No Monte, I did mean $1.10/ah at LiFeP cell voltage. That's nominally,
what, 35 cents/wh at a cell voltage of 3.3v? Recently, we've even seen 5%
less than this price.
From EVDL on June 13th, 2009:
We have come across a situation between ThunderSky LiFePO4 factories in
China.
There are 10+ different factories (all separate companies) that produce
under the ThunderSky brand. Different companies specialize in different
sizes for the cells. They buy/sell/trade with each other to fill orders.
One of the factories that produces the 90 Ah and 160 Ah cells got caught
with too much inventory. They are now offering it at a discount to move it.
Normally at www.evcomponents.
Energy cells at $1.10 per Ah.
For this overstock in the 90 Ah and 160 Ah sizes, we are able to offer these
at $1.05 per Ah. Ignore the prices on the website that are currently listed
for these sizes.
90 Ah cells are $94.50 each
http://www.evcompon
160 Ah cells are $168 each
http://www.evcompon
We are going to gather orders for these 90 Ah and 160 Ah cells for 30 days,
then purchase the overstock based on whatever our customers have requested.
These are new cells produced in the last 60 days. We will be testing them
for quality before shipping to final customers. Our standard warranty of one
year will apply.
Please contact Dave Kois (dave@evcomponents.
these cells. This is a short term 30 day offer at $1.05 per Ah.
The link I had provided earlier was merely for a quick BMS link, not for
cells themselves.
If you want cells, contact one of the several importers of the Thundersky or
other equivalent LiFeP batteries.
These are pretty much the cheapest deep cycle large capacity rechargeable
lithium solutions available today.
And for applications not needing high C-rates (like many of our boats),
these are a decent option.
Indeed, you could simply go with 11 of the 160ah cells for nom. 36v and
spend approx. $1848 plus BMS and have 80% of what your target 200ah is.
So $8000 is probably 3x what it would cost with this approach.
In case this helps-
-Myles Twete
From: electricboats@
On Behalf Of Monte Gisborne
Sent: Sunday, July 26, 2009 4:53 PM
To: electricboats@
Subject: RE: [Electric Boats] Boston Whaler Project
Miles,
Thank you for your contribution, but I think you probably meant $1.10 per
watt-hour, not amp-hour, which is pricing I have seen for lithium power
previously for larger modules. To confirm this, I checked out the site you
listed and found that the listed batteries run about $54 per amp-hour (at
14.8 volts) or $3.60 per watt-hour! Also, these are smaller modules more
suitable for toys, methinks. Am I missing something?
My requirements are for 7.2 kilowatt-hours (36 volts X 200 amp-hours) or
thereabouts. Even at $1.10 per watt-hour, that would put lithium at about
$8,000 which is beyond the budget of this project and the safety concerns of
lithium also work against them. I have personally witnessed a
lithium-powered electric car go up in a ball of fire, literally nothing left
after the firefighters tried to put it out, and even scorched two vehicles
parked nearby. This is not to say I'm not impressed by lithium, I just
don't think that it is the right answer for this particular e-boat project.
Monte
I guess if it were me and cost wasn't as important as space/weight savings,
I'd jump on one of the many bulk orders of LiFeP batteries from China going
on these days.
Typical price per cell: $1.10/ah
So, assuming you need 36v and 200ah, you'd want 11-cells at say 240ah
capacity. That'd cost you 240*1.1*11, or $2864 plus BMS (e.g. here:
http://www.tppacks. <http://www.tppacks.
com/products.
installation.
-MylesT
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[Non-text portions of this message have been removed]
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