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LiFePO4 battery packs

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inventor61 .

LiFePO4 battery packs

Greetings to all from the Old North State ... which doesn't feel all that
'north' lately. 100F + every day.

There's a good contingent of portable-power aficionados here, and likely to
be even more ... with the new radio shipping in volume.

So, what is the opinion of the learned and experienced regarding these
battery packs?

http://www.batteryspace.com/customizelifepo414505battery128v600mah4sflat77wh06aratewith55x21mmmalebarrelconnectorandpcb.aspx

and/or

http://www.batteryspace.com/lifepo418650battery128v2700mah55mmmalebarrelplug3456wh4aratewpcb.aspx

What's the better deal? Two of the former? Anything awful about these
packs? Caveats in their use, other than the obvious?
They seem small, light, protected, and relatively inexpensive. Am I
missing something?

I am not associated with this supplier. Is there another one that's better?

Steve KZ1X/4
Chapel Hill

K2 # 0771 (the World's Most-Experienced Elecraft)
K3 # 6108
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Don Wilhelm-4

Re: LiFePO4 battery packs

Steve,

Temperature today was only 96 here in Wake Forest today, and the nasty
Thunderstorm mid-afternoon cooled it off some. Sounds like you might
want to move a bit East to the other edge of the Triangle area.

My answer depends on how you are going to use them - If you are going to
put them inside either the K2 or K3, then I would discourage that, but
then there are many reports that the LiFePo batteries are plenty safe.

Any of the Lithium battery technology batteries provide great
power/weight ratios.

Use the proper charger(s) for any battery. Most proper chargers want
direct access to the battery terminals, and that is one reason I do not
recommend putting them inside the transceivers. That can be done, but
do it safely and install a fuse.

If you are considering these batteries for the KX3, then think the
process through carefully. Are you going to be portable for extended
times? If so, stick with the internal NiMH batteries and the charger.
If those batteries are exhausted, go to the store and buy a pack of AA
size Alkalines and continue to operate. If instead you have converted
the battery pack to use LiFePo batteries, and they are discharged, you
are off the air until you can get the KX3 to a proper source of power to
recharge the batteries (you cannot use AAs from the store).

So, that is why my KX3 will retain the NiMH batteres, but I may use am
external LiFePo battery pack because the voltage is higher.

I do not have experience with either of the batteries you mentioned, so
I will have to let others answer that part.

Too many choices, too little time!!!

73,
Don W3FPR

On 7/6/2012 10:06 PM, Steve Jackson wrote:

> Greetings to all from the Old North State ... which doesn't feel all that
> 'north' lately. 100F + every day.
>
>
>
> There's a good contingent of portable-power aficionados here, and likely to
> be even more ... with the new radio shipping in volume.
>
> So, what is the opinion of the learned and experienced regarding these
> battery packs?
>
> http://www.batteryspace.com/customizelifepo414505battery128v600mah4sflat77wh06aratewith55x21mmmalebarrelconnectorandpcb.aspx
>
> and/or
>
> http://www.batteryspace.com/lifepo418650battery128v2700mah55mmmalebarrelplug3456wh4aratewpcb.aspx
>

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k6dgw

Re: LiFePO4 battery packs

In reply to this post by inventor61 .

On 7/6/2012 7:06 PM, Steve Jackson wrote:

> So, what is the opinion of the learned and experienced regarding these
> battery packs?

Well, there's the obvious ... 600mAh vs 3,000mAh of course. The LiFePO4
batteries have a very good capacity to weight ratio, and they are safe,
you can carry or pack them onto airplanes. Neither one of them allow
you to balance the cells however, something that should be done at least
periodically.

Assuming it is for your K2, you'd probably find that 600mAh was a little
small. My K2 draws about 280mA on receive, and at 5W, around 1.5A key
down. I use a 4Ah 4S1P LiFePO4 pack that I can balance the cells on
charge and it lasts about as long as I want to be off in the field
somewhere.

Li-Poly batteries have a higher capacity to weight ratio which is why
they are used by RC model folks. I have one that's about the size of a
small matchbox, weighs an ounce or so, and is rated at 800mAh, 11.7V. I
use it on my KX1. Li-Poly is somewhat unstable under some circumstances
and I've had one catch fire while I was using it. Mine is on a short
pigtail outside of the rig.

> What's the better deal? Two of the former? Anything awful about these
> packs? Caveats in their use, other than the obvious?

A123 cells are probably the highest quality, Buddipole sells them, they
are a bit pricey however. Whatever you choose, be sure to fuse the
cable to the rig. These chemistries can deliver anywhere from 10C to
15C or more if shorted. For mine, that could be more than 60A. Beware,
the 12V and RF connectors on the RF board are the same and the cables
from the KAT2 will interchange quite easily. I speak from experience
and now have a jumpered trace on the board that decided to be a fuse. :-(

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

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JP O'Connor

Re: LiFePO4 battery packs

According to the product descriptions, both of these battery packs have a
balancing board built into them. The documentation for the board shows that
the board has independent connections to each cell. It protects each cell
from over charge, over discharge, high current discharge, and short
circuit. Thus, you gain the benefit of balance charging while only having
to purchase a lower cost charger, such as the ones suggested for these
packs on their product pages. The larger of these two packs appears to be
very cost effective and a great solution for external power for a KX3,
K2/10, K3/10 or other QRP rig.

A123 branded cells are more expensive, although EP Buddy has them at a very
favorable price. Their packs do not have internal circuitry, however,
requiring purchase of a balancing charger if you want to recharge at higher
rates. See recent KX3 batteries thread on this reflector for discussion.

72/73 de JP WF4Z

On Sat, Jul 7, 2012 at 12:59 PM, Fred Jensen <[hidden email]> wrote:

> On 7/6/2012 7:06 PM, Steve Jackson wrote:
>
> > So, what is the opinion of the learned and experienced regarding these
> > battery packs?
>
> Well, there's the obvious ... 600mAh vs 3,000mAh of course. The LiFePO4
> batteries have a very good capacity to weight ratio, and they are safe,
> you can carry or pack them onto airplanes. Neither one of them allow
> you to balance the cells however, something that should be done at least
> periodically.
>
> Assuming it is for your K2, you'd probably find that 600mAh was a little
> small. My K2 draws about 280mA on receive, and at 5W, around 1.5A key
> down. I use a 4Ah 4S1P LiFePO4 pack that I can balance the cells on
> charge and it lasts about as long as I want to be off in the field
> somewhere.
>
> Li-Poly batteries have a higher capacity to weight ratio which is why
> they are used by RC model folks. I have one that's about the size of a
> small matchbox, weighs an ounce or so, and is rated at 800mAh, 11.7V. I
> use it on my KX1. Li-Poly is somewhat unstable under some circumstances
> and I've had one catch fire while I was using it. Mine is on a short
> pigtail outside of the rig.
>
> > What's the better deal? Two of the former? Anything awful about these
> > packs? Caveats in their use, other than the obvious?
>
> A123 cells are probably the highest quality, Buddipole sells them, they
> are a bit pricey however. Whatever you choose, be sure to fuse the
> cable to the rig. These chemistries can deliver anywhere from 10C to
> 15C or more if shorted. For mine, that could be more than 60A. Beware,
> the 12V and RF connectors on the RF board are the same and the cables
> from the KAT2 will interchange quite easily. I speak from experience
> and now have a jumpered trace on the board that decided to be a fuse. :-(
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
> - www.cqp.org
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>