrolabe, whatever...

So, while the 33-ii's 12V system was at the upper end of typical on a stock production boat in its day, it had not been upgraded since, and had had only a few accessories added. These accessories had been mostly wired in an amateurish but functional way.
After two seasons of use, I realized that I wanted to address the following:

• excess and unused wiring in a few places.  (coiled, taped, lying loose)
• substandard terminations.
• areas of potential chafe that could become problematic.
• location of the 100A toggle breaker for the 12v panel,  in the nav station footwell, where it was regularly kicked to the off position.
• no indication of the impact on the state of charge of the 130AH group 31 house battery. 
• inline glass fuses in various hidden locations.
• lack of visibility to any 24/7 circuits. 
• missed potential.  Only able to use 50% of deep cycle capacity while protecting one battery for engine use.

A couple of intermittent grounds raised the project to a higher priority, as did my discomfort with using the autopilot and the fridge extensively while sailing or at anchor.

After some discussion with others and some self-education I determined that I would:

• Add battery monitoring capability.   I selected the  Victron BMV-700 which fits in existing voltmeter hole.   Very simple, and compact, it was the most cost effective unit for my purposes.
• Add a group 24 start battery and connect the existing pair of Group 31 deep cycle batteries in parallel at the battery switch. ( On the 33-2 there is very little space to increase battery capacity, and this is one of the biggest challenges in this boat when considering an additional battery, or larger batteries.)
• Revise the grounding to a clearly-marked and easily-understood buss configuration. (this was partly necessitated by the need to install a ground shunt for the battery monitor.)  Installed a Blue Sea 2127 bus bar.
• Add fusing to house bank battery terminals. Blue Sea 2151 dual MRBF.   Clever solution.
• Replace the existing selector switch with a Blue Sea 8690 battery management panel.   This thing is very well thought out and is worth a close look.
• Add a Blue Sea Systems 7601 M-ACR.   Also known as a VSR (voltage sensitive relay).  See below for explanation of its function.
• Add a 12v USB charger. (OK, scope creep, but very useful)    Blue Sea 1045.
• Clean and protect all ground points.
• Label EVERYTHING.
• Secure all wires and protect from chafe.
• I did not upgrade or modify the alternator and I did not add isolating diodes to the batteries.   (Research determined that the output of my 55A alternator was appropriate for the rate of charge reasonably accepted by my 260AH house battery bank,and that a smart regulator was really not needed.   Diode type battery isolators,(were recommended by one DC standby power systems designer I know) but are not required with my Blueseas switch/ACR combo, which isolates the batteries by design.)

As of July 2016, this work is complete.   I ended up to re-routing several wires, and re-securing harness bundles with larger clamps, as well as revising some grounding.   All good, and much less "spaghetti" greets the eyes.   Took a long time to do, but the intimacy with all aspects of the wiring is worthwhile and the result is more orderly and bulletproof.    Most terminals were crimped and soldered with clear heat shrink applied atop the termination to provide strain relief.

So, what's left?

Not much.     This project has made me pause and think through the idea of a remote key, mounted on the battery management panel, below the ACR  is panel, eliminating the exposed location in the cockpit.   More scope creep, but another irritant and failure-source removed.  This will take some more thought.  Gonna go sailing.




Ground bus on the left and battery monitor shunt on the right.  I had some extra cable and lugs so I grounded the engine to the bus via two cables, not just one.   At the bottom right of the image above you can see the bracket upon which is mounted a large bolt that serves as the harness ground.   This bolt can oxidize over time and the connection can become intermittent or resistive, resulting in my case with a dead tach and intermittent starting issues.   - Look closely at the above image, bottom right.    You will see a bracket that secures the shift cable.    Forward of the cable you see a clamp that secures the wiring harness, and below that you see the threaded portion of a machine bolt that secures not only that clamp, but the wiring harness ground, to the engine.   This is a key grounding point that should be inspected periodically and protected from damage and corrosion.   

It is easiest to remove the entire top of the engine box when doing any work at all.  

The only place in the entire boat I could happily fit a group 24 start battery.   It is mounted on an Aluminum shelf, bolted through the bulkhead which forms the forward end of the fuel tank base.

Essentially stock panel except the upper section has been replaced with 3/16 acrylic, wetsanded with 400grit for a satin finish.  The BMV700 replaces the original analog voltmeter and the USB charger can be seen on the same panel.  A few of the breakers have been replaced with correctly-sized units. 

The upgraded battery management panel is on the left.  This is a very well thought out unit which allows the use of a house battery and start battery simultaneously yet isolated from one another, OR if required they can be combined for an emergency start.  You can see 5 bays in which you can install additional switches or breakers.  In Windstar, these are being used to eliminate the glass fuses that seem to lurk, hidden in every boat.  Note the two on the left.  These are actually rocker breakers that can be operated like switches.  They are flush in the on position so cannot be accidentally nudged to the off position.   Cool!

The circular unit above right is the ACR.  This device essentially combines the batteries when a charge source is present, but isolates them otherwise.  Explanation below.

"The Voltage Sensitive Relay (VSR) allows two batteries to be charged at the same time. When the engine is started and the start battery reaches 13.7 volts, the VSR engages, allowing two battery banks (start and house) to be charged simultaneously. When the voltage drops below 12.8 volts (engine is stopped), the VSR disengages, separating the batteries.
This system eliminates the possibility of draining the start battery and protects sensitive electronics powered by the house battery from harmful engine start up spikes. Dual sensing allows the relay to sense the voltage of both batteries, activating if either is receiving a charge. Designed for systems where a battery charger or second charging source is connected to the house battery."

The access port was added to facilitate pulling wires from the panel down to the engine compartment.