If you are getting the alarm mentioned in Subject I suggest you first check the level of the electrolyte in the battery cells. The electrolyte is a mix of sulphuric acid and distilled water. You can top up with distilled/deionised water.
I had been getting this alarm intermittently since my Mazda 6’s first first service but had been getting worse lately.
Having read a few articles on the “Battery Malfunction” the answer seemed to be to change the battery, which is expensive because of the stop/start technology.
On checking the fluid level in the battery cells I found they were all low, I topped them up with distilled water purchased from Halfords for a few pounds and the problem has disappeared.
I again put this down to the Mazda dealership I was using to purchase and service my car. The dealer is now gone which probably says it all.