Talk:Automotive battery

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

little dusting of the deep cycle battery[edit]

Could any of your battery-geniuses maybe do a little dusting of the deep cycle battery -article? I'm really just starting to learn about energy-storage like this, and felt I should flag some folks over to beef up another energy-article. Koyae (talk) 15:13, 11 November 2009 (UTC)

"Charging" section mentions "gassing"[edit]

The "Charging" section mentions "gassing"-- I think this term should be defined in context or linked to an explanation. I assume it refers to the production of hydrogen gas discussed under the "exploding batteries" section, but I am not 100% sure. Dr. Queso, too lazy to log in. —Preceding unsigned comment added by (talk) 19:48, 3 August 2010 (UTC)

This article should mention non Lead Acid batteries[edit]

Some cars (I believe Porsche sells one) use Li Ion or some other form of battery because of the weight of the batteries. Other non lead acid batteries should be mentioned as cars will use alternatives more as the prices come down. It can save gas and take off a few pounds (which super cars love doing). Also mention automotive batteries used as a way to move the vehicle such as an EV or hybrid like the Prius. (talk) 19:27, 21 April 2012 (UTC)

  • Over 99% of cars on the road use lead-acid batteries, so I see no reason to promote exceptions. I suggest referring (or creating) a separate article on alternatives to lead-acid types, or alternative uses such as EV or hybrids. This article is general in nature and focuses on the typical applications (and some hazards) of using lead-acid batteries. This article isn't intended to discuss the pros and cons of alternative battery types for automotive applications. Other articles may be referenced.-- (talk) 23:55, 23 April 2012 (UTC)
  • I've suggested a merge due to this comment gringer (talk) 12:25, 9 July 2013 (UTC)

Reversion history[edit]

Hi all,

A little explanation about what happened here. I worked on the article trying to fix the English, etc... but a few hours later, User:DV8 2XL reverted my edits. I disagreed with his/her accession and saw on the talk page that there was a flag of vandalism by User:Tisquantum, and so I requested help and a second opinion from what I thought was an admin.

Well, it looks like the one I thought was an admin (User:Tisquantum) may be a vandal, and the one I thought was a vandal (User:DV8 2XL) was an honest user.

I apologize for my mistake. I still think the revert by User:DV8 2XL lowered the quality of the article, but I now believe they were made in good faith. I reverted everything that happened; but I still plan to work again on fixing this article :)

Tony Bruguier 03:37, 31 January 2006 (UTC)

I'm the one that should apologize Tony, I made the revert in haste without looking closely, I hope we can work together to get this article in shape. I am responsible for the "terms used for automobile battery power ratings" section as an anon (from work) so I do have some stake the the page. Again sorry I reverted back to your last version ( with a few small changes)--DV8 2XL 09:35, 31 January 2006 (UTC)

Explosion risks[edit]

Not that long ago I had my car battery explode, lead acid variety - turns out it was a wet cell and ran out of water. Could a note be added to this page about that? I would just think that an anon edit about exploding batteries would be considered vandalism. -- 03:16, 15 July 2006 (UTC)

Huh? Most car batteries are sealed. They shouldn't need to be watered. As an aside, I've learned through renewable energy magazine that if you DO have a wet and open battery, you should use a hydrometer to check water levels every day, and HydroCaps (or some other brand) can lower the need to water substantially (according to Richard Perez of Home Power magazine, who tested them on his marine batteries for several months). Usually, car batteries explode because someone (hmmm) hooked the leads up backwards while, say, jumping a car with another battery. Putting a wrench across the leads can do it too : )
Adding someone about your battery exploding wouldn't be vandalism, but would be original research. You'd need to find article explaning how and when and why car batteries explode. Source that, and it'll be great. 12:41, 29 November 2006 (UTC)

I don't know anything about a "renewable energy magazine" nor have I heard of a "wet and open" battery. I was in the automotive battery business for fifteen years, though, and I can tell you some batteries have removable caps and some don't. The batteries with non-removable caps are not "sealed". They have a venting system just like the ones with removable caps. A hydrometer is NOT used to check water levels, and either way a required daily check is silly. Finally, from my experience, most car batteries explode because a broken internal connection or an external source creates a spark in the presence of hydrogen and causes the sometimes severe explosion.Jimpatnmatt (talk) 00:04, 24 November 2010 (UTC)

