Electric Alerion Express 33, geek green


How about three cheers for Vincent Argiro, and guys like him willing to enthusiastically test the bleeding edge of marine technology.  That’s his first boat above, an Alerion Express 33, which is also the first Pearson ever fitted with an electric propulsion system.  Those are twin MasterVolt 24V 160Ah LiFePO4 batteries and 60a ChargeMasters feeding a 7.5kW DriveMaster motor also supplied by MasterVolt since it acquired e-propulsion specialist Bellman.  And the rest of Velica’s systems aren’t too shabby either…

Argiro, who already had background in biotechnology, worked with Pearson’s Wayne Burkett on the systems design, and I was pleased to hear that Panbo entries and comments were useful for his research.  For the rest of this entry, I’ll mostly use clips from Vincent’s emails over for the past couple of months, in which he detailed the gear, what does and doesn’t work well, and why the whole project was worth the effort:

I have instrumented the boat fairly heavily, since is something of a research platform for this configuration. It has an NMEA2000 backbone, Garmin 6212, VHF 300AIS, and two GMI 10’s, Airmar DST800 and PB200. It also has a link between MasterVolt’s proprietary MasterBus and the N2K bus, a direct USB link to the MasterBus, a MasterVolt GPRS wireless monitoring interface (not yet up and running), and an ActiSense NGT-1 N2K to USB link. I just bought an HP Mini 110 as a dedicated logging and diagnostic platform for the boat.
   I get lots of quizzical looks from people in the marina as I glide by in silence while maneuvering. Getting into and out of my very tight slip has become easy now, even single-handed. The intuitive and instantaneous response of the throttle is perfect in these spots.  I can stop the boat on the dock within inches of my target, and just step off with a line
in hand.  Motoring longer distances has been easy too.  Range is sufficient, but does require some attention to budgeting the battery, if one needs to go
more than 12 nm at a stretch. Slowing down to 4 knots extends range substantially, if needed. Noise is a little greater at cruising speed of 5 to 6 knots, but is just the low rumble of the prop noise. The motor itself is truly silent.

Velica_helm_courtesy_V_Argiro.JPGNote that the Maretron DSM250 above was just recently installed because the Garmin gear couldn’t deliver the exact power information Vincent was hoping for.  I asked him to detail the issues, hopefully so that Garmin and other manufacturers will adapt to the needs of future e-propulsion users:

The most crucial quantity not being shown by Garmin is battery “State of Charge”, contained in PGN 127506 – DC Detailed Status. However, I recently discovered that they DO support PGN 127508 – Battery Status, AND compute a power measure from V and A. However, they give power in watts, rater than (decimal) kW, and the display only reads up to 1000 watts– not useful for tracking the propulsion motor consumption. Also, they use the default update rate of only 0.67 Hz, which is too slow to monitor engine performance in real-time; and there seems to be lag in the V, A, and P values, as if they put in a long smoothing time constant– about 2-3 seconds! 
   Being impatient for better numbers at the helm, I have bought a Maretron DSM250, since it DOES display SOC and just about every other PGN under the sun.  I plan to replace the central display supplied by MasterVolt/Bellmann (manufactured by Curtis for forklifts, etc.), which does not correctly display SOC, and only shows motor power to the nearest kW — insufficient precision to gauge motor consumption — as well as RPM. I can do without RPM until MasterVolt completes a planned integration of the motor controller with their proprietary MasterBus. Since I have their MasterBus to N2K interface, that is how I can get all the motor parameters and battery parameters on N2K– it is a slick device (with some caveats).

{After testing:}  The new Maretron DSM250 installation works great at the helm!  I had to motor home about 7 nm last evening after the wind died, and it was really good to be able to monitor the motor and battery in real-time, finally!


One unexpected bonus is the ease of what I call “equilibrium motor-sailing”. If one is travelling in lighter and more fitful winds, one can easily add a little throttle from the motor to stabilize forward speed. When there is a lull, the motor drives the boat along more. When a gust comes, without adjusting the throttle, the motor’s current draw falls first to zero, then reverses as the wind-driven prop spontaneously becomes a hydro-generator.
   We are still working on getting full regeneration (neutral throttle) under sail to work reliably with the Seahawk AutoStream feathering prop I chose with an eye toward racing. Some tweaks of the prop pitch and motor controller programming are ongoing to get this to be a practical contributor to bulk charging of the batteries. This is the key to enabling secure longer-distance cruising.


