electric boat calculation

ok tnx

 

For about $600k Euros plus killer VAT tax you can buy something so so off the shelf http://www.greencarcongress.com/2008/08/island-pilot-to.html

 

sure I know about Steyr Motors Serial Hybrid Propulsion too!

see this one system too: http://www.greenlinehybrid.com/?id_g=6

 

And....


does it matter if you know about one (insufficient) hybrid system?


You asked for a fully electric driven 120 tonnes vessel! Your childish 55 t estimation was just another proof of your amateurish approach.

Forget it, it does not exist!

Even if your funds were already raised, even if they were sufficient to finance a vessel of this size (from 10 mio € upwards), there is NO WAY to get where you want to go.

A Diesel Electric propulsion is about twice the cost of a conventional. A so named hybrid (which is a combination of D / E and batteries / inverters, is about 3 times the conventional.

And you are on a budget!

Go and dream elsewhere.

Your approach is a fake Goran! A lie. Not just a dream. You try to F%$ck someone, do´nt get us involved.

Regards
Richard

 

apex is of course right if a little harsh on innocent dreamers.

Hybrid on a boat is not much other than fashionable hyped nonsense. Hybrids work great for on land vehicles in traffic where the engine output needs to be sized for occasional acceleration (very high power) but most of the time the power need in cruising is way below that. Add generative braking and you have something.

Boats work in very different conditions - there is no "waste" energy in same way as in cars/trucks.

 

Very true.

The key to making a hybrid system work in any environment is the peak to average power ratio. For land vehicles this ratio is high - the Toyota Prius, for example, has a peak power of 134hp, but only uses on average about 15hp, giving a peak to average ratio of nearly 9:1.

Such high ratios allow the option of using a primary power source (ICE) that is only capable of delivering around 11% to 12% of the peak power requirement (although the Prius ICE is much bigger than this) and relying on the battery back and much more powerful electric motor to deliver the short duration peak power bursts.

The majority of boats (and aeroplanes, for that matter) are completely different in terms of their power requirements. Their average power requirement may be around 50% to 70% of their peak power requirement, or in other words a peak to average ratio of 1.5 to 2:1. This makes a hybrid system of very limited, if any, advantage, as the additional losses from the extra power conversion steps (ICE > electricity > battery > electric motor) would outweigh any minor saving from reducing the size of the primary power plant.

Jeremy

 

There are very ligitimate uses for diesel electric propulsion but most of them revolve around commerical uses.

I have seen some enthusiasm for trying to justify diesel electric hybrids or electric boats based on wanting to be green or save the planet. These folks, like people who play the power ball lottery, are basically people who are not very good at math or science.

Now a bass boat is a good use of petrol electric blend.

 

Jeremy
Not only the peak to average but the benefit of energy recovery in braking particularly in stop-start traffic.

From what I have seen in a few places around the world the Prius and hybrid Camry are making big inroads into the taxi industry. I have heard that the maintenance costs are also lower due to reduced wear and tear on braking and smoother transmission.

Anyhow none of these benefits apply to boats.

I have no doubt that solar-electric boats are technologically possible for crossing oceans but such boats do not look much like existing cruising boats. I expect maybe 10 years or more before they are in common use.

Rick W

 

True, regenerative braking does add a bit to efficiency, but only around 8% of the energy used is actually recovered by regeneration by the Prius. I think that the main reason that taxi companies like them is the low servicing cost, low running cost and high reliability, as much as anything else. Another reason here in the UK for them being attractive as taxis is that they are zero rated for road tax and don't pay the daily congestion charge in London (currently £8 (~$12 US) per day.

I have looked at using regenerative charging on a boat, using excess energy when sailing, or when moored in a tideway, to generate power, but the gains don't look to be too good overall.

Jeremy

 

Hi everybody,
This is my firts post here and I have to say that I know almost nothing about boat designing!
However, I've studied electronics and I work many years now in the off-grid solar market both designing systems and installing them.
I've run into your forum and this post by accident, while searching for something else in the internet and I find gp333's project quite interesting, although it is very optimist and not easy at all.

