Friday, May 8, 2020


--Protect your Battery --
-- Protect your Alternator --
-- Optimize your System --

These are the three guiding principals of the VSR Alternator Regulator.  Today’s DC systems are more than a simple alternator & battery with a few lights.  In addition to recharging your battery, alternators need to also support ongoing loads and power equipment, even large dynamic swings from perhaps an inverter + washer/dryer which can interrupt a recharging session mid-cycle.  All makes for a complex environment to try to understand and adjust for.   The Alternator Regulator uses a series of sensors to fully understand these complex issues.  Now in its 3rd generation it has been deployed in Marine, RV, as well as off-grid applications across the world supporting battery technologies ranging from traditional lead-acid to modern LiFeP04 technologies.

Protect your Battery:

By carefully monitoring battery voltage, battery current, and battery temperature, the VSR Alternator Regulator is able to closely follow manufactures recommendations for complete and safe recharging of your battery.  High precision voltage monitoring and regulation  – often to within 0.02v of manufactures targets assure no over-stressing of batteries.  Monitoring of battery acceptance current allow for accurate measurement of the battery's charge state (vs. time based estimates) to properly determine when to end charging and prevent chronic undercharging of batteries – perhaps the leading cause of early storage battery failures.  Combined with temperature compensation and a philosophy of "Protect the Battery 1st" the VSR Alternator Regulator delivers proper and safe charging of your battery.

Protect your Alternator:

High capacity storage battery banks combined with high-acceptance rate battery technologies (e.g., AGM, LiFeP04) can cause stresses to your alternator.  The VSR Alternator Regulator is able to monitor the real-time operational status of your alternator and adjusts its output to assure long life while at the same time maximizing its output.  By actively regulating the alternators temperature (as opposed to simple pull-backs), the VSR Alternator Regulator operates your alternator at its peak capacity while not over stressing it.

Optimize your system:

The VSR Alternator Regulator is simple to install and use.  In the simplest installation only 4 wires are needed along with basic configuration via DIP switches.   Adding additional sensing wires (current shunt, temperature sensors, stator signals) each unlock additional capabilities.  The 3rd generation design introduces a CAN (Control Area Network) to provide for coordination and prioritization between different charging sources in your system.  It also allows for the option to utilize the industry proven method of Remote Instrumentation – allowing battery voltage, current, and temperature to be communicated and eliminating the need to route individual dedicated sensor wires all the way to the battery: simple install a BMS or Battery Monitor at the battery and click in a CAT-5 cable.

Able to support a wide range of engines, be it a dedicated engine as part of a DC generator, a large prime mover, or a small sail boat auxiliary engine, the VSR Alternator Regulator is able to match the alternator load to engine and drive belt capabilities –  critical importance when utilize  high-capacity alternators on engines of modest horse power.   A unique Adaptive Idle capability furthers adjusts the alternator load to match the engines power curve throughout its RPM range – assuring maximum alternator output while preventing engine stalling and/or sluggish performance at or near idle.

A full set of ASCII configuration commands allow detailed configuration beyond the simple DIP switches – providing complete control to fit YOUR exact installation needs.  Real time status and configuration is communicated via additional ASCII strings, allowing you to confirm configuration and monitor ongoing operation via simple apps on your phone, PC or tablet – or via available Signal-K providers.  Capable of supporting battery voltages from 12v to 48v with no hardware change (including hard to find 32v) and another unique capability to utilize an alternator field voltage different from the battery voltage, allowing the use of 12v alternators to provide a low-cost high efficiency 24v or 48v battery charging heads.

Gen3 VSR Alternator Regulators may optionally utilize the CAN to communication with other alternator regulators and charging sources as well as battery monitors and BMSes to deliver a well coordinated ‘systems’ approach of all charging sources:  each understanding the exact needs and status of the battery and delivering that in a well coordinated and prioritized ‘systems’ approach.  The CAN also allows for remote configuration and ongoing monitoring of the status as well as limited ‘NMEA2000 type’ status messages.

