The Great Taiko Electrical Rewiring Project

After months of rumination, research and planning, it was finally time to start on the Great Taiko Electrical Rewiring Project of 2021.  In a nutshell, this involved installing a new Lithium Ion battery bank, a new Victron inverter/charger/monitoring system, all new 120v wiring and switching, and significant upgrading of the alternator charging system and the nav station electrical distribution panel.

Goals for the upgrade:

  1. Design a system that allows us to have power for reasonable off-grid needs, while protecting our ability to reserve enough power to always start the engine in an emergency
  2. Have enough reserve capacity to last 2 – 3 days without needing to run the engine
  3. Have enough charging capacity – alternator, solar, wind – to quickly replenish the batteries as needed
  4. All wiring will be done according to ABYC standards (and hopefully also correspond to European CE guidelines)

First, a little background. Like many older boats, Taiko has a combination of original 80’s-era wiring, as well as various owner upgrades layered on over the years. Per USCG regulations, boats are required to certify that they meet current regulations at the time of construction. These requirements change over the years as the industry matures. Owner upgrades are another matter, and few owners are aware of, or care about, ABYC (American Boat and Yacht Council) standards. These are voluntary industry safety ‘guidelines’ that have been established for the design, construction, maintenance, and repair of recreational boats.

First attempt to diagram and understand the original wiring. After looking closely at this, and knowing that the two big AGMs were shot, it eventually became clear that the entire boat was running from the starter battery, via that little black mystery box at top left – no matter what position the battery selector switch was in.

For the most part, Taiko’s wiring is adequate. The previous owner had made some additions, and generally done a good job. But our two 270Ah group 8 batteries were essentially dead and beyond recovery. In addition, some wiring went down the port side of the bilge, intermingling with the plumbing, while some went down the starboard side. It was functional, but a mess, and very difficult to troubleshoot. For a previous re-plumbing project, I re-routed some of the wiring  from the port side away from the water pipes, but only temporarily – I just re-attached them temporarily on the other side of the bilge.  Now I needed to properly route that wiring, as well as make all new high-current cables for the new battery bank.

After a lot of research, I decided to go with Lithium batteries – specifically LiFePO4 chemistry – from Dakota Lithium. After the difficulty I had removing our two 160 pound group 8 batteries, I chose four 100 Ah group 30 size batteries. Since Lithium gives you the ability to discharge to 20% or even less, for the same size, but less weight, we essentially get more power than when our old batteries were new, and they should last longer if we treat them carefully. It would have been easy to just replace our old bank with drop-in LiFePO4 batteries and call it good. But I wanted to use the opportunity to reconfigure our old wiring. Lithium is also a little more particular about how it’s charged.

Step 1 – Out with the Old

Our totally depleted AGMs. Note the large bulge in the lower one!

Step one was removing the two extremely heavy group 8 batteries. They were wedged in so tightly I had to remove some wiring to be able to get them out. I quickly realized I was not going to get these out with muscle alone. I purchased a cheap electric automotive winch from Harbor Freight, powered by a small 12v battery I usually use for testing mast wiring. I attached this to a piece of 2×6 lumber, and laid it across our saloon hatch.  That allowed me to get both batteries out of the bilge and onto the cabin floor.  I then had to scoot them across the floor to the base of our companionway. I lashed my winch to the boom, which allowed me to very carefully lift both batteries into the cockpit.  From there, I released the mainsheet and traveller allowing me to swing each battery out and over the lifelines onto the dock.  I was so happy I invested in that cheap Harbor Freight winch!

As I removed the batteries, I did my best to diagram my existing system as much as possible, tracing (and labeling) every wire I could find crisscrossing the bilge. I planned on replacing many of these, but some will stay, so it was imperative to understand how the old system was set up.

With the old batteries gone, I needed a way to keep the house voltage going while I waited for my new batteries, and designed and installed my new system. The easy solution was to temporarily replace both banks with a single deep-cycle battery from West Marine.  This wouldn’t keep us going for an extended weekend on the hook, but was sufficient since we are at a dock with constant shore power. And I had a plan for how I would reuse that battery later.

