Unsolved Battery Drain (with detailed troubleshooting)

FWIW, the new Toyota battery AGM battery I bought last year measured 13.0 volts coming out of the box. I doubt very seriously it had been charged just before I bought it as I watched the guy cut the tape on the box.

I have seen more than one new AGM type battery measure 13.0 volts sitting on a bench with NO load connected.

I will agree that a "flooded" type battery will measure 12.6 volts with no load, however the AGM type batteries normally measure 12.8 to 13.0 volts or more with no load when fully charged after resting for at least 24 hours.

 

OK, maybe I learned something new today.

I have seen several that come out 12.8; I've seen none above that........but I haven't looked recently either.
Maybe the internal composition is changing a bit over time.
Any chance there is a meter error involved ?
I wonder if applying a very small load......like a 10W bulb, would drop it back some ??

Oh and an AGM battery still is a "flooded type" just of a special construction.

 

I also would say that a new, fully-charged AGM battery should measure at least 12.9V. That is my experience with GS Yuasa batteries that I have bought from my local Toyota dealer.

The digital multimeter I normally use is a Fluke 87 and I have also confirmed its readings with a 5-1/2 digit precision Hewlett-Packard lab DMM.

An AGM battery is not flooded. There is no free liquid within. In theory, you could operate the battery on its side or upside down.

AGM means "absorbed glass mat". The battery construction consists of fuzzy white mats separating the lead plates which contain electrolyte.
VRLA battery - Wikipedia, the free encyclopedia

 

You are picking at nits now.
The fuzzy white mats are not created with the electrolyte already IN them.
At some point, the electrolyte is POURED into the battery and the mats absorb it.
That sounds an awful lot like "flooding" to me.

 

This really is not a nit.

Flooded means there is free liquid acid floating around in the battery. That makes a big difference with regards to vehicle safety.

If your 2G vehicle is hit hard in the right-rear fender and the battery case is crushed, whether the battery contains liquid acid or acid safely contained in the AGM mats might make a difference to a rear seat passenger.

 

After an AGM battery is completed and before it is "sealed" (with a pressure release valve), the cells are filled with (flooded with) liquid acid. It's basic operation is still that of a "wet cell" or "flooded cell" battery.

All of what you said about safety is absolutely true but does not change the fact that an AGM battery is just a modified version of a wet cell or flooded cell battery. You cannot just make up your own definition of "flooded".

I'm done. This discussion about whether or not it is appropriate to apply the term "flooded cell" to an AGM battery IS a nit picky argument over semantics. Whether or not it will later leak out is not a factor; neither is the fact that it is safer.

 

Im just throwing this out there for whatever its worth, but my new (2 weeks old) Toyota "true start" Yuasa battery shows 12.6v after sitting all night. 15f degrees ambient temperature and SKS.

 

Sometimes, we are forced to go with "common parlance" rather than technicalities. That way life is easier for everyone

" The major construction types are flooded (wet), gelled, and AGM (Absorbed Glass Mat).".


Frpm: Deep Cycle Battery FAQ

 

BTW, I am with Patrick and others as far as the definition of flooded Vs AGM. There's a reason, "true AGM" batteries are allowed to be operated in any orientation, are allowed to be shipped Air, etc. No free liquid in the battery as opposed to a "flooded" battery where free liquid is all sloshing around and even requires adding of water once in a while in many cases. "Flooded" means "free" liquid and Gel and Absorbed means no "free" liquid in my mind.

 

I'm all for sticking with "common usage" but here it depends on the context.
The key words in the above statement are "construction types".

OTOH, if you are talking about technical specs., load measurements or operational characteristics, there is no point in saying that an AGM is not a flooded cell type of TECHNOLOGY.........because it IS, just slightly improved.

Time to quit. The horse is still dead !!

 

Well, all that I can say is "Ride Easy!"
[pun intended]

 

I think it is important that Prius owners should understand two differences between traditional 12V batteries that have liquid acid covering lead plates (which I call flooded) and AGM 12V batteries:

1) The traditional battery has substantial free liquid acid within, compared to AGM which has little or no free liquid. This results in a safety improvement when an AGM battery is installed within a passenger cabin environment, as is the case with 2G/3G Prius.
2) The fully-charged voltage of an AGM battery is 12.9V-13.0V compared to a traditional battery at 12.6V. One impact of this is that an older, "normal" 12V battery charger will undercharge an AGM battery. A further impact is that the Prius 12V bus, operating at ~13.8V, takes a long time to charge an AGM battery. Some owners think that after a no-start incident due to a weak 12V battery, that they can drive the car for 15 minutes and the battery will be fully-charged. The reality is more like the car needs to be READY at least 8 hours or more, before the battery will start to get back to full charge.

Further, AGM batteries are claimed to survive deep discharges better than traditional batteries, although I question the extent to which this is marketing hoopla vs. reality.

If we can agree that those differences exist, I don't care what names you choose to assign to the different batteries. However I believe that "flooded" is a commonly used name for the traditional battery, while that name is generally not used to refer to an AGM battery.

