Amp-L-Start: What is it? Do I need it? Can I install it?

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It’s true that I do a lot of tinkering with our RV.  But I’d like to think that much of my tinkering – though onerous in the moment – actually makes things simpler and easier for me in the long run.  And that brings us to this project, where I installed an Amp-L-Start battery maintainer in our Lithium-powered Winnebago EKKO.


I’ll just say up front that I don’t ever want to have to attach a battery charger to our Ford Transit chassis.  Like, ever.  That’s where this device comes in.  The concept behind the Amp-L-Start (and it’s older-but-smaller brother, the Trik-L-Start) is pretty simple.  When you’re charging your RV’s house batteries, the Amp-L-Start senses this, and opens a pathway to your engine starting battery so that can charge as well.  It will charge your engine starting battery regardless of what charging source you happen to be using (solar, shore power, generator, nuclear fission, cat on a treadmill, whatever), and it all happens more or less automatically once you’ve got it installed.

We aren’t full timers, so there are some times that we’re not using our RV and it sits idle.  This is when I’ve noticed that our engine starting battery can start to slowly lose its charge.  That problem isn’t unique to the EKKO; our last RV, Lance, had the same issue.  In Lance, I solved this problem by installing a solar charge controller that could charge two batteries at once.  The Amp-L-Start is an improvement on that solution because it will work if the battery is being charged by solar, but it will ALSO work if the RV is plugged into shore power.

So How Was The Install?

Not too bad, actually.  There are literally only three wires required to install it.  I elected to add a fourth wire to a circuit breaker that I installed.  Finding locations to access the two battery banks and physically running the wire will be your biggest challenges if you want to try this yourself.

The only hiccup I hit on the install was that the protective terminal covers supplied with the Amp-L-Start don’t have big enough openings to fit over the crimp-on connectors that are supplied.  I wound up cutting the supplied connectors off and using some smaller ones I had on hand to get them to fit.

Other than that, I completed the install with no blood, no sparks, and no smoke.  So if you’re reasonably handy, you should be able to pull this one off yourself (as long as you have some good crimp-on connectors).

How Has It Been Working Out?

Very uneventful, actually – which is my kind of mod.  I’ve done spot checks here and there, and our engine starting battery always seems to be at about 12.6 volts.  I don’t think I’ve seen it less than that since the Amp-L-Start install.  At home, we keep the RV under a carport that has solar panels on top – so most of the time, we can count on a reasonable solar charge keeping both house and chassis batteries topped up.  There was a period during the shortest daylinght months – mainly December – when I wasn’t getting quite enough charge to keep our house batteries topped off.  But even during those months, the chassis batteries were always ready to go.

I’ve also done spot checks when we’ve been camping in spots with electrical hookups, and each time I did, I found the Amp-L-Start to be charging as designed.  So I can confidently say it works with both solar and shore power.  We’ve had no issues with it at all.

Random Links

And finally, here’s a collection of random links that I think people will ask me for.  (I really do try to anticipate.)

The Amp-L-Start:  This one has the jumpers to get it to work with Lithium house batteries

The Trik-L-Start:  The original, less powerful sibling to the Amp-L-Start.

My Retro Radio Shack Multimeter:  Obviously, this is quite old, since it’s actually from Radio Shack.  I can’t find this model still sold, but the link is something that looks like its descendant.

Self-Resetting Circuit Breaker:  This is the one I went with for this install.  There are others.

Victron Lynx Bus Bars:  I love these things, and my wiring would be even more of a mess without them.  I have two in Number One.

My Wire Terminal Crimpers:  I have so many of these things, but this is the actual pair you see in the video.


And that’s going to do it for this one.  If you have questions, or if I left out a link to that one thing you really wanted, sound off in the comments below!

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.

    33 thoughts on “Amp-L-Start: What is it? Do I need it? Can I install it?

    1. Michael Blake

      Hi there! We bought an EKKO last year and drove it to Alaska from Phoenix. All went well (except a large rock into front windshield in BC). After the chassis batteries were dead in spite of being on shore power we had a local Winnebago dealer install the AMP-L start.

      That’s where the problems started. Since, the chassis battery gets drained even while on shore power. We only have the stock solar installed (with a pop top so even less). I can’t confirm the installation was correct. Now the water pump doesn’t work and we’re thinking of pulling the new mod.

      If the Amp-L start is correctly installed, it sounds like it’s draining our coach batteries but I’m not clear as to why this happens if on shore power. No ground fault could be found.

      Any thoughts on this would be greatly appreciated.

      Michael and Angie

      1. James - Post author

        Shortly after we made that video, the Amp-L-Start went out of production, so I can’t tell you to ask the manufacturer.