After extensive digging around in our old wiring to make myself a wiring diagram, I discovered that the house and starter banks were essentially in parallel all the time, regardless of the position of the 1/2/All selector switch, and in fact my house was mostly running off the starter battery. (There was also a distinct lack of fuses on many of the wire runs). I knew I wanted a system that would keep my starter battery fully charged at all times, but still allow me plenty of voltage to last for several days off-grid. And having previously experienced an electrical fire at sea, I wanted to be absolutely certain the wiring was fully protected and up to ABYC standards. 

Step 2 – Wiring Diagrams

With the old gone, and a temporary system in place, step two was to create a comprehensive wiring diagram so I could be sure my new system met all my needs, was safe, and up to ABYC standards. 

My research had convinced me that an inverter/charge from Victron would be the heart of the system, supported by a Victron battery monitor and controller.  I especially liked that this system allowed me to configure and monitor status from an app on my phone – either locally via Bluetooth, or even remotely over the Net. 

For my circuit diagrams, I used a program called This can be used either in a web browser, or as a downloaded program for Mac or PC. If you’re familiar with Visio, this is an impressive – and free – alternative that has a lot of functionality. (I also used this for an earlier complete overhaul of my hot/cold freshwater system).  I first used the program to fully diagram my existing electrical and charging system. But rather than patch the existing system, my goal was to build a new system from the ground up. I could use some existing wiring, but would make new wiring runs where necessary – and add appropriate fuses for all wire runs. I built several iterations of the new wiring diagram, improving and tweaking as I went. When I felt like I had a good diagram, I would print it out and examine it, marking up in pencil as I found areas for improvement. I also printed out some of the sample circuit diagrams available from the Victron site, examined these side by side with my evolving diagrams, and made upgrades as I came to better understand the concepts. 

While I was working on my diagram, I also started to slowly procure some of the items I knew I would need. Luckily I have a pro account at a local chandlery, so I was able to get a significant discount on the heart of the system – a Victron Multiplus 3000. This would be supported by a Victron BMV-712 Smart Battery Monitor, and a Color Control GX to monitor and control all of the parts of the system. I also started to get various bus bars and terminal strips I knew I would need as my system design came together. 

My diagram went through several iterations as I came to better visualize how the many parts would work together. My first few versions I printed out on one sheet, but as I added parts this eventually expanded to two landscape pages, which I printed out and taped together. This step was very useful; scrolling around on-screen is ok, but seeing the whole printed allowed me to see areas I had missed, and pencil in missing items to be included on the next version. I would highly recommend this if you undertake a similar upgrade project. While I thought I had a good mental picture of the overall project, these printouts helped greatly in finding bugs and missing items.

Final version of the system. Now to just fit all of that into an 18 inch square!

With a ‘finished’ wiring diagram and most of the components in place, it was tempting to just dive in and start wiring. I think I’m a pretty competent electrician, and do in fact have some formal training, as well as significant experience with boat wiring. But I am not ABYC certified, and I know there are some gaps in my knowledge. I decided it would be a worthwhile investment to consult with a certified Victron technician to go over my design and point out any items I had missed. I was particularly interested in getting advice on proper fusing of the various circuits. As I mentioned, I’ve experienced first-hand a fire at sea caused by faulty wiring, so I wanted a second opinion from an experienced installer before embarking on this project. Since Victron operates on a dealership basis, this would also protect my investment by having a Victron certified support technician sign off on my install, and be available for phone support down the line. By and large, I got most of it right, and he only had a few changes to recommend.

Step 3 – Install

While I waited for my consultation with the Victron-certified technician, there were a number of projects I could get started on. The first was to find a location for the Victron Multiplus unit.

The Victron Multiplus and a case of IPA are the same size. Coincidence? I don’t think so!

