Testing the Efoy Comfort fuel cell, and the value of premium amp hours

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

18 Responses

  1. Leftbrain Stuff says:

    Thanks for the detailed review. I haven’t bothered to look in depth at the EoFY units as no trustworthy reviews were available. I’ve spent time on Methanol race cars (drag and Indy) and have worked with fuel cells in defence so am familiar with the technology.

    We hardly use our generator now since we added 1kW of solar. If I was considering a generator today then the EoFY would probably make much more sense. I certainly wouldn’t bother with a generator today unless I was planning electric propulsion.

    Currently we can meet all our living needs with just one of our 350W panels deployed except on very cloudy days. On sunny days with all three 350W panels deployed we can even heat our hot water. We’ve just moved to Southern California from the Pacific North West so solar is a no brainer.

    We do have provision for two wind generators but I’m going to revisit wind generators or an EoFY unit or update our generator.

    The attractiveness of solar and wind is the zero cost of fuel and no human input required anywhere in the fuel supply chain.

    The big negative for the EoFY units today is the proprietary fuel option. That makes no sense for methanol which can be sourced easily.

  2. Colin A says:

    The proprietary fuel is the big annoyance to me. Plenty of boats that don’t have room for solar could benefit. I noticed the Hydromax also uses a proprietary fuel but at least it’s less expensive and cheaper to ship.
    I have been watching the Watt fuel cell https://www.wattfuelcell.com/ for a while but they still seem a little away from having a consumer product available. Plenty of boats already have Propane on board which might make this a bit more appetizing.

  3. Grant says:

    Ben – nice article on the EFOY…I’m sure it’s the right answer for some folks. I see them heavily promoted at boat shows as an alternative to large house banks, but I’m not quite convinced that’s a good substitute…
    Also – when you “strip the poor boat down and start fresh”, make sure you add an insulating cover to that high-amperage DC positive distribution busbar – or even sooner would be better. Blueseas makes a nice product for that, # 2718:

    It’s listed as compatible with different busbars than yours (which appears to be a 2104), but it will still work nicely.
    Alternatively, you could remove everything from your toolbag not made of rubber or plastic, I suppose… 😉


    • Ben Ellison Ben Ellison says:

      I agree, Grant; if you can fit more batteries, especially ones that you can safely drive down to low SOC, like Fireflies or Lithium, it’s probably a better trade. On the other hand, EFOY makes sense in situations that aren’t obvious. For instance, I know that Gemeco has sold some to high-end center consoles that are rack stored, hence no shore power, but have various 12v loads.

      And I appreciate your concern about the photo of my exposed and potentially highly loaded busbars. But not shown in the photo is large neoprene insulated panel that fits over all four batteries and the positive busbar. It would still be good to have specific protection over the latter, for when the panel is off, but that hasn’t made it off the to-do list yet.

      • Grant says:

        Roger that Ben, I didn’t see the cover. My to-do list is usually a one step forward, two steps back affair as well!
        I think you’ll like the B/S 2718 when the time comes – I fitted one recently to a similar exposed DC busbar (on a factory installation!)….roll eyes..

  4. Barb Malden says:

    Great review. We are toying with the efoy purchase concept and rationalizing the cost with its plug-and-play ease to use it in whichever “home” we’re in:: boat or camper.
    I agree the proprietary canister is bothersome. Would be nice if West Marine was a distributor! The distribution map in Europe vs USA /Canada/Mexico is envious!
    And I wish I d known or I would have snatched up your test efoy in a blink! 🙂 thx for your review.

    • Ben Ellison Ben Ellison says:

      Thanks, Barb. I wish I could find more online or elsewhere about folks who have tried using high grade methanol from other sources like this one:


      While I understand the convenience and safety of EFOY’s own canisters, thin distribution originating in Germany necessarily adds a lot of cost to what is apparently a fairly widely available fuel. But how does an intrepid EFOY owner decant the methanol into empty EFOY canisters without introducing impurities or water? Or how does Gemeco get West Marine to carry the canisters efficiently?

  5. steve says:

    There is a lot of Hydrogen vapour ware on the wires these days, most embeding hydrogen in a liquid and using it like gasoline.

    The generator people Panda have a real product. It costs 20K and runs on Propane. I hope you will have a chance to review it.

    For sailors the end of ICE engine seems to be around the corner.

  6. steve says:

    I was looking at the Efoy site today. They have a 250 watt propane fuel cell, and a 500 watt methanol. The internet says I can buy pure methonal for $1.14 a gallon. I wonder if you could fill up a 100 gal tank? For a blue water cruiser with deep pockets and the patience to wait a day if necessary, it may be the ICE engine is something no longer needed.

  7. Rick Nicholson says:

    A couple of comments. 1) I looked into Hydromax in British Columbia and was not impressed with the sole distributor for BC or maybe further. When I told him what I wanted to do, using it to run some occasional electrical things like a toaster and hair blower. I was told it wasn’t suited for those operations (it is) and I should look elsewhere. When I sent an email for a quote on fuel I never got a reply back. I think Hydromax is the better system but its infrastructure sucks and I wouldn’t want to be at some distant location like the top of Vancouver Island or Southern Alaska attempting to get the fuel for the unit. 2) The author states the Efoy is a good system, especially as a supplement to solar. In the Pacific Northwest, coastal BC and southern Alaska, I’d say the reverse if you cruise out of season a lot. Solar is a nice supplement to Efoy. In other words get Efoy first if you want power on cloudy days which can go on and on in the West Coast. If I was in California or Florida I’d agree with the author.

