Are AGM batteries worth it?

-
AGM needs venting for the same reason as serviceable wet cell; hydrogen. AGMs that don't have nipples for a vent hose will have a less obvious vent/safety valve. Charging from near dead makes the most hydrogen. If you look at bmw and miata replacement batteries, they have the fittings for a hose so no box is needed to catch hydrogen. They usually come with the hose.

The mustang owner should fix his charging system.

I find the most cca case size that will fit the car then build a tray to hold it. The excess cca adds years to the useful life. I get about 9 years out of wet cell if used regularly.
 
MV8 said:
AGM needs venting for the same reason as serviceable wet cell; hydrogen. AGMs that don't have nipples for a vent hose will have a less obvious vent/safety valve. Charging from near dead makes the most hydrogen. If you look at bmw and miata replacement batteries, they have the fittings for a hose so no box is needed to catch hydrogen. They usually come with the hose.

The mustang owner should fix his charging system.

I find the most cca case size that will fit the car then build a tray to hold it. The excess cca adds years to the useful life. I get about 9 years out of wet cell if used regularly.
Click to expand...
If the battery is in the trunk, then I'd imagine the hose would need to vent to the outside of the trunk, or be contained within a sealed box that is vented outside. Is that correct? That's interesting considering none of the folks I've seen running Optimas vent them to outside of the trunk compartment. Maybe that's just because NHRA rules don't require it if a firewall is installed?
 
MV8 said:
The hose goes through a grommet in the trunk floor. Here is what optima says about battery venting:
https://www.optimabatteries.com/custom-fitment
Click to expand...
Thank you! I had no idea that Optimas had that provision. It's interesting that some AGM batteries have a proper vent port while some just vent through one way valves to "regulate internal pressure" like the Odysseys and the ones East Penn makes.

I just spoke with a gentleman at a battery dealer who mentioned the amount of off gassing in AGMs in negligible as compared to lead acid and that only the AGMs that come with a proper port should be vented (which hardly any of them do). He went on to say that even then, it's nowhere near the hazard as compared to a flooded battery.
 
Out of curiosity, I called Optima and was told none of the red top Optimas have a provision for venting. From what I'm gathering, any AGM battery only vents when in an extremely overcharged state. Under normal operating conditions, they should be fine un-vented.
 
mopowers said:
Out of curiosity, I called Optima and was told none of the red top Optimas have a provision for venting. From what I'm gathering, any AGM battery only vents when in an extremely overcharged state. Under normal operating conditions, they should be fine un-vented.
Click to expand...
Sounds like "what we have here is a failure to communicate". Seriously though, I don't know that you are quoting a random optima employee verbatim so I won't assume he is wrong, but the valves vent and they are present on the red tops (those black discs in two corners). AGMs are also called VRLA for these vent valves. I agree that apples to apples, the hydrogen generated should be less than a wet cell and less than flat plate AGM. Will it be "ok" and not burn your ride and everything around it the ground? High probability. Is it possible to use a hair dryer or toaster while taking a bath? Yes.

Red tops are to be maintained/used like a wet cell where the charging system is always maintaining close to full charge. Yellow (deep cycle) is better for cars that sit and are allowed to discharge. Sulfation (shortens life) and hydrogen generation occurs from big and/or rapid changes in charge level (like jump start from too low to crank).
 
MV8 said:
Sounds like "what we have here is a failure to communicate". Seriously though, I don't know that you are quoting a random optima employee verbatim so I won't assume he is wrong, but the valves vent and they are present on the red tops (those black discs in two corners). AGMs are also called VRLA for these vent valves. I agree that apples to apples, the hydrogen generated should be less than a wet cell and less than flat plate AGM. Will it be "ok" and not burn your ride and everything around it the ground? High probability. Is it possible to use a hair dryer or toaster while taking a bath? Yes.

Red tops are to be maintained/used like a wet cell where the charging system is always maintaining close to full charge. Yellow (deep cycle) is better for cars that sit and are allowed to discharge. Sulfation (shortens life) and hydrogen generation occurs from big and/or rapid changes in charge level (like jump start from too low to crank).
Click to expand...
Correct. They all vent when in an overcharged state. What I meant was that the majority of Optimas (at least most of the ones we would consider for our old Mopars) don't have vent tube provisions. They simply vent out of the caps on top of the batteries.
 
I had a good run of Interstate about 15 years ago.
The 5 year ones lasted about 7, but the last 2 I bought didn't make it to 5.
Then I switched to Rural King branded Exide combo/deep cycles.
Had a great run with those but now the models I used aren't made any more.
The last batteries I've bought have been for my scooter and Sportster.
I bought a Li Po for the weight savings on the 125 but-
I found a standard NIB battery at a thrift store for $10 so the LiPo ended up in my 18 HP lawn mower.
It's under rated for that (230 vs 350 CCA), but as mentioned above, cranks way faster than expected and has not required charging at the start of the season (this year is season three) like the lead acid ones usually do. The one for the Harley died from sitting with the key on over night. I was nervous about charging it without a Li spec charger but I found online that if you use at least a 15 amp charger and pay attention (mine has a charge percent readout and a charged voltage readout) it can be done, so that's what I did.
Based on that, I'd consider a LiPo for a car.
Most current generation Lithium batteries have a charge controller built in, under the case top.
Early ones do not.

BTW and FYI- Duracell was bought by a Chinese company a few years ago.
 
Last edited:
Vertex_Jeff said:
If you let your AGM sit for months at a time, that seems to be bad for them. You need to hook them up to an AGM friendly trickle charger. If you are not inclined to remember this AGM battery maintenance, then probably not a good fit for you.
Click to expand...
That has been my experience. I have an AGM (Red Top) in the race car and keep it on a battery tender between races. Seven years now and still going strong.
 
Thanks guys. I appreciate the input. Luckily I found a great local brick and mortar outfit. I called him the other day and picked his brain and he offered me a great deal on an AGM group 34 Deka. I'm going to go in on Monday and pick it up. Time will tell how it performs, but it's nice to know I will have gotten it locally if I ever have any problems with it.
 
ValiantRacing said:
I love my XS agm battery, only weights 22 pounds, and i can race all weekend and never put a charger on it.
Click to expand...
I have 2 XS14 volt AGM's in my drag car and an XS charger. The agm batteries have given me zero problems. For drag racing without an alternator, they have been far better than anything else I've tried.
 
RockinRobin said:
I have 2 XS14 volt AGM's in my drag car and an XS charger. The agm batteries have given me zero problems. For drag racing without an alternator, they have been far better than anything else I've tried.
Click to expand...
I'm curious - do you have them in sealed boxes vented to outside the trunk compartment?
 
Should be
But hes just running them 1/4 mile at a time
 
RustyRatRod said:
All the old Optimas were good. The newer ones starting about ten years ago are all now made overseas, so it's hit and miss anymore.
Click to expand...
That's right! We have people convinced enough, so lets save costs so we can maintain profits! It doesn't matter now that people Think we build a good product, only keeping profits up matters now that we're successful!
 
Dartsun said:
I got this interstate battery from a car I got from an acquaintance. It's been the best battery, vehicle even sits and I start it few times a year. Almost 11 years old now.
View attachment 1716438735
Click to expand...
Interstate Batteries used to be very good quality, back when they sponsored big nascar teams. After all that exposure they seemed to let the quality slide & you'd increasingly hear how they didn't last.
 

Damn I get a Mercedes battery cheaper
And seen those last 12 years
 
You must log in or register to reply here.
-
Back
Top Bottom