The Offshore Voyaging Reference Site

Tips, Tricks & Thoughts:

electrical

  • No, Lithium Batteries Don’t Burn Boats

    Every so often, someone sends me a link to this article, originally published in Professional Boat Builder and repeated at Sailing Anarchy, that starts with the line:

    Lithium-ion batteries start fires.

    First off, the author does not differentiate between lithium cobalt oxide (the battery type in your phone) and lithium iron phosphate (LiFePO), the chemistry generally used for service batteries on boats, which is much safer and less volatile.

    In fact, recently, ABYC tried to set one of the latter types on fire and had no luck.

    Second, he goes on to say that a large number of boat fires are caused by batteries.

    I don’t think that’s true.

    What I would agree to is that a large percentage of fires on boats are caused by poorly designed and installed electrical systems, and that includes those installed by the “professionals”:

    The electrical system on our new-to-us J/109, as installed by the builder in 2004, was a fire looking for a place to happen, mainly because of inadequate fusing.

    And then in the years after she was built and before we bought the boat and rebuilt the electrical system, “professionals” had made the fire risk far worse with stupid changes and additions.

    This is a distressingly common situation, and don’t make the mistake of thinking that just because your boat has passed survey that the electrical system is safe. Ours did and wasn’t.

    And don’t get me started on the dangers of electrical systems designed and installed by boat owners who watch a few YouTube videos, source lithium cells from some vendor on eBay, and have at it.

    So to me, the correct statement is:

    Lithium batteries don’t burn boats, poor battery and electrical installations burn boats, regardless of battery chemistry.

    Me

    I have written a lot more about this in this Online Book, including how to decide if lithium batteries are right for your boat:


  • Sneaky Power Users

    We were on the boat for a couple of days last weekend and one evening I decided to check email and the weather on my iPad.

    But when I picked it up, it turned out I had forgotten to charge it—it was as dead as John Cleese’s parrot.

    Not a problem, we have a USB charging port on the boat and a USB C (it’s a newish iPad) cable.

    I plugged in the iPad and, since this had reminded me, my iPhone 13, then at about 50% charge, into a different port.

    The photo at the top of the Tip shows the total current draw before plugging in these devices:

    • Five LED lights on below,
    • AIS with drag alarm,
    • propane sniffer,
    • boat monitoring system,
    • and two anchor lights
      • will be another Tip and is why the radar is on (in standby).

    The photo below shows current with both devices charging, and no other changes.

    Yikes, these two handheld devices are drawing 3.5 amps at 12 volts, or 160% of what it takes to power a small boat at anchor at night.

    Yes, I know, in a couple of hours or so both devices will be fully charged and only require a trickle of amps to keep them there.

    Still, suppose Phyllis charged her iPad and iPhone, too, and then maybe we have guests with devices, and then there’s the iPad we use for navigation. And many boats have one or two laptops…

    It’s stuff like this, albeit not by itself, but added to other sneaky users of amps, that push cruisers into expensive electrical system upgrades including: excessive arrays of solar panels and/or the clutter, noise, and weight of wind turbines; or a generator.

    Worth thinking about.


  • Good LED Steaming/Deck Light

    We fitted a MarineBeam LED Steaming/Deck Light on the mast on our J/109 a year ago, and so far I’m impressed.

    Small, light, relatively inexpensive, and amazingly bright, with incredibly low current draw.

    Of course we don’t know how reliable it will be over time, but so far so good.

    By the way, I have never used deck lights at sea. Too dazzling and disorienting, and, worst of all, our own bodies throw shadows just where we want to see. Much prefer, and recommend, head lamps.

    The primary reason we have a deck light is to reduce the risk of someone running into us because they did not look up and see our masthead anchor light. Yes, it happens.


  • Tidy Up The Wiring

    One of the most satisfying jobs we can do in a refit is to simply tidy up the wiring.

    I took the above picture a few days ago. Certainly not perfect, and not as nice as I could do if I tore the whole works out and started again, but a heck of a lot better and easier to troubleshoot than it was when we got the boat two years ago.

    Everything is now properly fused and labeled, and I also must have taken 50 pounds of unused or over-length wire out of the boat.

    Cleaning up gave me space to move the AIS that some lazy tech had installed in the head to where it belongs, and to install a boat monitoring gadget (far left)—more on that coming in an article.

    And best of all the high-voltage wiring is now safely covered. Here’s how.

    And here’s a pic of the dog’s breakfast I started off with when we got the boat.

    Much more on electrical systems.