    • Ben Ellison Ben Ellison says:

      The Hydromax does look like an interesting alternative to Efoy, if it works as promised:


      But I agree with the dealer that serious loads like toasters and hair dryers don’t make much sense for low output and relatively expensive fuel cells. Also, my boat is mostly in Maine, at nearly 45N with fairly frequent fog or overcast skies, and the solar panels do very well as prime power source when not motoring (which is sadly most of the time). Two of the last three winters, the boat stayed in the water and rarely needed topping up from shore power.

  8. Anonymous says:

    I have four Fire Fly batteries (117 amp each) for a total of 468 amps. You can drop Fire Flies down to 80 %, some claim even lower, but at 80 % I have 374 amps per day. Taking points from the Inverter store in assisting calculations, assuming a 2000 inverter going full time for one hour is 166.6 amps used. My fridge & freezer use about 100 amps a day (I’m talking about stationary use, no engine juice from the alternator – I don’t have a generator). Using a toaster for 15 minutes a day and a hair blower (at medium power) for 5 minutes a day means roughly another 55 amps of use. So my daily usage is 155 amps. So its not until day three that I begin to need the Efoy to catch the batteries up, but of course the Efoy would be on some of the time on each of the three days. I have a new Merc engine (refit) with a 70 amp alternator and I can’t bump it up to 140 or higher or my warranty will be affected. But eventually a larger alternator will go into the boat. Cruising an average of about 3 – 4 hours every couple of days will also help top up the batteries along with the Efoy.

    • Ben Ellison Ben Ellison says:

      Anon, I also have a four FireFly AGM house bank (I’m pretty pleased with after 3+ years of heavy use) and it might be useful to you to see how it works in the real world beyond spec sheets. And you can, thanks to the amazingly detailed Victron monitoring I installed last winter:


      If you go to the Advanced section you can select any date period since February and you can also zoom into the data graphs. The SoC is not very accurate in my estimation but the voltage levels and amps in/out are.

      The constant 2a loads you’ll see now and throughout are AIS, WiFi router system and various monitoring systems like Victron Venus and FloatHub. Sometimes there’s another 2a of NMEA network adding to the monitoring. And most of the season there’s refrigeration loads similar to what you estimate, though of course they vary some with use and weather. On the many days I was on the boat testing electronics there are all sorts of loads including running the microwave at half power on the Multi 2000 inverter, or variable boiler systems loads when it was chilly.

      You’ll see that most of the Firefly use was covered by the two 140 Watt solar panels I installed in 2012, but the (nominal) 140a alternator did contribute on various day trips and during the August cruise (though it’s shown as positive load because the Victron system can only see the shunt, not the alternator). But the panel output is monitored in detail.

      I know this data means much more to me because I usually know what’s actually happening on the boat, but I hope it also illustrates real battery life on a sometimes cruising boat that hasn’t seen shore power since April and doesn’t have a generator.

      Incidentally, I’m pretty sure that I have run the Fireflies down to 20% at times — again I don’t have accurate SoC, and don’t think many boats do — and I’ve definitely charged them partially a lot. But I’ve also done restorative high rate charges when on shore power, and I believe that the solar panels often help to top them up and maintain capacity.

      PS There are detailed entries about Gizmo’s batteries, Victron system, solar panels etc. here on Panbo.

    • Grant says:

      Anon – you might want to reconsider holding off on that alternator upgrade – your Mercruiser 70A unit is internally regulated at a fixed 14.4V – and your $2,000 worth of new Fireflys are not going to like that long-term. They have specific float voltage requirements of 13.4-13.5V, and other criteria – see manual. They’re a great battery, but I wouldn’t make the investment until I had all my charging sources sorted out to deliver the appropriate charge profile they recommend…

  9. steve says:

    another promising contender with some real wattage. Bonus you can use your own methanol.

  10. Steve K says:

    I have installed and used 2 efoy fuel cells consecutively on a sailboat, for single handed sailing. I have used one for an Atlantic crossing. The other for sailing in the Caribbean.
    In Europe the use case is ok, since the cartridges to re-fuel are available in many locations. In remote places it is close to impossible to get cartridges – and believe it or not most of the Caribbean islands are ‘remote’ for Efoy cartridge re-supply.
    In addition, both fuel cells failed. The first (an efoy 140 comfort) started to reduce power-output after only 900 hours of usage. I then had to purchase a replacement and opted for the larger efoy 210. It worked fine for one journey only. After that it sat on the boat for a few months without being used, and upon my return failed to start, citing a ‘firmware update required’ that was impossible to be fixed, even with the firmware update box that was sent across the globe to the Caribbean island where I was… The efoy service team was ok in providing feedback, and in sending the update box. But in terms of really helping me to solve the problems with their products the service is a disaster. I ended up having to carry all the replacement costs (both cells cost approx 8 k USD). I would now be forced to carry the shipping cost for the basically new efoy 210 to have it tested, and then would probably have to carry the repair work, and the shipping back to the Caribbean – or again buy an new one…
    I feel like being an ‘alpha-tester’ of an unfinished product that is not really tested for the application on a yacht, albeit this is exactly what it’s made for, supposedly.
    In short

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