It's sometimes useful to look at the dates of comments; 4 years is a long time to go between contributions to a thread. --Wtshymanski (talk) 03:14, 24 November 2010 (UTC)
Sorry, I didn't pay any attention to the dates. I guess misinformation doesn't improve with age.Jimpatnmatt (talk) —Preceding undated comment added 23:38, 24 November 2010 (UTC).
Much has been said about "exploding batteries" and the hazards of overcharging (which also causes the water in electrolyte to be lost in the form of Hydrogen and Oxygen gasses). Short circuiting can also cause internal resistance of the battery to generate heat in discharge, boiling the electrolyte and also risking explosion. Either way - don't do that.-- (talk) 00:52, 25 April 2012 (UTC)

Typical metal content[edit]

Can someone tell me the typical metal content of a lead acid car battery?

Hi, Can someone help me out with the following car problem: As soon as I accelerate while driving the dash board lights consisting of the battery, A/T Oil, engine etc light up & the battery meter drops to halfway on the gage - but if I pull over & turn off the engine & restart it, no problems at all - only when accelerating.

Regards Baffled

Alternator? (talk) 13:54, 9 March 2010 (UTC)Lance Tyrell
  • Take it to a shop, Tyrell. This is not a forum for diagnosing car problems. IMO battery is unlikely to be the problem.-- (talk) 00:58, 25 April 2012 (UTC)

Environmental impacts of car batteries[edit]

Can anyone add information about the environmental impacts of car batteries? I often wonder whether people who are buying hybrid vehicles are doing more damage due to the batteries which are required. informedbanker 16:14, 20 May 2007 (UTC)

Exploding Batteries: revisited[edit]

I have added a section on the problem of exploding batteries to address the issues already raised. I am a consulting forensic engineer, and dealt with a recent problem where a mechanic lost an eye through lifting an old battery from a car. I am posting the section because it is an unusual hazard that users should know about so as to prevent possible future problems. Peterlewis 16:37, 20 May 2007 (UTC)

Prolonging battery life with "pulsers" or "activators"?[edit]

The german version Starterbatterie [1] contains a reference to Rahmann-Solarstrom [2] (a solar energy company) which contains a good description on how pulsers ("Megapulse", [3], engl. short description available) and "activators" are supposed to work including a link to the manufacturer of the "megapulse".

The "Megapulse" is supposed to work with a high current and a frequency of 3,26 KHz to destroy sulfation crystals (Lead(II) sulfate, supposed to be their inherent frequency).

The cheaper "Activator" sends a very high current of 80A - 100A every 15s through the lead-acid battery. Both devices are powered by the battery itself.

I think this would be a good addition to the english article as well but this is the first time I contribute.

I would also like to find facts / test results / links and user experiences about such devices and other alternatives which are not known or availabe in germany as the very comprehensive "Battery University" [4] does not cover this and just mentions pulsed charging in BU13. The "Battery University" is already linked at the Lead-acid_battery article. 23:39, 31 August 2007 (UTC) runeb / Germany

If a battery is solidly sulfated, nothing will help. I wouldn't add references to various battery restorers as in general, they can't work. Once the active material is gone off the plates, it's gone - no chemistry or physics will restore it. --Wtshymanski 02:47, 1 September 2007 (UTC)
Even if they work only sometimes they should be mentioned, probably in their own article, just because they exit ;-). 21:39, 1 September 2007 (UTC) runeb / Germany
The activators do not claim to restore the material to the electrodes (plates), they claim to remove the sulphate crystals which cover the active surface of the plates and so increase the surface usable for the chemical process during charge and discharge. So I agree they cannot repair batteries whith no reaction mass left or which are shortened by fallout which accumulated over time on the bottom of the battery until it reaches the plates.
Runeb2 (talk) 14:04, 8 December 2008 (UTC)
I found that this article now contains a link to (redirects to "Lead–acid battery") which contains a section about the topic I requested.
Runeb2 (talk) 10:07, 18 September 2013 (UTC)

That topic would be better under the Lead Acid battery topic, or better still, under Battery Chargers (under methods). This topic is too specific for a discussion on car batteries. (talk) 12:09, 7 September 2018 (UTC)


I am suggesting/requesting a small amount of information on proper battery disposal be added where appropriate.Quickmythril (talk) 04:19, 11 January 2008 (UTC)

I added my 2¢ on this topic. "Core" fee at auto parts store, etc.— ¾-10 00:49, 12 January 2008 (UTC)
Gee, my "core fee" on a new battery was $12, and I had to pay it despite not turning in an old battery. So now I have to keep a receipt for 10 years and MAYBE avoid paying another disposal fee?-- (talk) 23:58, 23 April 2012 (UTC)

myth of car battery discharging when placed on ground[edit]

Hi, is the myth true that a car battery can discharging when placed directly on the ground?

