Charging Performance in the Winnebago EKKO – AT IDLE!

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Maybe they’ll eventually regret it, but our Winnebegan friends left us all alone with the Winnebago EKKO prototype for several hours recently.  What happened then is precisely the kind of thing you would expect if you left me alone with an interesting RV.  I ran a test!

I just couldn’t resist the opportunity to see exactly how much of a charge one could get from the Balmar alternator in the EKKO, and how much of that could be taken up by the Lithionics batteries.  Want to know how much?   Watch the video!


The results in the video are pretty self explanatory.  We recorded over 120 amps going into the two Lithionics batteries in the EKKO prototype.  (And those batteries were charging at 13.5 volts, not 12.)  That’s in addition to about 8 amps of running lights and other loads.  How does that stack up with the other charging sources in the EKKO?  I made this handy graphic to spell it all out.


There is one little bit that I didn’t mention in the video that’s worth noting.  In the Lithionics battery monitor app, it gives you the time remaining to either fully charge or fully discharge the batteries (depending on if you’re currently charging or discharging).  I don’t know if anyone caught this, but the time remaining to fully charge both batteries – at idle – is about 55 minutes.  It would be shorter if you were driving!  Interesting stuff!  Beyond that, there’s not much else to say that isn’t already in the video.

Yes.  The Winnebago EKKO charges at idle.  The Balmar alternator seems to put out about 1700 watts, and the Lithionics batteries seem more than capable of taking all that charge in.  We’ve been saying this for a while.  Now, we have numbers to back it up.

Case closed!

(And yes, I am working on a much more detailed review video.  It should be out within the week.)

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.

    38 thoughts on “Charging Performance in the Winnebago EKKO – AT IDLE!

    1. David Milgrim

      Hi James,

      Did you ever talk about adding a dc-dc charger (like a Victron Orion) from the chassis alternator to decrease the charge time? Do you like that idea?

      Of everyone I’ve seen and read out there, I’d trust you first, just FYI. Thanks!

      1. James - Post author

        We got a new alternator with higher capacity (both at idle and at run), so I’ve never pursued it.
        It’s a completely valid idea though. Winnebago even built that in to their latest Revel iteration.
        A Victron Orion would be a good choice for that application. They even have a model now that is CAN capable, and should work with our batteries’ data streams.

        1. David Milgrim

          Thanks, James! I saw that video at Nations and loved it.

          According to your comparison video, I think, the Transit has a less smart Balmar charge controller. Would a DC-DC Orion off the chassis alternator go straight to the battery or to the controller first, and could the Balmar handle it if so? This is way over my head, but I’d love to have the dealer do it if it isn’t complicated. Thanks again.

        2. James - Post author

          Installing a DC-DC converter in the Transit EKKO is not hard. Freedomvango, I believe, even has a kit with instructions.
          The Orion (or any similar DC-DC converter) will connect between the two battery systems (often at a battery boost solenoid, because it’s easiest there) and will not need to run through another charge controller.

    2. Randy Stonesifer

      Spoke with Winnebago today about never seeing our battery being charged by the engine (using Lithionics app). He said the alternator will not charge until the battery voltage is below 13 volts! “They do not want to be over charging the battery”. While this sounds reasonable, your video seems to show that is not the case. One chart I saw says 13 volts is about 30% charge. If this is true it seems they should be using the Lithionics state of charge rather than a simple voltage to control the alternator.

      1. James - Post author

        I’m not sure who you spoke with, or what information they had been given… but that’s not correct.
        You can run your battery down below 13 volts to disprove that statement if you need proof.

        The alternator charging in the EKKO is governed by a Balmar 614 charge controller.
        That charge controller is programmable. (There is a manual on the Balmar site that shows you how to do it – but it’s not super intuitive.)
        While there are many parameters, and I’ve long since changed mine from the default Winnebago ones, “don’t charge until over 13 volts” isn’t one of them.
        And a properly programmed Balmar 614 will not overcharge the batteries, so you don’t need to worry about that.

        You need to look elsewhere for the cause of your battery not charging.

