On Mon, 21 Jan 2013 20:38:32 +0000, Jim Higgins
wrote:
On Sat, 19 Jan 2013 21:57:51 -0800, Jeff Liebermann
wrote:
Our radio club is currently at 35 years for our batteries. Previously,
they were running a small telephone central office:
http://www.LearnByDestroying.com/k6bj/K6BJ%20Repeater/Batteries.jpg
They look like C&D type KCT-720.
Yep. That's the model.
http://www.cdtechno.com/product/vla/kct_kt.html
The originally came from the Aptos central office. My guess(tm) is
that they had about 6-8 years of operation at the CO before they were
donate to the local radio club (K6BJ). The original pile was for
48VDC or 24 cells. The others were distributed in groups of 6 cells
to other radio clubs operating emergency repeaters. One of the clubs
managed to partially ruin theirs with a poor quality charger. Ours
has done well mostly because of the quality charger (donated by West
Marine). It's a 40A West Marine by Statpower/Xantrex charger:
http://members.cruzio.com/~jeffl/k6bj/K6BJ%20Repeater/slides/40A%20battery%20charger.html
Another reason it has survived is because I refused to allow anyone to
run an "equalizing" charge. I'm a bit worried about temperature
tracking as the charger and batteries are essentially in separate
rooms. So far, no problems, but with the large thermal mass of the
batteries, they're unlikely to track the ambient temperature. The
charger does NOT have a remote temp sensor, and I don't want to mount
anything that might corrode in the battery box.
Incidentally, a real tragedy was this collection of fine cells:
http://802.11junk.com/jeffl/crud/battery-jv.jpg
They were in good shape, but because there were only 4 of them, we
would have needed to build a voltage booster to use them on 12VDC. We
tried really hard to find two more cells, and gave up after about 8
years of searching. So, they went to the lead recyclers. Bummer.
And they look to be in VERY good
condition. No appreciable swelling or plate distortion and no
appreciable sediment.
We take good care of them. The photo is from 2003 when we let things
slide a bit. Here's a better photo (showing the dried out electrolyte
accumulation) also from 2003:
http://802.11junk.com/jeffl/crud/k6bj-batteries-02.jpg
The club was lucky to find a ham locally that knows how to take care
of big telco batteries. Much of the power wiring, interconnect
straps, bolts, hardware, and washers were replaced after the picture
was taken. I was at the site yesterday and could have taken a current
picture. Maybe next week when I clean up my mess.
Looks like the positive post seals are leaking a bit and cleaning up
those areas (including removing and cleaning the connectors) and
applying those oil soaked felt washers you can get in most auto stores
would help a lot to prevent further corrosion of the connectors. Maybe
just clean selected positive posts that seem to be leaking the worst.
The battery box is excessively vented to the outside. That results in
condensation inside the battery box, which is where most of the dried
out puddles around the posts originated. Most of the acid came from
various individuals that just had to unscrew everything dripping
battery acid from the caps. That has been mostly cleaned up. There
was a slight leak on one of the posts (I forgot which one), but I just
smeared some grease around the post to keep it from spreading.
I don't recall if we put greased felt washers on the wire end
terminal. I think it's likely, but I'm not sure. I'll add it to the
next preventive maintenance exercise.
For sure keep the covers dry.
We try, but the condensation doesn't make it easy. A few boxes of
baking soda and rice soak up much of the moisture.
If they were made before early 1978 I may have been the Process
Engineer in the plant where they were made.
I would guess(tm) that they were delivered to the CO in about 1982. No
clue when they were actually made. We had the documentation and
maintenance history on the batteries, but that disappeared in a
misguided shack "cleanup". Argh.
Thanks for the info. Please send me an email (address below) as I may
want to bother you with battery maintenance questions in the future. I
consider those batteries irreplaceable and the #1 asset of the radio
club.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558