Regards Chad —Preceding unsigned comment added by (talk) 09:31, 7 July 2008 (UTC)

  • In general, no - the battery case is insulating. Both the positive and negative terminals must have a resistive path to ground for that to happen - not likely with the battery itself, unless the terminals are touching the floor surface. Some spilled electrolyte on the case could create such a path, but that is abnormal. However, any battery sitting around long enough, whether on the ground or not, will discharge over time. -- (talk) 00:01, 24 April 2012 (UTC)
No. No it's not. (talk) 12:10, 7 September 2018 (UTC)

Epyon nano batteries?[edit]


Does anyone know is there any differences with Nanosafe, Epyon Nano, A124 batteries? —Preceding unsigned comment added by (talk) 10:15, 30 September 2008 (UTC)

I am wondering also about this Firefly composite battery technology-> Is is better than Nanosafe and all the rest litium batteries?? —Preceding unsigned comment added by (talk) 14:58, 30 September 2008 (UTC)
Suggest take that topic to some other forum. Not applicable to Automotive battery, or specific brands unless there is a clear technological variation.-- (talk) 00:03, 24 April 2012 (UTC)

Possible censoring / Sabotage of article?[edit]

I am wondering where did all the new battery tech info go from the article??? Some one has deleted all Lithium car battery //other futuristic data.

If I am correct this article should be in general about all car batteries, not only about Lead Acid batteries??

Now there is 2 similar articles about Lead Acid batteries: and

  • there are three classes of Lead-acid battery (gel, AGM-sealed, and Flooded). Cars generally use the last two types. Car in general refers to lead-acid - over 99% of cars on the road use this technology. Alternative batteries deserve separate articles until such time as they become mainstream.-- (talk) 00:06, 24 April 2012 (UTC)

If some on could return the futuristic battery stuff also that would be swell. —Preceding unsigned comment added by (talk) 10:52, 3 October 2008 (UTC)

Also note the voltage/charge numbers on this page are inaccurate.

The lead-acid battery page mentioned above has the correct voltage/charge numbers. — Preceding unsigned comment added by (talk) 02:29, 26 August 2011 (UTC)

Car Battery Sizes?[edit]

Are the different sizes?

  • Absolutely. Motorcycles use much smaller batteries than cars, for example. Trucks with larger engines need more starting power than smaller cars. -- (talk) 01:08, 25 April 2012 (UTC)

Are vehicles of significantly different sizes and/or with significantly different engine sizes equipped with different sized batteries?

How do car makers determine the appropriate battery size for a particular vehicle? —Preceding unsigned comment added by (talk) 16:02, 16 April 2009 (UTC)

  • There is no standard formula. Obviously car makers want to save money and for weight/fuel efficiency, would prefer to use the smallest battery that can start the car. But customers also want reliable starting over a long period of time, and margin for other electrical loads not related to starting.-- (talk) 01:08, 25 April 2012 (UTC)
They use the cheapest battery that they can get away with. Whatever provides the cranking amps and a minimum number of estimated cycles. (talk) 12:12, 7 September 2018 (UTC)

Positive ground[edit]

In the "Changing a battery" section, it's mentioned that some older cars had a positive ground and that it caused corrosion problems. A positive ground is counter-intuitive, so there must have been a reason for doing it in the first place. My memory is hazy, but about 50 years ago I think I read somewhere that the positive ground reduced spark plug electrode erosion. Can anyone expand on this? -- (talk) 21:01, 4 July 2009 (UTC)

  • Historically it relates to corrosion on telegraph terminals, which is quite irrelevant to cars - but some standard had to be picked. Negative ground won over time. Technologically (at least in cars) it should not matter, other than the electrical equipment in all cars built in the last 50 year or more all use negative ground. I know of no advantage to changing to positive ground, and by deviating from the standard, there is likely to be cost detriment in today's technology.-- (talk) 01:16, 25 April 2012 (UTC)
  • Late to the discussion, but English cars used "positive earth" as recently as 1974. My uncle's MGB had two 6-volt batteries connected in series, with the positive terminal attached to the frame.Fcy (talk) 02:05, 21 April 2019 (UTC)fcy


Why? Car battery is the _widely_ accepted term.

