So why do some people believe manufacturers have the best interest of the consumer in mind? The Maximum profit at any cost mentality rules this day and age. Lawyers and bean counters always overrule what the engineers would design if they were allowed. Vehicular charging systems rarely allow the high enough voltages for long enough to allow an auxiliary battery to reach full charge, and thus will not offgass nearly as much anyway.
Perhaps these same people drive the speed limit in the left lane and hold up traffic, pissing everybody off, because that is what the government says is safe and nobody should drive faster than the speed limit anyway.
Freaking ridiculous.
Starting batteries will Not offgas as much as a Deep cycle as the chemistry of their plates is different to minimize offgassing and water loss. So much so that some flooded 'maintenance free' batteries are basically sealed, meaning one cannot replace lost water as the battery manufacturer have calculated that the battery will die before enough water loss has occurred that it would benefit from refilling. Also most consumers this day and age expect anything remotely expensive to never need maintenance, so a 'maintenance free' battery is especially marketable to the crowd dependent sheeple.
Not one of these flooded 'maintenance free' batteries is a deep cycle. I doubt any marine or dual purpose batteries are either.
Even these batteries in newer vehicles that do have them inside the cab, are either using AGM batteries, or have them in a sealed ,vented to the exterior, container.
And as said, there is a huge difference between topping up a minorly depleted starting battery, and properly recharging a flooded deep cycle battery that was cycled down to 50%. Huge. Not even comparable.
I just did my weekly equalization on my US battery Flooded deep cycle group 31, requiring voltage upto the 16v range, and taking 5 amps to reach and hold voltage.
This 130 A/h, true deep cycle battery, located under my hood, was bubbling and gurgling up a storm, and I could smell the acid mist from several feet away. This particular battery requires these extreme voltages for the Specific gravity to return to the maximum baseline of 1.290. If I do not perform this weekly EQ session, the specific gravity will read 1.225 or less after a week of 14.8v+ several hours each day and a nightly depletion of 25 to 40 amp hours, and the battery will perform abysmally, in terms of voltage held for the amount of capacity removed from it and will get worse each night until I do the EQ recharge session.
No way would I subject my interior to the smell or the amount of acid mist that properly and fully recharging this battery requires, and anybody who wants to share their interior with such a battery when it is being PROPERLY recharged, would be wise to put it in a sealed container vented to the exterior of the vehicle, seeing as how Sulfuric Acid mist is a known carcinogen.
Or you can go with Cole's logic, drink the kool aid, and win the Darwin award.