For anyone with a sport boat, club racer, or who primarily does daysail/weekending, this is the way to go for sure. It is such a pleasant way to keep sailing more pure, both aesthetically and environmentally.  In BC, the environmental argument is that much stronger, since 70% of our electrical power is already renewably generated, and a full charge of the 8.6 kWh MasterVolt batteries costs about 65 CENTS!  These LiFePO4 batteries are extremely stable and safe, and have an 80% available depth of discharge, so energy density is nearly three times higher than AGM. Cycle life is expected to exceed 2000 deep cycles and overall life to exceed 7 years.
   Sailing is a highly aesthetic pursuit, and one of the oldest most elegant technical disciplines we humans have. It always seemed horrible
to me to have to ignite a smelly and noisy engine at the beginning or
end of a great day of sailing, or when the wind was insufficient.
Electric propulsion has SO many advantages over internal combustion
engines– high efficiency, no flammable fuel on board, no risky
refueling, no smell, no pollution, high instantaneous torque, compact
size and more flexible placement options, regeneration potential under
sail, and more. The ONLY disadvantage, in my mind, is limited range. But
even that is now becoming less significant with lithium battery
technology. So for a boat primarily used for daysailing and racing,
there is NO reason not to go electric!

PS 10/14,  Pearson Composites kindly granted permission to publish this diagram of Velica’s e-propulsion system:


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Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now excited to have Ben Stein as very able publisher, webmaster, and editing colleague. Panbo is going to the next level in 2019 and beyond.

19 Responses

  1. Always like to see incremental steps towards making electric propulsion viable.
    Even though the battery technology still has a long way to go, I think that if I were re-powering a boat with a dead internal combustion system, I would go this route. With a new build, it’s a no-brainer, as long as resale value isn’t a concern.
    Thanks again.

  2. Noel says:

    Brad Van Liew has a small hydro generator on the transom of his Open 60 which produces around 40 amps at 10 knots.
    If you want extended range, just add a genset.
    Electric and diesel/electric was the past and is the future. The real holdback has been a well designed diesel/motor/generator/controller/battery combination.
    Perhaps the Mastervolt is a start.

  3. Jeff H says:

    My diesel died two years back and I have been using two, 24vdc trolling motors from Navigator to get my Carter 36 TX 1 ton the 2NM down the creek to the bay for day sailing and back when there is little wind. When the budget allows I hope to install a similar system from Mastervolt. Ben, keep this kind of information coming.

  4. The batteries look really nice, any pricing info? I couldn’t find it with a short search.

  5. Russ says:

    Mastervolt says 2,000 cycles at 80% DOD, then gives the battery a 2-year warranty. They give their gel cells a 7-year warranty.
    I applaud the early adopters, but when MasterVolt puts their warranty behind the product, we’ll know it’s ready for the real world.

  6. Oceanplanet says:

    Regarding the hydrogenerator (that Brad has), I’m working with Watt and Sea to bring them to the U.S. market. There are two versions; cruising (up to 12kts or so) and racing (hydraulically adjust prop pitch to keep the power output constant at higher speeds). As you would expect, the racing version is quite a bit more expensive.

  7. Last year I built a 24v, 40ah LIFEPO4 battery, using Sky Energy (Now CALB) cells) for use with our Torqueedo electric Dingy motor.
    A month ago, we took delivery of our new to us 1985 Wauquiez Pretorien sailboat. The house goes on the market Friday – we are going sailing!!! The boat came with 4 almost dead T-105 trojans + a starter battery. Instead of going the wet cell route, we “Bit the speeding bullet”. I have in my garage now a 200ah 12v LIFEPO4 battery, built by Dimitri Butvinik of Cleanpowerauto, to be installed in a few weeks. Dimitri has been designing and building Battery management systems for electric car conversion enthusiasts for awhile now. He found a thread about using LIFEPO4 on http://www.cruisersforum, joined in the discussion, and then built a BMS designed for boat/rv house banks. I ended up buying his prototype he built to test it all out, nicely fit into a 4d battery box. So the entire unit weighs about 65 lbs, and I hope it will replace the functionality of that 240lb, 450ah wet cell bank. Time will tell!!!!
    The cells on paper have much of the same characteristics of the mastervolt ones. Little/No Perket effect. 2000 discharges to 80%, high rate charging/discharging, and can take full charge to 90%, so charging times if using the engine are much reduced.

  8. Noel says:

    I’ve used these (under another name) for six years. They are everything they claim to be.