As a somewhat poor - but indicative point - compare the google hits - 90000 vs 1.6 million.

Starter battery is also an incorrect term. The battery is used for far more - in a modern car - than simply starting. It's used for running assorted electrics when the engine is not running, and also performs a role in regulation of the vehicles main bus voltage.

Was there a discussion anywhere prior to this move? --Speedevil (talk) 18:15, 19 August 2009 (UTC)

Agreed. An arbitrary choice, but fairly easily fixed. --Wtshymanski (talk) 03:25, 28 August 2009 (UTC)

Quite frankly, much in this article is redundant to that in the article about Lead-Acid Battery, although less technical.-- (talk) 01:18, 25 April 2012 (UTC)

Requested move[edit]

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was moved.Juliancolton | Talk 00:18, 6 September 2009 (UTC)

Starter batteryCar batteryWtshymanski (talk · contribs) wrote "restore original and accurate title of the article, which replaces this redirect." This move could potentially be controversial, so I have listed it at WP:RM. I have no comment about whether or not this article should be moved. Cunard (talk) 02:35, 29 August 2009 (UTC)

Support — Car battery is a more accurate description of the battery. It is used for more stuff than just assisting the Starter. 『 ɠu¹ɖяy¤¢ 06:07, 29 August 2009 (UTC)

The initial move was done by a user with a long history of getting reverted on most edits. Though this is not of course a reason for the move back - I feel that the lack of discussion, and the poorly thought out move is a fair reason.

As outlined above - Starter_Battery is a poor name choice - theoretically Main_Batteries_of_Vehicles or some similar name might be preferrable - as the same content is largely applicable to cars/boats/... - however - car battery is by far the most common term, and starter battery is certainly not.

--Speedevil (talk) 11:42, 29 August 2009 (UTC)

Support move- nominator. "Car battery" gets 206 Wikihits on search, "starter battery" only 9 Wikihits. Google is also pretty one-sided, about 1.7 million to 97,000 "Starter battery" isn't even accurate because the batter does starting,lighting and ignition. Except in a diesel, where it's only doing starting and lighting. But every car today has one of the objects described in this article in it, hence, "car battery". --Wtshymanski (talk) 15:43, 29 August 2009 (UTC)
  • Support Un-discussed move, not supported by references.
    V = I * R (talk to Ω) 01:54, 30 August 2009 (UTC)
  • Support as per all foregoing. -- P 1 9 9 • TALK 18:30, 1 September 2009 (UTC)
The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.


Weight ranges of common automotive battery types may be helpful. Are they extremely heavy, light as a feather? One might infer from "lead" that they are heavy, but for completeness I suggest information on weight may be provided. Perhaps, even weight to power ratios and how they compare to other energy sources may be valuable as well.

It's an ill-defined question. Which is heavier, a kilogram of bricks or a ton of feathers? According to the Interstate batteries Web site, a replacement battery for my car (two door, 6 cylinder) would weigh 44 lbs. A motorcycle or garden tractor battery would be less, (Kawasaki motor cycle 6 Volt is 1.94 lbs.) and something in an earthmover or highway tractor would be quite a bit more (Caterpillar D9N 99.2 lbs). We could make the incredibly fatuous observation that big batteries are heavier than little batteries, but such generalizations are useless to the reader. --Wtshymanski (talk) 13:54, 8 July 2011 (UTC)


Under the Freshness section, a "top-up" charge of up to 15.1V is recommended for new (12v) batteries prior to installation. Gassing voltage is 14.4 V elsewhere in the article. Excessive overcharging is dangerous (read "exploding batteries"). I removed material from this section until safety is verified.-- (talk) 22:54, 18 July 2011 (UTC)

Battery correct capacity[edit]

Batteries run out every few years. To prevent this the industry needs to build a battery with multiple chambers which run out of sulfur in each chamber. When one chamber runs out of sulfur it moves to the next. I think a electrolysis version of electromagnetism can devert the liquid slowly and effectively. Say if you have a 4 chamber 12 volt. The 12 volt chamber would divert the liquid after the sulfur runs out in one chamber to the next via cylinder holes lodge in the chamber. The more the battery is used, the higher the holes get. Therefore the battery lasts much longer. This quadruples the lifespan of your standard 3 year 12 volt ac battery. — Preceding unsigned comment added by Asfd777 (talkcontribs) 15:00, 1 October 2012 (UTC)


my charger has less AMP then my battery is that ok. mine is at 550 only 400 and 750 were available. Also my battery keeps discharging and I don't drive much like 1 fill up a monthMrp8196 (talk) 18:15, 24 July 2011 (UTC)

