Electric motor for prop

[Alastair]

So if you got 2 x 150 watt alternators, stick them on the motor that requires 2.2kwh. you have about 2.7kwh going into your batteries, 0.5kwh over what you need to run the motor?

 

Or am i way out?

Sticking alternators on the drive shaft is pointless. All you are doing is using up the energy that is being supplied to the motor in the first place. Since the alternators aren't 100% efficient, you are wasting energy.

 

You are also mixing your watt-hours and watts. One is energy the other is power.

 

A motor could be, say 2.2kW. That's its power rating. At full power, it draws 2.2kW of power. If run for an hour, that would be 2.2kWh.

Your 150W alternators can supply 150W of power each. Two of them therefore supply 300W. Run for, say, two hours, that's 600Wh.

[Dalslandia]

Dave, we can not get more power or energy out of a motor-generator set then we put in.

just as an example, we have a 1000W (1kW) motor, that realy make 1kW of rotating power on the shaft (if we load/brake it to that power) we need 1050-1250 watt of power to drive that motor when having a load on it of 1000W

 

if that motor have a direct coupling to an alternator or generator, that is made to be as most efficient at the same rpm, with a 1000W input that generator will produce 700-900W

 

due to friction in the bearings, in air drag on the rotor, on resistance in a wires/cables, and magnetic losses, we never get out what we put in.

 

BUT Electric motors is very efficient, modern AC motors can be up to ~95% meaning 5% losses, but then it takes for a traction/propeller drive a control unit that also is ~95% efficient, so total 10% losses, and that at optimal load/rpm.

 

The often used Lynch or Agni motor, (the original rights for that motor was "stolen" of the moder company of the manufacturing company, the Agni motor is improved upon the original, and made in India) is a DC motor with a efficiency of 88 -90% (on 48V)

 

The industrial AC motor I have in the bow thruster, (11kW-15HP) is 80% efficient.

 

A diesel ENGINE is 30-40% efficient at best.

 

we cant have a 1kW motor driving a 2 kW generator and think we can load the generator to 2 kW, not even 1kW.

 

I hade that idea when I was 12, I made drawings on a half scale SAAB J35 DRAKEN with a electric motor fed by a much larger generator.

 

But no one on this world have made a self going machine that don't need energy added.

Edited January 9, 2014 by Dalslandia

[Arducius]

I haven't read through the whole thread so others might have said some of this this already, but I do have an electrically powered 60' narrowboat! It was converted (before we bought it) from a butty by Hugh Swann who owns the solar boat company. We have 24 2v cells in series to create a 48v battery bank, and eight 80W solar panels on the roof (two sets of 4 in series-parrallel). The motor is a 48v lynch motor.

 

We haven't cruised extensively, but managed from Bradford-on-Avon to Hungerford on one charge because I hadn't reconnected the solar panels properly after some work at the beginning of the summer! We also rather foolishly went though Newbury bridge when the river was pretty high, so we get a decent amount of power, but it does lack the grunt of a deisel.

 

We haven't been cruising much recently due to the river levels but have been using power tools etc on the weekends and have no trouble keeping the batteries topped up from solar.

 

Hopefully we'll be living aboard from this summer so will have to see how it goes with full time power consumption but hoping we won't need a generator if we're careful with our useage.

[Beaker]

So if you got 2 x 150 watt alternators, stick them on the motor that requires 2.2kwh. you have about 2.7kwh going into your batteries, 0.5kwh over what you need to run the motor?

 

Or am i way out?

 

As far as I'm aware, no-one has sussed out perpetual motion yet.

[Willber G]

As far as I'm aware, no-one has sussed out perpetual motion yet.

http://www.canalworld.net/forums/index.php?showtopic=62973&page=5#entry1210413

[RLWP]

 

As far as I'm aware, no-one has sussed out perpetual motion yet.

 

 

http://www.canalworld.net/forums/index.php?showtopic=62973&page=5#entry1210413

 

 

OK, no-one, other than Lisa Simpson, has sussed out perpetual motion yet

 

Richard

[Paul G2]

Personally, I would do the maths on solar panels as follows.

 

A 14 metre narrowboat has a roof which measures approximately 12 metres in length and 2 metres in width Therefore 24 sq m of solar panels could be mounted on the roof.

 

The power of raw sunshine at noon on a cloudless day is around 1000 watts per sq m, and solar panels are around 15% efficient in converting this to electricity.

