Lead-Acid Automotive Batteries with Welded Caps - Page 1
Forum section: electronics / general

author: Brutte
author_rank: Frequent Contributor
timestamp: November 07, 2015, 09:36:36 pm
content: I have noticed that there is an increasing number of manufacturers that weld the caps on their automotive flooded lead-acid (FLA) batteries so that topping up and maintenance is impossible.Intro:Wikipedia on that. I am not talking about numerous automotive battery technologies that trap electrolyte inabsorbed glass matorgelor commonsealed lead-acidas these are not competitive in automotive starting battery market (compare prices of AGM or VRLA of similar performance with raw FLA to understand what I mean).The subject is about automotive batteries where electrolyte isliquid(flooded battery) as this technology is proven for highest instantaneous starting power from buck per watt available, keeping overall mass low (10kg, 3kW, $50). Some manufacturers add bells and whistles for FLA such as built-inhydrometersor technologies or what not for limiting water evaporation (so that you could save a spoon of distilled water, 1$/3L bottle), catalysts for recombining H+O back into H2O, calcium alloy to limit bubbling and to make the product "maintenance-free"Back to the subject:I have used several automotive batteries marketed as "maintenance-free" (some reputable, like Varta and Bosch) and although these performed well during typical 2-year warranty period, I could rip off the cover sticker, unscrew the caps and top cells up. If regularly maintained (once a year) such battery lasted for over a decade. However, I cannot recall a situation where none of the cells required topping up..Winter is coming and my battery begs for retirement. For some peculiar reason now many FLA batteries are sold with welded caps/top covers. I bet I could get inside with a driller but I would prefer to avoid that.Example of such batteryand theeffort neededto get inside (some retrofitted bottle caps cover drilled holes).My question is:How come the (FLA) caps had always(since 1859)been user-accessible for a reason and now these are notIf there is some technology under the hood that prevents electrolyte from escaping, does this mean these welded batteriescannot fail by exposing platesbefore other failure mode takes place (during regular use)? Or is it that they cannot fail by the end of the warranty only?My suspicion is however that these are raw FLA batteries (perhaps with a bit higher initial level of electrolyte) that fail by exposing platesby design. Can someone confirm/reject my theory? Do you happen to replace a worn-out (but not purposely killed), reputable, welded battery and could check ifanycell (it is enough to expose one) has exposed plates ?Yes, I did google on that but to no avail. Only marketing BS. Some interesting topics, none of which touches the problem of welding:BatterystuffbatteryFAQLead-Acid Battery WikipediaTheuatochannelAny thoughts?

author: Kilrah
author_rank: Unknown
timestamp: November 07, 2015, 09:59:36 pm
content: My take would be either someone managed to find a variation ofQuote from: Brutte on November 07, 2015, 09:36:36 pmthat really works (hmmm....), or they just want you to buy a new battery every 2 years because planned obsolescence / we'll die if we make something too good that doesn't need replacing.There have been agreements about not making light bulbs too durable in the past for that reason, with manufacturers making sure they don't last more than 1000h or so. I'm actually wondering how it'll work with LED lights now as a properly designed one will last pretty much forever... well the answer is obvious, not design it properly, use the poorest caps on the market in the PSU circuntry, etc...

author: SeanB
author_rank: Super Contributor
timestamp: November 08, 2015, 02:56:56 pm
content: Welded caps are cheaper to manufacture ( no multipart mould with a set of demountable inserts for the threads, or a motor to unscrew them after moulding) and as well they can cut cost by having less water in the cell and making the top thinner, as the welded cover is a structural member. That it lasts for the warranty period, perhaps, as I replaced one this year which did 14 months then failed, I will go get another when the identical replacement fails if it lasts less than 2 years, as I will argue that the replacement also has a 2 year warranty. Most people do not have the required backup proof of purchase, and buy a new one, leaving the old one to be recycled in the lead scrap chain. The plastic parts are easy to recycle as well, only 2 plastic types easily sorted by colour, and the lead soaked plastic goes into making new batteries and as inner plastic parts in children’s toys. The lead plates are remelted and recast. Even the acid is redistilled and reused. Only loser is the consumer and the environment in China where the recycling is done.

author: johansen
author_rank: Super Contributor
timestamp: November 10, 2015, 02:51:43 am
content: the story with calcium vs antimony is that calcium causes the open circuit effect, or the "antimony free effect" or, other names.You cannot buy an antimony battery today unless you buy a forklift battery, or a railroad traction battery, because they are simply no longer made.About 15 or 20 years ago all the battery manufacturers switched to calcium at the same time, and the reason was purely the cost of antimony became excessive. but keep in mind that the lead is only up to 2% antimony.allegedly the us navy has switched to AGM batteries which are very likely calcium. my brother says they did NOT last as long as the manufacture said they would.. no shit.anyhow, he says they trickle discharge the batteries, rather than constantly trickle charging them, and they last longer that way. yeah, i have no idea how that could work.far as i know, you have to float the lead calcium battery at >50mv above its open circuit voltage in order to keep the calcium from corroding (making a layer of calcium oxide between the active material and the grid plates) thus, open circuiting the battery.it is these lead calcium grid plates that make those "pulse desulphaters" almost plausible. if you can just punch through that calcium oxide layer...anyhow the other reason car batteries fail is the grids are just too thin, and they break due to vibration. typically they break off the positive battery post only.

