Ventless Battery [Archive] - MX-5 Miata Forum (2024)

CDUBS

29th March 2019, 13:43

This might be a dumb question but I just want to verify. I need a new battery. I have the original OEM Mazda battery and it has the connections for the vent tubes. I found a battery at Pep Boys which is a Bosch and said its specific for the Miatas. However it is a "Ventless" battery. Doesn't have the vent holes or anywhere to connect the tubes.

With it being "Ventless" does it mean it's ok to use on my 03' NB? Or do I need to use a specific battery with the Vent connections? If its "Ventless" I'm assuming it's good to go and just doesn't NEED to be vented. I just want to make sure I don't kill myself with some battery gasses.

SilverMiataRacer

29th March 2019, 13:46

I would not use that battery. It's going to vent, you just can't collect the gas in a tube. There are plenty of batteries out there that fit correctly.

Online and in stores.

AutoZone sells one.

Batttery Mart online sells one.

CDUBS

29th March 2019, 14:07

Thanks for the reply.

I checked on the Bosch site and it specifically said "Venting not necessary ". So idk? I'm gonna have to try and get a solid answer on this. I don't want to drive a rolling gas chamber.:bang:

SilverMiataRacer

29th March 2019, 14:18

X-Ray Rich

29th March 2019, 14:39

Thanks for the reply.

I checked on the Bosch site and it specifically said "Venting not necessary ". So idk? I'm gonna have to try and get a solid answer on this. I don't want to drive a rolling gas chamber.:bang:

Regardless of what Bosch says, automotive batteries expel corrosive/explosive hydrogen gases.
If the battery is located in the "open" engine compartment the gases are diluted and dissipated.
If the battery is located in the sealed trunk, like the Miata, the corrosive/explosive hydrogen gases have no where to go and attack the surrounding body and in the worst case may cause an explosive situation.

Trust me, Mazda put a Vent Hose on the battery for a reason.

O'Reilly's sells a battery, "Super Start Platinum Group Size 46A24L Top Post Battery," for the Miata. I have this battery and I'm very happy with it. And the battery has a solid warranty.

MMoondog

29th March 2019, 14:53

The Miata was designed to use a vented AGM battery. There are tons of them available made by Penn Deka and sold under that name, Marathon and many others. They are the same battery. A vented AGM batter designed to properly fit in the Miata battery tray and stay in place with the hold down.

There is ABSOLUTELY NO REASON to not choose one of these widely available and well known replacements for the original battery.

If your vent hoses are intact, this is a total reason for choosing one of these batteries. If your vent hoses are not intact and routed correctly, it is a $2 self fix to get them correct.

I can't imagine why you want to go against all logic here. I do understand curiosity about the battery you found. But remember this. Curiosity killed the Miata. :ohno:

CDUBS

29th March 2019, 19:58

Rich Wilkman

29th March 2019, 20:03

The battery is going to vent gas. If a space is designed in such a way that there's tons of free air exchange then the specific problem the vent tubes protect against (explosion) is mitigated differently. In tighter spaces, the tubes do that work.

Under the hood is one spot, in the tight trunk of the Miata is a different one.

I'm sure some have used the wrong battery in each location and didn't blow up. Use the right battery for the application and location.

-Rich

It's not that I'm intentionally going against using a vented battery. I was just wondering if anyone has used the ventless battery or know specific problems with them. If a ventless battery is designed and marketed to directly replace the OEM and states that vent tubes are not necessary and it's safe why not use them? If there not truly ventless and others had problems with them. I'll get a vented battery. I was just wondering if anyone knew about them.

Ted Crilly

29th March 2019, 20:06

It's not that I'm intentionally going against using a vented battery. I was just wondering if anyone has used the ventless battery or know specific problems with them. If a ventless battery is designed and marketed to directly replace the OEM and states that vent tubes are not necessary and it's safe why not use them? If there not truly ventless and others had problems with them. I'll get a vented battery. I was just wondering if anyone knew about them.

I have a ventless Bosch battery in my NB, (it was purchased by the previous owner about 12 months ago). I’ve had no problems in the 8 months I’ve owned the car and see no reason to change it. When it is time to purchase a new battery I will probably get a vented battery, because as others have stated, the Miata was designed with a vented battery in mind.
There probably is a safety risk in using a ventless battery, but is it really any greater than all the other safety risks we accept when we choose to drive a small and lightweight car on today’s roads? If it was $5 to eliminate this tiny risk then I might do so, but if it is $150 for a vented battery, then I will accept this small risk and put the $150 elsewhere.

Ted.

concealer404

29th March 2019, 20:14

It's not that I'm intentionally going against using a vented battery. I was just wondering if anyone has used the ventless battery or know specific problems with them. If a ventless battery is designed and marketed to directly replace the OEM and states that vent tubes are not necessary and it's safe why not use them? If there not truly ventless and others had problems with them. I'll get a vented battery. I was just wondering if anyone knew about them.

A specific problem is that it will vent gases into the passenger compartment. If you care about that or not is up to you. But that's a specific problem. One that is easily avoided by using the right battery.

