--- In [email protected], Tony VE6MVP <[EMAIL PROTECTED]>
wrote:
>
> At 10:33 AM 2006-01-14 -0600, you wrote:
>
>>I have in service an Interstate brand 8D-PHD lead acid deep cycle
battery
> that is nine years old and at nearly 80% of its brand-new capacity.
>
> How do you know it's at 80% of it's brand-new capacity?
Here's how I arrived at that number... Every six months I switch
the repeater to batteries and track the number of days it takes to
discharge down to 10.50 VDC. The discharge time has dropped about
20% since it was brand new. Obviously this is not a precise
measurement due to varying traffic on the repeater. But since
machine usage is pretty consistent and the discharge takes place
over a period of 10-12 days I feel comfortable using it as a
performance benchmark.
>> * Regular checks of electrolyte level topped off with distilled
water
Electrolyte level was checked every couple weeks when new until I
was satisfied I wasn't cooking the battery. Then checked about
every three months. At a float of 13.20 VDC I added about 1/4 inch
of distilled water per year.
>> * Regular specific gravity checks to watch for cell degradation
I check every six months after the discharge I described above.
>> * Regular cleaning of the battery case and terminals
Every three months the battery top is wiped down with distilled
water and paper towels (watch out for acid residue on clthes!). The
terminals are visually inspected for any signs of corrosion; usually
a whitish powder appearance. At the first signs the top-post
battery connectors are removed and soaked in a solution of one pint
water and a couple Tablespoons of baking soda. Same solution is usd
on the posts. Followed y a scrubbing with an old toothbrush.
That's followed by a clear water rinse, a pat dry and a thin coat of
No-Oxid (commercial anti-oxidant goop) is applied to posts and
connectors. Connectors then installed on the battery and tightened.
>
> How often is regular?
See above...
What do you look for when deciding to clean the case
> and terminals?
See above....
>
>>* Semi-annual discharge followed by an equalization charge and
then
> return to float
>
> What do you mean by equalization charge?
After a discharge a battery needs more than a normal float to bring
it back to a fully charged state. While "Float Voltage" will
*maintain* a charge, an "Equalization Charge" kicks the battery in
the pants. In my case I use a commercial automotive charger and
monitor the specific gravity of the cells during charge. (I have the
luxury of a site that's a ten minute drive away.)
The commercial charger is a huge compromise because I need to take
the battery off-line during charging. I'd love an intelligent power
plant like I have at work for telecom sites. These plants monitor
AC outages and calculate drain on the batteries. When AC is
restored, they calculate the equalization charge duration needed and
apply the appropriate charge accordingly. Sweet but $$$$.
*** DISCLAIMER ***
There are as many ways to configure backup batteries and supplies as
there are Repeater Builder subscribers. And my Interstate Deep
Cycle battery and charge/float configuration are far from perfect.
In my case, though, it's served it's purpose well at a cost of $130
for a battery that's going on ten years old. It gives me the bang-
for-the-buck I need. But not right for everyone.
FYI.... Interstate Battery Tech Support was impressed by this
battery's longevity. They and I chalk it up to careful maintenance
in a well-controlled building environment.
As always... YMMV.
Doug
>
> Tony
>
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