LifePO4 12v20A - What do you think about these?

M

MyPC8MyBrain

100 mW
Joined
Jan 20, 2008
Messages
48
Found these while cruising around china web.
http://www.gd-battery.com/ois/usersites/longhui1/productlist.jsp?seriesId=53252
1205331178609.jpg

$137 each on 100 qty.

They said they would sell me 4 as a sample for testing.

Many thanks for your inquiry from Alibaba about the Li-ion LiFePO4 battery pack (GD-LP12V20AH).
Please kindly find the following info:

Model No............Capacity......Operation Voltage.....Weight.......Dimension (W*L*H)......Price
GD-LP12V20AH......20Ah..........12V-17V................3kg±200g.....180X75X168(mm)........US$137.00

Here please find the charging information for this item (GD-LP12V20AH):
Max Charge Current: for constant current: 20Ah; for impulse current: 50Ah
Max Discharge Current: for constant current: ≤20Ah; for impulse current: ≥200Ah
Operating Temperature: for Charge: -30~75centigrades; for discharge:-30~75centigrades
 
Are you sure these are LiFePO4? I'm probably wrong, but the discharge curve just doesn't match what I expected.

LiFePO4 single cell
http://www.thunder-sky.com/pdf/TS-LFP40.pdf

Li-Mn single cell
http://www.thunder-sky.com/pdf/TS-LMP40.pdf

LiFePO4? 4-cell pack
http://www.thunder-sky.com/pdf/TS-LP12V20.pdf
 
Forget those! How about these?

1205392490296.jpg


Nominal Capacity ：9000AH :shock:
Operating Voltage：2.5V～4.25V
weight：350kg±6kg
Dimensions：1700×360×360(mm)

So, 29,700Whrs in a single batt (assuming 3.3V nominal), 326,700 in a 36V pack. Would only weigh just short of 4,000kg. :roll: :p

Looking at the dimensions, it's interesting to imagine a battery about twice my size :shock:.

Also, WTF would you use that in? Seriously, there's no way you're getting more than two in even a big car, and backup power systems would be better off with cheap lead.
 
Maybe 4 in series for an off-grid solar application. You could have 12V DC and an inverter for standard household current.

4 cells provides 108kWh. Assuming 6,000kWh/year (an average household for southern Calif.?), or 16kWh/day, that would be enough for ~6-1/2 days of electrical storage. Maybe that's enough to get you through your worst period of cloud days?

You'd need $20-30K of solar panels to keep up with 16kWh/day though, right?
 
Don't know if these are the actual units, but there are some very large batteries being tested in a few municipalities for peak loading scenarios. You know, summertime, 3000 degrees, all the air conditioners west of the Mississippi running.
JJ
 
OneEye said:
You'd need $20-30K of solar panels to keep up with 16kWh/day though, right?
Click to expand...

Plus, why even use lithium? Sure it won't take up as much space, but that's not really such a critical factor when you're talking about a pack the size of a small closet. Not to mention a four cell pack could easily cost $200,000. A lead pack would probably be $10,000 if you get really big ones. A lead pack wouldn't suffer noticeably from the Peukert effect if it were that big. Plus, you would get plenty of cycles out of them since you're usually hardly draining them at all.

I'm really having trouble finding a suitable application for these. Maybe a Mac truck? :?
 
These(20AH) are what Myth busters used for their go carts, so they must think they are worth it.

Anyone know where we can buy them in Atlantic Canada(or close to it)?

.. not to mention what chargers will work with them as well?
 
Mythbusters have go karts?

I think I read somewhere that Thunder Sky don't offer a warranty to anyone outside China, but I could be wrong.
 
wow! about 140 usd for 240va that's not expensive.
i'm wondering how cell balancing is working with this pack.
is there any internal cell protection?
 
To the original poster of this thread:
Did you receive these batteries from the supplier? I am very interested in these, but would like an independent review before I try to purchase.
Thanks
 
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