The Offshore Voyaging Reference Site

An Even Better Alternator Regulator?

There has been a lot of excitement recently about the release of a new alternator regulator that takes direct aim at the WakeSpeed WS500‘s position as the only truly smart regulator, primarily because it measures the current (amperage) that goes into the battery and then acts on that information, rather than making a bunch of guesses about the state of the battery that are usually more wrong than right, like, for example, the regulators from Balmar—I explain all this in more detail here and here.

The new regulator is the Zeus from ARCO, and both Panbo and Rod Collins, who advised during the development, are pretty excited—I recommend that you read Rod’s article for an insider’s view on how this new regulator came to be.

I’m super excited too since the new regulator fixes a problem that I have been beating on Al Thomason, inventor of the WakeSpeed, about since the WS500 came out: no easy way to program it and see what it’s doing over Bluetooth—Al and I seem to chat every six months or so about one thing and another and I’m sure he is getting sick of hearing it!

And the Zeus seems to be easier to install and program in a bunch of other ways; for example, the harness it comes with will work with both N- and P-type alternators.

But here’s the thing.

I know from our chats that since the WS500 was released, much, possibly most, of Al’s energies and smarts, which are prodigious, have gone into making his regulator work seamlessly, mostly over CAN bus, with the ever more sophisticated lithium battery management systems from companies like Lithionics and Victron, as well as many others.

Here’s an example of how tightly Al has integrated the WS500 with Victron’s products, including their system monitors.

We are talking close cooperation here. For example, in a multi-BMS multi-battery Lithionics setup, if one of the BMSs goes offline, the WS500 will know that and automatically adjust its charging profile accordingly.

The point I’m making is that it’s all very well for ARCO to claim that they have all this cracked on day one, and much more besides, but is that real when one of the smartest engineers in the business has a five-year lead on them?

And process control programming and communication, which is what this is, is an iterative process of try, debug, try again, debug…

And further, keep in mind that with this stuff one bad bug could take out thousands, or even tens of thousands, of dollars worth of equipment in the blink of an eye, or render your system down until sorted out.

And one of the things that I know Al has focused on, because he’s a deeply experienced process control engineer, is failsafe, so if his regulator ever gets confused about what’s going on it defaults to shutting things down, or at least switching to less potentially damaging charge parameters.

This is actually one of the reasons it can be a bit frustrating to get the WS500 working the way we want it to. The default configurations are very conservative.

So sure, if you have a nice simple and robust lead-acid battery-based electrical system, give the Zeus a try, if you wish.

But if you have, or are contemplating, installing a sophisticated lithium battery-based system, I suggest sticking with the WakeSpeed WS500 for a while while ARCO make the almost inevitable early-days mistakes on someone else’s boat. And also until the manufacturer of your battery and BMS tell you they are 100% happy seeing their batteries charged by the Zeus.

And one final thought. The Zeus page claims to make it super easy to change parameters with your phone. Sure that’s cool, but with ease of change comes the temptation to play around indiscriminately and changes can lead to big problems, so be careful.

All that said, don’t get me wrong, I’m still super-happy to see a competitor to the WakeSpeed WS500—bet we see that Bluetooth capability I have been bitching about for four years real soon.


I like Al Thomason and he has been good to me by tirelessly sharing his smarts in phone calls and emails.

On the other hand, I’m on record as more than a little sceptical about Firefly/Battle Born, the company that bought WakeSpeed, so I think those two kinda cancel out.

You should also be aware that Al has arranged for AAC to get two WS500 regulators for free, one of the early ones (now working on our J/109), and a month ago, one of the newer ones with a NEMA 2000 output that I will install this winter and play with next summer.

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Stein Varjord

Hi John,

Good sobering thoughts! Thanks.

James Greenwald

Some cool features for sure. I reallly like the Generator mode and Bluetooth.
Already have a property installed WS500 24V system FireFly (no issues so far). Will standby for how the Zeus pans out.

Evan Effa

It looks like ARCO Zeus now claim to have Victron Cerbo GX compatibility…

A compelling option.