  • Battle Born Batteries Get The Memo

    Great to see that one of the largest vendors of lithium batteries has finally got wise to the fact that when used on boats, lithium batteries with an internal BMS must be able to communicate with external devices and the user to be safe and compliant.

    That said, Battle Born are making a lot of noise about the phone app (user communications) but are ominously quiet about CAN bus communication, which is the best way to manage a safe and functional marine installation.

    However, given that Dragonfly, the parent company of Battle Born (not to be confused with Firefly Batteries), bought Wakespeed last year, hopefully Al Thomason, designer of the best alternator regulator out there, the WS5000, will pull levers behind the scenes to make sure they actually do this right, rather than just produce a pretty phone app to bamboozle the non-technical.

    One other point, Battle Born are making a big deal out of now being ABYC compliant with this announcement, but kind of glossing over the fact that, as I read the standard, all of the tens of thousands (guess) of batteries they have sold to yachties over the years without these features are not compliant.

    I wonder how long it will be before insurance companies start requiring ABYC E-13 compliance before renewal? Could be a lot of secondhand Battle Born batteries looking for a home, and some very pissed off boat owners.

    Seems to me that the very least Battle Born should do is offer a very nice discount on the new batteries to anyone who bought the old batteries, say in the last two years. Some sort of trade-in would be even better. Heck, maybe they could even upgrade the old batteries with the new communications technology.

    Anyway, moral of the story: Don’t buy batteries with an internal BMS that can’t communicate with charging sources or warn you before things go wrong.


  • Recommended Deck Wiring Glands

    I have a pathological hatred for drilling holes in the deck of our boat, but sometimes it’s unavoidable, and when it is I’m guided by a healthy dose of deck-leak paranoia—it only takes one passage with a leak over your bunk to instill said condition for life.

    The cables in the shot will be under the instrument pod, but even so I wanted them properly waterproof, since green water hitting the pod would definitely find a way in—see…paranoid.

    These glands from Scanstrut are the best I have used. Multiple sizes and styles and each comes with several seals with different-sized holes and even a blank in case we need a custom size as I did on the one on the right.

    Highly recommended.

    And if you are wondering how I built the little shelf for them, here’s the hack.

    Now all I have to do is get over my case of the sulks at Tillotson Pearson for building a boat with a nice instrument pod and then not providing a sensible way to get wires to it. I ask you.

    This is the kind of stupid, but far too common shit we want to fix with the Adventure 40.


  • Wire Routing Hack

    I have been running a bunch of new cables up to the instrument pod on our new-to-us J/109 while installing a better on-deck navigation system, including radar.

    The cables run through the head under some trim in a very tight space with no room for wire ties, and they needed to stay put while I got the trim back on.

    The answer was a hot glue gun. Worked a treat as you can see in the above photos and only took a few minutes.

    I bought a low-temperature gun (100c) to avoid any risk of melting the insulation on the cables (105c).


  • While Converting To Lithium

    Member Rob sent us the above photo of the very cool (in more ways than one) equipment and battery bay he and his installer built in the aft cabin of his 2002 Beneteau Oceanis 473 while they were changing the boat over to a lithium house (service) bank.

    Prior to that change, as is so often the case with productions boats, the batteries were in much less functional positions, too low in the bilge and subject to engine heat.

    This brings to mind two thoughts:

    • Lithium battery systems are way more fragile and complicated than lead-acid, so when making the change we want to make sure everything is well away from the engine, well ventilated, and easy to access, as well as laid out in an organized way to make troubleshooting easier.
    • Lithium batteries are about four times lighter and three times smaller than lead acid for a given usable capacity, so improving location and installation is way easier than it would be with lead acid.

    Does this make changing to lithium a no-brainer for everyone? No. Here’s how to decide if lithium is right for you.

    For those of you who want to nerd-out, Rob was kind enough to provide the following details on the photo:

    Equipment from forward to aft in this locker under the starboard quarter berth (forward = bottom of picture):

    • Two Damp Rid containers in process of being changed and secured with cable ties
    • 3 x LiFePO4 batteries secured with truck-style ratchet tie-downs
    • 3 x Blue Sea safety relays https://www.bluesea.com/products/7700/ML-RBS_Remote_Battery_Switch_with_Manual_Control_-_12V_DC_500A
    • 3 x high-capacity fuses
    • At right slightly out of picture on longitudinal bulkhead, MasterBus interfaces
    • Hidden behind bunk crossbeam is the mains 240V residual current device (RCD)
    • Top right is the MV shore-power charger and inverter Mass Combi Pro
    • Top left are the two MV solar controllers
    • Out of picture and the other side of the boat is the MV AlphaPro regulator connected to MV 130A alternator

  • Answer to Electrical Quiz

    The Answer

    A bit over a week ago I posted an electrical quiz question.

