At 20:05 04/02/1998 MST, Mary-Frances R Bartels wrote:
>Hello all,
> I have a Yaesu E-DC-12 mobile DC adapter/charger. As its name
>implies, it is a charger, not a battery eliminator. I have used it as my
>sole battery charger for my FNB-38 and FNB-35 batteries. Problem is, I
>don't seem to know exactly how long to charge the batteries with it
>because I can't seem to get any of my batteries to last longer than
>several months! I am now faced with replacing ALL of my batteries
>because they are all dead, one won't even register ANY voltage after
>charging.
> I have discovered that keeping the battery connected to the charger at
>all times ruins the battery. I have found that only keeping it connected
>during use doesn't work well either. I would like to keep using the
>charger as my sole means of charging my FT-51's batteries because I aim
>to have my amateur station powered only with solar energy (see my qsl.net
>homepage for more info), thus my E-DC-12 is a great asset --- IF I KNOW
>HOW TO USE IT PROPERLY.
> Since the instructions that came with the charger are vague, could
>anyone out there help me in determining the best way to use this charger?
> Thanks in advance for any information anyone can provide! :-)
> 73,
> Mary-Frances
>
>Mary-Frances R. Bartels KI0DZ DM79lt Denver CO (((#))) ^ ^
>http://www.qsl.net/ki0dz ki0dz@juno.com | ^ - ^
>Watkins products Rep. #92389 ------- (o o)
>** Beyond Infinity - scanning & WWW develop. ** |ooOoo| >{ | }<
>http://www.freeyellow.com/members/beyond-infinity ------- RRR)*
Hi Mary-Frances,
The problem with most of the stock chargers from all the manufacturers is
that they don't know when to stop, even if they are constant-current type
chargers. When the NiCd batteries have been fully charged, the chemical
changes that take place during charging cease to take place, and the energy
being delivered to the battery has no where to go except into heating the
cells. This causes the electrolyte to dry up, killing the cells. Many
schemes have been proposed and tried over the years to determine when the
cells have been fully charged and allow the charger to automatically turn
off or switch into trickle mode - there've been a few articles in QST for
homebrew chargers based on the various schemes, including solar charging
applications. To avoid really serious overcharging of your batteries, which
is what it sounds like is happening here, I'd suggest measuring the current
flowing from the charger into the pack. Then divide that into the amp-hour
rating of the pack, add about ten percent to the result, and charge your
batteries for that length of time - I've used a wall timer like those used
to turn a lamp on and off when you're out of the house because I always
forget to do it myself. I'm sure a lot of people will get on my case for
this not being scientific enough, either I will be chronically overcharging
or undercharging the pack, but it's gotta be better than what you are doing
right now, and has worked for me for quite a few recharge cycles on some
rebuilt Kenwood battery packs I have. I keep a sticker on each pack, and
make a mark on it each time I recharge it, to keep track of how many cycles
I'm getting out of it before it dies.
For my FT-51R, I bought a "smart" charger from W&W Associates (model
MasterCharger Ia) which automatically switches into trickle mode when it
thinks the battery is fully charged. I haven't used any of the packs enough
to tell you whether the charger is taking good care of them or not, but if
they die in a few months, I'll begin suspecting the packs themselves are
faulty. BTW, W&W have a really high capacity FNB35, model
WC-091B3A-FNB35(S)(S) (whew!) that is 1500 mAh, and gives me several days of
14 hours dualband monitoring and talking. The downside is it is a lot longer
(and heavier) than the OEM FNB35, extending a good 6.5 cm below the bottom
of the rig. For me, the tradeoff is worth it.
73 de Avi 4X6UA
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