Here's what I did to solve the rechargable battery issue with the
MFJ-269B antenna analyzer.

The charge rate is way too slow using the internal charge circuit, so
to speed up the charging process using intenral AA NiMH internal
batteries, in the factory battery holder, I installed a power barrel
jack on the bottom of the meter. To charge, I plug in an external
charger into this new jack, and when plugged in this disconnects the
batteries and charger from the unit. You can NOT simply plug a charger
into the factory ext. power jack, so now my analyzer has two jacks, of
DIFFERENT sizes so I do not accidently plug the wrong thing into the
wrong jack. I inserted a 0.5amp fuse inside the charger, in series
with the + battery wire so that if your external charger is set for
too fast a charge rate the fuse will blow (e.g. I have a charger which
can be set for various charge rates, for AAA to D size batteries,
NiMH, etc., up to 50w total).

73,
Dick N7EMW
www.repdesign.us


On May 6, 2:27*pm, Cecil Moore wrote:
Andy wrote:
How long does the Ni-Cads take to charge in the MFJ-259B and how long will
they run for?

IMO, Ni-Cads are a royal pain in the neck. Instead,
I use a YUASA gell cell NP1.2-12 at ~$20. I Velcro
it to the MFJ-259B as it has almost the same form
factor. It is easily recharged using an Astron 12v
(13.8v) power supply, i.e. no "battery charger"
required. After using the NP1.2-12 to power the
MFJ-259B, I would NEVER go back to standard batteries.

If one removes the battery holder, the NP1.2-12 will
almost fit inside the MFJ-259B. When I get time, I am
going to modify the MFJ to accomplish that feat. MFJ
missed a selling point by not making the 259B case a
couple of mm larger to accommodate a standard gell cell.
--
73, Cecil *http://www.w5dxp.com