12V Gel Cell

[k6dgw]

A little off topic but this is the battery I power my K2 and KX1 from so...

Without intending to, I allowed the 12V sealed gel cell 12 Ah battery to
dischage to about 6.2V when I finally discovered it after coming home
from a trip.  It was slowly being discharged, not open circuited.

I started charging it through a light bulb, and then directly from a 13V
voltage regulated supply.  Charging current began at about 1A and rose
to 9A when I stopped it, and put the battery outside in the cold.  It
wasn't hot but was warmer than when I started.

When it was at about 35 deg, I started again with charging it, it
started at about 2A and after about 30 mins, had risen to 4.5A.  Still
not perceptebly warm although not 35 deg either.

1.  What is the probability that I will get this charged to power my K2?

2.  Should I trash it and just go get another and be more careful in the
future?

3.  If I just let it float on the 13V voltage regulated supply, what are
the odds I'll set the house afire or have a major chemical explosion?

4.  Is there some charging protocol I could use to try to resurrect this
heavy rectangular thing.

73,

Fred K6DGW
Auburn CA CM98lw
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[John Lonigro]

Fred:
After all of this charging, has the voltage of the battery risen at all
or is it still 6.2 volts?  If it hasn't risen much, I'm thinking 3 of
your cells might be shorted out and you might be out of luck.  Like a
car battery, a 12V gelcell has 6 cells in series.  6.2 volts sounds
suspiciously like the voltage of 3 of them.  If 3 cells are shorted, you
are effectively overcharging the 3 remaining good cells.

As an example, PowerSonic recommends a maximum charge current of 3.6A
for a battery the size of yours, until the voltage reaches 14.5 volts.  
4.5A or 9A is too much!  Then you are supposed to switch to a constant
voltage supply and watch the current decrease until it is about 120 ma.  
Also, their charts show a battery is considered discharged when the
voltage gets down to about 10.2 volts.  Unless someone knows some
battery restoring tricks, yours might be hosed.  Good luck and 73's,

John AA0VE

Fred Jensen wrote:

> Without intending to, I allowed the 12V sealed gel cell 12 Ah battery
> to dischage to about 6.2V when I finally discovered it after coming
> home from a trip.  It was slowly being discharged, not open circuited.
>
> I started charging it through a light bulb, and then directly from a
> 13V voltage regulated supply.  Charging current began at about 1A and
> rose to 9A when I stopped it, and put the battery outside in the
> cold.  It wasn't hot but was warmer than when I started.
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Michael Jensen]

Hi



Just to get my curiosity under control. Do any of you now the main
difference in the procedure taking place when tuning in Auto mode and in ALT
mode. ALT cover more combinations, maybe ALT cover all of them ?

If so how are the combinations selected that Auto try, by a cleaver
algorithm or is just the same limited combinations selected every time?

Do a tune always start by relay reset, rather then from the current relay
position ?



I just had a hard to tune antenna experience where auto tuned 80m 9:1 and
20m 4,5:1 Alt did 3:1 and 1,5:1 on the same bands there for my question.
(The antenna was not very good)



Br.



OZ1BZJ

Michael


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[wayne burdick]

Hi Michael,

ALT mode doesn't prune the search tree as aggressively as does AUTO
mode. (The tree-pruning algorithm is based on SWR trend around local
minima.) This makes it more likely to find the optimal LC values with
high-Q antennas that produce a sharp SWR dip as you approach resonance.

73,
Wayne
N6KR


---

http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com