K2 NiMH Battery pack

[AD6XY]

I am interested in peoples expieriences with internal batteries in the K2.

I have just removed the lead acid gel cell battery from my K2, it is 8 years old and still working - but it is very heavy to carry.

I have replaced it with a case of 10xAA 2000mAH cells which fit nicely in about half the battery space. I used a 10 cell holder configured as two rows of 5 cells. Once they have been fully charged a few times I will see whether they are any use but the specification implies they should be good for at least 2A for 5W of RF.  They seem good enough for the FT817 and it is much less efficient than the K2.

I have also looked at LiPo battery packs designed for model cars and planes but I am worried about miss-charging them. These have higher capacity, are lighter and hold their charge longer but can deliver very high currents in case of faults. I have seen one person using LiPo on the web - any others using LiPo or NiMH or something else to replace the heavy gel cell?

I am pleased with the space left over and I am thinking if a small 144MHz transverter will fit inside for microwave use, like the DEMI but small enough to fit in half the battery volume. Transverters for microwave IF use do not need high specifications, low gain, low power and minimal filtering so designing one should be straight forward. I already have the transverter interface which can be used to provide selection logic and access to the RF ports.

[Don Wilhelm-4]

No 'experience' to report here, only an opinion.
I would not put LiPo batteries inside the K2, but would consider them as
a lightweight external power supply.
Even though they are heavy, sealed lead acid batteries do offer some
advantages.  They do not self-discharge as the NiMH batteries have a
tendency to do.  OTOH, SLA batteries do not like to be left with a
partial charge, so there are pros and  cons for each choice.

The "what to do with the additional space" question is one left for your
imagination and creativity.

73,
Don W3FPR

AD6XY wrote:

> I am interested in peoples expieriences with internal batteries in the K2.
>
> I have just removed the lead acid gel cell battery from my K2, it is 8 years old and still working - but it is very heavy to carry.
>
> I have replaced it with a case of 10xAA 2000mAH cells which fit nicely in about half the battery space. I used a 10 cell holder configured as two rows of 5 cells. Once they have been fully charged a few times I will see whether they are any use but the specification implies they should be good for at least 2A for 5W of RF.  They seem good enough for the FT817 and it is much less efficient than the K2.
>
> I have also looked at LiPo battery packs designed for model cars and planes but I am worried about miss-charging them. These have higher capacity, are lighter and hold their charge longer but can deliver very high currents in case of faults. I have seen one person using LiPo on the web - any others using LiPo or NiMH or something else to replace the heavy gel cell?
>
> I am pleased with the space left over and I am thinking if a small 144MHz transverter will fit inside for microwave use, like the DEMI but small enough to fit in half the battery volume. Transverters for microwave IF use do not need high specifications, low gain, low power and minimal filtering so designing one should be straight forward. I already have the transverter interface which can be used to provide selection logic and access to the RF ports.
>  
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.0.238 / Virus Database: 270.11.51/2052 - Release Date: 04/10/09 06:39:00
>
>  

______________________________________________________________
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