Upgrading Our RV’s Charging System with Nations Alternator

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Shortly after getting our Winnebago EKKO, I plowed into a massive electrical upgrade.  We called it “The 20k Project” because it brought our total battery capacity up to 20,480 Watt-Hours.  As part of that project, I upgraded nearly everything electrical in the RV – but the second alternator and its charge controller remained stock EKKO items.  That changes with this video!


There really were two separate goals for this upgrade, as you’ll hear in the video.

Increased Alternator Capacity

This shouldn’t be a surprise.  The stock alternator (a 170 amp Balmar) is a good match for the Winnebago EKKO and its battery bank.  But our battery bank is now two and a half times larger than the largest factory EKKO!  So it stands to reason that we’d want more charging capacity to pair with that larger battery bank.  To get this capacity, I turned to Nations Starter and Alternator.

We had a Nations alternator in our last RV, Lance, as a second alternator charging our Lithium battery bank.  We were satisfied with the performance and reliability of the alternator (although, admittedly, not fans of the location for the second alternator in a ProMaster).  Adam told us he had a 300 Amp second alternator available for the Ford Transit, and that it fit directly into the factory spot.  That sounded pretty good, and we were off to Missouri.  And honestly, just the alternator itself would have been a pretty cool upgrade, but there was more…

CAN-Based Charge Control

I explain exactly what this is and why it’s a good thing in the video, and it takes me about a thousand words to do it.

The really really short version is that it’s just a lot smarter to charge based on what the batteries are telling you they want, versus measuring a bunch of parameters to infer what the batteries want.  The Wakespeed WS500 charge controller replaces our Balmar charge controller, and can be configured to read data from a CAN network.  In our case, the CAN network will be created between our 5 batteries and the Wakespeed charge controller (so, a 6 node network).  Our batteries already have the CAN network capability built in, so completing this upgrade was just a matter of physically connecting the devices.  There are a number of advantages to using CAN data for charging

  • Charging decisions are now made by the BMS, which remembers its state of charge from one engine-start to the next.  This means no more overcharging on startups.
  • Battery temperature sensors are eliminated, as the battery temperature becomes just a piece of data sent over the CAN.  Only one of our 5 batteries had a temperature sensor anyway, so I always wondered if I had picked the right battery to mount it to.
  • Current and voltage sensing is improved.  They become just other pieces of data – not something that has to be measured remotely.
  • Running other loads won’t affect the charge delivered – because the target voltage and current are just data delivered by the batteries.  (Tough to explain, but it means we can run the air conditioner while charging, and it won’t keep us in a bulk charge any longer that it needs to because running the air keeps the alternator field at XYZ%.  The batteries are calling the shots, and when they’re full, the delivered voltage will drop as it should.)

So How Did It Work?

In a word: Awesome.

First off – hats off to Adam and his team for the install.  If we hadn’t been interrupting them with filming, they probably would have gotten us in and out of there in half a morning.  Even with us in their way, we were out by mid-afternoon.  In the end, they figured out how to run exactly zero new wires.  They were able to reuse the wiring harness from the Balmar, and simply splice into it to get the connections they needed.  This saved them a TON of time.

Besides the awesome install, the performance from the alternator itself has been outstanding.  We get around 230-250 amps while driving along in bulk charge mode.  This charges our batteries quite a bit faster than before.

We haven’t done much testing at idle yet, because it’s kind of cooled off outside.  BUT, you can see some of the idle performance in the video!  You can see that with the air conditioner running, we’re still getting a net of about 100 watts to charge the batteries at idle – so we’ve exceeded the 100 Amp target.

And before you say, “yeah, but that wasn’t at hot idle”… yeah it kind of was.  We had been tinkering with the alternator for a while before we filmed that bit, and the battery and alternator temperatures are reported in that same data stream you see in the video.  I’ve put the picture of the data here below, and you can see that the batteries are at 28 degrees Celsius (82 degrees Fahrenheit), and the alternator is at 46 degrees celsius (115 degrees Fahrenheit).  Now granted, I can get it hotter than that, but it clearly wasn’t a cold alternator.