You'd have better luck asking at the Reference Desk or possible calling into Car Talk. Recall that the battery charger can run for a long time to restore energy to the battery, but the battery's ampere rating is a measure of how much current can be drawn for a short time to crank an engine. There are many devices in car that draw current even when the car is stopped, so you'd need to talk to someone familiar with your make and model to suggest what is discharging it; even a small bulb in the glove box can run down the battery after a few days, or the standby load from all the electronic devices (alarm system, etc.) --Wtshymanski (talk) 18:46, 24 July 2011 (UTC)

I meant a portable charger its rated lower than the battery. The horn don't work either. Could that draw power. Mrp8196 (talk) 20:27, 24 July 2011 (UTC)

Terminal voltage[edit]

"All voltages are at 20 °C, and must be adjusted -0.022V/°C for temperature changes (negative temperature coefficient - lower voltage at higher temperature)."

This sentence is unclear. There are two voltages, the actual battery voltage, and the voltage in the table. As temperature drops, the open-circuit output voltage of an actual battery drops; so battery voltage has positive temp coefficient. To allow for low temps, you can either add a bit on to the measured voltage, or subtract a bit from the values in the table. This needs to be stated explicitly. I also find it a bit weird to talk about a bit of tabulated data having a -ve temperature coefficient or a voltage.
Also, I have seen wildly variable values for the actual temperature coefficent. I think some of this is caused by people getting muddled between °C and °F, but sometimes it varies by an order of magnitude. It probably depends on chemistry a bit. Could a reference be provided? JBel (talk) 23:33, 30 January 2012 (UTC)

That was very confusing. I attempted to resolve this with a table (referenced). The open circuit voltage temperature coefficient value that was in the article (0.022 V/°C) was invalid. The open-circuit voltage cannot be adjusted with a simple temperature coefficient because it is non-linear (coefficient varies with temperature).Chris goulet (talk) 04:58, 7 February 2015 (UTC)

Merge with Lead-acid battery[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
The result of this discussion was Not merged

I've suggested a merge because the discussion (or dissenting discussion that represents the current article) indicates that this article is essentially only talking about that specific automotive battery (i.e. Lead-acid battery). There is a lot of unnecessarily repeated information, so it would be better to only have one of these pages, with the other redirecting. In the spirit of wikipedia, any automotive battery article should probably have a link or disambiguation page that directs people to the other batteries that are used in automotives, regardless of their rarity of use. gringer (talk) 12:33, 9 July 2013 (UTC)

  • Oppose Besides the fact that electric vehicles are automobiles and use other types of batteries than lead-acid, lithium-ion batteries are being used in internal-combustion automobile racing and in motorcycles,[5][6] such as the Lithium iron phosphate battery from Shorai and other brands. I use one myself. Conversely, lead-acid batteries are used in energy storage for home solar and wind power, in non-automobiles like boats and aircraft, and more. The solution to the redundancy and unequal coverage of all uses of lead-acid batteries is to fix it in the article, not merge. --Dennis Bratland (talk) 16:21, 9 July 2013 (UTC)
  • Oppose I agree with Dennis Bratland who has said what I wanted to say, but much better than I would have said it.Tishtosh20 (talk) 13:20, 16 July 2013 (UTC)
  • Oppose Lead-acid batteries and auto batteries have some overlap, but are distinct in many important ways. Perhaps transclusions would be better for this. (talk) 14:37, 18 July 2013 (UTC)
  • No-no-no' I have a "luggable" computer from the 1980s with a lead-acid battery.--Froglich (talk) 23:22, 1 August 2013 (UTC)
  • Oppose For all the reasons above. Plus, lead-acid types like VLRA's and gel-cells are not used in cars. Maury Markowitz (talk) 15:29, 21 August 2013 (UTC)

The above discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

12.6 volts at full charge.[edit]

Except that this is the "automotive battery" article, and most "automotive batteries" are charged twice a day, and, as claimed lower down, it only ever drops to that value after it has been left uncharged for a day, so you wouldn't expect a fully charged automotive battery to actually be at 12.6, unless there was something wrong. Perhaps use a range in the header? "12.6 - 13.8V at full charge" — Preceding unsigned comment added by (talk) 23:53, 6 October 2014 (UTC)

