Wednesday, Aug 05, 2009 at 08:17
I can only imagine one way, an AGM could produce noise... by gases venting through the (with moisture covered on inside) overpressure relief valve(s).
I'm with Mike DID on that one, who suggested to turn off all connected loads while charging in order not to interfere with the charge algorithm/routine.
And I'm also with Maîneÿ on having the battery load tested to see if its still holding 100% of its rated charge of 120Ah - and get this documented.
You could also try and load
test it yourself by hooking it up to a heavy load. I
test all my batteries with a 660W (55A) load over 30 minutes which discharges them to 50%. Taking voltage measurements at the battery terminals every minute and plotting them along the time axis of the discharge curve diagram (manufacturer supplied), I get a pretty good idea of the battery's health/quality.
If you'd like to take a closer look at how such a load
test result of a new and healthy quality AGM might look like, go to www.batteryvalue.com.au
I'd do the following:
Since the batt has been sitting on charge now for a while it should be fully charged. Give it a light discharge by running the fridge/DVD player for half an hour off it. And while the load is still drawing current, measure the voltage across the battery terminals. A healthy 120Ah AGM should still hold the voltage around 13 V then.
If it fails this simple
test, it's either not 100% charged or already been damaged (or it was already a dud when you bought it).
If it passes this light load
test, give it the heavy treatment as described above.
Good luck with it all!
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