  9. Noel;
    Those cells are very nice — they are AGM cells, in a form factor used in the Telephony/computer backup industry. Compare their 500 cycles at 80% discharge to 2000+ cycles at 80% for most LIFEPO4 cells.
    Another interesting point about LIFEPO4. It is actually good for them to be left partially discharged. The current “On the street” recommendation is to leave them at 50% if you are not using them for awhile, like over the winter, no need to keep them topped off. AGMs, on the other hand, do not like to be left partially discharged. They are perfect for use in emergency power backup, gels are very good at this too. This is contrary to the way that batteries are often used by cruising sailors, where the bank may sit at a lower state of charge for much of it’s life.

  10. Noel says:

    LIFEPO4 does sound great. That’s what I believe they’re using in the Telstra, but I think they’re quire pricy. How much do they cost compared to the advanced AGM? How do you put them out if they catch on fire (they’ll burn a hole in most boats)?

  11. Noel;
    If you are willing to do DIY, the cost for the LIFEPO4 is competitive considering cycles. The BMS I got costs $450, and the cells about $1200.00. Current cost on LIFEPO4 is about $1.40 per AH (at 3.2v)
    The BMS is not “expendable” like the cells, but no doubt new technology will mean that a new BMS will be Called forthe next time you need to replace the cells.
    BTW, on neat thing you can do with LIFEPO4 is expand the size of your bank without much of the issues of doing it with GEL, AGM or Wet cells. Lets say you have a 200ah pack, meaning four, 200ah 3.2v cells. To expand to 300ah total, just wire the four 100ah additional cells separately to each 200ah cell, in essence, creating a new pack with four, 300ah cells. Apparently this is done all the time in the DIY electric car world, with good results.

  12. Note that this morning I was able to add a system diagram to the bottom of the entry.

  13. Noel says:

    At $1.40 /AH, 225 AH would be $1,260 for the bank (not including BMS). A 225 AH advanced AGM is around $600. So if both were discharged to their specs, the AGM is twice the ultimate cost, but only half the initial cost. With battery development driven by electric cars proceeding rapidly, it is quite likely that by the time the AGM dies, new options at a much lower cost will be available.
    Granted, it’s great to be experimenting with the latest, but it’s rarely the lowest cost option.

  14. Noel;
    Your numbers look correct. However, the consensus seems to be that if comparing LIFEPO4 to AGM or Wet cells to LIFEPO4, for purposes of sizing the LIFEPO4 bank can be 1/2 of the AGM size, and still function as the otehr bank would in real world usage. I personally think this may be a bit opomistic, but that is how I sized my bank, to replace roughly 400ah of wet cells.
    There are a few factors that make this possible. The first is that Perkerts effect is almost nil for LIFEPO4. So when charging, almost every am produced ends up in the batteries. Since acceptance happens later in the charge cycle, and you can charge easily over 2C (that would be 400 amps in my case!!!) alternaor charging is MUCH more efficient. Also, if discharging at rates higher than the 20ah rate (of a wet cell) then you don’t have to de-rate the capacity, again, because of Perkerts.
    Finally, since you can discharge these things so low, you useful capacity is much higher. For the cruising sailor, the practice of living between 50 and 80% charge are over. The cells I have were tested to 100% discharge, one thousand times, and capacity was still 80%!!!
    If you have a working bank now, by all means keep it and get your $$$ out of it as long as you can. When they time comes, I am sure things will look even more promising, and hopefully some big US battery maker will be reselling LIFEPO4 cells, with a good price, and warranty.

