How does the WS500 work on a dual alternator setup?


  • What do I do if I have two alternators?  Do I install one WS500 for both?  If not, what keeps them from fighting with each other? In a dual alternator setup, each alternator gets its own WS500 Smart Regulator.  This way you do not end up with a single point of failure and the regulator can monitor and control each alternator to get its maximum output.  The WS500 includes CANBus and OSEnergy communications protocols which allow the regulators to talk to each and share important data so as not to fight with each other, potentially reducing their outputs unnecessarily. It\'s also possible to run the Config app twice on the same screen so you can monitor both Smart regulators at the same time!   Maybe Al can expand on this! @al-thomason


  • High Rick,   Yes - a question we get a bit.   So, there are perhaps two flavors of this:
    1. Two alternators on the same engine.
    2. Two engines, each with an alternator.
    For the 1st case (Two alts on one engine):  If they are of the same type, then often one can simply parallel them and drive both with one WS500 regulator.  If need be a custom High Field Amp cable may be ordered to support field currents up to 30A    To be honest, we do not see this install very often. For the 2nd case, two engines - each with an alternator, then yes, two WS500 may be installed - one for each engine and alternator.  In this way each install may be customized to the given equipment, even if the two alternators are not the same model / capability, set up each WS500 to match what its alternator needs.  Then by linking the two WS500\'s with a CAT-5 cable (remember to install terminators as well), the regulators will talk with each other and settle in where one in effect becomes the master with the other working under its direction.  You will be able to see the Master still blinking the LED as Green, while the Slave will blink out a kind of orangeish / yellow color.  When in this mode a few things will happen:
    1. Both reg will work towards the same charging goals, as defined by the master regulator
    2. If the battery does not need the full output of both alternators, the regulators will work to scale back equally -- ala, both running around 60% of its allowed capability vs one hard and other turned off.
    A note:  Some times folks alternate running on one engine and then the other.  The CAN also helps here.  If you have been running on one engine for a while and want to switch over to the other, start the other, let the WS500 warm up and get in sycn with the already running one.  Maybe a minute or two.  Then when you turn off the 1st engine, the new reg will have already picked up the status of that 1st regulator and carry on in the same charge mode as opposed to just starting all over with no transfer of information. Hope this helps some! -al-  

  • Hi Rick and all, I have a twin power motor yacht with two Caterpillar 3126’s, each rated at 420 hp. One engine has two x 12v 190 amp alternators. The other has one of the same alternators plus a 24v 50 amp unit which supplies the starter batteries for the main engines only. I have two WS500 units which I have yet to instal. how should I connect the 12v side of these two systems? Appreciate any help with this. also, I am currently running Deep Cycle Lead Acid batteries and intend replacing them with some 48v LIFePo banks when they finally fail. Any tips on setting up for my current system (lead acid) would be appreciated. thanks, Phil

  • Sorry Phil, I just caught this one.  I didnt get flagged as it was just a comment on another post. From what I understand all 3 12v alts feed your house batteries and you have 2 WS500s.  On that basis I would suggest you connect the engine with 2 alts to one WS500 and have it drive the fields together in parallel.  The WS500 is rated for 30 amps on the field so it can power both.  Then connect the single alt to your other WS500.  Then connect the two WS500s together with an RJ45 quality cable, so the two can communicate over CAN bus.  This will allow all three alts to work together as one large alternator and not fight each other. Hope this helps :)   Rick

  • Hello Rick, About dual alternators on a single engine.  I\'m wondering why Al said this:  \"To be honest, we do not see this install very often.\" I have a single engine monohull (w/ Yammar 4JH4-HTE) and want to make changes to support a large LFP house bank, probably change my House to 24v, and then install two 24v x 185a alternators.  The idea is to push big power into my House during my routine movements, which is lifting or setting anchor, and some limited motoring while setting sails.  The more I push in with alternators, the less generator time I\'ll need - and hopefully I can eventually ditch the generator.  (yes.. I have very little solar...  I don\'t like the appearance of my boat with large amounts of solar.) I\'m thinking to install 400-600AH of 24v House capacity (two Victron Smart 24v x 200AH, or possibly 3 units).  But even with just two, each battery can handle the ~150-160amps from a 185a alternator.  Yeah? But, the regulator...  Is there a supported design that\'s similar to what you describe above...  e.g.  two high-output alts managed by a single WS500, pushing dual power into one House bank? What are the pros/cons, and why does Al say this:  \"To be honest, we do not see this install very often.\" Sincerely, Randall

