Stupid Alternator Regulators Get Smarter…Finally

If an alternator voltage regulator is not connected to a shunt, it's not smart.

One of the biggest snow jobs in boat gear sales is the myth of the smart three-stage alternator regulator. In fact, the alternator voltage regulators that have been available to us cruisers for about the last 15 years are not that bright...OK, they're downright stupid.

They're so stupid that they can't even perform their primary function of charging our batteries properly until full.

I know what you're thinking:

John is saying that a piece of gear with tens of thousands of units installed (that's a guess) in boats, and thousands more sold every year, that's so fundamental to comfortable live-aboard life, does not even work. Clearly he has lost his grip.

I totally get your scepticism. Heck, when our old, and sadly no longer made, Link 2000-R regulator died—the last cruiser's alternator regulator that was actually smart—I bought the then, and now, most popular "smart three-stage regulator" thinking that it would work, too.

I settled down and read the whole manual looking for the fundamental capability that would make it usable on a liveaboard cruising boat, and got to the end to find...nada. So I figured there were pages missing...nope.

What Matters in Alternator Regulators

What's that fundamental capability? The ability to measure when our batteries are full and reduce the voltage output by the alternator to float.

Lead acid (liquid-filled, gel, AGM, whatever) batteries are fully charged when the current (amps) they are accepting at their specified acceptance voltage—typically about 14.4 volts at 70˚F (20˚C)—has dropped to about 0.5% of their total capacity measured in amp hours. (Check with the battery manufacturer, since these two numbers vary between brands, though not by much.)

Sounds pretty simple, right? And it is. All you need is a shunt in a cable to the house battery to measure that current—often already there on a cruising boat to support a battery monitor—and a bit of simple logic in the regulator to turn the charge voltage down to float (typically 13.4 volts) when the above threshold is reached, but not before.

Easy peasy. But since the death of the Link 2000-R, and a rather complicated regulator from Ample Power (no longer in business), there has been no alternator regulator available, at least that I have found, that could do that simple fundamental thing.

How Could This Be?

Why? Beats the crap out of me. Maybe because few boat owners really understand how batteries charge and, even more distressingly, very few technicians in boatyards do, either, so the industry got away with selling stupid regulators for years, and they even had the nerve to call stupid smart—the power of marketing.

Stupid Is As Stupid Does

Rather than making that simple required measurement, these stupid regulators guesstimate using a combination of time and how much the regulator needed to juice the alternator field coil to maintain the acceptance voltage. That's bad enough, since different alternators have different relationships between field and output current (amperage) and, of course, how long a battery will take to charge will depend on how much it was discharged...duh.

But gets worse. These stupid regulators have no way to understand how much of the alternator's output is charging the battery and how much is supplying loads—they truly operate blind.

Making Stupid Worse

The way the manufacturers of stupid regulators get around this fundamental weakness is by shipping the regulator factory programmed to chronically undercharge the batteries, to the point that the regulator will typically cut the charge current back to float in less than two hours, even though a lead acid battery bank discharged even just 25% will typically take at least four hours to fully recharge, no matter how big the alternator—if you don't believe that, see Further Reading.

Now this can be kind of fixed, in a klugy way, by reprogramming the regulator, which is what I did, and then wrote an article about it to help others, recently deleted since this new regulator makes it obsolete.

At Last, Real Smarts

But now, finally, we have, once again, a truly smart regulator. Let's take a look:

  1. Why Most New-To-Us Boat Electrical Systems Must Be Rebuilt
  2. One Simple Law That Makes Electrical Systems Easy to Understand
  3. How Batteries Charge (Multiple Charging Sources Too)
  4. 5 Safety Tips For Working on Boat DC Electrical Systems
  5. 7 Checks To Stop Our DC Electrical System From Burning Our Boat
  6. Cruising Boat Electrical System Design, Part 1—Loads and Conservation
  7. Cruising Boat Electrical System Design, Part 2—Thinking About Systems
  8. Cruising Boat Electrical System Design, Part 3—Specifying Optimal Battery Bank Size
  9. The Danger of Voltage Drops From High Current (Amp) Loads
  10. Should Your Boat’s DC Electrical System Be 12 or 24 Volt?—Part 1
  11. Should Your Boat’s DC Electrical System Be 12 or 24 Volt?—Part 2
  12. Battery Bank Separation and Cross-Charging Best Practices
  13. Choosing & Installing Battery Switches
  14. Cross-Bank Battery Charging—Splitters and Relays
  15. Cross-Bank Battery Charging—DC/DC Chargers
  16. 10 Tips To Install An Alternator
  17. Stupid Alternator Regulators Get Smarter…Finally
  18. WakeSpeed WS500—Best Alternator Regulator for Lead Acid¹ and Lithium Batteries
  19. Smart Chargers Are Not That Smart
  20. Do You Need A Generator?
  21. Efficient Generator-Based Electrical Systems For Yachts
  22. Battery Bank Size and Generator Run Time, A Case Study
  23. Battery Options, Part 1—Lithium
  24. Battery Options, Part 2—Lead Acid
  25. Why Lithium Battery Load Dumps Matter
  26. 8 Tips To Prevent Lithium Battery Load Dumps
  27. Building a Seamanlike Lithium Battery System
  28. Lithium Ion Batteries Explained
  29. 11 Steps To Better Lead Acid Battery Life
  30. How Hard Can We Charge Our Lead-Acid Batteries?
  31. How Lead Acid Batteries Get Wrecked and What To Do About It
  32. Equalizing Batteries, The Reality
  33. Renewable Power
  34. Wind Generators
  35. Solar Power
  36. Hydro Power
  37. Watt & Sea Hydro Generator Review
  38. Battery Monitors, Part 1—Which Type Is Right For You?
  39. Battery Monitors, Part 2—Recommended Unit
  40. Battery Monitors, Part 3—Calibration and Use
  41. Battery Containment—Part 1
  42. Q&A—Are Battery Desulphators a Good Idea?
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