# electric boat calculation

Discussion in 'Boat Design' started by gp333, May 23, 2010.

1. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

Have here someone that help me calculate range for possible electric boat calculation
480HP electric engines power (6 x 80HP electro engines)
Displacement empty appr. 55 tons

how much batteries I much have? count that is possible have 22 meters of batteries 3 lines of accumulators x 22 meters

How much will be generally range of yacht like this?

Note: pls. focus on answer.. no ask me where you will buy electro motors? or you have money buy it all and ask here etc. pls. no imagine any other 'movies'

2. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

1) 50Kw water cooled electro motors (67 HP) are available from http://www.propulsionmarine.com/price_list.htm

2) At present good technology, I would go for the Altair Nano technology

3) 22 meters x 3 = 66 meters would give you. Probably 1 Mw / 250Kwh battery-pack Maybe 2 battery packs from Alair Nano www.altairnano.com

4) You would do +/- 40 minutes with 6 x 50 Kw motors. Or just over an hour with 2 packs and with your engines.

5) My vision is that within 20 years , they will be on the sea, but with a different kind of battery system, not the one of today’s world.

6) Today we are restricted to small boats, with added solar and wind energy , we could go along the coasts and rivers, but not yet across the ocean. .

7) In your case you could go to 1000 Volt motoren to reduce the massive current flow..
Bert

3. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

1) 50Kw water cooled electro motors (67 HP) are available from http://www.propulsionmarine.com/price_list.htm
RE: http://www.piktronik.com/index.php?...category&layout=blog&id=20&Itemid=115&lang=en
here have 80HP electro motors water cooled too

2) At present good technology, I would go for the Altair Nano technology

3) 22 meters x 3 = 66 meters would give you. Probably 1 Mw / 250Kwh battery-pack Maybe 2 battery packs from Alair Nano www.altairnano.com
RE: what you mean by "2 packs"? How much batteries is 2 packs generally?

4) You would do +/- 40 minutes with 6 x 50 Kw motors. Or just over an hour with 2 packs and with your engines.

5) My vision is that within 20 years , they will be on the sea, but with a different kind of battery system, not the one of today’s world.
RE: :-(
http://www.electric-boat-association.org.uk/
Four 250 ton Rolls-Royce Mermaid™
electric propulsion pods totalling
86 Megawatts drive the QM2
along at almost 30 knots.

and Queen Mary 2 - She's the
world's largest electric boat !

What engines are here in case?

Is this electric engine too?
http://www.rolls-royce.com/marine/products/propulsors/podded/index.jsp

6) Today we are restricted to small boats, with added solar and wind energy , we could go along the coasts and rivers, but not yet across the ocean. .
RE: yes solar can be added.. but voltage can be charged in marinas too

7) In your case you could go to 1000 Volt motoren to reduce the massive current flow..

4. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

My apology, I thought you were only thinking of pure battery energy. The Q2 has diesel engines with electric generators , which feeds the electro motors I assume. That is a different ball game. You need to ask a NA about the construction.

5. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

GP, there are two methods to run your propulsion.

1) You have Direct Current motors, (DC), but because if you exceed the 48 Volt and have a 200 Volt DC system and you would touch between the + and minus, you are dead. Your hands will cramp, it will not be able to let go and you will die. Therefore on an electric boat it is not recommended to go over 48Volt DC.

However you could convert the (DC) battery voltage via an inverter and keep the heavy current cables short , close to the battery and bring the Voltage up to 300 Volt AC (Alternating Current) and if you now touch a part, you have a hell of a shock, but probably will survive, provided the body resistance is high enough to let less than 20 MilliAmpere to go through your hart.

Thus, if you have 48 Volt motors / 50 Kw, it means a direct current of just over a 1000 Ampere from your battery. Your cables will have to be at 6 Ampere per mm2 , massive. Your losses are therefore also high.

If You have a dieselgenerator and you generate 1000 Volt AC, your current at the 50 Kw motor is only 50 Ampere and that is about 10 mm2, but better to be 16 mm2 to keep the losses low. Most likely QE2 will have high Voltage motors like they use in the mines, greater than 10 KVolt (just to keep the current low)
Bert

6. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

I was mean pure battery energy too. If we have dieselgenerator we again must use same amount of diesel like we have diesel boat engines? Or this solution have lot lower diesel fuel usage?

You are not answer me this below:
3) 22 meters x 3 = 66 meters would give you. Probably 1 Mw / 250Kwh battery-pack Maybe 2 battery packs from Alair Nano www.altairnano.com
RE: what you mean by "2 packs"? How much batteries is 2 packs generally?

Regarding higher voltages.. sure it can make dead, but connectors will not be opened to hand touching! They will be isolated and you cant touch directly at all! I am looking any solution but that calculation make possible over ocean trip. Can you show any calculation that can realize it maybe? count that we can have lot batteries really...

7. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

It is convenience, ONE big diesel engine and possible 20 or whatever electric motors. Most likely it could save some diesel, but it will be for debate. I think
it is just the control from a central point and convenience in my view. An electro motor has 2 bearings, that is all, no battery to start up, no drive belt to make it to start up etc. Convenience to me for the Captain of the QE2

This depends on the voltage of the motor, how many batteries are in serial and parrallel, there is no generally. A small boat can run on 3 or 4 big single batteries and a bigger boat needs maybe 16 batteries 4 x 4 parallel / serial. However in your case you have to calculate what Voltage and current is required. Those Altair packs are massive packs for solar energy installations. You have to visit Altair website for dimensions.

Yes, but I would not take the risk on a boat which moves and is not stable. At one stage you need to work on it without the insolation.
I don't think you are able at this present time to consider a trip with batteries only. You need Diesel/generating power.
Bert

8. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

To enable you to travel with a total of 480 Hp engines i.e. 360 Kw and assuming your speed is 36 Km per hour (displacement boat) and the distance accross the ocean is 3600 km , you need (3600 divided by 36) x 360 Kw = 36.000 Kwhour i.e. 36 Megawatthour. That is 36 massive Altair Nano packs You need probably to tow a QE2 to store those batteries.

I like you, keep on having a vision or dream, nothing wrong with that. At any time you can ask more direct questions, if it is still unclear.

Bert

9. Joined: May 2007
Posts: 461
Likes: 32, Points: 0, Legacy Rep: 458
Location: ohio, USA

### Pierre RSenior Member

A rough guess would be needing 85,000 watts to drive a 55 ton boat of that length about 10 NM. A rough guess on 22 meters of batteries in three lines would give 47,000 amp hours. Now to drive the boat 10 NM you would need 6,900 Amp hours. You would not want to discharge to more than 50 % so that means about 34NM before recharge.

This is assuming a displacement speed in knots equal to the square root of the water line length in feet. This is also assuming a lead acid type of battery.

10. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

ha it seems possible! we can have 9 lines of batteries as example
any idea how much cost so lot batteries generally?

how much time need it charge it by classic voltage connector in port?

how much time generator can charge batteries too?

and addon is solar power on roof as example, 15 meters x 3 meters of solar cells: I am happy if this can cover electricity for rooms and living people on boat. Can this cover it?

11. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

If count right:
http://en.wikipedia.org/wiki/Altairnano

1000w/kg

36 000 000 : 1000w/kg = 36 tons of batteries :-(

12. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

I cant have more than 10 tons of batteries (in 55tons of displacement I was count inside these 10 tons)
than this is 10.000 Kwhour and if I understand good this is 1000km range?
Pls. confirm?

13. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

Shortest points over Atlantic ocean is 2,575 km

14. Joined: May 2009
Posts: 2,521
Likes: 47, Points: 58, Legacy Rep: 223
Location: South Africa Little Brak River

### BertKuSenior Member

Hi gp, but then you must come down with your 460KW motors to something more realistic, like 85 Kw motors, like PiereR suggested. But with 85 Kw it also only bring to not more than 10.000 Kwh divided by 85 = 117 x 10 Nm = approx 2000km. You need like safety in an aircraft at least 50% reserve, otherwise you deepcharge the batteries. You sure like to ensure some reserve for the unforseen? But the most important question is how are you going to re-charge the batteries at the other end of the world? You may only get an 25 Ampere wallplug and you could maybe only charge with single phase. It can be done, but it is too risky.

PierreR with what Voltage did you make the assumptions.
Bert

15. Joined: Mar 2009
Posts: 98
Likes: 0, Points: 0, Legacy Rep: 10
Location: Italy

### gp333Junior Member

Hi gp, but then you must come down with your 460KW motors to something
more realistic, like 85 Kw motors, like PiereR suggested. But with 85 Kw
it also only bring to not more than 10.000 Kwh divided by 85 = 117 x 10
Nm = approx 2000km.
RE: I see that minimum need be 4 motors x 80HP (320HP) by 55 tons vessel, because bad weather conditions etc.
But sure we must not plan full power all the time. Sure construction like that can have on/off switch motors, and simple shut down
2 motors in some moments etc. And with other 2 use 50% of power and in this moment you use 80HP as example...

yes, and maybe is for project 1 must not be over ocean availability, but with above availability you can use vessel in lot other locations.. practically all except over ocean!
this is good enough that project not be only 'dream'...

You need like safety in an aircraft at least 50%
reserve, otherwise you deepcharge the batteries.
RE; yeh I see

You sure like to
ensure some reserve for the unforseen? But the most important question
is how are you going to re-charge the batteries at the other end of the
world? You may only get an 25 Ampere wallplug and you could maybe only
charge with single phase. It can be done, but it is too risky.
RE: why risky not understand? I assume that I can charge batteries at any marina usual voltage plugin! Is not problem stay more hours till all loaded...
what wrong here now?

and addon is solar power on roof as example, 15 meters x 3 meters of
solar cells: I am happy if this can cover electricity for rooms and
living people on boat. Can this cover it?

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.