author: djQUAN
author_rank: Frequent Contributor
timestamp: November 10, 2015, 04:14:59 am
content: I was researching for RE batteries before and stumbled upon a doc where they make a certain battery model with either antimony or calcium alloy plates for different applications.From what I recall, calcium is suited for standby use as it has low water loss in extended float charge but will not survive deep discharges.Antimony alloys are better in deep cycling use but have a rather high water consumption.I believe that is why car batteries use calcium alloys for low maintenance and they are not deep cycled in normal automotive use.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: November 10, 2015, 04:59:18 am
content: I've switched to "yellow top" deep-cycle spiral-cell batteries.They cost about twice as much as a regular battery.I get +10 years service from them, and they don't open up after getting drained once or twice.

author: Brutte
author_rank: Frequent Contributor
timestamp: November 10, 2015, 11:18:17 pm
content: QuoteInterestingly, I have seen a type that does have caps but with a unidirectional clutch so caps are only possible to lock in place and impossible to remove without drillingQuoteI have never seenthose and other cylindrical AGM batteries. I did search on OPTIMA website shop. I was looking for something near 12V, 45Ah battery with 400CCA SAE rating that I use. The closest Yelowtop I could find was8071-167 D51at $215 which is 38Ah and 450CCA. It is definitely not twice as expensive as raw FLA and I bet it is also harder to buy locally (added shipping)..I believe the advantage of deep discharging+starting is targeting niche applications (off-road 4x4? mining industry?) so it is not within the range of the problem I describe here (giving little or no advantage). I bet there are other interesting and even more sophisticated batteries available (planes also have starting batteries).Consider regular people drive their cars by cranking engine for a second or two perhaps once per 10km trip and that is about it. I do understand that if someone wants a starting battery for a car that needs cranking for 3 minutes at a time or drives a car once a month - deep discharge version is suitable, sure. That is niche application.BTW, starting a petrol engine even at full 400A for 1s uses below 0.25% of the 45A*3600s charge stored so it is close to nothing (in terms of deep-discharging context).EDIT: Ok, I did search - 8071-167 D51 is available locally and it isover 4 timesthe price of a raw FLA.. No, thanks.

author: johansen
author_rank: Super Contributor
timestamp: November 11, 2015, 02:18:47 am
content: i bought some lead acid cells from battery sharks dot com and by amp hours.. they were probably cheaper than a FLA sold for cars.however, it takes some work to make an agm cell last in a vehicle. you have to ensure that the float voltage will not cause the battery to lose water and "boil away" but they should last just as long in a car as a FLA.there is some talk on other forums about folks complaining that the float voltage of certain APC UPS's is set so high that the batteries only last 2-3 years. the general consensus seems to be: suck it up and deal with it, replacing the batteries every 2 years is a negligible cost. others have figured out how to reduce the float voltage on certain models. there indeed seems to be a conspiracy at work here because most people don't want to deal with replacing the batteries.. so they order the entire cartridge from apc for a whole lot more than the batteries are worth.Quote from: djQUAN on November 10, 2015, 04:14:59 amfar as i know the only problem with calcium is the open circuit effect caused by calcium oxide building up a layer between the grid plate and the active material.this explains why some batteries go open circuit, others don't.the difference could be 1% calcium vs 2%.i have batteries from 5 different manufacturers i could cut in half on the bandsaw, and ship the grid plates to someone who could tell me exactly what is in them.. this is an interesting idea because one of those manufacturers, all of those batteries went open circuit in the 2 years they have gone without being charged.. but this isn't really a solid datapoint because its hard to say, did it go open circuit due to self discharge, or open circuit due to open circuit effect. hard to say, the other batteries still light up a 100 watt halogen bulb at 12 volts (8 ah batteries)when i acquired the batteries 2 years ago they all had open circuit terminal voltage of 13.0 to 13.15 volts. now they are all at 12 to 12.3v.

author: johansen
author_rank: Super Contributor
timestamp: November 11, 2015, 02:24:06 am
content: Quote from: Brutte on November 10, 2015, 11:18:17 pmmany smaller cars have starting currents of only ~100 amps. my ex toyota, 22R engine for example.--however, after replacing the head with a 20R head, (results in a 10:1 compression ratio) the starter couldn't crank the engine over unless i had two batteries wired in parallel. this wasn't so much the battery couldn't deliver the cranking amps, but the starter couldn't supply the torque)my parents jeep (2.6L ) only pulls 115 amps.my brother's vw Jetta (2.2L, i think) probably pulls less than 100 amps.