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3 month old Duralast AGM is toast?
- Thread starter atikovi
- Start date
It's always no if you don't ask
- Joined
- Jul 24, 2023
- Messages
- 125
I was going to say you might have been able to bring the old one back with a manual charger... but nothing beats new
I've got an ancient Duralast Gold that's been through hell, drug down flat many times in a family members car that's mostly parked, and it's still working great.. after I worked on it 
I'm surprised the Platinum couldn't survive 3 months?
GON
$100 Site Donor 2024
No programming required for the battery in your W221 S-class.
If a W220/W221 S-class sits for an extended period, the battery will drain deep and WILL be unchargeable- regardless of the age of the battery. Very common issue you experienced.
If a W220/W221 S-class sits for an extended period, the battery will drain deep and WILL be unchargeable- regardless of the age of the battery. Very common issue you experienced.
GON
$100 Site Donor 2024
Manual charger will not bring a AGM S class battery back to life. I spent months, yes months trying multiple S class AGM batteries using numerous methods. Bringing back a S class AGM battery that has had a continual draw down without relief is not feasible....I was going to say you might have been able to bring the old one back with a manual charger... but nothing beats new
I'm surprised the Platinum couldn't survive 3 months?
GON
$100 Site Donor 2024
Please let us know how the wheel sale goes.....
GON
$100 Site Donor 2024
The S- Class (post facelift W221 ) ATIKOVI has- has two batteries. One main battery under the hood, and a second small backup battery under the dash. The small backup battery is to keep setting if the main battery fails/ gets swapped.
I did bring the small backup battery back to life, but the main battery can't be. I think I actually posted pictures of the small battery being brought back to life on BITOG, from a hotel room.
f355spider
$50 Site Donor 2024
Same, all the AGM H8, H7, H6, Hx...whatever have the same distinctive white "made in Germany" sticker....I have seen AC Delco, Interstate, Walmart and now Duralast. With that sticker, one can simply buy based on freshness, free replacment warranty period and price. They are all the same.
More important stuff needs attention. Transmission has problems and hoping it's just the conductor plate and shifter module and not something internal. I can now see why the last owner bought it August 1st and sold it August 15th.
Nope. It has a small starting battery under hood, and this big one in the trunk. No way would it have started after sitting a week with the under dash battery you mention.
GON
$100 Site Donor 2024
Ahh. I thought your car was a 2012? The 2007-2009 w221 had the main battery in the trunk. The 2010+ post facelift w221s moved the main battery under the hood and the backup battery under the dash.
2007
We made industrial AGMs and when some failed the initial testing we would discharge them into negative voltage of about -1.0v per cell. Then a slow two day recharge. 50/50 chance of making them pass but some did.
I bought an Odyssey PC680 (?) off eBay once. The guy was local. Battery had been sitting for at least three years but was otherwise unused. it took me 5 days on constant charge from my industrial AGM charger before it started taking a charge. Then worked OK for about three years in my Taurus as a starting battery.
I bought an Odyssey PC680 (?) off eBay once. The guy was local. Battery had been sitting for at least three years but was otherwise unused. it took me 5 days on constant charge from my industrial AGM charger before it started taking a charge. Then worked OK for about three years in my Taurus as a starting battery.
Not too side track this, but do you know if this technique can work for gel cell type batteries(which seem a close cousin of AGM)?
I have a rather niche application(non-automotive, actually photography related) that can use a 6V gel cell among other options, and this was by far and away the most common(the others were a flooded lead acid, which I don't think has been made since the 60s and also isn't great for something designed to be portable, and a Ni-Cd pack which I've never actually seen). I bought a new battery-branded as a "Dry fit" battery in their catalogs-in 2018 and that one still works great but I also quite literally have over a dozen that are totally dead(completely open circuit) and some others that sort of work but will only charge to ~6.5V or so and won't properly operate the equipment they fit.
I've been trying a lot to bring some of these back to life(and mostly have one there-its performance is less than great but it does power on and work the equipment), primarily because, as best as I can tell, it quite literally is not made anymore. The OEM supplied battery was made by Sonnenchein(I have one branded that and Exide) with a small modification to the casing to "key" it. Specifically, if anyone is interested, it's an A506/4.2s but I THINK A506/4.2K could probably be made to work. The issue is that the battery needs to essentially match the original in all 3 dimensions, and something too large in any of those dimensions won't fit at all. There are batteries out there that claim to be an A506/4.2k or to cross to it, but they are too big-the original is nearly square and about 2"x2", and everything I can find with that part number is closer to 2"x3"
So, that's my reason for trying to revive dead ones. I've tried things you're not supposed to do like pop the caps off the cells and try rehydrating them(moderate success) as well as charging at serious overvoltage(like 2.5V/cell or even higher in a few cases-I won't say how high but I found some guidelines from a reputable source and monitored gas evolution closely). I've even dropped battery casings in the ultrasonic since that supposedly breaks up sulfation. I have one that, through a combination of these methods, went from totally dead to being able to charge to ~6.4V, so apparently it's not totally ineffective, just not enough. I've also given up one and sawed the case open, carved out the cell dividers with a die grinder, and dropped 5xsub-C NiCds in it...
