I am no battery expert, but I have found that the rechargeable battery
jumper boxes sold at Harbor Freight, etc. for as little as $39 have the
same (yes exactly the same) battery as sold by the race suppliers for
$80 - $120. No difference in performance that I can detect. When they
get weak, as any battery will, I just get a new one.
Bill
Derek wrote:
> 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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