Will it kill you? Probably not. Seems like an easy thing to avoid though.

"Ventless" means that it doesn't have a dedicated vent line. It does not mean that it doesn't vent.

MMoondog

29th March 2019, 22:38

A specific problem is that it will vent gases into the passenger compartment. If you care about that or not is up to you. But that's a specific problem. One that is easily avoided by using the right battery.

Will it kill you? Probably not. Seems like an easy thing to avoid though.

"Ventless" means that it doesn't have a dedicated vent line. It does not mean that it doesn't vent.

This is exactly right. In addition there is a ton of wrong information about what fits your Miata. Sure, about 90% of the things I see on Amazon that say they fit my 2001 Miata do fit just fine and work just fine. Then there is the other 10%. There are some cheap knock offs of fuel injectors for example that are very attractively priced and swear they are meant for the Miata in their description. They are not even close. If I did somehow manage to jam them in there, they would leak and fuel is even more dangerous than battery gases. I could go on.

Use the right battery. It is simple to do in this case and it WON'T cause problems.

For whatever reason the seller of that battery is making the claim is not the important thing here. Probably the ad writer got bad information for that listing.

Hey, its your money and your Miata. All we can do is advise from all our experience. The choice is up to you.

monkeylizard

31st March 2019, 15:10

The one with vents from O'Reilly's has a part# of "MIATA"....not kidding.

I have a Duracell with vents from BatteriesPlus. It looks the same as all the others with vents to me and I suspect they all come from the same one or two factories with different stickers slapped on the side. It works and I can say my car runs on Duracells :)

NW Bill

31st March 2019, 18:39

This might be a dumb question but I just want to verify. I need a new battery. I have the original OEM Mazda battery and it has the connections for the vent tubes. I found a battery at Pep Boys which is a Bosch and said its specific for the Miatas. However it is a "Ventless" battery. Doesn't have the vent holes or anywhere to connect the tubes.

With it being "Ventless" does it mean it's ok to use on my 03' NB? Or do I need to use a specific battery with the Vent connections? If its "Ventless" I'm assuming it's good to go and just doesn't NEED to be vented. I just want to make sure I don't kill myself with some battery gasses.Yes, it is OK to use the Bosch battery, assuming it is the correct one for a Miata. When I bought my '04 it had a sealed (ventless) Bosch AGM battery already installed by the PO. I had no problems with it until a cell eventually went bad. I replaced it with a vented AGM battery rather than another sealed one, but only because the vented one at a local O'Reilly's was about 25% cheaper (with the usual O'Reilly's discount coupon) and available for immediate pick-up. If a sealed AGM battery was price competitive and available when I needed it, I'd use it without hesitation.

Sealed batteries are commonly specified for cars and pickups where the battery is installed inside the passenger compartment. None of these cars I have owned had provision for venting tubes. Sealed AGM batteries may vent if the battery's internal pressure rises too high, generally several psi above normal, to relieve the excess pressure. Generally a small amount of gas escapes and then the battery reseals. The excess pressure is typically due to the charging system malfunctioning and overcharging the battery. On the other hand, with a vented battery, if a rubber venting hose splits or comes loose the battery vents into the trunk continously.

Both problems are possible; neither is especially probable.

zoomer210

31st March 2019, 18:39

Ski-Patroller

1st April 2019, 13:53

konakona

3rd April 2019, 08:44

It's not that I'm intentionally going against using a vented battery. I was just wondering if anyone has used the ventless battery or know specific problems with them. If a ventless battery is designed and marketed to directly replace the OEM and states that vent tubes are not necessary and it's safe why not use them? If there not truly ventless and others had problems with them. I'll get a vented battery. I was just wondering if anyone knew about them.

I did, because in my country AGM is only sold in 90AH+ sizes which will definitely NOT fit in our puny battery compartments without some serious mods. I even contemplated importing a AGM one from FM, but the tech there convinced me otherwise saying that a battery is a battery is a battery and there is no substantial performance gain to be had as long as the it cranks well enough. Obviously, he wasn't talking from the safety standpoint but that's that.

Locally, I've been told conventional flooded batteries have been pretty much phased out in our market more than a decade ago in favor of SLA types - the ones that are meant to be completely sealed until they are scrapped and therefore no vent holes to speak of. I am no expert on batteries so feel free to educate and correct me on that if wrong.

Got my miata back in 2012, and throughout my 7 years of ownership I haven't had any corrossion/explosion problems with the two SLA batteries I've gone through. Are SLA batteries supposed to be vented?

Rich Wilkman

3rd April 2019, 21:35

How do you know it isn't venting/offgassing? The gas is generally a product of charging/recharging, not from passive discharge. My UPS systems (large and small scale) had to deal with it and there were requirements around how/where they could be used, etc. Only takes about 4% concentration for things to get fun.

-Rich

The batteries in most home USP units do not appear to have any vents. The older ones are lead/acid, I think AGM. I use one to run my telescope, and it never leaks or vents, regardless of the position.