Really, though, where I was going with this is I have one that I acquired that would charge but not enough. Through a combination of all of the above, I FINALLY today got it to actually work, meaning it will power the equipment fully but just not quite where a new one will.
I do most of my messing around/rehab of these with a bench PSU that of course gives me a ton of control. At one point, the one that I sucessfully revived to fully working I'd actually inadvertenly reverse charged. IIRC, when I stopped, it was around -2.1V, which would have been about -.7V/cell. I'm wondering if that was part of its sucessful revival.
I have one sitting beside me now that I managed to get charging today. As I sit here it's drawing 12mA at 7.2V, and after about 4 hours sitting there has charged to 3.4V. I'm tempted to try reverse charging it now...
You can try the reverse charging. Gel cells just have the acid in a jelly state. AGM is Absorption Glass Mat is a nano tubular fiberglass mat that has astounding absorption properties but still uses liquid acid, and very tight construction. AGMs also have different lead alloys, cadmium is one.
Thanks, I have one that I'm going to try that with. I started working on it last night, but it was up too high and the battery got too hot for my comfort so I stopped and let it cool down. I hooked it up this morning, after cooling, to 2x 1000Ω resistors in parallel(so 500Ω total) to try and running it down closer to zero a bit more gently before I get more aggressive on the reverse charging. I was pumping about 3A through it trying to reverse charge, so it's no surprise I was getting that kind of heating on such a small battery.
IIRC gel cells use silica gel mostly(I'm sure there's some proprietary magic there) to make the electrolyte into a "gel".
I'm playing with trying to stuff some Cyclon AGM cells into one of the cases, or maybe even getting enterprising and 3D printing a new case for them. I've ordered some DT sized cells, which are actually higher than the design capacity of the original battery, but I'm afraid they're going to be too tall to actually fit in the case(I have another related task for them, so all is not lost if they won't work). I know 3 standard Cyclon D cells will work, at about half the capacity of the original(4.2Ah) from test fitting with standard alkaline D cells, but Batteries+ around here tells me that D Cyclons are on back order now and most of the online sources I seem to find either charge a fortune per cell(Batteries+ is $13, I've found them as low as $10 other places) or if they have an attractive price charge a fortune-think $150 or more-for shipping. I actually have several applications I need D Cyclons for as they are a direct fit(manufacturer installed) so I need to get some.
This I know is a lot of work for an obsolete photo flash, and some would tell me I'm nuts for even bothering, but they really are that good both in terms of output and light quality. Weight aside, the various lead acid options really are ideal since they have such low internal resistance(important for flash recycle time)-even lower than Ni-Cd which is already low-and such low self discharge too compared to nickel batteries.
Sorry for the diversion, but I've been spending way too much time on this lately...
The construction of AGMs is very tight and forced into the jar. The positive plate has a complete wrap of the fiberglass and the negative used a plastic envelope that was electrically open to the flow of electrons. But there was no space at the bottom for the sulfate shedding and with the tight construction kept the active material tight in the plate grid.
The formation of each cell took a specific volume of acid initially and that would boil down over the 4 day initial formation charge rate. The acid comes out stronger at around 1.325-1.350 sp gr finalized full charge vs the 1.250-1.275 in flooded.
Flooded car batteries just get charged, then dumped and filled with the final sp gr acid. This is from 25 years ago though. I assume they have found different ways.
The formation of each cell took a specific volume of acid initially and that would boil down over the 4 day initial formation charge rate. The acid comes out stronger at around 1.325-1.350 sp gr finalized full charge vs the 1.250-1.275 in flooded.
Flooded car batteries just get charged, then dumped and filled with the final sp gr acid. This is from 25 years ago though. I assume they have found different ways.
Where the magic happens…I wonder what kinds of precautions are needed before they start slicing?
Interesting to see they are making pure lead grids. This is what the original Plante style battery was from the 1800s. We made them in large industrial sizes. They just took a solid sheet of lead and put a 'million' slices in it. They never wore out but were a daily maintenance item due to the excessive gassing.
