E-meter [RE-wrenches]

[Bob-O Schultze, Electron Connection]

<x-flowed>John,
I have seen at least three conditions that make the E-meter lose it's 
way without tweaking. One is high charge or discharge rates as you 
describe. Tweaking the Peukerts Equation setting will compensate for 
it. I almost never do this as it's pretty rare that an RE system will 
have either those kinds of loads or charge rates. Another is hybrid 
systems, especially where you have a good winter only hydro that keep 
the battery bank above 90% for weeks or months at a time. When the 
DOD finally does fall below 90% then you recharge and the meter 
rezeros, it sees your battery as being pretty damn inefficient and 
either drops the CEF too far or kicks it up to 98-99% depending on 
the situation. The third is huge winter to summer battery temperature 
swings. You can keep the meter on track by either manually resetting 
the Temp factor (F-3) or using the external temp sensor.
When you first set up a meter, it's best to start with a full 
battery. The meter will figure it out eventually, but it may take 5-6 
cycles to get it together otherwise.
Of course, battery voltage is always depressed when the little 
darlings are cold, but 23V or so with less than a 3A (the 4024 eats 
about 16W) load would translate to somewhere between 75-85 DOD unless 
the batts were damn chilly. Too far.
BTW, as someone mentioned, Xantrex has cut the E-meter down to just 
three models. The Standard, "Choice" which has both the LLO and the 
RS232 features, and the "Deluxe" which has all that plus EV filtering 
and 1000A shunt and range capabilities. All are now available. I'm 
guessing that now that Xantrex owns a metering company, the 
Tri-Metric in Trace clothing will soon be a history item.
Bob-O

>Bob-O,
>    Now that I know there is another installer partial to E-meters, maybe you
>will be the one to answer this question.  Are there any scenarios of loads
>(ie high amp draws by multiple large loads) where the E-meter is unable to
>correctly track and show percent of battery remaining.  I  am seeing a
>situation with a customers system where the batteries appear to be at a lower
>s.o.c. than the emeter is indicating.   The amp hours down from full and the
>percent displayed seems to agree.  My own system is also showing the same
>symptoms and I have seen it on a system I installed last winter.   All summer
>when I had surplus solar at my house it seemed to be tracking fine but now
>when we are stretching the batteries to make it to the next sunny day, I am
>seeing low battery voltages (22.8 to 23.6) in the morning when we had only a
>12 watt total load plus the SW4024 running during the night.
>Battery voltage was about 24.6 with a 10 amp load during the late evening and
>the % charge displayed and amp hours down looked correct.   The owners of a
>new system I just completed (1200 watt PV array, 16 L16PF batteries) are
>questioning the performance of the batteries as they are seeing the same
>thing..... batteries down 250 amp hours out of a 1400 amp hour battery and
>voltages below 24 volts with only one compact fluorescent on.  I have an old
>BCM from SunAmp Power that was my only meter for years with my bank of T105's
>and I tried to keep the batteries at 40% or above on that.  Now I am seeing
>10% on the BCM when the emeter says 85% ???    Any ideas?  I still have 12 e
>meters in stock to sell and I like how they look... I just need my faith
>restored in them.
>
>John Blittersdorf
>CVSolar

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