  • I thought each cell was 2.2V? which makes a six cell battery 13.2V. Is that right? Jokem (talk) 08:44, 26 January 2015 (UTC)
Official e.m.f. of a standing lead acid cell is 2.1 volts. That makes a 6 cell battery 12.6 volts. DieSwartzPunkt (talk) 11:32, 28 January 2015 (UTC)
A citation would be good - it should also give the official temperature at which this is rated. --Wtshymanski (talk) 16:40, 28 January 2015 (UTC)
You could try this one. The discharge curves clearly show a little over 2.1 volts max. per cell. The document doesn't specify the temperature, but it is usual to specify battery characteristics at 25°C (77°F) - don't ask me why. Open circuit voltage rises as temperature falls, but the internal resistance of each cell also rises with falling temperature, so the overall effect is a drop in capacity. The voltage temp coefficient of −0.0235 V/°C means that it will be even closer to 2.1 volts per cell at 20°C (68°F). (talk) 18:00, 28 January 2015 (UTC)
See discussion about the temperature coefficient at the #Terminal_voltage section on this talk page. Chris goulet (talk) 05:15, 7 February 2015 (UTC)
Added: "Each cell provides 2.1 volts for a total of 12.6 volts at full charge." with reference. --Cornellier (talk) 17:22, 18 February 2016 (UTC)

Batteries frequently charge to over 13 volts DC. Just put a meter on the battery while it's running, and then when the engine is off. The charging system will be over 13 volts (usually) when the engine is running. I typically see batteries with 13.2 volts on them when parked after running a while. This is normal. 12 volts is a rounded number. — Preceding unsigned comment added by (talk) 12:17, 7 September 2018 (UTC)

Authenticity of the comment that battery can be a voltage stablizer[edit]

A reference used is : This article is by Battery Council International but I could not find from where they are picking up their technical information.

As per my knowledge (which may not be complete), the car electronics are protected by filter (near the protected device) and regulator circuit (right after the voltage generating source the alternator), then someone please elucidate the role of battery in regulating voltage. What if the battery is about six months old and reduced to a fifth capacity, its internal resistance would be similarly increasing, would it still be able to smoothen out the voltage as well as a factory fresh battery would be able to. Then can six month old battery be depended on by the car for its electronics system.

Could it be the above reference sourced its knowledge from other people and not credible sources (Otherwise citations should have been on that page). For example, some people say that if the battery is removed than voltages as high as 40V can be produced in the car circuit. Does anyone know if such a statement could be a factual statement or assumed statement. Then what about when the inserted battery gets fully charged then is it being excessively charged at 40Vs instead of being trickle charged at 13.8 to 14.2V.

If someone still feels that the statement is correct - can that person please provide a more academic or research oriented reference having someone to standby its credibility. It would be also better if someone has seen a reputable car manufacturer manual stating a requirement that battery of maximum such low internal resistance must be installed to ensure sufficient voltage stablization needed for the car and thereafter keep getting the battery tested for its internal resistance and change it when the resistance increases beyond that maximum level. As far as I know car manufacturer are just bothered about the cracking amperage (may be RC also to decide engine idling angular speeds) and the battery load tests similarly measures this amperage delivered over time 30 seconds mostly (or 15 seconds).

Further for regulating transients, what about the correspondingly transient increase in resistances created by surface charges in the electrodes, increasing the resistance sufficiently to block the voltage clamping action of the battery being depended upon. — Preceding unsigned comment added by (talk) 12:37, 5 September 2016 (UTC)

