[RE-wrenches] Amp hr meters

[Dan Fink]

Mac;

I'll give it a shot here.

1) Yes. EVERYTHING that might consume or produce energy needs to be 
connected thru the shunt off the main negative battery terminal for the 
amp-hour meter (watt-hour meter, these days) to work correctly;
	1a)  I am just getting familiar with the Outback Mate and Flexnet DC 
stuff, as we mostly deal with much smaller systems and just use a 
trimetric, BUT if you program the Mate correctly, it appears you can 
tell it exactly what that functions of multiple shunts in the system 
are.....as in, one shunt is wind power in, one is PV in, one is inverter 
use, maybe one for DC loads, and the meter then knows what to tally as 
gain and what as use. just not enough experience here with this 
fancy-pants monitoring networking stuff. I like the trimeteric.

2) Don't know.

3) Your first step after installing an amp-hour (w-h) meter is to charge 
the battery bank full and into float, so the meter learns an initial 
"zero" and starts working correctly (counting down from full). And set 
the charge controller(s) and the meter so that working together they 
will trigger this meter "zero" setpoint. So if you install one on a 
system with an old battery bank it will "learn" that setpoint for the 
old batteries right away.
	3a) As far as how much these meters can actually "learn" I am 
skeptical. But if you see big discrepancies -- large tallys of positive 
amp-hours for example, or large negative readings when the batteries 
show "full"....you can adjust the Peukert coefficient on the meter to be 
more accurate for the aged battery bank. As far as how this affects the 
"learning" ability, changes all that, I just don't know.

So, as far as 3a) be aware of it, and maybe tweak the meter settings if 
amp-hour readings are consistantly above or below zero. Many off-grid 
folks only dream of positive amp-hour numbers. LOL

Anyway, that's how I would approach it.

Dan Fink
Executive Director;
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC / ISPQ accredited Continuing Education Providers
http://www.buckville.com/
info at buckville.com
970.672.4342 (voicemail)
970.373.1311 (fax)



mac Lewis wrote:
> Hello wrenches,
> 
> I am a "greenie" and am curious to know more about amp hr meters.  I've 
> gone on quite a few service calls on existing systems in the area, and 
> I've never seen one on any of the systems around here.  With that being 
> said, I know on some of the new inverter/chargers incorporate these in 
> their devices, Apollo Inverters for example.  My questions are:
> 
> 1.  Is the sole purpose to measure energy into and out of the batteries?
> 2.  On modern inverters such as the XW, is the SOC meter on the control 
> panel based on Amphrs or is it simply a voltmeter?
> 3.  Does an Amphr meter need to be calibrated to older batteries to 
> account for the increase in internal losses?  If so, how?
> 
> Thanks in advance.  I really appreciate tapping into this amazing 
> knowledge base.
> 
> -- 
> 
> 
> 
> Mac Lewis
> 
> *
> 
> "Yo solo sé que no sé nada."  -Sócrates
> 
> *
> 
> 
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