[K2] LiFePO4 replacement for internal SLA battery in K2

[inventor61 .]

Hello

My older K2, #771, is still in use after almost 16 years since I built it.

I have the internal sealed lead-acid gel cell battery option.  I have the
charge circuit slightly modified using the kit from ProAudio Engineering,
and I use their superb external power supply as well.

I get great results, but I know one day this battery (the 2nd I have had)
will eventually need to be replaced once again.

I contacted Batteryspace.com and asked them to fabricate a LiFePO4 pack
that matched the dimensions of the SLA in my radio, and to also include a
matching Elecraft pigtail to plug in to the PCB connector, with a
protection circuit board to prevent over discharge, shorts, and the like.

The SLA is rated at 2.9Ah and the new LiFePO4 pack is rated at 4.5Ah.  The
new pack also has the benefit of running at a slightly higher voltage for
most of the longer discharge curve.

One key operating difference versus the SLA is that you should not
continuously float charge the LiFePO4 pack.

The new pack is not inexpensive, but it roughly doubles both the discharge
period and the cycle life of the SLA.

The new pack has shipped and I expect to get it after Labor Day / Shelby
weekend.  The pack has to come via ground (to NC from W6) due to the hazmat
restrictions on such cell packs.

If you look at their website, the pack is now listed :: item CU-J1087 (prod
id: 9647).

I will report back here after I get the pack and try it out.  I am not
affiliated with this firm in any way.  Rather, I am reporting this
information as a courtesy to the other Elecrafters who recently mentioned
the need to replace their K2 SLA batteries.

73

Steve KZ1X
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[Fred Townsend-2]

Steve I recommend you get a LiFePO4 charger. The two batteries may occupy
the physical space but they charge differently.
73
Fred, AE6QL

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of
inventor61 .
Sent: Friday, August 28, 2015 6:52 PM
To: [hidden email]
Subject: [Elecraft] [K2] LiFePO4 replacement for internal SLA battery in K2

Hello

My older K2, #771, is still in use after almost 16 years since I built it.

I have the internal sealed lead-acid gel cell battery option.  I have the
charge circuit slightly modified using the kit from ProAudio Engineering,
and I use their superb external power supply as well.

I get great results, but I know one day this battery (the 2nd I have had)
will eventually need to be replaced once again.

I contacted Batteryspace.com and asked them to fabricate a LiFePO4 pack that
matched the dimensions of the SLA in my radio, and to also include a
matching Elecraft pigtail to plug in to the PCB connector, with a protection
circuit board to prevent over discharge, shorts, and the like.

The SLA is rated at 2.9Ah and the new LiFePO4 pack is rated at 4.5Ah.  The
new pack also has the benefit of running at a slightly higher voltage for
most of the longer discharge curve.

One key operating difference versus the SLA is that you should not
continuously float charge the LiFePO4 pack.

The new pack is not inexpensive, but it roughly doubles both the discharge
period and the cycle life of the SLA.

The new pack has shipped and I expect to get it after Labor Day / Shelby
weekend.  The pack has to come via ground (to NC from W6) due to the hazmat
restrictions on such cell packs.

If you look at their website, the pack is now listed :: item CU-J1087 (prod
id: 9647).

I will report back here after I get the pack and try it out.  I am not
affiliated with this firm in any way.  Rather, I am reporting this
information as a courtesy to the other Elecrafters who recently mentioned
the need to replace their K2 SLA batteries.

73

Steve KZ1X
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[RobertG]

Steve...
Thanks for the info and for your effort in getting this item up and
running. Question: installing this battery in the K2 requires the
Elecraft battery mounting hardware, yes? Charging the new battery uses
the SLA battery charging circuit, yes? Thanks in advance.

Elecraft...
If this battery stands up to Elecraft scrutiny, perhaps they will make
it available like they did with the PowerWerk power supply.

Like many people out there, I'm hanging on to my K2 forever, and having
this battery/etc with the auto turner installed makes for a nifty
portable package.

...robert

On 8/29/2015 01:51, inventor61 . wrote:

> Hello
>
> My older K2, #771, is still in use after almost 16 years since I built it.
>
> I have the internal sealed lead-acid gel cell battery option.  I have the
> charge circuit slightly modified using the kit from ProAudio Engineering,
> and I use their superb external power supply as well.
>
> I get great results, but I know one day this battery (the 2nd I have had)
> will eventually need to be replaced once again.
>
> I contacted Batteryspace.com and asked them to fabricate a LiFePO4 pack
> that matched the dimensions of the SLA in my radio, and to also include a
> matching Elecraft pigtail to plug in to the PCB connector, with a
> protection circuit board to prevent over discharge, shorts, and the like.
>
> The SLA is rated at 2.9Ah and the new LiFePO4 pack is rated at 4.5Ah.  The
> new pack also has the benefit of running at a slightly higher voltage for
> most of the longer discharge curve.
>
> One key operating difference versus the SLA is that you should not
> continuously float charge the LiFePO4 pack.
>
> The new pack is not inexpensive, but it roughly doubles both the discharge
> period and the cycle life of the SLA.
>
> The new pack has shipped and I expect to get it after Labor Day / Shelby
> weekend.  The pack has to come via ground (to NC from W6) due to the hazmat
> restrictions on such cell packs.
>
> If you look at their website, the pack is now listed :: item CU-J1087 (prod
> id: 9647).
>
> I will report back here after I get the pack and try it out.  I am not
> affiliated with this firm in any way.  Rather, I am reporting this
> information as a courtesy to the other Elecrafters who recently mentioned
> the need to replace their K2 SLA batteries.
>
> 73
>
> Steve KZ1X
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

--
Robert G Strickland, PhD ABPH - KE2WY
[hidden email]
Syracuse, New York, USA
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[k6dgw]

On 9/11/2015 10:39 AM, Robert G Strickland wrote:
> Steve...
> Thanks for the info and for your effort in getting this item up and
> running. Question: installing this battery in the K2 requires the
> Elecraft battery mounting hardware, yes? Charging the new battery uses
> the SLA battery charging circuit, yes? Thanks in advance.

Don't know about your first question, but LiFePO4's require a cell
balancing charger.  Charging a 4S1P LiFePO4 on the same two wires you
discharge it with will generally really reduce the battery life.


73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[Bob N3MNT]

Some of the better LiFePO SLA replacement batteries, have built in Over-charge, balance, Over-discharge circuitry in the package enabling you to use a standard 2 wire SLA charge setup.  They are usually more expensive than the standalone battery pack, but for internal use, a useful option.