Battery power, the way forward ?

PaulRainbow

PaulRainbow

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Always lots of threads about batteries on here and a few discussing the the viability of using batteries for propulsion. Mercedes have recently launched a new electric car, could this technology be ported to the marine World ?

The compact nature of the batteries would work well on a boat, fitting into some of the areas of wasted space, or even in the keel itself. The ribbon release would need some modification though.

https://www.youtube.com/watch?v=iEjTwsfqHOY
 
I like the idea of a common battery format being used in diverse applications. The ubiquitous AA battery is a tad too small for convenience for applications like outboard motors. No worries - how about an electric outboard that can use a battery pack from an electric bicycle? As we don't have an industry standard form factor for bike batteries, I'd settle for a Torqueedo or ePropulsion outboard that uses a Bosch ebike battery. One outlay, multiple uses.
 
The key issue is where the batteries will be recharged. Better on a sailing boat, but on a power boat almost certainly this will need an engine at least as get you home power if the batteries go flat.

The early Green battery power boats look bloody awful, a bit like the latest BMW electric cars, still they all have to try don't they.
 
I think there are a few boats on the canals which are electrically powered and propelled. I am aware of one quite big one which is mostly powered from an array of solar panels.

No reason this cant be utilised on seagoing boats, subject to space for the panels/

Without solar, you would need some way of charging the batteries to run the engine....... running a genny to charge the batteries to run the electric engine would seem to defeat the object.
 
Lon nan Gruagach said:
I think things have moved on a bit since 2016 when that vid was posted. As I understand it you can now get rechargeable AA batteries.
Click to expand...

I use them all the time for camara and other small electronic devices, like GPS.

Doesn't Tesla use a large number of small batteries?

This subject has been discussed frequently here and most agree it will be a while before sailing boats go electric, due to the recharging problems. Also, cars tend to run at quite high voltages, which might not suit a small damp boat.

On the Charente river here, there is a tourist all electric boat, it replaced a diesel powered glass topped bateau mouche from Paris. Ideal situation for electric, as it runs a fixed distance from a base.
 
Years ago I and a friend were serious about building new Anderson 22's and I was very keen to see if we could use electric engines, I had some serious talks with people from Torquedo.

Long story short, batteries to give a realistic range are still both too expensive and too bulky for this format boat.

Such an application would suit a traditional long keeler using a serious lot of batteries as encapsulated ballast - in other words the same approach as a U-Boat without the diesels for surface use - though a generator to end up as a ' hybrid ' seems sensible.
 
It takes 300Wh to drive my 2.5T car a mile. The battery is 90kWh. The battery weighs about 1.5T. My previous diesel car would go 10 miles on a litre of diesel, thus let's assume that 1L of diesel contains 3kWh. My 12T boat will burn 4.5 litres of diesel an hour at 6kts, so goes 1 mile / 750ml so that's 2.25kWh/mile. I can currently go 400 miles on a tank of diesel, so I need 900kWh of battery storage to do the same. I have 350kW of solar on my boat, it would take 2,500 hrs of mediterranean noon-day sun to charge the battery, which would weigh 15T. The 90kWh battery for my car costs around £10k, as it's made up of about 7000 cells the cost is pretty much proportional to the kWh. NB, we haven't yet talked about wiring or motors...

So to summarize, the battery you need would have the following properties:
Size required: 900kWh
Charge time from solar: 2,500h in ideal conditions
Weight: 12T
Cost: around £100,000
 
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There are a few all-electric and hybrid narrowboats around. Beta even have a hybrid greenline now. Capacity isn't so much the issue - on a sewer tube you can just throw a couple of tonnes of traction cells in the engine hole, it's recharging the huge bank off grid that's the problem. 4-5 Kw of panels on a flattish cabin roof with no occlusion from rigging isn't enough to putter about for any great distance at 3kt.
 
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It’s a total non starter unless you can get to mains charging regularly. Batteries in lithium are 50 times less energy dense than diesel, so work out how much diesel you would need in a boat then multiply that diesel weight by 50 and if you can make it work go for it. For an ocean capable yacht it is unworkable. Volumetrically it also difficult and unworkable probably, needing about 20 times the space of diesel. It is also a bad idea to pay for energy storage you will only use once a year if that.

There’s an old and cheap, lightweight and well proven renewable energy that is much better - sail power.
 
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Lon nan Gruagach said:
I think things have moved on a bit since 2016 when that vid was posted. As I understand it you can now get rechargeable AA batteries.
Click to expand...

That would be useful, would do away with the ribbon release, which you obviously wouldn't want to use in a marina, especially one behind a lock. The marina owners would likely take a dim view of having to dredge millions of AA batteries from the marina each year.

Edit ; Just found some rechargeable ones. All one would need is a fast charger to keep them charged in batches. The charger could be powered by an inverter, connected to the batteries that were not on charge :encouragement:
 
Richard10002 said:
I think there are a few boats on the canals which are electrically powered and propelled. I am aware of one quite big one which is mostly powered from an array of solar panels.

No reason this cant be utilised on seagoing boats, subject to space for the panels/

Without solar, you would need some way of charging the batteries to run the engine....... running a genny to charge the batteries to run the electric engine would seem to defeat the object.
Click to expand...

Friends had a solar powered narrow boat; they have recently sold her as they no longer feel able to handle her as the years advance. The technology was fairly simple - a modest solar panel installation that charged the battery (lead-acid), with a generator that cut in if the state of charge dropped below some level. They reckoned a week's solar would give them a weekend's operation; longer holidays would rely on the generator. Presumably a larger solar panel installation (I think they had less than a square metre) would alter the balance, but equally require a larger battery bank. I've been aboard her; it was very pleasant to pootle along the river with little or no noise.

Their main problem was that the generator they had wasn't terribly reliable, and I think there were issues about the battery sensing system.

Of course, this was all working within the parameters of a river boat - low speed operations with small waves, so little need for power in excess of that required to push the boat along - and traditionally, these vessels operated with 1 HP ambling along the bank! And, equally of course, the weight of the batteries isn't a big issue on a boat designed to carry heavy loads! That said, the rivers of East Anglia aren't as sheltered as the canal network, and there are some long reaches where a respectable chop can build up. Also, I know that she has coped with tidal waters when switching from one river to another at Kings Lynn, though her owners were a bit nervous about that.
 
Electric tourist boats (based on moorings) carrying up to around 10 people seem to work OK with 4 large solar panels but I don't know for how many hours in service. A guy I was speaking to recently was looking at converting his Westerly 33 to electric and he says the cost is about the same a new diesel engine but, only 15 hours range which may well be OK for weekend sailors but not for long passages when extended power range may be necessary - we spent 40 hours on engine during one Biscay crossing.
 
Chichester Harbour has a solar powered tripper boat doing tours around the harbour, it takes up to 50 punters - no idea how long the batteries last or if there's shore charging as well but it spends a few hours each trip.

My main impressions are from watching the helmsman twiddling the wheel furiously in a slight quartering wind and sea, apparently it handles like a tea trolley on ice :)

https://www.conservancy.co.uk/page/solar-heritage/349/
 
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