    A couple of members came close in the comments, but no one got it exactly right.

    Answer

    I had the volt meter connected between a reference anode, immersed in the water next to the boat, and the boat’s bond system, and was looking to see if the meter kicked when I disconnected and reconnected loads and charging sources from the main positive busbar.

    If the boat had been metal I would have been connected to the reference anode and the hull.

    The clues to the right answer were that I was measuring volts, not amps or continuity, and that neither of the meter probes are present in the picture.

    I’m pleased to say there was no kick, but if there had been, that would have indicated stray currents flowing from the battery positive, through the connected piece of gear, through the water, and back to the bond system, and eventually the battery negative—we must always think about circuits.

    This is a good test to perform regularly on any boat and that goes triple for metal boast and those with saildrives.

    Further Reading


  • Instrument Loads

    Seems like a lot of cruisers are leaving their instrumentation on, even when at anchor, these days.

    Do what you want, but this practice could push you into a major electrical system makeover that might not be necessary if we just turned that stuff off.

    The above photo shows the load (battery monitor to the right) from the instrument package and NMEA 2000 network on our J/109, added to a 9″ plotter.

    Nearly two amps at 12 volts. Leave that on for 24 hours and that’s nearly 50 amp hours out of the battery!

    And our system is comparatively small and miserly. Add in a big plotter, AIS, and worst off all, a laptop computer running navigation software, and we can easily burn through 100 amp hours or more.

    To put that in perspective that’s over a third of the power Phyllis and I used in the run of a day for everything on our 56 foot live-aboard boat!

    When left on all the time, small loads add up to big usage.

    Here’s how to estimate usage and choose the right battery bank size, the easy way—no long boring spreadsheet to fill out…we provide a short, and not boring, spreadsheet.


  • A very bad place to put a solar panel

    Seriously? One wave strike, or even a gale, and this will end very badly. More on why we should not do stuff like this, at least if we plan to go offshore.


  • Electrical Quiz

    Quiz is closed, here’s the answer.

    Why am I methodically disconnecting each load from the battery, and then reconnecting it while looking at a volt meter? And what’s the meter connected to?

    Answer in the comments:

    First right answer wins an Adventure 40 T-shirt.


  • Gel Batteries a Winner?

    While researching for an upcoming article I noticed something interesting:

    Victron rate their Long Life Gel batteries at 2500 50% cycles, as against their AGM Super Cycle Battery at 1000 cycles, and not a lot less than their much more expensive lithium batteries at 3000 cycles.

    Could it be that the pivot away from gel cells toward AGM that occurred in the sailing community some 20 years ago was a giant mistake?

    I do know that both members Dick and Ginger Stevenson, and Phyllis and I, had very good service from Prevailer Gel batteries back in the day.

    Now before we get too excited it’s important to note that gels have one Achilles’ heel: they can’t be conditioned to get rid of sulphation from being left in a partial state of charge, as is common on cruising boats.

    Hit ’em with any more than 14.2 volts and they are toast in very short order.

    Whereas AGMs from both Victron (14.9V) and LifeLine (15.5V) can be charged at higher voltages to blow off that nasty battery wrecking stuff.

    Still, these days, with cost effective and efficient solar, fully charging a lead-acid battery regularly without shore power is a lot less of a problem than it once was.

    Should those who want to avoid the expense and complications of lithium be thinking of poor old neglected gels?

    Don’t know, but it’s worth thinking about.

    Anyone out there using gels?


  • Wire Tie Best Practice

    Our new-to-us J/109 was filled with wire ties like the one on the left. Horrible things because when changes and additions are made people tend to just add more wire ties over the existing bundle.

    So, as I clean up the wiring, I’m replacing the ones on the left with those on the right (first photo). Way better, because when I make changes at a later date I just snip the old tie and replace it with new, like so:


  • Q&A—New Lead Acid Batteries From Victron

    Question

    Member Kimbal asked:

    I’m looking at an ad on Yachtworld for a boat that has “New Victron Super Cycle AGM batteries – 3 x 125ah (2022) – Note: These batteries are a new type of AGM which approach lithium in some respects, and matches the Carbon Foam Firefly batteries performance – capable of up to 100% depth of discharge occasionally, and 60-80% frequently without damage.” Have you heard of this, and does it sound legit?

    Answer

    Yes, in fact that’s what we have installed on our new-to-us J/109, and testing at Ocean Planet seems to indicate that they do very well on deep discharges.

