Weird thunking sound when charging lifeline AGMs

[Freep]

We went out for a quick weekend trip with no issues and I plugged the camper in when we got home. At some point over the next week the AC outlet tripped its circuit breaker and I drained my two 100 AH lifeline AGMs. That sucks. But the weird thing is that the batteries(or one battery) are making a weird intermittent thunking sound. It's been doing that all day.

Does anyone have any idea what that sound is and if I should be acting on it?

[pnichols]

Freep wrote:
I just got off the phone with Lifeline. They said it's normal for that noise to happen when you discharge deeply and then start charging again.

Hmmm .... that is a STRANGE THING for a battery to "normally" do!!

I would have guessed that it was the automatic pressure relief valve opening up on one or the other of your AGM Lifeline batteries due to vapor build-up inside one of the batteries because it was being charged too quickly.

I've never had this happen on my (other brand) of AGM RV batteries, but I wouldn't be surprised if there was some kind of "noise" connected with the opening up of the vapor pressure venting valves that all AGM batteries have.

[Freep]

I just got off the phone with Lifeline. They said it's normal for that noise to happen when you discharge deeply and then start charging again.

[midnightsadie]

YC 1 is right I,ve seen a battery explode under a controlled test ,ain,t pretty.

[YC_1]

If it is actually a battery making the noise I would cover it with a blanket as I carefully take it out. Safety goggles, gloves, water hose nearby and on.

No battery should ever make a noise like that. If the plates are somehow moving about this thing could be about to explode do to an internal short.

Water anything down that might get splattered by acid. This is a no joke dangerous situation.

[MEXICOWANDERER]

Multiple coincidences point to a problem.

• Disconnect power from batteries
• Take an image of wire connections
• Disconnect batteries from one another
• Take individual voltage readings from each battery
• Wait three days
• Take another voltage reading from both batteries
• Do not reconnect
• What did you find?

[dapperdan]

Inverter went "south" on ya??? Or possibly needed to change the setting on your inverter to "AGM"? Just a guess.....

Dan