The Multiplus is a very heavy item, but as luck would have it, is very close in dimensions to a case of beer – so I was able to take my empty Lagunitas IPA box and try various locations in the boat for size! This proved difficult; it needed to be relatively close to the batteries to avoid long cable runs and voltage loss. I also didn’t want to use up prime closet space. I eventually found a small lower closet with a clear run to the bilge where the batteries will go. This is a little close to the autopilot heading sensor so there’s a possibility of electrical/magnetic interference, but we’ll see if this creates a problem later.  

This is what our home looked like on a regular basis!

I should probably re-name this section ‘Rip our house apart’. The batteries on Taiko are right in the middle of the floor, so there’s no good way to work on them without causing major obstruction. While working on this project, we’re also living here, and May is working from home; making all of those coexist was a constant struggle.

Dry fitting the various parts to see how everything would fit – or not
Our new batteries!

I was now ready to start installing the batteries, but they were still back-ordered. Instead of the four Group 31 batteries, I decided to switch to just two 200Ah Group 8 batteries which were readily available; they turned up 2 days later.

Because of the constraints of the area, I only had a roughly 18 inch square area to fit all of the components – as well as the batteries. It was a puzzle to make everything fit and still be able to run heavy 1/0 and 2/0 wires between the various parts.

I decided to build a box to hold the Lithium batteries, and install all the other components on the lid of this box. For some parts I didn’t have yet, I made cardboard mockups for placement.

It turned out to be a real struggle to get all the parts in that small area; 1/0 and 2/0 gauge cables are not easy to bend around tight corners.

Towards the end of the project I left to help a couple sail their boat from San Diego to Cabo San Lucas, Mexico in the annual Baja Ha-Ha rally. All the parts were in place, and I had switched it on to test, but I didn’t want to leave May to discover any bugs while I was out of the country, so I left her with the temporary setup while I had a blast sailing down the coast of Baja.

Once I returned, I took another week off work to wrap up the install, then rip out all of the old spaghetti wiring from the previous system. The last task was to disconnect the temporary battery and hook the entire house system to my new Lithium batteries.

Shore power showing separate ground busses

After all the work, there was one annoying bug that took some work to solve. Our marina recently upgraded shore power to new ABYC standards. And as soon as I plugged into shore power, I tripped a major breaker that shut down several boats to either side of me! Our helpful marina manager helped me determine it was a ground leakage issue.

But knowing the cause didn’t equate to knowing the source of the leakage. There are two shore power sections on my electrical panel. The water heater and air conditioner are configured to only ever work when we are connected to shore power. All other electrical outlets can work from the inverter, which has a transfer switch to either run from batteries, or shore power if available.

After a lot of Googling, it turned out that the Victron inverter waits a short time to test shore power before passing it through to the house circuits. But the system on shore detects a mis-match between the power on the hot wire and what’s returned on the neutral, and reads that as ground leakage. I popped the shore breaker several times trying to debug this. The solution was to ensure that there was no ground connection between the “shore-only” circuits and the inverter circuits. The diagram here shows a simplified explanation; in reality I needed to significantly rewire the existing 110v, and took the opportunity to improve some marginal and dangerous existing wiring.

So for now I’m going to consider this project ‘done’. There are still things to upgrade and ways to make it better, but as of now we are running full time on the new system. As a final test, we took the boat over to participate in the Alameda Lighted Boat Parade. With the entire rig strung with lights, and lots of cooking down below, we were able to run it all (the engine was running the entire time). I had a generator as backup, but we didn’t need it. The new system kept all that power flowing without problem!

Deck the Hulls …. (Photo by May Leong)

Still To Do

I’m not super happy with my charging system. Since right now my only charging source is either the engine/alternator or shore power, I want to figure out a way to more efficiently charge the house bank.

I need to research and install solar panels to provide our main charging source.

Need to fabricate a plexiglass cover for the 110v section so I don’t accidentally touch any live wires while doing future 12v upgrades.