SailNet Community

SailNet Community (https://www.sailnet.com/forums/)
-   Electric/Hybrid (https://www.sailnet.com/forums/electric-hybrid/)
-   -   Cheap Tesla battery modules now available (https://www.sailnet.com/forums/electric-hybrid/246865-cheap-tesla-battery-modules-now-available.html)

Captain Canuck 03-28-2016 11:40 AM

Cheap Tesla battery modules now available
 
There's been something of a seismic shift in Lithium batteries lately. Lightly used Tesla packs have been showing up for about $1200 on ebay. They hold 5.3kWh, and come in 24V packs.

This puts them at under $250/kWh, with the BMS and fuses already built in. This is roughly half what building your own packs would cost.

Their dimensions are 3"x11"x27", with the two terminals at one end on each corner, and they weigh only 55 lbs. You should be able to get at least 800 deep cycles (down to 20%) out of them, possibly more if you cycle them less deeply, you should get far more than that.

Does this change anyone's equation as far as moving to EP?

jdazey 03-28-2016 12:28 PM

Re: Cheap Tesla battery modules now available
 
I was under the impression that Tesla batteries did not use the LiFePo4 chemistry. If they do, it might well make a difference.

Cheers,
Joe

Captain Canuck 03-28-2016 12:39 PM

Re: Cheap Tesla battery modules now available
 
They don't. They use 444 Panasonic 18650 3.7v lithium-ion cells grouped into banks and then wired in serial to make a 5.3kWh 24v pack.

The upside is every single cell has a fuse so one cell failing will make almost no difference.

newt 03-28-2016 04:02 PM

Re: Cheap Tesla battery modules now available
 
But how used are they, and does it make a difference? I am always one for more amp-hours, but what is the catch?

RobGallagher 03-28-2016 08:02 PM

Re: Cheap Tesla battery modules now available
 
Quote:

Originally Posted by newt (Post 3413753)
But how used are they, and does it make a difference? I am always one for more amp-hours, but what is the catch?

I believe the catch is that the salvage yards don't really know what to do with one. Nissan Leaf batteries are also surprisingly cheap $500-1000 from a salvage.

There is no secondary auto market for them yet and shipping just one battery would be expensive.

So, they get one battery or so, every year or so, and sell it to a hobbyist for what they can so they don't sit on it until it turns into a brick.

I'm sure the drivetrain, battery, charger and controls would make for an interesting boat project.

Captain Canuck 03-29-2016 10:25 AM

Re: Cheap Tesla battery modules now available
 
Quote:

Originally Posted by RobGallagher (Post 3414065)
I'm sure the drivetrain, battery, charger and controls would make for an interesting boat project.

Transplanting a drivetrain wholesale would be overkill for most monohulls. The Tesla motor on the single-motor version is capable of 503HP, so you'd have to reprogram the throttle to dial it waaaaaaay back. Either that or learn to enjoy hydroplaning on your wing keel. :P

On the upside, you'd never have to worry about overheating or wearing out the batteries or the motor. Working so far below spec, they'd probably outlast the boat.

Charging might be an issue, though. At 85kWh, that's a 28 hour recharge from empty at a standard 30A 120V shore power connection, or 7 hours at a 50A 240V.

RobGallagher 03-29-2016 07:58 PM

Re: Cheap Tesla battery modules now available
 
Quote:

Originally Posted by Captain Canuck (Post 3414593)
Transplanting a drivetrain wholesale would be overkill for most monohulls. The Tesla motor on the single-motor version is capable of 503HP, so you'd have to reprogram the throttle to dial it waaaaaaay back. Either that or learn to enjoy hydroplaning on your wing keel. :P

On the upside, you'd never have to worry about overheating or wearing out the batteries or the motor. Working so far below spec, they'd probably outlast the boat.

Charging might be an issue, though. At 85kWh, that's a 28 hour recharge from empty at a standard 30A 120V shore power connection, or 7 hours at a 50A 240V.

I'd be impressed with the stopping power...Imagine coming into your slip at lull speed and stopping on a dime :) :captain:

Erindipity 03-29-2016 10:16 PM

Re: Cheap Tesla battery modules now available
 
Quote:

Originally Posted by Captain Canuck (Post 3414593)

On the upside, you'd never have to worry about overheating or wearing out the batteries or the motor. Working so far below spec, they'd probably outlast the boat.

Lithium Batteries have limited Shelf Life from Date of Manufacture, even unused. The _original_ Li Battery on my backup-to-the-backup Powerbook G4 just died after ~8 years, even though it was plugged in to the Charger 99% of the time.
Note that I was only getting two years out of the Lead-Acid batteries in my old Powerbook 100, and when those Batteries died, they had a nasty tendency of taking out the fuse on the Motherboard. So things have improved.

Quote:

Charging might be an issue, though. At 85kWh, that's a 28 hour recharge from empty at a standard 30A 120V shore power connection, or 7 hours at a 50A 240V.
Or ~850 hours out of a 100 watt Solar Panel= ~110 days, assuming good conversion efficiencies and ~8 hours of Sunlight a day. Say three months in reality to recharge, assuming no other Electrical load.
That's the energy content of ~2 Gallons of Diesel Fuel... and by now some wheels should be spinning...

Diesel Fuel Cells!
Diesel-Powered Fuel Cell Produces Clean Electricity - IEEE Spectrum
(Generating Diesel Fuel on the run is difficult, unless one does a fair amount of deep-fat frying with vegetable oils.)

The _only_ reason that Electric Cars on the road, like the Tesla, makes sense now is that the Charging Infrastructure mostly already exists. (Formula E is making inroads in off-road Motorsports, and I think that it's really cool. Still, only a handful of Tracks are equipped so far.)
Such Infrastructure does _not_ exist for Sailboats, and it is very unlikely, given the diminishing market, that it ever will.

ČErindipity

capta 03-30-2016 01:28 AM

Re: Cheap Tesla battery modules now available
 
This is going to be an interesting thread to watch.

Salty Mike 03-30-2016 07:34 AM

Re: Cheap Tesla battery modules now available
 
Quote:

Originally Posted by Erindipity (Post 3415601)

Or ~850 hours out of a 100 watt Solar Panel= ~110 days, assuming good conversion efficiencies and ~8 hours of Sunlight a day. Say three months in reality to recharge, assuming no other Electrical load.
That's the energy content of ~2 Gallons of Diesel Fuel... and by now some wheels should be spinning...


ČErindipity

So 110 days of solar charging = ~ 12 knots/ miles of motoring, cut the days in half for 200 watts of panels then add a few wind and drag generators and you're all set.

I keep looking at my 16hp gasoline driven 200 amp DC welder thinking it would be a great backup for an electric boat. Can't remember all the specs right off but I'm thinking it puts out 24v to the welding leads and is a 7500 watt generator as well.


All times are GMT -4. The time now is 05:01 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
(c) Marine.com LLC 2000-2012

 
For the best viewing experience please update your browser to Google Chrome