 

24 x 150 w = 3.6kw.

 

3.6 kw = 4.83 hp. This is about one-eighth of the output of a BMC 1.5 diesel engine, and less than half of the legally limited output of a 125cc motorcycle.

 

If anybody wants to check these figures over and say if I've missed anything then I'm more than willing to stand corrected. Failing that I'd say that would be insufficient to act as a means of propulsion in any realistic way.

 

Your arithmetic is correct, but your reasoning is not. You are ignoring the fact that power can be stored and used in greater amounts.

[Phil Ambrose]

 

Your arithmetic is correct, but your reasoning is not. You are ignoring the fact that power can be stored and used in greater amounts.

Agreed but how big a battery bank need to be to store a worthwhile or usable amount. IMO hybrid is the way to go.

Phil

[Dalslandia]

http://www.canalworld.net/forums/index.php?showtopic=62973&page=4#entry1209617

 

on a NB we see a useful batt bank from 15-30 kWh, motor using 2-2,5kW from the batteries with losses.

if using the expensive Odessey batteries PC-1800 at 2340wH on a 10h rating it's 8-12 batteries, in sets of 4 and 4 to get 48 volt (if having a 48 volt motor/system) a 60kg each.

400-600 Ah at 48v

 

Marin-Hybrid have banks of 400 to 800 Ah useable (to 80% discharge I guess) 24 * 2V traction batteries.

With sun panels the bank can be smaller then without.

[RLWP]

http://www.canalworld.net/forums/index.php?showtopic=62973&page=4#entry1209617

 

on a NB we see a useful batt bank from 15-30 kWh, motor using 2-2,5kW from the batteries with losses.

if using the expensive Odessey batteries PC-1800 at 2340wH on a 10h rating it's 8-12 batteries, in sets of 4 and 4 to get 48 volt (if having a 48 volt motor/system) a 60kg each.

400-600 Ah at 48v

 

Marin-Hybrid have banks of 400 to 800 Ah useable (to 80% discharge I guess) 24 * 2V traction batteries.

With sun panels the bank can be smaller then without.

 

Stepping back a bit, this is exactly why I see this as still being an experimental technology. Not because it doesn't work but because it needs a lot of technical knowledge to put a system together

 

You are not going to nip down a chandlers and have a choice of branded systems, you are going to have to work it out for yourself

 

Richard

[cereal tiller]

 

Stepping back a bit, this is exactly why I see this as still being an experimental technology. Not because it doesn't work but because it needs a lot of technical knowledge to put a system together

 

You are not going to nip down a chandlers and have a choice of branded systems, you are going to have to work it out for yourself

 

Richard

Twenty years ago did the electrical installation on a brand new 38 foot wooden boat on the Thames.

 

it was a traditional style "Edwardian launch".

 

IIRC the total cost of the ceramic disc motor,controller,batteries and mains charger were approx. 6 thousand pounds.

 

This boat could run for sixteen hours on a full charge.

 

New batteries @ 4 years or so.

[Dalslandia]

from real world data, from this nice forum, sun panels give 1/3 of its rated power, average from early spring to late autumn.

 

IF cruising every second day? 3-6 h a day ~ 4,5 but say using the motor 3 h a day, in the locks it is not nesseserly, if needed the power is there intantly, a diesel maybe needs to run all the time, even if propeller is stoped.

 

if having one kW of sun panels not covering the whole roof. 10 hour of useful light at 1/3 rating = 3.3 kWh a day, 6,6 kWh in 2 days.

using 2,1 kW per hour for 3 hour propelling is 6,3 kWh.

 

Looks realistic to me, in days with sun higher in the sky, 3 hours every day would be possible, in rainy days the diesel in the parallell hybrid will be used more, using every possibility to charge from shore line when needed is economical, instead of using the diesel.

[Dalslandia]

 

Stepping back a bit, this is exactly why I see this as still being an experimental technology. Not because it doesn't work but because it needs a lot of technical knowledge to put a system together

 

You are not going to nip down a chandlers and have a choice of branded systems, you are going to have to work it out for yourself

 

Richard

 

Yes, but that goes for engines as well, you and me can put an engine together, but most can't or want, the same goes for the installation,

 

We do have most of the needed parts alreaddy. maybe not just the better one for a hybrid installed, as sun panels, chargers, inverters, batteries, diesel engine.