 

Having seen AGM batteries in production I can state that at no time is the battery filled with acid as stated by
Easy Rider.
The glass mats are saturated with acid and then pressed to reduce the amount of acid they contain or it contains before the battery is assembled. I say it because some AGM batteries are constructed with one long mat per cell woven between the plates.
The AGM batteries are also never supplied dry with acid to be added. This is common practice for some flooded battery manufacturers as this can prolong the shelf life, by only activating the battery when it is required for use.
Again as pointed out by others here the voltage of an AGM is higher than flooded batteries as can be seen in my post Fitting mobility 12volt AGM battery. The post is over a year old, and shows the voltage of the battery being fitted at 13 volts before being removed from it's packaging. The voltage can be as high as 13.2 depending on the design of the battery and it's state of charge.

John (Britprius)

 

That might be true in the EU but not on this side of the "pond".

Discounters like WalMart absolutely DO sell batteries claimed to be AGM, and the evidence says that they ARE, that has the user add the "acid" and apply the seal to the cells.

How many different manufacturing plants have you seen ?
What exactly leads you to believe that the process you have seen is the only one that exists ??

 

I have been to 5 different battery manufacturers in 4 countries. With my work in industrial robotics and automated production processes.
The main reason "although there are others" for AGM batteries are there safety in use, and transport. There is no free acid to spill as the maximum saturation of the absorbed mats is 95% meaning that if the battery is broken open no acid is spilt.
This is the reason why they are considered safe for transport and use on aircraft along with medical applications such as mobility vehicles, safety applications as in fire alarms, and emergency lighting in buildings. Certainly within the EU and I would be surprised if this did not apply in the litigious US there are regulations about what can and cannot be called an AGM battery. If companies are selling a battery as an AGM and and someone gets burnt with acid as a result of it not being so the ramifications are boundless.

John (Britprius)

 

Here is the Walmart battery website. Please find an example of an AGM automobile battery sold on this website, so that we can see whether the user has to add liquid acid. I would like to review the evidence that you have.

As far as I can tell, Walmart only sells traditional automobile batteries made by Johnson Controls. At my local Walmart, I haven't noticed any AGM batteries for sale.

Walmart.com - Battery Center


Here is a webpage that discusses Johnson Controls AGM batteries. I see nothing on the page about the user having to add acid.
AGM battery technology | Johnson Controls Inc.

I haven't noticed any automobile batteries for sale that require the retail buyer to add acid, over the past 30 years or more. Frequently the batteries are designated maintenance free and totally sealed up. If the batteries have removable vent caps, the owner is only supposed to add distilled water if needed. No sulphuric acid.

Since you believe this to be a current business practice, please provide a webpage from a reputable automobile battery supplier that documents this. Share with us the evidence that you have, so we can be enlightened.

 

I too would like to see a link to an example of this "AGM" type battery that requires the end user to add "acid" and then seal the cells.

Please provide a link to a website or some other sort of documentation.

I am NOT doubting you, but I have not heard or seen any thing like this in a AGM type battery.

I have seen flooded type batteries and used the same (flooded type) that can be purchased dry and the end user add acid, but NOT a AGM type. Most of the time those particular batteries are sold for use in motorcycles, lawn mowers, generators and other small engine usage where electric starters are used to start the engine rather than a pull cord.

FWIW, it is not nitpicking when using the different terminology. The names implied is how the industry designates the various products. It is not names made up by individuals. Understanding the product and the terminology is up to the individual, but the names applied are specific to specific products. A flooded battery and a AGM type battery are NOT the same thing.

Battery Types: Flooded versus AGM and Gel

Battery Basics: A Layman's Guide to Batte | BatteryStuff Articles

 

I might be wrong, especially regarding car batteries.
My experience was a couple of years ago and with a motorcycle battery.

I have better things to do with my time that search out obscure crap that isn't really important anyway.

So let's just say that I am full of crap and no such thing exists.
And that calling an AGM battery just a slight modification of a flooded cell type is ridiculous........
so that we can move on to something that really matters.

 

No one has implied anyone is full of anything or that xxx is ridiculous, people were only talking about what they have seen and experienced, so please don't be hard on yourself, especially after you graciously mentioned your experience with these things was some years ago and that too with a motorcycle battery. Absolutely no need to take this personally.

I, for one, being very immature and inexperienced come here to learn and find it a valuable experience learning from people like Britprius, Patrick and others. Typically, unless I am an expert in a subject area that I can back with studies, experience, etc., I approach things in a cautious manner and offer any uneducated guesses as just that fully expecting folks to correct me and thus learn. Just my attitude to these things that I wanted to share. These days what I am finding is that kids and young adults are turning out to be more and more defensive. Not sure what in the system is causing that.

In any case, just to reiterate, please don't be hard on yourself Just appreciate the opportunity to learn, gently share/communicate and move on.

 

I would not know how experienced you are in any particular area, so on that I cannot comment, but to describe yourself as immature after the above comments I cannot agree.

John (Britprius)