  • I recall talking with Al about this about 5 years ago and he was saying that it would be great for this application but most dual alternator setups seemed to comprise leaving the factory alt. on the engine to service the cranking battery and using a bracket set up to drive a \"house only\" high output alt. Times have really changed since then and it sounds like your application may be a good one for this configuration as you have a matched set of alternators powering a single cell pack.  There is even the high output alternator harness that was designed for this application. The only factor to consider would be to decide how important redundancy was for your application.

  • I think redundancy is pretty important once I’ve tossed the Genset…. So maybe a spare WS500?? I believe the dual alternators would by default be operating as a fault-tolerant scenario… as nothing would need to change if one alternator failed.  Correct? For the starter battery…. Would a B2B be sufficient, or a Sterling CSVR?

  • My first choice would be something like an Orion B2B. And yes, a single alt failure should not affect the output of the other unit.
    And one other item that Ben reminded me of, in this config both of the temp sensors are used for alt temp monitoring, so no battery temp sensor is available, but in an LFP installation this should be handled by the BMS.  Thanks Ben!

  •   Hi @rick_tech_support, @al-thomason, I\'m planning to install this weekend my new Balmar alternators with two WS500 on my boat (with Victron Smart Lithium battery bank, VE.Bus BMS and Cerbo GX). Can you please confirm that my plan (simplified to focus on this part of my project) is correct or if I need to change something? Thanks! Eric

  • One thing I forgot to mention... I need to derate (using WS500) both of my alternators from 100A to 75A because of the small belts/pulleys that I have on my engines. Should I go instead with the configuration proposed in the manual with the shunt on the DC negative side?  The only thing I don\'t like with this configuration is having separate B+ wires unfused from the alternators.

  • Eric,   For your install I would refer you to the Victron Lynx website - it has a few very extensive examples of how to install the Lynx BMS with dual alternators and the WS500. In order to reduce belt loading the simplest way to to reduce the Max Field Drive to a lower value.  If you are using White-box WS500 (Simplest to use with Lynx installs, make sure to use a cross-over cable on the RJ45 connectors between Wakespeed and Victron), then DIP #8 may be turned on to restrict field drive to no more then 75%    That alone might get you what you need; but if you need finer tuning either manually edit the config.txt files (refer here, towards the end of guidance on how to edit the file to reduce max filed drive:  http://www.wakespeed.com/CU/ConfigurationUtilityGuideWeb.pdf  )   or use our Wakespeed app to create a fully customized config for your system:  Battery, BMS and ALt.  You can toggle on the \'limit max field drive\' and enter the % there. Installing an alternator shunt is another approach, though is getting into some more advanced designs.  For most folks, simply capping the max field drive works very well for the need you talked about.      

