[Elecraft] RE:FINALLY, a Gel Cell charger

[Steven Pituch]

Hi all,
I would be suspicious of a charger like this.  I do not see how the =
charger
would know what the AH rating is of the battery.  If the charge rate was =
not
adjustable then you will be overcharging any battery under 10 AH in =
size.

The proper way to charge a battery is to give it a slow charge of no =
larger
than c/10.  For a 7 AH battery that=92s 700 ma.  (I believe) the way the
uc2906/uc3906 charger chips work is they go into a taper charge at 13.8
Volts and then stop charging at about 14.4 Volts at about a c/100 or 70 =
ma
current.  At that point the battery is assumed to be 100% charged.  Then =
it
will switch to float charge and maintain the voltage at 13.8 volts.  =
This
agrees with the Powersonic recommendations.

A regular 13.8 volt float charger will never properly charge a battery.  =
It
will only maintain the charge after the above regimen is followed. This =
1000
ma charger from Ham Source says it is a 14.0 volt charger.  In that case =
the
battery will not fully charge, resulting in an immediate permanent loss =
of
capacity, and death to the battery in 1 or 2 years.    The UC 2906/3906 =
chip
is a good way to properly charge a battery but you must set it up =
manually
for the correct AH of that battery.  Done properly the gel cell could =
easily
last 10 years.

I wrote an article on a gel cell charger for QRPARCI magazine many years
ago, that I have used for many years and the gel cells are 10 ears old.  =
I
have a copy at:
http://users.ev1.net/~spituch/Steve's%20Page/Radio/Charger/charger.htm

It basically follows the recommended charging regimen specified in the
Powersonic literature.  But the UC2906/UC3906 does it so much better, =
that I
am going to build a separate charger for each of my critical (ARES)
batteries.

The UC2906 literature is in a PDF at:
http://focus.ti.com/docs/prod/folders/print/uc2906.html#features

There has been a very good discussion of this topic (right now) on the
Flying Pigs List.  I know, its quite an impressive discussion =
considering
that List. ;>)

Actually a 3906 based charger customizable by the builder would make an
excellent mini-kit for Elecraft to feature.

Regards,
Steve, W2MY/5
http://users.ev1.net/~spituch/, Corpus Christi, TX, ELl7
QRP/ARCI 8351, FPQRP 1025, NJQRP 25, QRP-L 269, FISTS 3150, ARS 142, =
NEQRP
281, NWQRP ??, 10-10 61720, NORCAL 691, K2 #402=20




-----Original Message-----
From: elecraft-bounces+spituch=3Dev1.net at mailman.qth.net
[mailto:elecraft-bounces+spituch=3Dev1.net at mailman.qth.net] On Behalf Of
Robert McGwier
Sent: Sunday, May 01, 2005 3:28 PM
To: Njqrp at Njqrp.Org
Cc: Elecraft Mail
Subject: Re: [Elecraft] FINALLY, a Gel Cell charger

Ooops.  I meant to

http://www.hamsource.com/

Bob
N4HY


Tom Hammond wrote:

> Hi Bob:
>
> Thanks for the glowing report... care to share an Internet link to=20
> this vendor? If available?
>
> 73,
>
> Tom   N0SS
>
> At 09:51 AM 5/1/05, Robert McGwier wrote:
>
>> I recently purchased the 1000 MA Gel Cell charger from Ham Source for =

>> $18.95.  This is the very first charger I have tried that actually=20
>> works on my gel cells and for topping off my larger gel batteries. =20
>> The very first one.  It is nicely package and has very nice terminals =

>> for attaching cables and they supply two very useful ones with the=20
>> package.
>>
>> Bob
>> N4HY
>>
>>
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>
>
>
>


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