Designed for high reliability / efficiency, featuring transportation grade design practices and components, internal software logic self-checks as well as independent external fault / limit checking, fall-back / failover modes (both hardware and software) and more.  The VSR Alternator Regulator takes seriously the task of Protecting your Battery and Alternator, while optimizing your System.  Learn more from the resource tables above, as well as the information blocks to the right.

  • Precision voltage regulations, often within 10mV  vs 100mV or more of many commercial regulators.
  • Monitoring of battery amperage to properly implement manufactures defined battery charge profiles, providing increased safety and less stress to batteries while truly fully charging them.
  • Ability to actively regulate alternator current 
    • Protecting batteries, alternators, and load placed to engine.
    • Providing a truly safe self adjusting ‘float’ mode for modern LeFeP04 batteries (0A in and out) while allowing the alternator to power ongoing electrical loads.
  • Support for 12v to 48v systems, including less common 32v or 36v,  with no hardware changes.
  • Battery voltage does not need to be same as field drive voltage:  Allows use of ‘12v’ alternator as a high efficiency 24v battery charging source.
  • Battery temperate monitoring to protect the battery from over/under temperature situations, as well as adjust voltage targets based on temperature.
  • Active regulation (vs. simple capping) of alternator temperature allows safe operation of alternators in high temperature / high load situations.
  • Alternator load capping, to prevent overloading engine as well as help save belts and increase their life.
  • Adaptive idle pullback to further reduce the load on engines while at low RPMs – allows use of modern efficient / high capacity alternators in engines of modest size
  • Support both P or N type alternators.
  • Multi chemistry, predefined charge profiles for traditional FLA, AGM, GEL, LiFeP04 batteries
  • Custom definable charge profiles allows complete tailoring beyond predefined profiles  to fully implement battery manufactures specifications
  • Flexible feature-in port:  One comm usage is to allow a BMS to signal "Stop-Charging" on LiFeP04 batteries.
  • Simple to upgrade firmware for future enhancements and bug fixes.
  • Participation in the OSEnergy CAN based fully integrated systems approach.  Bringing all its benefits of simplifying installation, increased reliability, and better battery / DC charging systems integration 
    • Also supports relevant NMEA-2000 type PGNs.
  • Simplified installation with industry proven Remote Instrumentation ability
  • High-reliability installation options, to allow for continued operation during component and/or wiring failures. 


An App!   ----    After long last an application is  being developed!  Monitoring, configuration, diagnostics -- once completed an application will unlock so much capability in the VSR Alternator Regulator for both the simple user as well as the advanced installer.   Have an early look and download a copy!

And the application user forum:

Last Revised March 8, 2018


  1. Have you gone back to the future?

    1. OK, a LOT slow - but I think I get this comment now...
      The dates. Well, I figured out I can force placement of posts by using different dates. Hence, this into page is 'posted' some time in 2020 - which makes sure it is the 1st displayed page. (Actually, look at the bottom to see when updated it)

  2. Hi, I have a large lithium battery bank and am not happy with conventional regulator options. Your arduino based solution is very interesting and I keep a rasp pi and arduino on board. Do. Have you made any progess with your n2k interface? Nema0183 might be easier. Do you have any for sale?

    1. Rick, hello. I am so sorry I did not see this comment post sooner. Hope you have had some better luck with your Li battery bank, there are now several people using this regulator with their LiFeP04 type batteries - with good results.

      I do have blank PCBs, and have made some progress on a simple NMEA-2000 bridge - (Click on the NMEA-2000 label link at the top right). There is more to come, do drop me an Email @ if you wish to talk more!

    2. And more update: the CAN enabled regulator (3rd gen) includes 'NMEA2000 type' messages and support. Give it a try!

  3. Hello,
    Where do I find the schematic, pub layouts and the source code?
    Thanks in advance,

    1. Hello. All those are under the resource tabs at the top of the bog. See the boxes "Links to files" and the associated tabs.


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