My Experience with EV – Part 2 Planning Time

Out with the Yanmar! On to craigslist it went. A few months prior I started watching some sailing channels on YouTube, one of which was Sailing Uma. I would highly recommend this channel and their website here, they have loads of do it yourself information, and are just inspiring to watch.

The inspiration for the electric drive came because of a few episodes Sailing Uma did about going electric.  It looked clean, simple, and absolutely great! My interest was piqued. Conventional wisdom would tell me “battery technology isn’t there yet” “you won’t have much range” “electric motors are fine on flat water, but what about wind and waves”

That last one that really hit me hard. If there is wind I will… SAIL! After all, Cinderella is a sailboat, and we do intend to SAIL around the world. So I started researching, lots of researching.

Unlike internal combustion engines, I had no experience with electric motors. I didn’t even know how they worked. Are there different kinds? Which is best?

This took me down a path that lead me all the way back to Nicola Tesla, inventor of more electric gizmos that I realized. After lots of articles, a book, My Electric Sailboats, and some searching of the various electric vehicle forums, I was convinced. Electric is the way of the future, and oddly enough, it was the way of the past.

Electric, Sailboat, Propulsion

I began by calling around the local scrap yards and electric motor shops here is Seattle to try and source a cheap, used electric motor. No luck. To Ebay!

I was eventually persuaded to small permanent magnet electric motors in the 5000 – 7000 watt size. Due to the limited capacity in batteries and the cost of components, 48 volts was the goal, which would require 4 batteries. There are a slew of battery options out there, which tohoose?

During one of my many stops at Fisheries Supply, I was handed a business card for Alex and Jack Wilkens at Seattle Boat Works. It’s amazing how tight knit the boating community here in the PNW really is, and everyone seems to be trying to help each other out.

I gave Alex a call the following week. I told him of my plan and asked for some advice. Alex was really helpful and after I sent him Cinderella’s specs, he happily did some calculations and gave me a rundown of what I should expect of my proposed system. Alex was really up to date with battery tech and gave me recommendations . It boiled down to really two options, use a conventional AGM system or a bank of Oasis Firefly batteries.

 

Ultimately, I hope to go the route of the Oasis Firefly, but cost unfortunately is keeping me away from them at the moment. I have way too many projects on my hands with Cinderella already. In the meantime I will make do with the tried and true cheap ol’ lead acid marine deep cycle batteries, 4 of which should cost about $400 and I already have one compared to the $2000 of a Firefly system.

The picture started coming together, let’s take a look at the expected cost:

Motor – $400

Controller – $400

Batteries – $300

Charger – $200

Misc – $300

Total – ~$1600

All in all, not too bad considering the cost of a new diesel engine is ~$7000 and this has the prospect of “maintenance free” operation which should simplify things considerably. I could also fit the motor beneath the floor boards in Cinderella which would completely open up the cabin! No more obtrusive coffee table.

I was also excited at the idea of regenerative breaking, or the ability to charge my battery bank with my propeller while under sail. According to the web forums, this is theoretical, and I shouldn’t expect much, but Alex at Seattle Boat Works said he saw as much as 7 amps  at 48V DC going back into the batteries while under sail, and only at 4 kts! I was intrigued.

I have an idea of current draw from installing a fancy Blue Sea Systems electric panel in Cinderella. Cinderella draws about 20 -30 amps of 12V DC while underway with instruments, lights, Ipad charging, fridge, stereo and stove on at any given point in time. Granted this is a rough estimate, but by switching to LED for running and interior lights I have room to dramatically reduce my current draw, and while under sail I can offset a large portion of this without any solar or wind!

Follow along on My Experience with EV – Part 3 where I buy expensive electronic things.

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