Answer to Electrical Quiz

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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.


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

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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.

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.

This one is a mild manifestation. There were bundles with 20 different wire ties in the space of a meter.

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



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?


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.

Great Risk Quote

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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.) 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. Big shout to member Michael for pointing that out.

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

I think ABYC should have required all BMS to be able to communicate with charging sources. This could be as simple as a set of contacts, but CANBus is better. More here on why. And here on ways to do that.

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.