        From your description, it definitely sounds like a wiring issue – as in, they connected it backwards, or to something that has power all the time.
        My electrical system is different than yours, so I can’t say exactly what they did wrong, but we have not had any issues with ours.

        1. michael blake

          Thank you! for the timely reply James, we are grateful. If you want something done right….


    2. Randy Lum

      Hi: That is exactly what I am looking for. Do you know where it can be purchased. Seems company is no longer around. Is there something comparable?

      Thank you

      1. James - Post author

        Yeah, I was kind of bummed when I realized they quit.
        The Xantrex Echo Charge is a similar product, but I have no experience with it, so I can’t recommend or dis-recommend it.

    3. Don Kane

      So, who’s on second?
      No. What’s on second. Who’s on first.

      Okay. Start again.

      I said “…driving down the highway charging your house batteries with a BtB charger (so the house battery goes up to 14V), isn’t this device (the the Amp-L relay) going to open up, letting charge go unregulated backwards?”

      You said “We don’t have a B2B charger, so I can’t duplicate the scenario you describe to test it out personally.”

      So then how do you charge your house batteries when you are driving? You need to get them (ultimately) to over 14V, and that’s going to open the Amp-L relay, But then power can just go through the relay backwards not through the proper circuitry. I use a (Sterling) BtB charger for charging off the alternator, because it regulates the power charging the house batteries. Don’t you do something like that as well?

      1. Don Kane

        On the other hand I can imagine is that if your really really really big batteries are even slightly discharged, the alt is not going to be able to push them over 14V unless you drive a few thousand miles. (Because the charging house battery clamping the voltage in the 13V range, and the relay doesn’t open.) But I got the feeling that you batteries are topped out when you start a trip, so it’s prob’ly not that.

        On the third hand, I can imagine that by the time the relay opens there is not enough of a voltage difference to drive much amperage. But that doesn’t work out either. 0.4V delta with 10 ft of 10G wire (0.01 Ohm) is still over 40A current.

        I am thinking that there are a few diodes in that thing. You should check what the voltage is across the relay in different conditions: engine on, solar on, etc.

        So maybe we just talking past one another.

        “So will you tell me the name of your pitcher?”

        1. James - Post author

          See my other response about the second alternator, which is where I think our disconnect is.
          But yes, I believe you’re right. There must be some configuration of diodes in the Amp-L-Start to prevent current from flowing the “wrong” way.
          I don’t know exactly what the chassis alternator is at while the vehicle is on, probably 14.something? I’ve never seen higher voltages than expected on our house batteries though – and they float at 13.4.
          I’ll be playing around with the RV today. I’ll try to remember to check.

      2. James - Post author

        We have a dedicated second alternator. The EKKO comes that way from Winnebago.
        The second alternator is a Balmar that charges at about 170A while underway.
        The chassis and house electrical systems are only connected if I were to push the “battery boost” button.

      1. James - Post author

        Multiple ways to get the job done, for sure.
        I didn’t have any Xantrex in this rig, so I didn’t think of them up front.

    4. Scott

      Perfect timing James! I’ve been searching for a device to do exactly what this does, but hadn’t come across the Amp-L-Start yet. Just ordered one with the cut-off relay kit. Thank you for the great info 🙂

    5. Michael Yates

      Added a Trik-L-Start to my ERA and I love it. The Trik-L-Start maximum amperage is 5 amps and I like that better for my install since I only have 200 AH (I know 2,600 WH). I added lithium house batteries and have solar and for me the Trik-L-Start works well. One thing I added to the configuration was a switch to allow me to turn off the Trik-L-Start. I use the switch when I’m boondocking for a couple of days and want to keep the house batteries at their maximum charge. I know my chassis battery can last that long without a charge. btw I would never have DIYed the lithium batteries without having you show me with Lance that it can be done. As always, thanks for the inspiration.

      1. James - Post author

        Glad to hear it’s working for you.
        Adding a switch is not a bad idea. That brings up a point I didn’t mention in the video. THere’s an audible alarm that is turned on or off depending on which battery is connected first. If you connect the engine starting battery first, as I did, there is no audible alarm. So adding the switch makes sense from that standpoint as well.

    6. Erwin van Leijenhorst

      One of your more smaller mods. And as always very clearly explained what you’re doing. 🙂

      I have a question though. The fact that you’re doing this mod, suggests that it is not standard for main power or solar panels to also charge the vehicle battery. Is that a US, or more a Winnebago thing?
      The reason that I’m asking is because here in Europe, as far as I know, all the campers have it standard that main power or solar panels (should they be installed), also top off the vehicle battery.

