Battery test by conductance?
Battery test by conductance?
(OP)
Anyone familiar with the Midtronics conductance based battery testers?
Just wondering if these were the real deal.
Thanks,
Todd
Just wondering if these were the real deal.
Thanks,
Todd





RE: Battery test by conductance?
take a look at Enersys's white papers and ap notes.
Impedance matching of cells is covered.
They think matching by impedance quite important.
RE: Battery test by conductance?
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A major issue is around the use of AC impedance measurement techniques.. versus DC load testing..
Judge for yourself...
And, talk to the engineering people that design the batteries in question and ask if they will support a warranty claim based on conductance tests..
We talked to the engineering folks at two major manufacturers of industrial batteries the the answer was no.. They will only support warranty claims based on DC load test results.. Also ask if the same folks if they publish reference conductance values on their batteries.. again the answer was no..
We also talked to Alber..
We use only DC load test method at our customer sites..
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In God we trust. All others state the facts and cite references.
RE: Battery test by conductance?
We test capacity and charge/discharge efficiency.
Most specifications are for ampacity delivered..
We are looking into impedance matching for additional
data in building series parallel packs.
Having issues with a 42 cell pack (sealed lead acid)
arranged 3 cells parallel every stage, 17 stages.
Discharge rate, 2C; CC mode charge rate at C/5.
Question is how do mismatches in the 3 cell parallel
banks effect the aging of the battery cells
over the design life.
Designed for 5 year life, getting 3 - 4.
Occasional packs show high corrosion from
outgassing and acid expulsion.
Corroded terminal cell location very random.
Thanks for the great reference.
B1388
RE: Battery test by conductance?
With respect to parallel 3 cell monoblocks, the unequal resistance of course promotes deterioration of the better cells especially during equalize and charge cycles. But there is absolutely nothing that you can reasonably do about it. Even replacing a suspect block with a new "impedance-matched" one from the factory will never truly align the values. Run the string until it dies and make sure you have a redundant string, hopefully staggered in age. Replace the strings when their values or performance indicates. Max expectancy for 10 year VRLA is 7-8, for 20 year VRLA 10-15, for 20 year flooded, they can actually go beyond 20 if babied.
As far as warranty claims...these puppies are pro-rated so the warranty value is about as attractive as the one on your car battery.
RE: Battery test by conductance?
Why parallel the cells? I mean, why not run three independent strings that are common connected only at the +48V and ground terminals?