VRLA Batteries

[varri79]

Which testing method (Load test / internal impedance measuring method) is recommonded for testing the following specified battery banks for maintenance purpose? And also recommended frequency of testing?
Specs: Make: Hawker,Type of battery: Lead ACID, dry type, Individual cell Voltage: 2V, No. of cells:108, Bank Voltage:230V, Cell AH capcity:4500 and other Battery banks are rated from 800AH to 1200AH.
And also please advice me good battery testing kit for internal impedance measuring if it is recommended.
Thanks..

 

[rbulsara]

Load test is normally done during acceptance testing. Since you need to take the system off line to to a load test, it is not done so frequently.

Inernal impedance test is more common and a necessary test. These two test are not substitute for each other or alternatives. You need to do both at approprate time.

As for a kit, unless you are in business of battery testing, I would hire a battery maintenance company experienced in the work.

 

[varri79]

Thank you Mr.Rbulsara,
For finding healthiness of batteries, how frequently the above tests need to be carried out? As we have more than 20 battery banks, we would like to purchase testing kits. Could you recommend any other test to ensure healthiness of batteries?

 

[dbaird]

FYI Check the following starting at page 93:

http://www.stanford.edu/group/Power-Systems/ESOP.pdf

David Baird
mrbaird@hotmail.com
Sr Controls Engineer
EET degree.
Journeyman Electrician.

 

[rbulsara]

Without referreing to any standards such as IEEE, I would say at least every six months for VRLA type batteries.

I am not personnaly familiar with any particular testing kit..but the battery mfr. can be of help.

 

[mpparent]

There might be something at

http://www.alber.com.

Mike

 

[DanEE]

I concur with the post above that you would be better off to hire a battery maintenance company with the experience.

There's no simple kit answer that works...

If you really want to get into this, do some extensive reading e.g. here

http://www.alber.com/TechLibraryPublishedPapers.htm

I've read everything I could find on the subject and, the above papers seem to be the best collection of sound engineering on the subject, with the least amount of self interest bias among folks hawking impedance testers.

Battery Impedance Testers have been around for a long time, but the controversy on their ability to produce meaning results still lives on..

Personally, Alber is the only one I would even consider because it does a true DC load test versus some testers using AC impedance measuring techniques that grossly ignore the capacitor (or surface charge) effect.

Many of the AC impedance testers are based on baseline impedance values not published by the battery manufacturers, nor supported by the battery manufacturers.

We have talked to the engineering staff of several major industrial (stationary) battery manufacturers and the DC load tests are the only data they will accept on a warranty claim.

If you don't want to use something like an Alber, measurements at 6 month intervals of the individual cells looking for voltage deviations on a per cell basis can be done. But this method needs knowledge of fall back techniques to verify questionable looking cells (e.g. individual cell load tests, etc) and experienced judgement to make the right call whether the battery string will hold during an outage.

If you decide to do this on your own, you need to do a candid analysis of what is the price of failure is to you, and your organization, if you have an system outage due to battery failure...

 

[sreid]

The two "Gold Standard" tests for automotive lead acid batteries are

1)Hydrormeter checking the Specific Gravity (SP) of the battery acid. The SP indicates the charge state of the cell.

2) A "Breakdown" test that puts a high current load on the battery and displays the voltage. If the voltage "Sags" too much, a cell is getting weak.

 

[nukeman]

IEEE 1188 specifies VRLA testing. The best way to detemine the "health" of a battery is a capacity test. As mentioned in previous postings Alber offers excellent test equipment for performing both discharge test and internal ohmic test.

 

[ScottyUK]

sreid,

Hydrometer readings on a VRLA are tricky because the battery or cell is a sealed unit. Good advice for vented cells though.


----------------------------------

If we learn from our mistakes,
I'm getting a great education!

 

[felixc]

There is also a "battery engineering" forum in eng-tips. See what they have to say too.

 

[dwftx34]

I work with a D/C tech within our company the test schedule used to test VRLA batteries at a Telecomm Site. Is every quarter test cell voltage (we use an Albercor Cellcorder) then annully test Inter-cell reisitance
and Scotty is right on you cannot test VRLA cells with a Hydromter only floaded lead acid batteries (wet-cells).

 

[varri79]

Nice response,
Pl. advise me with your exp, which test equipment is recommended - Internal cell resistance / Internal cell impedence test equipment(for VRLA, 2V, 800 to 4500AH Batteries), Different sites are giving different opinions.
Thank you..