The manual for my 1984 BMW (bought in France) says, "Ne jamais déconnecter les câbles de sur [sic] les bornes de la batterie lorsque le moteur tourne, sous peine de détruire l'électronique de bord par suite de la surtension qui s'ensuivrait!", which means "Never disconnect the cables from the battery terminals when the engine is turning, so as not to destroy the automobile electronics as a result of the over-voltage that would occur!"
It doesn't matter if the battery is six months old (that's not very old, by the way!). The internal resistance is quite low compared to relevant impedances in the car. Even an old battery will keep the voltage down around 13V and prevent spikes.
I think it's quite reasonable that you could get 40V spikes if you don't have a battery connected. I suppose that if the battery is really fully charged, then it would cease to provide protection. If there is no lead sulfate left to come off the plates, then the usual charging reaction cannot take place. If you put a high voltage across a fully charged battery then I suppose you could start to get electrolysis of water (producing hydrogen and oxygen) so it could still draw some current, and that would mean that its internal resistance would not be infinite. So it would still stabilize the voltage a bit, but maybe it wouldn't be sufficient.
I suppose you meant to write "cranking amperage", not "cracking amperage".
I don't understand why there would be "transient increase in resistances created by surface charges in the electrodes".
Eric Kvaalen (talk) 16:06, 20 September 2016 (UTC)
The purpose of the SLI car battery is to start the internal combustion engine (ICE). Once the ICE is running, all of the power for the accessories is supplied by the alternator, via a voltage regulator. The battery is not wired in series with the accessories and the alternator, it is actually a load on the charging system, like the accessories. If you Google something like car wiring schematic, you'll see it in the diagram. --Cornellier (talk) 13:02, 21 September 2016 (UTC)

Older motorcycles (Hondas from the early 70's, for example) used the battery as a load / ballast. Without the battery acting as a load resistance and as a regulating capacitor, the voltage would spike to over 30 volts, and have a significant AC component, because the DC regulator / rectifier circuit was of a poor design and was inadequate to the task. For that reason, if one ran the engine without a battery installed, it would usually blow the headlamp and other lights. Modern regulator / rectifier circuits are much better in design, and often have "smoothing" capacitors built-into the circuit in addition to rectifier diodes in some form of bridge configuration. (talk) 12:24, 7 September 2018 (UTC)


The article implies that the following are standards for battery specifications: Hot cranking amperes (HCA), Reserve capacity minutes (RCM), and Battery Council International group size. All of this needs references. None of these is defined at the BCI site. It appears HCA in particular is more of a marketing term than a testable specification. --Cornellier (talk) 16:27, 12 September 2016 (UTC)

@Cornellier: Well, the article doesn't really say these are "standards". I think we should leave the information in even if they are not official standards of some institute. Eric Kvaalen (talk) 16:06, 20 September 2016 (UTC)

Peukert's law[edit]

@Cornellier: I don't agree that Peukert's law is not applicable. It has been used for decades for lead-acid batteries because it works (so long as the rate of discharge is not too low). The Peukert's law article does say (as you point out), "A 2006 critical study concluded that Peukert's equation could not be used to predict the state of charge of a battery accurately unless it is discharged at a constant current and constant temperature". That's true, but that's what the law is meant to predict! After that the paragraph goes on talking about lithium batteries. It may be that it doesn't work well for lithium batteries, but that's not our subject. Eric Kvaalen (talk) 16:06, 20 September 2016 (UTC)

The reason for removing it is that it is tangential to the subject at best. Relevant to the lead-acid battery yes, but this article is about the SLI battery, which is defined by its function, not its chemical makeup. --Cornellier (talk) 11:21, 21 September 2016 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just modified one external link on Automotive battery. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

As of February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{sourcecheck}} (last update: 15 July 2018).

  • If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
  • If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 07:01, 22 October 2016 (UTC)

lead acid battery voltage vs temperature[edit]

  • ((cite web|last1=Darden|first1=Bill|title=CAR AND DEEP CYCLE BATTERY FREQUENTLY ASKED QUESTIONS 2015|url=||accessdate=6 February 2015))- (talk) 15:26, 1 May 2017 (UTC)
I deleted the copy-paste from the source, See WP:COPYVIO. Also, while this information is nice, it's apparently just some guy's personal website, and not a reliable source. --Dennis Bratland (talk) 15:48, 1 May 2017 (UTC)

Lead needs more topics[edit]

I added section titles for the well-written text on how a battery and alternator work in modern cars. That removed that text from the lead. This article has History, Environmental impact and more, that ought to be highlighted in the lead. I am using my phone right now, which limits me in making a try at a better lead section. This article is really clear for a technical topic. —Prairieplant (talk) 18:20, 25 January 2019 (UTC)

Sorry this was added twice. I will delete duplicate when not on my phone. Prairieplant (talk) 18:29, 25 January 2019 (UTC)

Lead section needs enhancing[edit]

I put a section title on most of the old lead. This article covers more topics, History and Environmental impact, that ought to be mentioned in new paragraphs for the lead. I like how this article is easy to read while covering a technical topic. —Prairieplant (talk) 18:27, 25 January 2019 (UTC)