And it’s occurred to me that in the video, I only showed aggregate data for all 5 batteries.  Rest assured, each of the 5 batteries is indeed reporting in on the network.  To show that individual data, you have to enter a debug mode.  We did that, and here’s a snapshot of that data.  The individual batteries are IDs 70-74.  We can see each of the batteries is asking for a 14.4 volt charge of up to 300 Amps.


So I’m calling this upgrade a resounding success.  We’re getting faster charging, and that charging is better regulated to exactly what the batteries call for.

I’ll finish off with a couple links that may be useful to anyone contemplating this kind of an upgrade – or who just wants to have a really close look at the data file snippets above.

The first is the communication guide from Wakespeed that tells you how to read the files.  It’s the answer key basically: http://wakespeed.com/Wakespeed%20%20Communications%20and%20Configuration%20Guide%20v2.5.0.pdf

Here’s a marketing chart from Wakespeed that compares their charge controller with others available on the market.  Despite being a marketing piece, I found the information accurate.  https://nationsstarteralternator.com/v/vspfiles/Wakespeed-Comparison-Guide.pdf

And that’ll about do it for now.  If you have any questions, leave them in the comments below and I’ll try my best to answer.


James is a former rocket scientist, a USA Cycling coach, and lifelong fitness buff. When he's not driving the RV, or modifying the RV (or - that one time - doing both at once), you can find him racing bicycles, or building furniture, or making music. In his spare time, he works for a large IT company.

    49 thoughts on “Upgrading Our RV’s Charging System with Nations Alternator

    1. John Plisinski

      So my EKKO is getting the Balmar /Electrical recall done. If I ever have a problem with the Balmar again can this CAN controller be installed in its place with only wiring changes being done?
      Note I don’t have the battery bank like yours I only have the single Lithionics Battery with the generator. (E22/F21).
      Would the CAN work with the stock alternator or would that have to be updated to the National Alternator?
      Also the opposite situation can the Balmar work with a National alternators?

      1. James - Post author

        Yes, you should be able to use a Wakespeed controller with a Balmar alternator, and a Balmar controller with a Nations alternator. You’d have to make sure to get the right wiring harness to connect them, but it should be doable. (Caveat – I haven’t personally used a Wakespeed with a Balmar alternator. I have used a Balmar 614 with a Nations alternator in the past.)

    2. Missy

      I saw the new regulator was placed under the hood where the old Balmer regulator was it seems. Have you had issues with heat the way the Balmers seem to be having that has caused the recall 174 for new wiring etc and moving the regulator to the battery compartment?

      1. James - Post author

        We have not had any issues with heat. I did ask Wakespeed what the temperature limits were for their regulator. They told me it was good up to 180 degrees Fahrenheit.
        Just to make sure that it stayed under that, I did put some heat shielding around it. We haven’t had any problems.

        Although, if we do have any issues, I’ll probably look to relocate it to the inverter compartment. If I were doing it starting now, that’s where I’d put it.

    3. Randy Stonesifer

      As a current Ekko owner, I’d like to know if your Balmar quit working and that’s when you decided to change the system. Our Balmar has quit twice, each time lasting as long as the trip from Iowa to Pennsylvania. Thinking it might be time to switch systems…

      1. James - Post author

        We have experienced Balmar failures – but our Balmar charge controller and alternator were both working properly when they were removed for this video.

        Generally, we need to plan stuff like this quite a way out. Besides the travel, we need to make sure we can have access to film it, the right people are there to interview, any special parts for our rather unique rig are planned for, etc.

        But I can tell you that you won’t be disappointed with the system performance or the installation experience should you decide to go with Nations.

    4. Patricia Page

      These videos are incredible! A wealth of information!! I had no idea you could put 20,000 “amp hours?” of lithium. Solar is watts… I’m learning. You do have a great way to explain things. I LOVE the EKKO. I like it even more if it came the way you modified it! LOL. I’m sure another 50,00 to 75,000 grand!

      1. James - Post author

        Glad you like our videos!
        Just to clarify – in case I said it wrong somewhere – our RV has 20,000 *watt-hours* of battery capacity. (That works out to 1600 Amp hours.)

