Category: Electric propulsion

At the eleventh hour I have found an affordable source for Lithium-Ion batteries. Everspring Global – a chinese company – has Li-Ion batteries that I need for about $10,000.00 It sounds like a lot but it just makes my budget and so I’ve ordered a bank of these last week. The delivery time is about a 1 month, and I hope to be sailing north just after that so the timing is barely achievable but I think I can do it. Not much time for installation and sea trials – but hey – life’s like that.

I’ll be getting 16 batteries each of 200 Ah, and each battery is 3.2 volts, so that will give me about 50 volts. The total weight of these is about 120kg and they can can be discharged to 80% which means I have 160 Ah available for use. To get this much power from lead-acid batteries, which can only be discharged to 60%, I’d need 12 batteries of about 120 Ah each. And these weight in about 35kg – which is a total of 420 kg – nearly half a ton.

You can see the huge weight advantage of Li-Ions – especially important on a lithe thoroughbred like Current Sunshine.

So, fingers crossed that they arrive in time…

There’s two styles of electric motor that you can use in a sailboat. The cheapest for boats with an in board engine is simply to replace the diesel engine with an electric motor and continue to use the same drive train. Such as this one from Thunderstruck. There’s lots of examples of this kind of electric motor and you have plenty to choose from.

Even though its the easiest way to change from diesel to electric, it still has the complexity of the existing drive train with its stern gland where the drive shaft passes through the hull. The electric motor also generates heat as it works – although not as much as a diesel engine – and it has to be cooled, commonly with a fan. This can be draining in hot weather, cos just like a diesel, it adds more heat to the already hot cabin.

The other type of electric drive for a boat is a pod – torpedo like submersible motor. The can be outside the hull where is cooled by the water flow over it, and it means also its extremely quiet. This is the kind of motor I’ve decided on.

The motor I’m getting is an E-Pod from Re-E-Power in Michigan and I’ve been talking to Kevin Plank there for many months now to finalise the details of my order. Because I want to use it in the existing well in Current Sunshine, it needs to be slightly shorter than the standard model. And when Kevin looked at making a shorter model for me, he liked it so much he decided the re-tool the whole operation to make this shorter one the standard model. The retooling has meant delays in getting the new model into production, but it is now done.

Here’s the new motor – lying on Kevin’s loungeroom floor. Pretty soon it will be shipped downunder and I can start making a frame for it…

This is the reply I got…

This is something that we could probably do but would cost several hundred
thousand dollars I should imagine.

So back to the drawing board you’d think huh.

But wait – there’s more. I also got another reply from _ www.accuwatt.fr _ about an alternative supply of Lithium batteries sourced from Asia (rather than France) and the price of these could be around 15k Euro. Despite what you might first think, this is close to my budget of $15k Australian… So the project might be back on track again.