Any battery experts out there?
Is my race car battery about to give up?
It's a Hawker Energy SBS-30 (Sealed Battery System) now
about 3 years old. Has always been trickle charged with a
"battery tender". While at the track I generally put the
charger on every other track session (no alternator on the
race car) and over the winter I've put it on about every
three months.
I was told last week that these batteries have a "memory"
and if you frequently recharge without fully discharging
them they will loose capacity. Recommendation was to
discharge it (with a load like a light bulb) - then
recharge.
Sounds good. Here's what I found.
Nominal capacity is 26 AH.
Used a 12v 50W trouble light as load. I make that a 2.9 ohm
load with initial current draw (at 12v) of 4.2A.
26 AH at 4.2A = over 6 hours capacity - right?
I didn't check the no-load volts but with the 50W load it
showed 12.1V, after 1hr 12.0V, 2hrs 11.7V - so far so good
- then after only 3hrs the light was very dim and the
voltage just under 7. Oops. Maybe it wasn't fully charged
when I started.
Recharged overnight on the Battery Tender. With it still
attached this morning it was showing 13.14V - presumably it
had been higher when starting to recharge but had settled
back to this "holding charge" voltage. Right?
10 minutes after disconnecting the charger the battery was
reading 12.77V. Switched on the load - only 12.32V. Hmmm.
After 10 mins recovery (no load) it was back up to 12.66V.
OK or not?
Switched on the load again - only 12.2V. After 1 hr 12.1V.
Then after 2 hrs only 8V. Hmmm. Worse than before. Switched
load off - rose to 12V after few minutes, then 12.1V 1/2hr
later - but it rapidly decreased as soon as the load was
re-applied - back down to 9V (and decreasing) after couple
of minutes.
Did I damage the battery by what I did?
Is it still OK? (i.e. is the above story typical?)
Or is it about to give up in the middle of the next race?
Anything else I should do?
It is a sealed lead/acid, gel battery but the plates are
pure lead which is supposed to be "good" (= expensive).
Originally designed to aircraft emergency power.
Thx for any info and advice.
Derek
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