On Thursday, 5 February 2015 04:30:04 UTC-7, Jim White wrote:
Reading the blurb referenced it would seem that the A123 batteries (which
are available from http://www.buya123batteries.com) seem to have the best
protection / charging electronics they only rated at 5Ah although this
should provide better performance than a 7Ah SLA.

The higher power batteries do not seem to have all the tricks in the
electronics.

Interesting note: although A123 is a US company using MIT derived
technology, they are owned by the Chinese!


At 17:37 04 February 2015, Charlie M. UH & 002 owner/pilot wrote:
On Wednesday, February 4, 2015 at 12:08:54 PM UTC-5, jfitch wrote:
On Tuesday, February 3, 2015 at 3:50:28 PM UTC-8, Dave Springford
wrote:
I'll preface my remarks with the statement that I sell K2 batteries.

The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee
to
the patent holder while the knock-off's do not. K2 has also had their
batteries UL certified and listed.

These items account for some of the price difference.

The K2 also have a higher Watt-hour rating at 123 vs 115 for the
Stark
and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark.
The K2's also have a better temperature range.

In my opinion, the K2 is a superior product and is worth the extra
cost.

I sell K2 batteries with the protection module for $150 US and
chargers
for $30 US and will have some on hand at the Seniors at Seminole Lake.
For
any one interested in purchasing a K2, contact me at the address below.

Dave Springford
dave at foxonecorp dot com

I don't believe anyone is building cells in North America for the
consumer market. These are all coming from China. It makes no sense at
all
to build the BMS boards here either. So as a point of differentiation
between vendors, there is nothing in it.

As an avid "Electric RC'er", while you are likely correct that most cells
come from a limited number of places, where they end up can be a case of,
"Give me cells" vs. "I don't want seconds/low performers".....
Price is not always a guarantee (there is a "very high priced" LiPO hobby
vendor that has performance numbers similar to "mid level" vendors.....),
but it can help out as well as "post sale support".

Not saying anything for/against any vendor mentioned here, just a
different
view.


http://en.wikipedia.org/wiki/A123_Systems as you can read this company started out in Massachusetts and received US Government grants, went bankrupt and was bough by the Chinese.