I have a backup sump pump, a 12V "Basement Watchdog".
However, immediately after installing it, I found the battery was basically dead.
Not wanting to buy a very expensive replacement battery, I got a Deep Cycle Marine battery, which works beautifully.
I've been told that the "Basement Watchdog" battery is specially designed to be safe to use indoors, as it is sealed, while my Marine battery "emits dangerous fumes".
The sump pit is in my basement, in a crawl space. While there is certainly a lack of ventilation, it does have an hvac register (which doesn't prevent the crawl space from smelling like standing ground water when there are a few inches in the pit).
There's no warnings on the battery regarding indoor use.
I thought the battery only released said "dangerous fumes" when rapidly charged, and mine is charged via a very low current charger. Is it safe to use this battery?