  • Quote from Al Thomason on May 25, 2022, 5:55 pm
    Eric,   For your install I would refer you to the Victron Lynx website - it has a few very extensive examples of how to install the Lynx BMS with dual alternators and the WS500. In order to reduce belt loading the simplest way to to reduce the Max Field Drive to a lower value.  If you are using White-box WS500 (Simplest to use with Lynx installs, make sure to use a cross-over cable on the RJ45 connectors between Wakespeed and Victron), then DIP #8 may be turned on to restrict field drive to no more then 75%    That alone might get you what you need; but if you need finer tuning either manually edit the config.txt files (refer here, towards the end of guidance on how to edit the file to reduce max filed drive:  http://www.wakespeed.com/CU/ConfigurationUtilityGuideWeb.pdf  )   or use our Wakespeed app to create a fully customized config for your system:  Battery, BMS and ALt.  You can toggle on the \'limit max field drive\' and enter the % there. Installing an alternator shunt is another approach, though is getting into some more advanced designs.  For most folks, simply capping the max field drive works very well for the need you talked about.
    Thanks Al  for your answer. But I’m not using the Lynx BMS, I’m using the VE.bus BMS.  What you see on my diagram is the Lynx Shunt VE.Can.  And I don’t think I can connect the « current sense wires » from the WS500 to this Lynx Shunt? But if this Lynx Shunt connect to the Cerbo GX with the CANBus and if I connect the WS500 to the Cerbo GX on the same CANBus (I have purchased the crossover cable), then do I really need to connect the « current sense wires » or I can leave them disconnected and the WS500 will get the same information on the CANBus from my Lynx shunt? I really hope I can avoid to have to add another shunt inline with my existing Lynx shunt just to connect these wires, because I’m tight on space and my Lynx system (Power In, Shunt and Distributor) is already nicely integrated/connected? What exactly these « current sense wires » do?  And if it doesn’t work using my configuration with the Lynx shunt and CANBus, what would be the risk (or downside) of not using these « current sense wires »?

  • including Al in this last request for clarification @al-thomason

  • Quote from Al Thomason on August 14, 2019, 4:27 pm
    High Rick,   Yes - a question we get a bit.   So, there are perhaps two flavors of this:
    1. Two alternators on the same engine.
    2. Two engines, each with an alternator.
    For the 1st case (Two alts on one engine):  If they are of the same type, then often one can simply parallel them and drive both with one WS500 regulator.  If need be a custom High Field Amp cable may be ordered to support field currents up to 30A    To be honest, we do not see this install very often. For the 2nd case, two engines - each with an alternator, then yes, two WS500 may be installed - one for each engine and alternator.  In this way each install may be customized to the given equipment, even if the two alternators are not the same model / capability, set up each WS500 to match what its alternator needs.  Then by linking the two WS500\'s with a CAT-5 cable (remember to install terminators as well), the regulators will talk with each other and settle in where one in effect becomes the master with the other working under its direction.  You will be able to see the Master still blinking the LED as Green, while the Slave will blink out a kind of orangeish / yellow color.  When in this mode a few things will happen:
    1. Both reg will work towards the same charging goals, as defined by the master regulator
    2. If the battery does not need the full output of both alternators, the regulators will work to scale back equally -- ala, both running around 60% of its allowed capability vs one hard and other turned off.
    A note:  Some times folks alternate running on one engine and then the other.  The CAN also helps here.  If you have been running on one engine for a while and want to switch over to the other, start the other, let the WS500 warm up and get in sycn with the already running one.  Maybe a minute or two.  Then when you turn off the 1st engine, the new reg will have already picked up the status of that 1st regulator and carry on in the same charge mode as opposed to just starting all over with no transfer of information. Hope this helps some! -al-  
    I have an installation using (2) Balmar alternators on a single engine, Oldsmobile Rocket 455. There is a 12v (Balmar XT-VT-170-K6) alternator and a 48v (Balmar 96-48-60-K6) alternator each connected to its own dedicated WakeSpeed WS500 regulator. The 12v alternator is charging a 12v battery bank comprised of (10) BattleBorn BBGC2 batteries connected in parallel (12.0 kWh). This Battery bank is also charged by a Victron MultiPlus II 12v inverter/charger. It is also charged by a (15) panel SunPower solar array (1,530w). The 48v alternator is charging a 48v battery bank comprised of (4) BattleBorn GC3 batteries connected in series (13.2 kWh). This battery is also charged by a Victron MultiPlus II 48v inverter/charger. It is also charged by a Sterling 12v to 48v battery to battery charger powered by the 12v battery bank. The 12v battery bank is also charging a 12v DieHard lead acid battery (800CCA) for stating the engine using a Sterling 12v to 12v battery to battery charger. The engine driven air conditioning compressor has been replaced by a 12vdc ProAir II air conditioning compressor.

