Just a side note on 12v batteries. Years ago, most batteries came with 6 caps on top where you could unscrew them and top off with distilled water. well, on a lot of today’s maintenance free batteries you will not see the caps. but if you peel the sticker on the top of the battery off you will see either 6 flat plugs that can be picked out or 6 with a slot in them to unscrew. then you can top off with some distilled water. removing the sticker will most likely void the warranty though.
Not to mention mowers again but my mower/cycle battery has the caps and I need to top them off from time to time. A word of caution though when they are topped off, they need to be charged up right away.
The picture below is of a 2015 Lexus RCF battery, the owner was a 75-year-old man who thought it would be helpful to “top off” the battery. The electrolyte expands with heat, after operating the engine there was acid spraying from the vents that caused damage to the paint.
I have performed many battery acid damage repairs that should not have occurred, the electrolyte level should be good for the life of the battery, do not add water to maintenance free batteries.