    5. Rob

      We’re wrapping up our diesel Sprinter van build which includes (2) Lithionics 315ah; a Nations 280a; and the Wakespeed WS500 (white box version) — we have the correct harness, the proper charging profiles for the Lithionics, can busses, and updated firmware… however, we’ve now had 2 alternators burn up just during testing at idle. No ground issues. Everything reads properly. No one can figure out the issue. Next course of action is to swap the Wakespeed with a Balmar regulator. Fingers crossed. There might be a stop at Nations on our way back east for their hands-on testing/assessment rather than just troubleshooting over the phone.

      1. James - Post author

        Sounds like a strange problem – burning up at idle isn’t something I would expect!
        What kind of charge are you generating when the alternator burns up? And isn’t the alternator temp sensor kicking in and slowing things down first?
        Very strange indeed!

        1. Rob

          The temp sensor was hooked up via two pin harness on the alternator side and input directly into the Wakespeed harness and the Wakespeed was programmed with the Lithionics BMS internal profile. Very strange. Especially when it’s isolated and the grounds all checked out.

        2. James - Post author

          Were you able to grab the telemetry from the Wakespeed during one of the meltdown episodes?
          There’s probably something in that which would give a clue.

        3. Rob

          They were only watching the Lithionics app to see charging status. At idle, was showing around 90-110, and then after a little while of running, they’d hear the alternator whining, quick turn off, and glowing and fried. Thought the first was a fluke after checking everything. Then it always starts off as situation normal… until it wasn’t. Hopefully the Balmar with the Nations will work, but it would be nice to know what the issue is, since it isn’t an uncommon setup.

      2. Chuck Curtice

        Hi Rob, Do you have an update to this situation. I also have a diesel Sprinter and would like a setup like James has. Thanks for any info.

    6. Chris Korn

      I don’t understand how your A/C can be pulling 100amps. My 5th wheel with 2 A/C units don’t even pull 50amps. I have a bulldog surge suppressor and can see what I am pulling.

      1. James - Post author

        Oh! I wasn’t clear on that.
        The air conditioner pulls 100 amps of *DC* current from my 12v battery bank.
        That runs through the inverter to create the AC.
        (The AC is less than 30 amps for the whole coach.)

    7. Greg Cummings

      James, with all the talk about watts/amps at idle how long can you idle your coach for while charging your batteries? Hopefully somebody at Ford has told Winnebago the answer.

      Thanks, Greg

        1. Greg Cummings

          Keep up the good work…I have a Sprinter RV so idling for extended periods of time is a big issue. If I find out I’ll let you know. Keep those electrons flowing …

        2. Greg

          Update on my question of how long can you idle safely. Well, it appears it is for ever. Or at least until you run out of gas. I talked to a local shop mechanic today who worked for Ford for 16 years and is a Ford Senior Master Technician and was actually working on a Transit 2500. The fact that there is a second alternator makes no difference. So…Happy Idling.

    8. Aaron

      You have a solar charge controller and the alternator charger. Can you reprogram the can do it’ll tell each charger to spit the batteries between both charging sources. the charge time would be shorter when you are driving.

      1. James - Post author

        I think what you’re suggesting is what we actually have working.
        Both the solar charge controller and the second alternator will charge the batteries simultaneously. They’re independent of each other, and both will charge to the best of their abilities.

    9. Joe McGuire

      I saw above that you wanted to do something with starlink. I just chopped the back off mine, 3d printed a new back, and mounted it flat on the roof rack. It’s been a game changer for us so far. Using it off a raspberry pi with speedify in redundant mode with a couple of usb tethered cell phones does a good job of covering up drops that happen if you’re around obstructions. Speedify also tunnels back to their nat gateways, so apps like VPNs and video conferences don’t bounce as it switches between starlink/cell.
      If you were starting over, would you still go 12v over 51v? 48/51v alternators really put out the kWs for a large pack. Volta came in my van, but I really wish I had an open system 51v platform. I would similarly upgrade it to 20kW+, and spend way too much time optimizing it. Hot tip – 51v lithium is perfect for PoE powering starlink – no dc-dc or inverting losses required.

      1. James - Post author

        Well, right now, Starlink is still in the box! Haven’t messed with it yet. I was thinking of maybe getting a dual-WAN router to combine our cellular hotspot and the Starlink, but Speedify/pi would work as well.

