When the battery set gets low [RE-wrenches]

[Darryl Thayer]

In my experiance the loss in the battery cables is too
small to have an effect.  This effect is large.  I had
a chance to measure last winter when I was called to a
site where the batteries were dangeroulsy low, the
trimetric was set for 92% efficiency and it read full
charge.  We ran the generatror for several days,
pumped in several capacities of charge before my
hydrometer said the batteries were full.  I can not
explain other than the charge efficiency was very low.
 The cells bubbled for and yet the charge was very
slow to come back.  They did and with summer the
batteries seem to be fine and are at full charge.  The
trimetric has been set to 84% battery efficiency I
think.  However the new charge controller (MX60) is
now in charge and I have the float voltage set higher.

Darryl

--- John Raynes <john at raynes.com> wrote:
> I wonder how much of that loss in efficiency is due
> to the fact that a lot 
> of the re-charging is happening at lower voltages,
> hence the cable losses 
> will increase as a percentage of total charging
> power.
> 
> Anybody have sufficient long term experience in
> observing the charge 
> efficiency calculations of an E-meter or Trimetric,
> that they can quantify 
> the loss in efficiency on a typical system, based on
> maximum depth of 
> discharge?  I'm always looking for more good reasons
> to give to customers 
> as to why they need to keep their battery state of
> charge higher than 
> they're inclined to.
> John Raynes
> RE Solar
> Torrey, UT
> 



		
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