  15. Oceanplanet says:

    Great discussion here!
    Something to remember is that the LiFePO4 cells themselves are already relatively inexpensive, for what they can do. What is still expensive at the moment is the marine-specific control and protection that is important to making sure you have a fool-proof system.
    Most of the EV-based BMS’s have a single positive buss rather than separate busses for charging and discharging. While this may not seem that important at first glance, experience has shown that on the vast majority of yachts it isn’t a good idea to rely solely on the external charging sources to regulate themselves. Or even if there is a CANbus system to “talk” to the sources (and not many boats have that now!). The BMS should be able to isolate the batteries from an errant charge source if something goes awry, while still leaving the load (discharging) buss on…rather than shutting off the whole boat.
    Conversely, the BMS should be able to cut the discharge buss while leaving the charge buss on, to allow charging when a source comes back online (like a solar panel, wind gen, etc.).
    Up (or down) to a certain point, that is. To fully protect the system, at some point if no charge source appears and the voltage continues to drop then the BMS should turn off not only both busses but ITSELF, to prevent any load on the battery at all.
    So when you come back to your boat after forgetting to turn the lights off and/or hook up some charging source (perhaps the power went out at the marina!), your expensive system is not harmed in any way.
    The marine-specific BMS should also have a built-in cutoff for the alternator field (in case of overvoltage) to prevent frying the rectifier diodes which is what would happen if the charging relay was cut while the alt field was on.
    So yes, once volume goes up prices will come down. But probably not as fast as the EV world…the marine market may not be big enough to drive the cost of the marine-specific BMS, containment (important to prevent the cells from swelling), and associated overhead down just as fast.
    The good news is that solid LiFePO4 systems for marine house and propulsion are already available and selling fast to the “early adopters” and higher-end yachts. I’ve been involved with Genasun and it’s getting busier every day! Some systems out there now include the new Gunboat 90, 2 new Morelli-Melvin 65 cats, the Huckins 45 (shown recently here on Panbo!), IMOCA 60’s, at least one upcoming Volvo 70, and even a J35 that raced to Hawaii this year!
    Fun stuff.

  16. Dave says:

    ” How much do they cost compared to the advanced AGM? How do you put them out if they catch on fire (they’ll burn a hole in most boats)?”
    LiFePo4 technology does not suffer from thermal runaway.
    WHile I have no wish to rerun the discussion on cruisersforum, I would argue that with conventional charging sources currently available, there’re is no need for a sophisicated BMS on a boat.
    Firslty the charging sources can not generate HVC events as they cant reach the required voltage. LVC events can be handled by a simple disconnect system, ( these are already widely available).
    However its noted that LifePO4 LVC events occur at a voltage that is so low ( compared to 13.8) that most marine electronics and systems will have long since alarmed and dropped out , giveing the user ample time to disconnect ( or recharge the batteries). The fact is that LVC events on lead acid technoology ( if left in that state) also do significant damage, but there’re isnt a preponderence of BMS’s in such situations.
    BMS thinking derived from EV’s cannot be transferred to boats, the paramaters are completely different
    There is no way that BMS should be anything more then 10% of a LifePo4 bank cost. Its simple electronics, But currenty there a lot of “white mans magic” about LifePo4 and its associated systems.

  17. Oceanplanet says:

    I would agree with you Dave, as that all sounds good. Unfortunately, a lifetime of cruising, racing, working in the marine biz, and recently providing LiFePO4 systems has me convinced that these protections are not “white man’s magic”. Everyone can, and does, make mistakes now and then and it doesn’t have to be a disaster if that happens.
    Now, for the DIY crowd who want to save $, watch things carefully, and take responsibility for their own system, I cautiously agree with you. In fact I do sell simpler LiFePO4 batts without the level of Genasun protection…though not so often. And anyone can order the basic cells from the EV market.
    For the professional installers, 99% of the feedback I get is that there is no way they would (or should) take the risk of providing a system that isn’t as fool-proof as possible.

  18. Matt Marsh says:

    Regarding the battery management systems: The BMS designs I’m familiar with are for Li-poly cells, which are vulnerable to thermal runaway, etc. Having dealt with a few of these, my preference is for simple, redundant analog circuitry to handle overvoltage / undervoltage / overcurrent / overheat. Data reporting via CANbus is great, but computerized control of the BMS introduces too many new failure modes for my liking.
    Regarding the AE 33: I’m really glad to see someone putting together what appears to be a pretty well-engineered take on the electric boat theme. For occasional aux or boost power on a sailboat, it does seem to make sense, and such a system could easily be expanded to include a small generator or fuel cell at some point. I must admit, I’m quite surprised to see the propulsion bank completely separated from the house bank. (I can see why they did it, but it’s not to my liking.) I’d suspect that a more versatile, possibly less expensive setup could be achieved with a single large lithium bank and 48-12 or 48-24 buck converters for the 12 and 24 volt loads.
    It’s been well known for quite a while that electric or diesel-electric can be a good option when the house loads are of comparable magnitude to the propulsion loads- just look at any modern cruise ship as an example. I think a lot of what’s held the idea back is poorly designed hybrid systems used in boats where the propulsion loads are high and the house loads are low. These are situations where a conventional setup, such as a straight shaft with a CPP, would be more efficient; the result is a heavy, overpriced and poor performing boat.

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