Electric Cruiser

Sorry, I didn't know you were an expert on electric drive trains. I certainly didn't want to come off as dismissive. I'm just going off the data I can find and trying to learn and discuss things.

If you have any better data on battery degradation over time or on life cycles and DOC please let me know.

And yeah you're right the capacitors in chargers and motor controllers have a limited lifespan and fail eventually. So I guess you'd have a service interval to replace those and actually need to carry spares and replacements.

 

I don't tout myself as a world expert. However, I have worked a few years of battery research and testing. I also have an ongoing electric car project. It started about 5 years ago as a way of creating a test bed to replicate real use conditions. Now it is an ongoing project for students. Buying electric power from a municipal grid is cheaper than buying gas. However, the whole electric system is still more expensive. Also, I designed it for 48V nominal because of safety issues.

 

Oh very cool. Sounds like an interesting project for your students!

What would you say is the maximum kW motor power you can reasonably get with a 48V system and a single motor? For 20kW @ 48V you'd have 420 amps and I think that needs 6mm (304mm²) thick wire. Plus a rather monstrous controller.

 

Here is a 10KW with controller at 48V and 4000RPM, which makes it directly applicable to a marine transmission with normal gear ratio. https://www.amazon.com/Motor-Controller-Electric-Motorbike-Cnversion/dp/B075K7PQX7
This is within the power range the OP posted. The price on Amazon is $1780.00.

 

Really gonzo, that's what you recommend to someone who says he is on a budget? How about he walks into the next best forklift repair shop and gets a refurbished 8-9" aircooled motor and curtis controller. After all this is a displacement boat, weight is not critical. Add a thrust block on the shaft and run direct drive.
It still does not solve the problems of making a tesla pack work reliably, not to mention charghing the thing efficiently from a generator. Not that it can't be all solved given the right budget.

 

If this is too expensive, he probably can't afford to buy batteries, or the boat. These are complete packages that work well.

 

I think that motor is amazingly inexpensive for the power it provides, particularly because it includes the controller. That, coupled with ~20 kWh of battery and a charger seems like a reasonable price point for a first conversion effort on a small boat (e.g. under $10K for parts). Thanks for the tip.

 

I would say stick with aircooled. The last thing you need is a pump and controller plus heat exchanger. You only go to watercooling for high power/low weight (small formfactor) applications. There are enough used forklift setups (AC or DC) that cover your power needs. Everything is industrial quality with distributors and repair facilities worldwide. A used forklift can donate motor, controller, contactors, "gas pedal", cabling, etc. All components are of course also available new.

 

In this, I believe you are absolutely correct. I was being somewhat hyperbolic in saying that "once installed, and the system sealed, there should be little to no reason to interact with any of the components." My thinking was (is?) that an electric drivetrain won't require daily (or sometimes hourly) checks to see if the oil is in good shape, that the raw water strainers aren't clogged, or any of the myriad other things that can go wrong in a gas or diesel drivetrain.

In your experience, what is the expected maintenance intervals for regular inspection of a professionally-installed all-electric drivetrain? And what should be done visually rather than by dash gauge?

I'm not being snarky here, I'm looking to learn.

JD

 

The system should not be sealed, because it needs a fair amount of ventilation for cooling. Batteries also generate heat and should have ventilation. There should be a temperature safeguard to reduce power and/or have a warning for overheating. It should be for the motor and batteries too. The thrust bearing and shaft seal are probably what will need most of the regular maintenance. A proper installation will keep all electrical components dry, but I suppose there may always be a high level of moisture. The second regular maintenance will be the contacts (on everything). I usually spray CRC battery terminal protector to prevent corrosion. It is a waxy product that works well. If it was my boat, I would also check side play (shaft clearance) on a yearly basis. It is probably less maintenance than a diesel, and definitely less dirty.

 

Hi Jdray,

I am also turning to Tesla drive train thinking it is a bit of a shortcut. Since I don’t know much about the area I figure why not turn to some one that does. And now you can find the whole thing, battery-cooling-engine, for less than $ 20.000.

I am just going to push a vintage 33’ Hacker Craft but the idea is the same.
I wish you good luck!

 

Where can you buy a new setup for that price?

 

Hi gonzo!

Since I am new to posting in forums all together I feel the need to point out that I am surpriced by the hard tone you have gonzo. It does not feel like you want to help find a solution. It’s more like you are bullying. But then again, english is not my mother tongue, so it might just be my missunderstanding.

I have no idea where to find a new setup! I was refering to salvaged parts.

 

Gonzo is not being a bully. He is just direct and unadorned in his language.

You'll get use to it.

-Will (Dragonfly)

 

I didn't think it would come through as a hard tone. The price seemed really low for a new setup. However, using salvage parts with no warranty is not a good comparison to a new installation. By the time the batteries reach the scrapyard, their capacity is greatly reduced. The motors are also going to be closer to the end of their life. If you consider used equipment, $2,000 will buy a used diesel in good condition. $18,000 is more than most people will use in fuel throughout their life.