so what batteries do you suggest that are safe to mount INSIDE a van? that was part of my reasoning behind buying an Optima. no fumes, etc, as I have my second battery mounted in the back, under my bed.

You definitely need an AGM battery for that application. They do make deep cycle versus starting AGM batteries.

These batteries are considered the best in the RV world.
LIFELINE
Odyssey batteries are also considered excellent.
Odyssey

Universal brand batteries(from china) are the cheapest AGM batteries. Here's a group 27 for 180$. I do not know if it is a deep cycle. This was just a quick search.
Universal battery

Make sure you do not get a Gel battery. They have vastly different charging requirements.

If you do get a pricey battery, you need to also upgrade the wiring leading to it so it is not chronically undercharged, sulfates early and dies prematurely.

Also be cautious, I read and saw pictures proving somewhere that all "sealed" batteries are not truly sealed.

On a side note, I have a Optima yellow top. It's been in the truck for 9 years. I must have killed it dead 50 times. It's still going strong...

Generally the only time an AGM battery will outgas is if it is severely overcharged. Even if an AGM battery's case is broken, there is no liquid within to spill.

No battery produces gas when discharging.

Now there are maintenance free sealed batteries that are not either AGM or GEl technology. They are just regular flooded batteries that are non servicable. It is a marketing scam for those afraid to put a little distilled water in their flooded batteries once in a while. The problem with these is they still use water, but it cannot be replaced.

Avoid this type as you would an Ebola plagued monkey.

Make sure whatever you buy clearly says AGM, and is basically twice the price. If you see "maintenance free" and only a 3 to 20% mark up over a similarly sized battery, it is the Ebola plagued rabid baboon.

Diehard Platinum (AGM)batteries are made by the same company that makes Odyssey batteries. They are considerably cheaper and have a loyal following. I don't know if they are built to the same tolerances/ quality.

And about the Optima batteries. There was a period of a couple years starting in 2003ish where they cut every conceivable corner to cut costs, and quality went into the toilet. As they did not lower their price during this greedy binge, and their executives just got fatter like the disgusting wall street schmoes, they should be avoided even now that they claim they have started using virgin Lead again and other measures to bring back quality.

My friend has a 10 year old optima which will not die even after severe abuse. Another friend has a ~5 year old Optima which has maybee 10% of it's capacity remaining despite being cared for and never deeply discharged.

wrcsixeight, your AGM theory is not correct. AGM batteries DO contain liquid, but AGM means Absorbent Glass Mat (or Material) which absorbs and contains the electrolyte (acid) so that it doesn't slosh or spill, and keeps the lead plates wet at all times... this allows the battery to be used in other positions than the normal "upright" way.... like if you put it in a 4-wheeler or jet ski that is often not horizontal. If your batteries plates become exposed to air they oxidize and it reduces the output capacity of your battery.

Otherwise you are correct. Yeah, I used to work at a battery plant and ALL lead-acid batteries create hydrogen when you charge them. Its the chemical nature of the beast. Even a "sealed" battery contains a pressure release vent. If this vent malfunctions and pressure builds up in the battery, it could explode! Or if you vent it somewhere contained (like inside the cabin of a van) where there's a chance of a spark.... kaboom!

BUT, the good thing is the batteries only vent hydrogen under charging. And the "sealed" type only vent under EXTREME charging... like say 200amp or higher... (when we charged them during manufacturing they whistled like birds!). And you might never use them that agressively. So the better choice is the "sealed" (or sometimes called maintenance free).... but by far the BEST choice is just to vent your battery. Build a little box around it with a nice sealing lid and find a way to create a vent to the outside. Better safe than sorry I'd say.

As far as a 100% safe battery for mounting inside your van... I don't know! Even little AA and AAA Lithium, Cadmium (etc) rechargeable batteries are vented. Look at the ends... there's a little pinhole. Just the amount of gas produced is so small because it's such a small battery.

I realise the liquid electrolyte is suspended within the glass matt.

Everything I've read about them indicates that if the AGM's battery case is punctured or breaks, this electrolyte will not drain out as a liquid.
Is this not correct?

A Question. No sarcastic tone intended.

I thought the electrolyte was suspended in gel, so in that sense no 'liquid' would drain. Maybe the mat has the ability to contain the gel? I don't know, never taken a pointy stick to one.

I am wondering how the agm's combat dendrite reversal? Better due to the lack of a liquid or worse because the mat gives them a structure to 'build' in.

...oh, I happen to like Ebola plagued monkee's

I am truly enjoying this thread Lots of good knowledge here.

Does anyone know or remember what color the Optimas were when they first came out for public use in the early 80 s ?

or

what aplication Optimas were originaly designed for ? (PS they failed this application .)

I have sold many Optimas, only because people demanded them, there are many batteries that offer better value. jus my 2 cents

That's ok.

Actually no... it can drain... well somewhat. AGM is a tight weave fiberglass, similar to house insulation, only denser, and with some additional ingredients. SOME will be retained in the matting somewhat permanently due to surface adhesion, but it is porous, so some amount of it will drain out. But much is retained. And often the batteries are overfilled slightly to compensate for any air pockets during the fill too. Any of that excess liquid will also be free to drain out. And the matting does not fill 100% of the battery. There are spaces along the outside of the plates, underneath the assembly, between layers, etc that will contain "free" liquid that was not absorbed. But overall, a great amount of it is contained in the matting. So it is nearly true.

There was a story about one of the sales guys in the plant, that during the inception of AGM batteries whipped out his hand gun and shot the case to "impress" a customer. Needless to say he was a bit embarrassed by the result. Shredding through the matting will release the liquid.

Now GEL batteries are a getting more like your description. The acid is mixed with silicone additive and then filled into the battery. After a short time the liquid "sets" (similar to how jello does) and results in an electrolyte approximately the thickness of molasses. Well THEN the liquid clings in there damn good. But ultimately it is still a liquid.... though it is very VERY thick and slow moving.

Though if you dissect either of these batteries, you will find the mat is wet to the touch. And you will be able to wring a good portion of the electrolyte out of the glass mat, much like a sponge.

I would have to say the only true "non-spillable" battery is a dry cell... and those are made with a "paste" electrolyte. Even that is a little "fluid". The idea is 100% contact with the plates for good conductivity and no air intrusion.