The whole point of a group buy is so everyone gets a better deal. I would
hope the price savings would be great enough that regardless of Ah size the
cost could not be beat. If you can buy these cells from a US supplier for
close to the same cost then it does not make sense to do a group buy. I would
only be interested in a group buy if it was a very good savings.
I have been contacting suppliers and the larger the quantity the better the
price. I have not looked at the SE before as I was concerned if they would
really last in EV use. Of the less expensive large cells TS, SE, HP the SE
appears to be the one to buy.
I was seriously looking at the Headway with their new 16Ah cells. They are
rated at 10C discharge which would be very good. The pack load was at peak
just less than 3C and not for an extended time. Cost a little more but not
much if your buying in large quantity. Then I came across a post on the EVDL
that Headway had a rust problem on one of the end caps. I just sent Headway
an email and if they do not take care of their customer then I am not
interested in buying their product.
In a message dated 2/28/2010 5:24:41 PM Pacific Standard Time,
Not sure how it would work out in battery box fill space, but running the
numbers for 100Ah TS versus 200Ah TS using evcomponents pricing, the cost
for a 50 unit pack would be:
$7,150 for 100Ah
$13,200 for 200Ah
That means purchasing 100 of the 100Ah would be $14,300. I have included
the costs of BMS. If only one "BMS master unit is required, then it would
be about $350 less so the delta is around $1K extra for going with a hundred
I just checked my model for 100AH TS batteries in the Force battery box.
With no box modifications, the max amount of batteries is 69. To go with
100 batteries would require making space for another 31 batteries. That is
quite a lot of batteries and would require significant modifications. I
don't see where that many more batteries would fit.
From: _solectria_ev@solectria_evsol_ (mailto:firstname.lastname@example.org
) ] On
Behalf Of _theoldcars@...
Sent: Sunday, February 28, 2010 1:21 PM
To: _solectria_ev@solectria_evsol_ (mailto:email@example.com
Subject: Re: [solectria_ev] Thundersky or HiPower
It would be best to pick out a size that would work for more people. I can
understand why you want the 160Ah cells. I think the answer is to get the Ah
rating you want with a size that more people would buy. Say four 40Ah cells
in parallel or two 100Ah in parallel.
There is a down side you would have more interconnects but I think the
trade off would be getting a better price. The positive side would be four
in parallel would help keep slightly lower cells in balance. If the larger
cells are little off from one another there going to be on there own.
Just something to consider
In a message dated 2/28/2010 12:49:22 PM Pacific Standard Time,
I would be interested in a group buy, however, I would be inclined to go
with larger form batteries, in the 160Ah plus range. The way I see it, if I
am going to do this, I want a car that can drive in the hills or to SF or
Gilroy and back. That means I want a consistent 100 mile plus range.
From: _solectria_ev@From: _solFrom: _solectri_solectria_ev@solectria_evsol_
) ] On
Behalf Of __theoldcars@_theold_ (mailto:_theoldcars@...
Sent: Sunday, February 28, 2010 11:55 AM
To: _solectria_ev@To: _solecTo: _solectria__solectria_ev@solectria_evsol_
Subject: Re: [solectria_ev] Thundersky or HiPower
It would be nice to see the same type of test on the HiPower as the Sky
Energy. As I understand it Sky Energy is now called CALB.
The information on ___http://evworks.http://evworks.http://evworks.htt_
) ) is just huge. The last
at the 3C rate is really telling. Not only did Sky Energy deliver the rated
capacity under a very high load it was done with SE heating up less. Less
heat is absolutely critical for long term use. If the cells are heating up
that heat is going to take a toll on the cycle life. Its too bad no one yet
has tested the SE cycle life at the 3C or even a 1C rate.
Since the SE has less heat during heavy use it should last much longer in
lighter loads or less DOD cycles. Going by the last test at the 3C rate if
you did not discharge more than 70% DOD. The SE should have a very long
life as 70% DOD is about where the heat starts rising.
It is apparent that SE has lower impedance under greater loads at least to
begin with. Which is a very good indicator of which will have longer cycle
life. So base on this test the clear winner is the SE with less impedance
uld last far longer then TS.
Thank you for posting the information. Anyone interest in a group buy?
In a message dated 2/28/2010 9:43:52 AM Pacific Standard Time,
I've been told by two different dealers of prismatic lifepo4 cells
that ALL brands require strapping. All the vendors supply the
compression hardware, you'll need to specify how many cells you want in
each module. The issue I've found with the Hipower cells is their
height which either requires modifying the battery boxes or possibly
laying them on their sides which makes wiring a challenge. Since I
) ) I convinced
myself that the Sky energy cells were well worth the price premium. In
a Force, the AMC325 will limit battery current to 280A, slightly under
the 3C rate for 100 AH cells. But even at lower discharge rates the Sky
cells store quite a bit more energy, meaning greater range.
Has the best delivered price on both Hipower and Sky cells and some
rather caustic comments about Thunder Skybb. For any lithium upgrade
you'll need a BMS. My favorite BMS is
) ) If you still have the NLG
412 charger, it has two general purpose inputs that can be used to allow
the BMS to control charging. You'll also need to reprogram the charger,
but that is fairly simple.
> I am trying to decide whether to upgrade to Thundersky 100 AH batteries
or HiPower 100 AH batteries. Does anyone have any data as to which would be
better, or it does not matter which one?
> Those of you that have upgraded to Thundersky, have you had any problems
with the cells swelling? I have heard that you need to strap the batteries
together and use compression plates on the outside batteries. Does anyone
have any experience with this. Do the HiPower batteries have the same
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