      1. James - Post author

        Interesting. Didn’t know that about EU RVs. As far as I can tell, there’s not really a standard here in the US. In our current coach, there is an emergency start relay that will jump start the engine battery (so I suppose this mod wasn’t necessary from a “stranded vehicle” point of view). That feature is reasonably common here.
        I had installed a dual battery solar controller in our last coach – but I’ve never seen one in an RV from the factory.
        Since I’ve never seen this in a factory RV, I’m going to say it’s generally a North American thing, though there may be exceptions.

        1. Erwin van Leijenhorst

          Interesting indeed. That there are these kinds differences in something like this.
          I’ve just checked the electroblock manual of our camper (took me a while to find it online, as the printed version is in the camper itself now and not available to me).
          Anyway. I’ve seen the exact connections (plus for both starter and leisure batteries, alongside a minus for the ground) as on the Amp-L-Start, but these are integral to the electroblock.
          There’s also a connection available for an extra charger (i suspect they mean a generator, not installed on our camper).
          This is our third camper and all have had something like this installed by the factory.

          As said. Interesting these differences.

    7. Don Kane

      So if you driving down the highway charging your house batteries with a BtB charger (so the house battery goes up to +14V), isn’t this device going to open up, letting charge go unregulated backwards? How is that current regulated?

      1. James - Post author

        Amp-L-Stat doesn’t provide a schematic, so I’m guessing here, but a couple of diodes in their design would prevent any backwards flow of current pretty easily.

        We don’t have a B2B charger, so I can’t duplicate the scenario you describe to test it out personally. I suppose I could start the engine and hold open the emergency start relay… but that’s not something I’d ever do in this coach.

        You bring up an interesting point though about creating a possible “loop” in a more traditionally wired motorhome. If the main alternator is wired to charge the house batteries, which are in turn run through the Amp-L-Start to charge the engine starting batteries… which are connected to and charing the house battery… etc. what would happen?

        It seems the Amp-L-Start folks have thought about this and made this add-on: It turns off the Amp-L-Start if the engine is running.

        1. Don Kane

          Oh. I thought for some reason you were able to charge the house batteries from the van generator, like in Lance. And yes a few diodes would work. I was also wondering how the device limits the current to only, what did you say, 10 A? Does the device ever get hot to the touch when it’s working? It would be a nice circuit diagram to look at for sure.

        2. James - Post author

          I had thought about some kind of B2B setup, but haven’t needed it yet, and honestly, I kind of like the simplicity of just having two separate systems.

          The Amp-L-Start says it limits current to 15A. I’ve never noticed it to get hot, but it’s not someplace where I would check it all the time.

        3. Don Kane

          The end your message only just come thru, so the Amp-L relay answers the question!
          But still not how they limit the amperage. I think a starter motor can easily pull 50A when it’s charging, and, that case, I think the 10 G wire would only be a fuse!

    8. Lynda

      Just wanted to take the time to tell you how much we love the Americanizer septic hose adapter! What a game changer that has been for my husband and I. Thank you James for that wonderful invention! We tell everyone we know with cassette toilet about about it!

    9. Tom Geriak

      Why install the Amp L start when the Victron Multiplus Ii has a built in battery charging circuit that does the samecthing?

      1. James - Post author

        I looked into that, and besides the documentation from Victron being spotty, non-existent, and just plain not clear on how that circuit worked, there was some limitation that I didn’t want.
        I think it was that it only activated the battery charging circuit when plugged in. And most of the time in storage, we don’t plug in – but just use the solar on the carport roof.

        1. Greg Cummings

          I have read that the Victron 4 Amp trickle charge is a constant charge whether plugged in or not. That is what I use. Wish I had to run a wire only two feet like what would be needed in your setup. Good Job!

    10. Claude Cartee

      Thanks for sharing your work. Half of doing something is just knowing what can be done. When you share, you inspire others and perhaps Winnebago as well.

      Wanted to make two points. First was just to kid you that if you wanted a Boldt, you should have just bought one instead of trying to make your own.

      Second is that I know you’re out West, but not in CA. Don’t know if you heard, but around 2024, CA is supposedly outlawing small fossil fuel engines that are used in RVs. So modifications that you’ve made to #1 may become more widespread as RVers try to figure out how to go off grid in the brave new world.

      Have you heard about this law? Any insight as to how Winnebago and other RV manufacturers will address this law? Hopefully Winnebago adopts what you’ve done to #1 and provides a totally battery powered solution.

      1. James - Post author

        Thanks for your kind words!
        Yes, we’ve heard about the generator thing in California. That, and other factors, have sent the demand for lithium batteries through the roof right now.
        I have no doubt that rigs like ours – or even like ours but with battery propulsion as well – will be more common in the years to come.
        I’ll have to find something else to mod! But I’m not too worried. The RV industry moves as slowly as it can.


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