  • I have also been in contract with DragonFly about getting the 12v WakeSpeed work on the 12v alternator and have been very upset with their responses. I hope that you can help me when they cannot. One of the most troubling issues is that I was told that they do not recommend using the WakeSpeed WS500 to regulate a 48v alternator. Does anyone know about this? The WakeSpeed alternator, in all of the documents I have read, always says that this regulator will sense the voltage and will regulate a 48v alternator.

  • Your installation seems to be well designed based on your overview and having a separate 12/48V system is actually quite common so I am not sure why they would say something like this.  Al is or was the \"go to\" guy on this.  That old Rocket should provide you with gobs of power for your system!

  • The WS500 can do 48V systems. I dont know the specs from your battle born batteries, maybe they can not be use as 48V system. I think there is a misunderstanding on this point.

  • Quote from Sailor1313 on February 15, 2023, 10:28 am
    I have also been in contract with DragonFly about getting the 12v WakeSpeed work on the 12v alternator and have been very upset with their responses. I hope that you can help me when they cannot. One of the most troubling issues is that I was told that they do not recommend using the WakeSpeed WS500 to regulate a 48v alternator. Does anyone know about this? The WakeSpeed alternator, in all of the documents I have read, always says that this regulator will sense the voltage and will regulate a 48v alternator.
    Disclaimer:  Al from Dragonfly Energy (aka, Wakespeed).   @sailor1313, Hello!   A couple of notes.   First, the Ws500 works with 48v alternators.  We have been involved in 1,000\'s and 1,000\'s of such installs, mostly in the RV world -- and they work very well, and have done so from the very beginning (The first usages of the Ws500 was 48v installs in Sprinter vans). What we do not support is 48v battery systems with no commutations between the BMS and the WS500. (such as the Battle Born drop-ins you noted)   12v, 24v fine (Approved batteries only, see website and app).  But for 48v, need some comms.  Lithionics, MG Energy, Victron Lynx are a few examples.   All good solutions, and all have been deployed in 48v installs.  REC should be OK as well, though I am not aware of any in the field. So, I think your first issue is using the Battle Born drop-ins with a 48v alternator; that is dangerous and a model we do not support.  12v, 24v fine.  48v, no.   (BTW, the recent announcement of Dragonfly IntelLigence address this).  You should be fine with the DCDC converter approach, but I would recommend you either change the 48v battery subsystem to a supported one with communications, or remove the 48v alternator.   You have not describes what issues you are having with the 12v alternator.  I would think it would be rather straight forward; make sure all the required wires are connected; using the app can ease in creating a config file.  As a initial troubleshooting approach, you might try removing the Blue Field wire from the alternator (Please be safe here), make sure the batteries are around 60-70% SOC or less, and then while the engine is running BRIEFLY touch the Field terminal on the alternator to +12v.  You should be able to hear the engine loading and notice amps being delivered.  If not, something is up with the alt.  Just do it for a second or so, no longer and should be OK.   Balmar alts are good units, and I do not hear too many issues with them, but at items there are issues - and a couple of customers went around for days trying to sort things out just to fine out some quality issue in the alt.  The quick full-field test is a way to quickly bring that to closure. As to the regulator, the most common issue we find is not connecting up all the wires (esp the two red and two blacks!), not installing the 15A alt+ fuse (though the Ws500 issue a FLT code for that), and also over-engineering the config  -- typically turning on Expert Mode in the app and adjusting the rose background values.  Assuming the alt is good (and they most often are), dbl check the wiring against the our User\'s guide (there is also a BattleBorn specifc .pdf on the Wakespeed website), create a fresh config w/o adjustments via Expert Mode, and get to a point of working.  Then you can fine tune things down the road as appropriate If you have any specific question on your 12v install, please let us know here and I am sure help will be on the way! Hope this helps! -al-    

  • This is good information Al, thanks for jumping in.  And to confirm yes, REC BMS does support a 48V LFP Victron/WS500 integrated system in both a single SI-Q Series BMS or up to 15 strings of cells when combined with the REC Master Controller

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