Here at work we have a golf course fleet of ~20 carts. The 2008 models came with the 'single point watering system'. After having several batteries go bad in the first two years, and finding the cells empty.. :beg We went back to watering the cells individually. We have not ordered carts with that option again. Battery life went back to 4 years, which is our fleet exchange rate.
And on the subject of filling batteries..
(https://images.homedepot-static.com/productImages/a10f7a61-714d-4afb-9f25-2860e5a305cb/svn/basement-watchdog-battery-back-up-sump-systems-bfb-64_145.jpg)
Using the 'automatic' shut off filler like the picture above tended to overfill the cells, and cause residents to complain of leakage staining their garage floor.
Back to basics - use a funnel and bottle to fill. Doesn't take THAT long.