        For now, I’m happy with our 12v system. Who knows what I would do if I were starting from scratch though…

    10. Larry Moore

      Hi James, thank you so much for your videos. I learn so much from you. My wife and I have ordered an EKKO. We ordered it with 3 of the Lithionics batteries (the 3rd battery to be installed by Lichtsinn RV). Do you think this upgrade would benefit us? Or would it be overkill since we do not have as many batteries to charge/maintain as you have?

      1. James - Post author

        I think faster and smarter charging will help everyone, regardless of the number of batteries you have.

        1. Larry Moore

          Thank you James. Good advice and I agree. I will be checking in with Nations Starter and Alternator soon after we take delivery.

    11. Jim

      You could have thrown a 2nd “charging inverter” like a 2200W unit off Amazon for $500 including wiring and 150A breaker connected to the Transit CCP2. With this approach you can pull 150A at idle or driving from the standard Transit 250A 12V alternator. You’d then send the 120V from this charging inverter to your new Victron Inverter/Charger to charge your 12V 20kW battery bank at 1,500-1,600W/h while idling or driving. So combined with your existing 170A Balmar 12V alternator, where you are likely getting about 1,200-1,500W/H on average as well, you could have a much cheaper system charging at 2.5-3kW/h that also weighs less. Overcharging should not an issue as it should be handled by the Lithionics BMS even without the CAN based Wakespeed alternator regulator.

      The setup you went with is probably at least $2.5k with install. If you don’t have the 2nd alternator bracket already, like you do on the Ekko, it would cost over $3k.

      Finally, Battle Born batteries has purchased Wakespeed so we will see CANbus integration with their batteries pretty soon as well I suspect.

      1. James - Post author

        Well, to do what you suggest would mean I had to find room to install a second inverter-charger, which I don’t have. I’d also have to develop a way to switch the input of the existing inverter from “shore power” to “other-inverter-that-I-don’t-have-room-for power”. My current inverter is CAN capable, but is not currently setup for CAN, so I would lose the CAN based charging (unless I also installed CERBO blah blah blah). It also seems unnecessary to go from 12v to 120v and then back to 12v, when a DC-DC converter would do. And, if we decide we want more charging, then a DC-DC converter is the route we’d pursue.

        What we installed has the virtue of providing significantly more charging while fitting in the existing space, utilizing the existing wiring, and also providing CAN based charge control. The whole install took just a few hours.

        Might there be cheaper ways to get more charging? Sure. They’re just not the way I’d choose. And given that we’re talking about an EKKO, “cheapest” probably isn’t a criteria for most owners.

    12. Denis

      Hey James,
      As I’m still working at putting my system together,(1,000 watt solar with three 320 AH Lithionics battery bank) I assume that the system you just add to your Ekko would be as similar for mine, what was the price for this package ( alternator, harness…)

      1. James - Post author

        Adam is working up some packages and pricing around this. I don’t have the final details yet.
        I’d suggest contacting Nations Alternator and asking them directly.

    13. Graham Smith

      This upgrade is of clear benefit for your 5 battery rig. I rather doubt that the cost/benefit ratio is there for a single battery. So, the question is, for those who have a 2 battery rig, where does it fit in. With my old Travato KL, upgrading my alternator to a larger unit did make a clear difference when I was in the SouthWest and the % difference in charge here is about the same. So, depending on cost, and where folks travel, this might be a worthwhile upgrade to look into. Thanks for the information.

      1. James - Post author

        Agreed, the cost/benefit may look different depending on each user’s unique rig capabilities and camping style.
        But even for a one battery rig, the new alternator and charge controller would still charge faster and smarter. How much that’s worth is something everyone will have to answer for themselves.

        1. Willie

          I realize that envy is a sin, but I am envious.

          Since we are wide ranging travelers who brave 100 degree Baja California without AC and zero degree Yellowstone with a diesel heater, we are happy with our two 8D AGMs and 570 AH of battery power. They perform very well in heat and cold.

          We’ve spend our upgrading dollars on minimizing electrical consumption and solar panels. So far it works for us. But ya, a butt load of lithium batteries and a high amp alternator sounds like it would work just fine!

