Charging gel cells for my K2 with regulated PS???

[Steve Kallal]

I hope this isn't off topic.
 
I bought an 18 AH gel cell for my K2 after the power went out last week.
Today I bought a charger from HRO that charges up to 750 mA, which will take
forever with an 18 AH battery. I've been told I can charge the battery with
my regulated power supply if I am careful to not overcharge it. How do I
know when it is close to fully charged? I plan to use the smaller charger to
keep the battery trickle charged with the lower current charger. I simply
want to get the battery charged faster.
 
The battery is far from dead, but the voltage to my K2 drops significantly
when the KPA100 option is used, even with a #12 power cord. I don't plan to
use very high power, maybe 30 watts or so.
 
73,

Steve N6VL
 
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[Phil Kane-2]

On Sat, 15 Sep 2007 17:11:22 -0700, Steve Kallal wrote:

>I hope this isn't off topic.

>I bought an 18 AH gel cell for my K2 after the power went out
>last week. Today I bought a charger from HRO that charges up to
>750 mA, which will take forever with an 18 AH battery. I've been
>told I can charge the battery with my regulated power supply if I
>am careful to not overcharge it. How do I know when it is close
>to fully charged? I plan to use the smaller charger to keep the
>battery trickle charged with the lower current charger. I simply
>want to get the battery charged faster.

  I have lots of experience running my entire comm room -
  including my K2/100 - from "big" Gel-Cells, 100 AH capacity
  class.  (See, it is on topic! )

  As a class, a "12 V" Gel-Cell battery is rated for 14.3 V
  "equalizing" voltage and 13.8 V "float" voltage.  A charger
  designed for this service is essential to avoid damage to the
  battery, and said chargers often costs as much as the battery
  does.  What these "smart" chargers do is to interrupt the charge
  current for a small portion of time and "look" at the battery to
  determine its state of charge, and then adjust the timing and the
  charging voltage appropriately.

  The 60A charger that I use is dual purpose - it serves as both the
  charger and as a primary source if I have to take the battery
  off-line for any reason.  It replaces a 45A allegedly-regulated
  supply and a 10A "smart charger" (I have the latter available
  if anyone needs it - contact me off-line).

--
   73 de K2ASP - Phil Kane
   Elecraft K2/100   s/n 5402



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[Steve Kallal]

Thanks for the replies about charging my 18 AH gel cell. I was a little
impatient waiting on my 750 mA charger get the battery topped off. I left it
on yesterday evening when I stepped out and came back 2 or 3 hours later.
The charger's green light was on.

I did some reading on gel cells, in addition to the replies. It seems that
my power supply, an Astron RS-35A, wouldn't have charged the battery any
faster anyway. My $30 charger from HRO will allow me to tickle charge the
battery and prevent overcharging. But I think I'll check out the 1 A charger
from A&A Engineering. Anaheim is very local to me and their chargers have a
good reputation in the ham community.

One responder said it would take 24 hours for that charger to fully charge
my battery. 750 mA / 18 A = 24. I guess that is where the 24 hours comes
from. My charger is a Deltran Battery Tender Junior from HRO. HRO
represented it as coming from powerwerx.com. Powerwerx has an larger model,
1.25 A. Its too bad HRO didn't have that model in stock.

I do wonder about using the gel cell with my KPA100 option. I don't need to
run 100 watts by any means. But 10 watts is a little too low for me. I
wonder how the 18 AH gel cell, a Power Sonic, will work and last with the K2
at about 30 watts. I'd been tickled to death to have had 30 watts when my
power was out. I don't know if the KPA100 looses efficiency at 30 watts
versus 100 watts. Just curious.

Again thanks for the comments! I still welcome more.

73,

Steve N6VL

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