Reply
 
Thread Tools Display Modes
 
Old 05-10-2015, 05:04 PM   #21
Guru
 
twistedtree's Avatar
 
City: Gloucester, MA
Country: USA
Join Date: Jan 2013
Posts: 3,202
There is another aspect of storing power in a battery that we seldom pay attention to, and that's the cost per kwh to store power. It costs some significant $$ for a battery bank, and that bank is good for about 1000 cycles. Then you need to replace it. When you look at how many kwh you can store and retreive in that 1000 cycle lifetime, you come up with a cost per kwh of stored power. We pay attention to the cost to generate power running our generators, but typically ignore the cost to store that power. So let's take a look.....

That 8D AGM battery in my previous post costs $518 per kwh of storage capacity. It can be cycled 1000 times in its lifetime, yielding a cost of $0.518 per kwh to store power. That's a lot, and it's in addition to the cost to generator it if you run a generator.
__________________
Advertisement

__________________
www.MVTanglewood.com
twistedtree is online now   Reply With Quote
Old 05-10-2015, 07:37 PM   #22
Guru
 
Aquabelle's Avatar
 
City: sydney
Country: australia
Vessel Name: Aquabelle
Vessel Model: Ocean Alexander Flushdeck
Join Date: Jun 2012
Posts: 538
T/tree: all good points. Some other comments on the Tesla PowerWall specifically:
1. must be wall (bulkhead) mounted, presumably because of its "liquid thermal control" mechanism. So this otherwise space-efficient packaging cannot be laid flat or on its side...but I wonder how it would cope with the movement (pitch,roll, yaw) of our vessels?
2. max draw is 2kW..(with a surge capacity of 3.3kW) .so around 18A if you are on the North American 110v system or around 8.5A if you are rest-of-world on 220-240v. That's just enough to run one 12kBTU air-con unit but I think more typically, would be used to supply the non-air con demands via an inverter. A genset would still be used to run air-con (but could be fully loaded to recharge the PowerWall)
3. Operating range is -4F -- 110F (-20C -- 43C). That would make risky engine room installations for those of us in tropical, sub-tropical and even temperate (Summer) locations...and have Winter-izing implications for those in colder climes
4. The advertised price before install costs works out at $250kWh according to Tesla reviewers...that's about 25% of the current typical pricing of Li-chemistry batteries. They are clearly trying to build a mass/consumer market and with volume and low margins, so the unit prices are low. Maybe its big benefit for boaters will be to change the whole pricing game for this battery technology, as the Chinese did with solar panel costs
5. Some reviewers indicate 5,000 cycles might be conservative. If $400per kWh installed and 80% efficient, that's around 15c/kWh storage cost.


A couple of reviewing sites, from both technical & economic perspectives:


Why Tesla's Powerwall Is Just Another Toy For Rich Green People - Forbes


Tesla Powerwall: A Battery For Your Home | Gizmodo Australia
__________________

Aquabelle is offline   Reply With Quote
Old 05-10-2015, 07:54 PM   #23
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,573
The Tesla powerwall is getting some press here. I wonder, re bolting one to the house, if the Li-ion fire risk has been resolved.
We had a new Tesla for an airport transfer in Amsterdam. Stunning car, electric or not, accelerates as if attached to a retracting elastic strap.
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 05-10-2015, 10:29 PM   #24
Guru
 
hmason's Avatar
 
City: Westport, CT
Country: USA
Vessel Name: Magic
Vessel Model: Grand Banks 46 Europa
Join Date: Aug 2013
Posts: 1,905
So my friend and his wife went to Italy. On his birthday, his wife gave him a small gift wrapped box. Inside was a picture of a stunning new Tesla that she bought him for his birthday. That car is awesome. I think I have a well off friend.
__________________
Howard
Magic, 1996 Grand Banks Europa
Westport, CT and Stuart, FL
hmason is online now   Reply With Quote
Old 05-10-2015, 10:51 PM   #25
Guru
 
N4712's Avatar
 
City: South FL
Country: U.S.A
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,613
Quote:
Originally Posted by hmason View Post
So my friend and his wife went to Italy. On his birthday, his wife gave him a small gift wrapped box. Inside was a picture of a stunning new Tesla that she bought him for his birthday. That car is awesome. I think I have a well off friend.

I was thinking he was getting boat shoes when I started reading, but then read tesla... Kind of a boring present when compared to a nice pair of boat shoes....
__________________

__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
N4712 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 10:55 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012