        2. James - Post author

          Our setup is nice, for sure.
          But if you’ve got something that works for you, that’s what it’s all about!
          Happy trails!

    14. AC

      What does this do to the fuel mileage and engine life hanging 30 extra horsepower of load out there eating 3 gallons an hour?
      Lots of drama with this setup, you should have reduced your loads and sized the system for a one hour charge driving cycle and a solar supplement.

      1. James - Post author

        Your estimates on horsepower and fuel consumption are way off. 1 horsepower is 750 watts – more or less. Even if this alternator was only 50% efficient, it would only pull about 8 horsepower off our more-than-300 hp engine. Fuel mileage is unaffected, and at idle, our engine consumes the same gal/hr as it always did. (The Transit shows this to you on the dash.)

        There’s more drama in your exaggerated comment than we’ve had in over a year with our battery and alternator setup. You should probably go back and read about our 20k project. (Among other things, you’d realize that there is solar already present in the system.)

    15. Sev

      Thanks as always for the video James – very informative. You didn’t really touch on why the individual BMS units on each battery can’t just compensate for that 14.4 V bulk charge they’re getting thrown at them when they’re at full capacity and don’t want any more current.

      It’s my understanding they can, but it’s not good for their longevity. As in the longevity of the FETs inside the BMS. I could be completely wrong though 🙂

      Could you go into this subject a bit perhaps please?

      Cheers, Sev

      1. James - Post author

        True, we were never worried about the batteries accepting too much charge – you’re right about that. Our Lithionics batteries are smart enough not to charge anymore when they’re full. Like I said in the video – “It’s not the end of the world, but it’s not great either.”

        As to exactly which components in what part of the battery it’s not good for… I’ll have to check with my sources at Lithionics and get back to you on that. But I’m happier just knowing I’m giving the batteries the charge they want – and not giving them more and letting them “deal with it”.

        Do keep in mind though that for a less sophisticated BMS, it could be more of a problem. I imagine a “dumb” battery/BMS would have a harder time with overcharging.

    16. Anton

      I feel like rather than letting it idle whole time it could be more efficient to raise engine RPM to charge batteries faster and then shut it down.
      Needs testing though *wink*.

      1. James - Post author

        Well, it’s true that raising the engine RPM would lead to faster charging.
        We haven’t yet tried idling for hours just to charge. As we’re headed into cooler weather, it’s not likely we would need to until next year. (Air conditioning is really the only thing that drains our battery bank enough to make that necessary.)
        If we find ourselves idling a lot, this is something I might look into.

        1. Phil Sandoval

          Hi James/Stef,

          Have watched every video since you purchased your Ekko.
          All the upgrades have been great & very informative.
          Have enjoyed watching you & Stef, very entertaining.
          Your explanations on the complex items have been super easy to follow & understand.
          As Einstein once said, “If you can’t explain it to a 6 year old, you don’t understand it yourself.”

          Forgive me, don’t mean to pry, but I am curious as to how much you have invested in all the upgrades. I’m guessing around $30k.

          Also interested in knowing what other upgrades you plan on doing, because this is better than anything on TV.

          Thanks for sharing & teaching.

        2. James - Post author

          Thanks for the kind words, Phil!
          I honestly haven’t kept strict track of the expenses. This is at least partly to protect myself from Stef, who would probably not be very happy with me if the truth ever got out.
          As far as other upgrades planned, I think I’ll be doing something with my bed, some more soundproofing, Starlink, some kind of bike repair stand… Nothing major though, at least not on the scale as some of the other mods.

    17. Steve

      I learn so much from your videos, even though I don’t own an RV!
      Question: why do alternators have lower output when it’s hotter outside?

      1. James - Post author

        I’m not an alternator designer, but the easy explanation is that electrical resistance increases with temperature. So as temperature increases, the alternator has to work harder to produce the same power.

      1. James - Post author

        I don’t think we’ll need to do much idling now with cooler weather coming in. But next spring, this might be something to consider if we find ourselves idling a lot. Integrating high idle with a DC-DC converter to pull power from the Ford alternator as well could really boost the charging.


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