Hull: Yep, a tunnel stern and the hull design is from William Atkin from the boat "Little Water" designed in 1947 (with changes to bow and stern line and cabin) and the cabin, layout was based on Dave Gerr and his boat "Escapade"
Prop: 3 bladed 16 inch prop, 22 teeth on the motor gear and 56 teeth on the shaft gear, Thoosa motor runs at 60 rpm per volt, so 2880 rpm at 48 volts.
Some measurements we took (the speed measurements were not precise unfortunately):
500W = 2 knots
1000W = 4 knots
1500W = 4 knots
5000W = 5 knots
6000W = 6 knots
More testing needed!
Cheers,
Jay
Thanks Jay. I'm sure I missed it, but can you comment on:
· Prop size/type
· Tunnel counter-stern design---looks super cool
· What speed was this data taken at?
My 26' boat www.evalbum.com/492
With a pack that has a capacity just under 30kwh, I get pretty decent range.
But it all depends on average speed.
The boat can do 7knots, but that's at about 10kw with a motor rated for just 8HP (6kw) continuous.
At 6kts, the motor draws about 5kw and so at most 6hours of cruising or 36n-mi and 750wh/mi.
At 5kts, power drops by half (2.5kw) and so at most 12hrs or 60n-mi and just under 500wh/mi.
At 4kts, about 1.3kw is used and range could go up to 92n-mi or over 100miles or about 330wh/mi.
Speed greatly effects power and range attainable.
Love the boat!
-Myles Twete
26' Reach Of Tide, converted to electric in 2003
From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Jay Johnston
Sent: Thursday, May 11, 2023 6:33 AM
To: electricboats@groups.io
Subject: Re: [electricboats] EV Gavia: Electrical suggestions
Thanks to all of you that provided suggestions on this (now old) thread.
We have tested the boat in the water and have promising results
Short video showing the test
Distance traveled: 12.05 km / 7.48 miles
Battery used: 2.1kWh to go 7.48 miles (!)
So that is (maybe): 3.56 miles per kWh
With the full battery, that comes to 15.2 kWh * 3.56 miles = 54.1 miles on a full charge!
I think this is very optimistic, and the accurate distance might be 20% lower, maybe.
Changes we implemented since previous email was sent to this alias:
- We are using a 12V bank (two battleborn's in parallel) in the forepeak to handle the heavy loads (bowthruster) and 12V house loads, vs DC/DC converter
- We charge the 12V bank using an AC->DC charger, powered by the Multiplus II on AC (yes, its not efficient but this maintains DC isolation between the 48V and 12V systems. We had trouble finding an isolated 48V to 12V charger)
No solar yet, really hoping the right semi-flexible panels at the right size will be available
On Fri, Jun 18, 2021 at 8:05 PM Reuben Trane via groups.io <rjtrane=me.com@groups.io> wrote:
I had it working till it caught fire. Quickly put out but the range extender was toast. Yanked it out of the boat.
It would have been fine if I'd 1) installed outside the boat & 2) tighten the oil drain plugs prior to running.
During early tests it put out about 3,500 watts max. These units are advertised as having higher output in watts but only at the higher voltages. They ate amp limited.
If you have a good outside place to mount I'd recommend purchasing a 4kW DELLENT from Tom's Machinery - AliExpress. They replaced broken items. These smaller units come pre-wired with internal electronics. They use the generator as the starter.
On Jun 18, 2021, at 8:03 AM, aasmith970@gmail.com wrote:
Reuben,
I am interested to know more about your range extender and how it's working.
I have a Newport 28 6000# displacement monohull and have re-powered with a 48 volt 7.5kw air-cooled 3 ph AC motor and what appears to be a fake Savcon controller meant for a large "tour" vehicle. I purchased the Chinese system unused from someone who was going to convert but never finished. I have limited range because of the AGM batteries that came with the set up but 350.00 all in I'm very lucky to have it all running for the second season now. I will be building a Lipo pack out of CALB cells soon, but I would like to have a back up. I rented a small 2000 watt Honda and tried some motoring with it and it seemed to work but is less than ideal and quite stinky to have in the cockpit.
I saw your post and thought that might be perfect for my situation. How does it work? Have you needed it?
Thanks for any input!
Aaron
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