We need more then one guy that have the consept finnished and can install it, if there is a demand there will be more guys and "brands" of collected, of the shelf items put together in a working system.

[Chalky]

from real world data, from this nice forum, sun panels give 1/3 of its rated power, average from early spring to late autumn.

 

 

it's not quite like that. get data from solar observatories and do the calculations for your own location. Power can drop off quite quickly the further north you go. I provided a link to solar data and described a method for processing it on hear a while ago.

Edited January 16, 2014 by Chalky

[Dalslandia]

 

it's not quite like that. get data from solar observatories and do the calculations for your own location. Power can drop off quite quickly the further north you go. I provided a link to solar data and described a method for processing it on hear a while ago.

 

No it is never as simple as we want it to be, but those numbers is from 2-3 boats that recorded sun panels power for long times, a house will be different, that don't move or turn. I honestly don't have a clue where they was cruising, except for that it was in UK canal system.

 

Someone that travel 5% faster then those number I used will burn 16% more energy, and my estimate is down the drain anyway. I just point out that it is possible and practical with todays products, then what to use and how to use it, is a different question. but we see that having more then one option to charge the batteries is a good thing.

 

There is always variables, depending on where we are, how many trees and hills there is, how many suns there is on the weather chart...

Also some panels is more sensitiv for shadows and/or the angle to the sun. the only thing we can be sure of is that panels get better and better, ~15% isn't much so a few % will improve a lot. In the next 50 to 100 years they will be a lot better, if we just wait and see ... well... hm.

 

Not two summers is the same, so statistics is yesterday, but we can be sure it will rain those days we need most power.

A solar boat in sahara would be perfect, if it wasn't for those nomads smoking camels. :-)

If 2% of the sahara was covered with sun panels, it will power the whole Europas need for electricity, someone said.

[T.A.P.]

I'm intrigued by this, not necessarily to use solar panels but as an alternative to hydraulic drive.

 

If you think about it a parallel hybrid with a decent battery bank could be a good alternative.

 

Let's assume that we have an NB that needs 60hp to run at top speed and 10hp to run at normal cruising speed. For a diesel boat we'd need a 60hp engine but for a diesel/electric we could have a smaller engine, say 40hp, running at optimum economical speed, generating electricity which is then stored in our battery bank. When we need top speed we can draw on that stored energy, and of course if we have some left over we can run all our 240v appliances. We could of course always add solar panels for extra generating capacity, but that is purely top up not primary drive.

 

There's probably an optimum motor size, engine size, battery size, solar panel size, etc. which I can't for the life of me work out. Maybe someone will come in and work it out?

Edited August 6, 2014 by T.A.P.

[Phil Ambrose]

Hmm a 8 month old thread resurrected.

Phil

[T.A.P.]

I figured better to resurrect than start afresh as there's a lot of useful stuff here. There's a couple of added benefits we could add. There's the ability to run on battery only for "silent running", the fact we could put the gen-set anywhere we wanted and the possibility of putting the drive in an external pod so no chance of a leaky gland (although it could look a bit odd).

Edited August 6, 2014 by T.A.P.

[lolbaker]

hi new on here (and new to canals)

i bought a 22.5 norman 4 berth boat (about a ton in wt) and without any outboard

on e bay at Northampton

The plan was simple move it to sheffield with a 24 volt electric outboard charging batteries at moorings

bad plan this was no good as the outboard doing about 1-2 mph kills 2 batteries in about 2 hours

and visitor moorings do not have power

the outboard was rated at 96 ft lbs push and i estimate = about 2hp

so a heavy boat will need a lot of batteries and a lot of charging

as the trip was grand union,oxford, coventry, trent and mersey, macclesfield, peak forest, ashton,

rochdale, calder and hebble, aire and calder, new junction and the sheffield and south yorkshire

you can see 1 to 2 mph was not going to work i bought a 5hp honda and did it in about 30 days

 

 

[ditchcrawler]

hi new on here (and new to canals)

i bought a 22.5 norman 4 berth boat (about a ton in wt) and without any outboard

on e bay at Northampton

The plan was simple move it to sheffield with a 24 volt electric outboard charging batteries at moorings

 

 

If you do Facebook John Wonford (some of you will remember him from last year) did all the broads with electric power https://www.facebook.com/john.wonfor.5/posts/296926603838016?pnref=story

[Dalslandia]

More info here, http://www.canalworld.net/forums/index.php?showtopic=71783