        1. Randy Stonesifer

          You are correct (no surprise there). A second call resulted in an answer in line with your comments. I also got the voltage below 12.7 volts and still no charging from Balmar system. I am going to turn off every switch and turn back on in the hopes the Balmar controller will be cycled off and reset. If that works I will post the result. Thank goodness for the solar charging! Still only plugged in about three times in six weeks with half of that time on the road!

        2. James - Post author

          Something easy to check: with the engine on, pop the hood and look at the Balmar charge controller. It’s a blue box that should be mounted under the hood on the inside of the passenger fender.
          There is a small display on it. There should be red LED letters and numbers blinking about on that display.
          If you don’t see the red lights, then either the Balmar isn’t getting power, or is busted. In that case, nothing you do with your batteries or voltages will work, and you just need to call for Winnebago service.
          If you do see red lights, and you’re still not charging, then there’s something else afoot.

        3. Randy Stonesifer

          Got the 614 manual. The 614 is getting power but the voltage sense wire on pin 9 is reading zero on multimeter instead of battery voltage (it displays 10.2 volts on 614 display which Balmar tech says is default output for zero voltage). Winnnebago support says LT wires with 5 amp fuse over inverter feed the battery sense wire to pin 9. However, I measure 12.3 volts at that fuse which is the chassis battery voltage. Odd, seems it should be the lithium battery voltage. I followed the wires from the alternator all the way to the electrical compartments. The red battery sense wire enters the compartment with the inverter and appears to enter a clear box mounted on the inboard wall along with a yellow wire (LT?) and two high amp red battery cables. With the rather low chassis battery voltage and the chassis battery voltage being on the sensing pin related wiring, I wonder if a failed relay for charging the chassis battery from the rv systems might be a root cause. Seems likely the problem is in that clear box. Winnebago drawings do not seem to show the clear box so not sure what it is. It seems the BMS will need to set that sensing pin to zero to prevent charging when temperatures dictate, so that may be the box’s purpose.

        4. James - Post author

          Interesting that “10.2 means zero”!
          Is it possible your battery boost solenoid is wired incorrectly, or stuck closed – connecting the coach and house batteries. That could cause all kinds of weirdness…

      2. Gily

        Randy, did you figure out the issue with the voltage sense wire on pin 9 reading zero on multimeter? I’m getting the same issue, with balmar not charging anymore. Thanks!

    3. john taylor

      just curious! what I really want to know is HOW LONG does it take for the batteries to show a “full charge” when the batteries are very low to begin with, with the engine idling on the balmar?..thanks!

      John Taylor

      1. James - Post author

        I don’t know, and the precise answer would depend on a lot of variables.
        But once you’ve used one of these type systems for a while – as we have for years – you realize that running your battery down to zero and trying to charge at idle just isn’t a likely scenario. In fact, in 4+ years with Lance, that happened to us zero times. We demonstrated here to show that it did work, but we don’t anticipate ever doing it.

    4. James A

      If you don’t get the generator, is the cabinet space heated? Since it’s on the same side of the coach, as the cassette toilet, it would be a better location to store the spare tank.

    5. Dave Duncan

      Where the batteries still mostly full when the system predicted 55 minutes to recharge? 55 min. at 1700W is less than 1700Wh. But the 650Ah of Lithionics batteries times 12.8V nominal voltage is a massive 8300Wh.

      1. James - Post author

        The entire process you see here (except for turning the seat!) lasted only a few minutes. The batteries were still in the 80% range when we finished.
        Nothing here is intended to mislead.

    6. Don Kane

      I was watching your struggles with the drivers seat…2 things come to mind. 1. The back needs to be collapsed all the way forward. 2. The steering wheel needs to be all the way in (forward). Not sure if this helps because our swivel is below the slider. Our front seat is pretty easy, but not as easy as the passenger seat.

    7. Davey Knapp

      Nice. The technician in me wants to learn the cost vs. benefit of exclusively using the engine alternator combo vs. the onboard generator. If the Inverter can run the AC to cool down the coach, having a 630 AH battery bank could mean extended run times. We camp 2-4 days at an off-grid location typically but don’t know how to calculate the impact to the EcoBoost & alternator running for 1,000 hours over 3-4 years vs. the generator. Good food for thought as usual.

      1. James - Post author

        Food for thought is the right way to look at this.
        Obviously, we didn’t have the time to do a full dry-camping evaluation, but this is the info we got to get the conversation started.

