Cost of a "proper" electric boat/series hybrid

[Mad Harold]

2 hours ago, Dr Bob said:

A folding prop on a canal????

...er No!

It would need its own weed hatch. 

Not necessary.

Just hang on to your wife's ankles while she clears the prop.

[Alan de Enfield]

4 minutes ago, Mad Harold said:

Not necessary.

Just hang on to your wife's ankles while she clears the prop.

Not having a weed-hatch I keep this onboard

 

 

[Mad Harold]

11 minutes ago, Alan de Enfield said:

Not having a weed-hatch I keep this onboard

 

 

That's much kinder to your wife than simply dangling her over the stern.

[George and Dragon]

13 hours ago, IanD said:

IIRC the BYD ones can be charged and discharged down to -10C.

You said that before... I'm wondering if this is done with a heater inside the battery box

[magnetman]

3 hours ago, Dr Bob said:

A folding prop on a canal????

...er No!

It would need its own weed hatch. 

No it wouldn't because the propeller would be outside of the profile of the stern of the boat due to being in the rudder itself. 

 

 

 

It would be incredibly easy to clear the prop using a cabin shaft. Just stand on the bank, reach down under the stern fender and you will find the motor. 

 

A small anti ventilation plate might be needed above the motor but that's pretty easy to sort. 

 

On my canal boat I use a cabin shaft rather than the weedhatch and yes it does get used as that boat is in London where there is a lot of rubbish. I have also used the shaft (with a sharpened boat hook on the end) to clear debris from other people's props while crouching or sitting on the towpath. 

 

Interesting to consider how a folding prop would work on the cut but I suspect it would actually tend to shed things like weed because it folds.. 

 

It might actually work very well indeed and be much better than a fixed prop if you got the design right. Plus of course with a pod motor there is usually not much space between prop and motor housing so less chance of wrapped up fouling to occur. And you could add some blades quite easily if needed. 

 

Not sure how folding props work in reverse but doing canal boating properly reverse should not be needed much anyway. 

 

I know people DO use reverse a lot there is a lot of fannying about and much revving of engines but in the new emissions free world people will have to change behaviour so asking people to learn how to handle a boat is not unreasonable. 

 

I think people would find the vectored thrust thing quite eye opening for close quarters manhoovering. 

Edited December 5, 2020 by magnetman

[Dr Bob]

44 minutes ago, magnetman said:

Not sure how folding props work in reverse but doing canal boating properly reverse should not be needed much anyway. 

That says to me that you have never had a folding prop!

They are not that simple. Just a smigin of cr*p on one blade can stop it folding/opening. As per Alan above, we had diving kit on our lumpy water boat to free up the prop - and we I used it quite a bit.

Why bother with a folding one? A fixed one may knock 1/4 knt off your speed in a 60ft steel sewer tube. Essential in a racing boat but little else.

[magnetman]

No I haven't used one I just thought it made sense for a rudder mounted unit. 

 

If they are that easy to foul then obviously I will bow to your experience on that. 

 

Maybe a normal prop wouldn't slow the boat down much but I wonder how the rudder would behave if the boat was being driven by the existing diesel inboard engine via its own propeller. 

 

ETA interesting about the diving kits. 

 

One of my boats is a seagoing trawler style vessel. Twin screw with all the required gear for foul weather offshore.

I have not used it at sea as that's not my scene but unusually it does have weed hatches which are steel box tubes brought up from above the props to deck level with lids. 

 

So no diving gear needed. Seems a sensible design. It's a wet boat with freeing ports the decks are all self draining. 

 

Edited December 5, 2020 by magnetman

[IanD]

1 hour ago, George and Dragon said:

You said that before... I'm wondering if this is done with a heater inside the battery box

I don't think so, that's just what the spec says. There's a long Victron video somewhere which mentions that the Premium LVL batteries have improved low-temperature performance, also referred to here.

 

https://krannich.com.au/byd-announces-next-generation-battery-box-premium-and-expands-production-capacity/

[IanD]

For those who do want to put their own 48V (low voltage regs) serial hybrid together and want power comparable to a typical diesel there are two problems, the first is a high enough power motor (assuming you want direct drive to avoid belts and reduce noise) and the second is a high-current PMAC controller -- pretty much nothing available at 48V goes above 15kW continuous rating.

 

After talking to these guys

 

https://www.voltsport.co.uk/engiro-motors

 

they suggested a 6-phase motor (Engiro 12203 -- not on their website but it is on the Engiro DE one) which is designed to be driven by two 3-phase controllers (Sevcom Gen 4 Size 6 48V); continuous output is 24kW/1730rpm at 48V which is 32bhp at the prop, probably at least equivalent to a Beta 38 allowing for gearbox losses and loads like alternators.

 

Cost for just motor and controllers is just over 5 grand, a little bit less than the 15kW Waterworld solution except you have to add on things like throttle, display, and cooling hardware, and make the hardware to mount it, and integrate/test everything, so a lot more work to do. Still only about half the price of the 15kW Bellmarine though...

 

This needs batteries that can sustain 500A discharge current, 2 of the BYD ones (600Ah total usable) can do this but cost 11 grand -- of course you could put your own system together and save a fair bit but at these power/cost levels you'd need to be very confident of getting it right ?

[magnetman]

I helped a friend strip out the motor and controller from a £250 yogurt pot Reva Gwiz electric car a while ago. 

 

Quite impressed with the motor actually. He is going to fit it in a narrow boat.  Inboard only propulsion unit  but boat not going on rivers.

 

Using a 2:1 gearbox. I did argue about the gearbox being the wrong approach but never mind. 

 

Interesting project anyway. The motor was good for about 11kw I think it was and a proper bit of gear. 

 

Its odd comparing electric to diesel for prime movers. 

 

Things like "maximum torque at zero rpm" don't make sense because at zero rpm nothing is happening so there is no propulsion. 

 

It's true that electric works very well right from the start but suggesting you get torque at zero rpm is a bit misleading because at zero rpm you get nothing.