Decades before CO2 investment returns
Thanks for the article about the electric propulsion survey. I have an electrical engineering background and some sailing experience. Our house is partly battery powered (20 kwh) and we drive an electric car. We have owned Torqeedo outboard for years. But if you look at CO2 spend we are less than virtuous. It will take a few decades before the CO2 investment is earned back if you look at full lifecycle data. So I agree very much with the report.
From my own experience regarding boat electric propulsion:
1. For most current devices, inclusive of Oceanvolt’s, the motors are currently limited for inrush currents. The effect is a slow response to the increase and decrease of RPMS. The ramp-up speed is terrible. It makes harbour manoeuvres something to carefully plan. It is very different to our electric car, where full acceleration is available at an instant. This is due to the compromises involved – thick, heavy cables vs engine size vs consumption. It’s the same issue with Torqeedo outboards.
2. Problems – I would say about half the installations I have seen have not been to ABYC standard or equivalent. Most were missing full battery disconnect switches or the correct fuses. One sailboat I looked at and had surveyed was supplied, but the install was atrocious.
3. As for the above – an epropulsion Pod 3.0-equipped boat we put an offer in on – it was installed in 2020. In 2023 you could no longer get some of the spare parts for that model so a pod replacement required a new control panel. This is a general problem with fast-moving technology. After waiting for parts from February to July, we then declined to purchase the boat. According to the broker they only got the issues fixed by September.
4. The specs listed on most electric propulsion systems are based on 100% battery consumption. But then the manual states you should leave 20% spare or risk bad battery degradation and loss of warranty, and not charge to 100% (95% is better). But that takes the calculated system full power at 1 hour 15 minutes down to slightly below 1 hour. That is just not safe in an emergency, even for coastal sailors.
In my opinion electric propulsion should limit sailboats to go no further than 20-30 minutes (40% battery consumption) full power from a safe harbour. You use some energy going out so you won’t have 100% charge after setting sails.
5. Some companies in the electric propulsion business will intentionally omit to show what miles they are counting. The prior mentioned company often quotes US miles or kilometres but without the designation of US miles or nautical miles.
6. There are currently no survey standards for second-hand electric propulsion systems in boats. No electric engine manufacturer has devised in-unit battery health systems to diagnose and test-run a battery set-up correctly. So to test the propulsion system’s batteries you have to run it close to dry and trust the built-in systems reporting of the state of charge. But in many batteries the last 30% is often counted optimistically, meaning 30% left often equates to less than 15% left. We need the right tools to reliably test and specify remaining battery life for surveyors. If that is not available, a battery bank should be counted as zero value’ and potentially requiring a replacement item even with a one-year-old battery set-up. If the battery has been misused it could be close to expired.
On our Tesla, I or a garage can run a complete battery diagnostics, giving a pretty good idea if all battery cells are working. But we do not have that on current marine propulsion systems. In short, electric propulsion is great for some things. But not for anything other than very close-tocoast sailing. You don’t get great response time and torque. What is here today, might be impossible to repair tomorrow.
In my opinion the only choice right now apart from small outboards is hybrid diesel/ electric propulsion.
Full electric is fine for outboards or river/ lake cruising but not for open seas. The CO2 investment will never be paid back and you are not green if you opt for a fully electric propulsion system at all.
Sorry for my rambling! I want a green world but my priority is safety before being ‘green’. Full electric propulsion is, in my opinion, not safe yet. Kasper Larsen