    So far we have not used them enough to say anything really useful, although they are looking good after one season.

    That said, it’s important to understand that Victron have two offerings with different strengths:

    • Super Cycle, which we selected because we have a very small bank and occasionally will need to take it a long way down, say when aboard for a weekend, but will be able to bring up to fully charged at our wharf when we get home.
    • Carbon Foam, which might be better for a long-distance cruising boat since they are more resistant to being left in a partial state of charge.

    Do note though that all discharge cycles of all batteries (lithium included) reduce life to some extent (batteries are expendables) so claims like “and 60-80% frequently without damage” are simply not true. Like with Firefly, it’s important to read the fine print.


  • Portable Solar Panels For Cruisers

    The good folks over at Ocean Planet Energy are selling these foldable and portable solar panels.

    A couple of these will provide a cruising boat with around 100 amp hours at 12 volts over the course of a reasonably sunny day at anchor.

    To me this is a way better idea, at least to supplement a reasonable number of fixed panels, a good cruiser’s alternator, and possibly a hydro-generator for offshore use, than festooning a boat with a huge unseamanlike fixed solar array.

    Might even get one of these for our J/109, and I also think this, or something like it, could be a great solution for many Adventure 40 owners.

    Update January 2025

    Member Terence bought these panels and reports that they are not waterproof, or even water resistant. Maybe not a deal breaker, but it does make this a more attractive option.


  • Great Risk Quote

    You should obsess over risks that do permanent damage and care little about risks that do temporary harm, but the opposite is more common.

    Morgan Housel

    Morgan is one of the best thinkers about financial risk around. Often his thoughts apply to offshore voyaging too.

    This one applies best to the majority of cruisers who worry about lithium battery load dumps blowing the diodes in their alternators, a comparatively easy problem to fix, and completely miss the much greater risks from load dumps.


  • Batteries And Generators Are Different Things

    It drives me crazy when sales people suggest that installing their lithium batteries automatically means we don’t need a generator.

    Batteries are a storage device, generators are…wait for it…a generation device. They are different things.

    Sure, installing a larger capacity battery bank (of any chemistry) might mean that we can anchor for longer, or sail for longer, without starting a charging source, but eventually, and in some way, those batteries will need charging…duh.

    And if we have enough solar to never need a generator, then we might not even need lithium batteries.

    Point being that confusing this basic difference between batteries and generators, sets us up to make bad system design decisions…and often spend our money unnecessarily.

    Navico should know better.

    More on the generator decision here (needs updating).


  • ABYC Bans Twin Busses For Lithium

    Turns out that the new ABYC E13 standard for lithium battery installations on boats in effect bans separate busses for loads and charging sources. (Thanks to member Rick for pointing this out.)

    13.7.2.1A BMS shall respond to any conditions outside the SOE by activating the output disconnect device.

    My guess, and hope, is that this is probably the result of poor drafting, rather than intended. The problem, of course, is the word output.

    In my view, compelling the BMS to dump the loads just because of an overcharge does not increase safety, it decreases it, since load dumps are dangerous in and of themselves and overcharge is the most likely scenario to cause a disconnect.

    Hopefully ABYC will fix what I believe to be a mistake soon. Banning something that most industry experts I have talked to consider much better design (separate charge and load busses) does their credibility no good at all.


  • Balmar Battery Monitor On-Test

    After two months and four defects:

    1. Bad cable.
    2. Despite paying full price we were shipped a beta test shunt that could not be updated to latest software.
    3. Ditto the display which did not have enough memory for the latest software.
    4. The final problem was a bug in the iPhone up-date software that it seems that Balmar’s support techs don’t know about, since they didn’t tell me when I called, even though it’s on their site.

    I finally got the SG200 we bought for our J/109 working. I will write a review once I have more experience with it.


  • Most “Drop In” Lithium Batteries Not ABYC Compliant

    The way I read this, batteries with BMSs that do not communicate are now obsolete:

    If a shutdown condition is approaching a battery system should notify the operator with a visual and/or audible alarm before disconnecting the battery from the DC system.

    ABYC E13-7


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  • ABYC Publishes Lithium Battery Standard

    The TE-13 technical note is now a standard: E-13. To me, a woefully inadequate one that relies far too much on the vendors to do the right thing, but it’s a start. Panbo has a good analysis, most of which I agree with.


  • Victron Chargers Rock

    I’m loving this little charger I bought. I will write more in an upcoming article, but the ability to check out, on my phone, exactly what happened in the last charge cycle is amazing. Tells me a lot about battery health and how to set up the charger best for our usage.