Hello everyone.
I've been working on my electric conversion on my cs30 for the past 6 months and this group has helped me a lot! This is a bit longer writeup as some people have asked for it. Any pointers or suggestions are welcome! There is a pricelist and some early testing data at the end of this post.
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I acquired this boat with a seized Volvo penta 2002 and the previous owner also left a 10kw thunderstruck kit that he never got around to installing. I didn't like the mounting brackets that came with the kit as it seemed like I had to drill new holes on in the spars, and I wanted this to be an easy (quick) replacement once the diesel was out using the same holes so I decided to make a platform for the gear reduction to be mounted on and then this platform would be mounted to the old engine mounts. I used librecad which is an open source version of CAD, to design my parts and then had them lasercut online. I used two different vendors:
Oshcut was cheaper for the large parts and sendcutsend was used for everything else. I can recommend sendcutsend as they are quite fast and I've had an overall pleasant experience with them.
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My main concern was/is that the bolts at the different connection points would vibrate loose. I used nylon locknuts and locktite to try to mitigate this. Also, I figured that the brace supports that attach towards the top of the gear reduction would help some. Nevertheless, I've taken the boat out a handful of times and haven't seen any movement yet, and I'll keep monitoring.
I put the gen4 controller on an aluminum plate and added some thermal conductive paste in between with the hope thst this plate would act as a heatsink. I also mounted the contactor and throttle on this plate.
I chose to use a traditional shaft coupling on my gear reducer that matched the one already on the propshaft. I mostly did this because I don't think I could have removed the existing coupling easily, especially without hauling the boat. I inserted a R&D flexible coupling in between to ease alignment etc. I had to drill another dimple in the reducer's shaft and add a longer shaft key as well.
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When it finally came to installing the drive, a friend and I dismantled the engine down to the point where basically only the block remained. This weighed just under 200lbs and we managed to lift it out by hand. I made a small rig out of plywood to keep the shaft in place and prevent water ingress from the pss dripless seal. This was by far the most nerve wrecking moment as I wasn't sure of how this seal would react. I read everything I could find about it and talked to some mechanics etc and most sources agreed it could be done but better to haul out. Here in the bay area there are only 2 diy yards that I'm aware of and one is in Napa and the other one in Richmond has over a year waiting list. So I decided to give it a go. In the end it wasn't too bad. Some water came in but not more than I could manage to remove with a sponge and bucket until the electric drive was in place.
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The seal kept dripping however, about 1 drop every 10 seconds until I managed to align the drive perfectly. Also, after recommendation from a mechanic, the seal stopped dripping after I ran the drive for 30 min and "flushed/burped" the seal.
The throttle assembly needed to be modified as well. I guess I could have used the shifter cable but it was so easy to put together some drawings and have it cut online that I decided to go ahead and use the original throttle cable.
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For the battery I was planning on DIYing a 48v pack around 200ah with prismatic lifepo4 cells and bms. In the end, if I was to order from a reputable vendor, and considering the cost of a good bms, a proper enclosure, charger etc etc the difference in price was not large enough for me to attempt it. I ended up ordering a 48v 160ah pack from a company called Roypow. It's intended for use in golf cars and comes in an Ip67 case with charger included as well. I realize these are most likely the same cells from the same factory as DIY builds but with everything else being diy with this conversion I felt that I could spend a bit more for a ready solution with the battery bank. So far its performed very well and the charger that comes with it is pretty fast at about 22amps.
I installed the pack where the old fuel tank was mounted.
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I've taken the boat out a handful of times and I am very pleased with the performance so far.
Current draw, on a calm day with flat waters and no current has been as follows (according to Clearview display and navionics.)
6 amps gave me about 1 knot maneuvering around the marina.
20 amps gave me 3.4 knots out on the estuary.
This is with clean hull and original folding prop.
I haven't done much more testing but got about 100amp draw when I was in the slip checking for vibration etc (about half throttle which seems reasonable) . I'll post more updated figures as I continue testing.
As for cost, well, the TS kit was included with the boat but I guess it's around 2000usd at the moment.
~200 for flexible and standard coupling
~3000 for battery bank, including charger and shipping.
~200 for custom crimped battery cables from
customboatcables.com (they have also been great to deal with)
~ 350 for the stainless steel parts. Most expensive was the mounting plate at 175 usd.
~ 500 in other supplies
By no means do I think this is the best or preferred way of making a conversion. This post is merely intended to give other people inspiration and hopefully some constructive feedback.
Thank you!
/Jesper
Summary of rescources;
Roypow bank bought from apex golf carts on eBay
Go2marine.com (their return policy is not so good so make sure you order the right parts)
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