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Comment by red75prime | Hacker News Reader

It should take around 50 hours to fully charge its batteries under ideal conditions. That is 5 - 10 days realistically. I guess it's impractical considering that it will ferry across the River Plate.

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If it can charge while sailing there is no downside. At least as long as a substantial percentage of total charge can come from the integrated solar.

> At least as long as a substantial percentage of total charge can come from the integrated solar

Yes, but that's highly doubtful. It doesn't work for EVs with panels on the car's roof - you don't get significant charge from it. It's far more practical to put the panels on a larger, fixed structure where the vehicles charges daily.

Sources e.g.

https://octopusev.com/ev-hub/why-dont-electric-cars-have-sol...

https://www.forbes.com/sites/billroberson/2022/11/30/why-doe...

https://www.reddit.com/r/NoStupidQuestions/comments/ykwd89/w...

When Argentine gets enough solar over-provision, ship owners might make money by charging during negative solar prices.

Any flat surface on a ship that is designed for electric should be covered in flexible solar panels.

Why do this if it can’t fully charge the ship? To offset the costs of charging the ship at port, to provide longer range by providing a lower voltage power source for 12V DC charging (cell phones, iPads, 5w LED lights).

So the commenter is correct, she needs panels and the fact that this isn’t part of the launch shows that they were more interested in being first than practical.

It's not a long range vessel, but it should have a fairly long service life.

Additional weight and complexity on a one off boat would be more expensive than a seperate much more standard solar and battery system on land. And you might be able to get additional value out of selling electricity from an oversized storage.

It's not sensible to draw your system boundaries around the boat by itself; there is significant terminal infrastructure; and even grid electrical infrastructure to consider.

I disagree entirely about complexity. It’s not complex at all.

I don’t draw a boundary around the boat. I see a missed opportunity to power non-drive electronics from a renewable source such as solar.

What exactly is the benefit of having solar panels on the ship? Her accumulators are more than capable of supplying all the electric needs during her ferry trips. Placing 0.002 square kilometer of solar panels on land is cheaper.

It’s possible adding panels could reduce the range because they’re heavy and so high up on the ship.

Weight won't matter much (you typically only accelerate it once, and the additional drag is small), it is just that the surface area is so small relative to what's needed that it just doesn't move the needle.

From the current top comment on this thread:

> It's made out of aluminum instead of steel. The resulting weight savings make it a bit more efficient. That's something this shipping yard specializes in.

According to that person, weight does indeed matter.

Solar panels are also made from aluminum frames or can be flexible in plastic sheets. The weight is negligible.

Yes, the weight of the hull, which is immense. Compared to that some solar panels probably weigh about as much as the paint. It's still ship, not an aircraft.

Also, thin film solar panels that can be stuck to a flat roof likely weigh less than the small portion of the battery capacity (250 tonnes of batteries total) they could theoretically substitute for.

If you were optimising for mass rather than ease of maintenance you'd probably put them on (despite the relative lack of surface area meaning you still needed to recharge at each end)

Drag is huge for boats, especially in seas and oceans that have tides and currents. Far more than a car... that also have to continuously burn oil to keep their speed, even on freeways.

See my other comment...

Weight matters for handling, particularly CoG and weather. It likely also has an impact on total cargo capacity.

There's also the matter of windage and what impacts that might have on the ship.

To say nothing of the capacity factor and reliability of electronics in a marine environment.

Pintegrated panel design,cost, and maintenance can be more expensive than the puchace price of electricity. Putting pannels on regular ground is vastly more efficient.

This is kinda like saying everyone should wear solar hats to offset their home electric bill.

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