I have some ideas about solar/off-grid technology integration into vessels which may help this conversation.

- Talking about vessels, for safety reasons, it would be wise not to rely only on the stored into the batteries energy! We need to have a back-up, a controlled power source. A generator! even a small one.
- The key point is the efficient power and energy management. We can have a generator running for a few hours in its efficient point of operation in order to run our loads (whatever they are) and to store the surplus energy in the batteries at the same time. Once the batteries are charged we use the stored energy to run our loads. The advantage is especially during the low-cunsumption periods where we don't have a large generator running insufficiently just for e.g. the lighting and a TV set!
- The current commercial off-grid technology is capable of handling power up to 300kW (230/400V, 50Hz), the way I described above. Electric motors with a continuous demant of up to 200kW (~260bhp) can be driven by such a system.
- Such a system weights something like 5 - 10 tons (depending on the battery bank total size and type) and needs more than 40m2 of space in the engine room. this is not a system for small boats. However, it can be smaller e.g. at 100kW / 130bhp.
- The system is capable of handling many different power sources such as a large 3-phase generator, a solar array, wind turbines, other DC power sources and shore power. Everything operates automatically (including the start / stop of the generator) and the operator can monitor everything on a PC.
- I would say that it could be the ultimate solution (in terms of fuel / energy saving)for medium vessels that do small trips and stay stable for larger periods e.g. small car ferries that connect narrow channels of less that 2 or 3NM and stay stable for more than 30 min.

- I have a good knowledge of the electrical part but I know only a few about vessels!

Hope I helped a bit!

 

great to see that someone have some electrical knowledge. Can you calculate how much two 50 Kw "eat" energy when work 2 hours and if 40m2 solar cells add energy into system at same time?

 

- 2 x 50kW x 2h would consume 200kWh of energy + loses.
- 40m2 of solar panels is about 5kWp of nominal power. It can produce 20 to 30kWh per day in a full sunny day with no shadows.

 

Altairnano batteries have this ratio: 1kw/kg

This mean 200kg of batteries = 200kWh
and if we wish not go below 50% in batteries we must have 400kg batteries for 2 hours full work? Is this right continue of your calculation?

 

If you run two 50kW motors at full power, then they will consume 100kW of power per hour. If you assume that cruise power will be 60% of full power (probably a reasonable assumption) then you'll need to provide 60kW per hour.

The maximum insolation of the earth's surface in full sunlight is assumed to be around 1kW per square metre. Typical solar cell efficiency is around 16 to 18% at the moment, so you will get a maximum power, in full sunlight, of perhaps 180 watts per square metre. 40m² of solar cells will give you a maximum power of around 7.2kW.

As a rule of thumb, you need to derate this maximum figure as you will rarely, if ever, get full sunlight on all the panels, at an angle that will generate maximum power. In Northern latitudes (around 51 deg N) I've found that I get maybe 30% of the panel rated output, so if you used this as a working assumption then you would get somewhat over 2kW of usable output per hour, during daylight hours.

There would be a massive shortfall between your power demand and the output from your solar array, so I doubt that it makes sense to use such a system.

At the moment, the only practical way to use solar power on a boat (other than indirectly by using sails) is to design a hull that has a very low propulsion power requirement and enough area to fit cells that will cope with the power demand.

Jeremy

 

This figure of 1kW/kg doesn't mean anything, the figure you need will be in kWh/kg. Currently, the best available batteries in terms of energy density (lithium) are around 0.6kWh/kg, so to meet your probable cruise power demand of 60kW you would need around 100kg of batteries per hour of cruise time, plus a derating factor for peukert factor (probably around 110% for typical high rate lithium technology cells)..

If you want to run at full power (100kW) then you would need around 167kg of cells per hour, plus the factor as above.

These figures assume 100% discharge, which will seriously impact cycle life. If you want the batteries to last for a few thousand cycles then you need to reduce the effective capacity by maybe 50%, doubling the weight of batteries needed per hour.