Electric conversion

[Lablitzwing]

Hey all,

I have an old Starcraft aluminum cabin cruiser with a Volvo penta aq120 in it. Previous owner didn't care for it well and I think the engine is pooched.

I got a hair brainled scheme to convert it to electric motor with solar battery bank power and gas generator backup. My question is how powerful of a motor would I need? Not interested in speed, just maybe 6-8 knots at most. I've heard that even a 5hp or less electric motor could move it at a decent cruise speed.

Thanks in advance!

 

[alldodge]

Howdy

Solar is not going to work, not even to recharge the battery unless you go high dollar and then they are to big, so skip that part.

As for the amount of HP needed, well your not going to go far or fast, but after removing the motor it won't take a lot. I'll guess you will still need a few large batteries. Be only on small lakes and ponds and get a large 24V trolling motor or the like

 

[southkogs]

Welcome aboard Lablitzwing:

This tends to come up a couple times each year which is probably why most of us will start sounding like we're just chopping it off. There are a few electric marine engines out there, but not too many of them seem to have a long duration to the charge. Do you have a trolling motor you can toss on the boat and give it a whirl to see what kind of results you get? In theory a 80 or 160lb thrust motor could give you decent motion, but you'll also want to see what kind of steerage you have with a boat that big (including stopping).

Solar charging is a whole other consideration ... If you're able to let it sit days at a time, and then only use a single charge, it might work. If you wanna' go out two days in a row: batteries and charging now become a bigger conversation.

You may want to do a search in the forums and look at some of the discussions of electric power. There were some pretty cool links in some of them.

 

[Scott Danforth]

welcome aboard.

as stated, solar wont work. plan on a lot of batteries.

here are some conversions

http://forums.iboats.com/forum/gene...my-2016-bayliner-175-bowrider-to-all-electric

http://forums.iboats.com/forum/engi.../523258-how-would-i-convert-to-electric-power

if it was me, I would rip out the old AQ120 with the drive (most likely an 250 or 270) and find a late 80's to early 90's VP 4.3 / 5.0 / 5.7 with a 290DP, DP-A, DP-B or DP-C, bolt it in and use the boat.

 

[Lablitzwing]

Thanks for the good advice so far.

I looked up some of the available electric engines and saw in one brand the smallest could potentially propel the boat decently.
The 4hp I used as a kicker could propel it at about 4kmph.

I was hoping to source a similar motor from a cheaper place in case my scheme did not work.

To elaborate a bit, I was planning on removing basically everything in the boat now (engine, fuel tanks, controls) except the outdrive and attempting to mate the electric motor to the current outdrive (probably need a motor with significant torque for that.)
For batteries I was planning two separate banks of up to 6 agm deep cycles where the fuel tanks used to be hooked up to a 250 watt solar system to charge each bank. Each bank would be independent of the other so if one drains then the other would still be full. As further back up I was looking into an inverter generator to power the engine if both banks discharge on one trip.

When I got the boat I basically paid for the almost mint tandem axel trailer only so I can play with it and if I destroy it I'm not out much (anything added can be repurposed later such as batteries etc). If I get the drive system working then it might be worth full restoration and updating.

 

[alldodge]

Turning the outdrive takes several hp

 

[gm280]

I have no suggestions, but I will say follow your dream. Only you can make the final decision as to what you truly want. Just bear in mind that the previous suggestions are from folks that know a lot about boats and engines. So heed their ideas and go from there. If you still have the wondering curious idea still floating around in your head, then follow it knowing it could be a no go. JMHO

 

[jbcurt00]

Good luck w your project

Post some pix, Chieftain?

Try not to do any permanent 'harm' to the hull. If it becomes a project you arent going to finish/keep, lots of interest in rehab'ng old Starcraft hulls.

Some might use the term fanatical
http://forums.iboats.com/forum/owner...tarcraft-boats

 

[Scott Danforth]

Turning the outdrive takes several hp

about 20hp or more is lost thru outdrives via the u-joints and the gear sets

 

[Lablitzwing]

At one point I was considering selling but only offers I was getting were super low balls (half of the value of just the trailer)

If the electric conversion fails I may look into the option of getting the newer Volvo motor like was suggested above.

 

[Bondo]

When I got the boat I basically paid for the almost mint tandem axel trailer only so

At one point I was considering selling but only offers I was getting were super low balls (half of the value of just the trailer)

Ayuh,.... Welcome Aboard,..... Unfortunately, an ole hull with a bad driveline is worth exactly what ya paid for it, which sounds like 'bout the same money you've been offered for it,...

I can't see yer electric motor idea workin', at All,...

Even if ya gut the boat, includin' the drive, 'n put an electric trollin' motor or 2 on it,....
Yer gonna be goin' very slowly, for a rather short time,...

 

[jimmbo]

Eventually Electric motors will find there way as main propulsion units. As in cars, the weight of the batteries will their the Albatross. A few years ago there were some videos on youtube showing an Electric Outboard on a 16 runabout with the performance of a 135 - 150 hp.
https://www.youtube.com/watch?v=ocBjwDom0rA

 

[MH Hawker]

their aint no cheep in boats, try golf

 

[km1125]

You can definitely do it. Search youtube for electric boat and you'll see all kind of variations.

If you don't want/need to plane, then it becomes much more realistic and much less expensive. Then the real challenge is how long you need it to run. There are larger Troqueedo electric outboards that you could pair up, or you could do an electric conversion to your outdrive (noting that you will lose some HP just through those gears)

On the recharging.... if you had a 250w solar cell dedicated to each bank of 6 deep cycle batteries (lets just say Group 29s for example), that would be charging at a peak of about 20 amps... with 6 of the batteries, they'd hold about 630 amp-hours, so it would take 31 hours of peak sunlight to fully recharge them... or about 7-8 days.