        1. Dave Duncan

          Don’t ask me how I know, but idling my promaster chassis for 8 hours to run the dashboard A/C took 5 gallons of gas. The generator running the RV A/C uses about half that. Still, between solar and alternator on my Trend 23L, I usually have plenty of juice in the 4 Battle Borns. I’d probably go without the generator on the Ekko.

    8. Barry Patton

      If the inverter/charger was upgraded from 80 amps to the 150 amp charger, I calculated roughly 1800 watts which is barely more than the alternator.

      I wonder what the result would be if the generator was started along with the alternator? Would the app show the combined results?

      Also what does the alternator output at highway speed? Since the app uses bluetooth, can ;you obtain readings inside the coach while going down the highway?

      1. James - Post author

        The charging sources do stack up. That would show in the app.
        The alternator output will increase as RPMs increase, so yes, more at highway speed than idle.
        No reason why the app won’t work while underway. (But don’t play with your phone while you’re driving!!)

        1. Dave Duncan

          Wow. Stacking the charging sources could mean 300amps (or more) flowing into the batteries with the generator, solar, and alternator supplying power. That’s getting close to the maximum of 0.5C for most LiFePO4 batteries–but they should be able to take it. But can the cables coming into the batteries take that much current for up to 2 hours? Yikes!

        2. James - Post author

          Well, don’t forget that each battery in this setup is only seeing HALF of that current. So the max to each battery would be 150.
          I didn’t gauge the cables in this rig, but for reference, our 4/0 cables in Lance are in line with a 300A fuse and a single battery. We’ve had no issues with overcharging in over 4 years.

    9. Jeff Banks

      I think these batteries take a higher demand charge as the state of charge is lower. I wonder if the batteries were at say 30% what the demand would be from the alternator?

      1. James - Post author

        There certainly is some of that. But you’ll notice that more at the top end of the charge (where the demand reduces) than at the bottom.
        The Balmar alternator only advertises an idle output of 140 amps. We were getting around 130 here, so I suspect we were getting the full output.

        1. Adrian Benton

          Hi James, an enjoyable interesting video as always.
          I believe the Balmar alternator has temperature monitoring which reduces the charge output as its temperature rises. I have seen figures that suggest that an alternator is about 50% efficient so 1700 watts of power may produce 1700watts of heat? So if the engine was idling the cooling fan on the alternator would not function as efficiently. An extended idle test may see the alternator output reduce as the temperature rises, perhaps the subject of a future test?
          Could I suggest viewing this video?

          Best Regards to you both

        2. James - Post author

          Yes. Clearly, we didn’t have time to do an extended idle test.
          There *is* temperature monitoring on the Balmar…

      1. James - Post author

        Depends on your RVing style.
        For example, if you like to take your small RV to one place, and stay there for an extended period without moving, a generator may make sense for you.

    10. Scott Baldassari

      OK, so that’s good to know.
      Now, for the really important question:
      What the hell is going on with that seat?

      1. James - Post author

        The driver’s seat is fantastically difficult to rotate – as I found out.
        It’s apparently a known thing among Transit owners.
        It’s not like the ProMaster, where there’s a slide on top of a swivel.
        It’s the other way around. The swivel is on top of the slide. So the seat will never move away from it’s linear front-to-back path.
        This results in problems with the seat impacting the B-Pillar and the steering wheel.
        The ProMaster swivels are a better design.

        1. Don Kane

          Hmmm. Why do they do that? We have Scopema swivels, and the slide is definitely on top of the swivel (in our Transit).

          The one reason Ford might have done that is so the wiring harness on the 10 way seat are not wrecked, what with the slide motor being directly over the hole in the swivel.

          I had to raise the seat about 15 mm to give the harness a little breathing space. Luckily, the 10 way can get a lot lower than the normal seat, so it’s okay.

        2. Don Kane

          Well, the 10 way is okay, we got it because Rachel is 5′ 1″ and that seat definitely gets her to the right position for driving. And I like the heated part of it (the 11th way) when the van is cold and I am driving into work.

          But for the most part, if you are normal size (over 5’6″) it does not signify. The normal seat is just fine.

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