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Questions tagged [battery]

A rechargeable device most often made of lead plates covered in an electrolyte and protected by a plastic shell which supplies consistent electrical energy to a motor vehicle. Often referred to as an SLI battery (starting, lighting, ignition). Powers starter motor, lights, and ignition systems of a motor vehicle.

23
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4answers
12k views

How do I test my car battery?

My car still starts fine but when I turn off the car (just the motor . . the key is still in and "on") I noticed the headlights dim to almost off. It's and older car and the headlights don't turn off ...
21
votes
9answers
90k views

Battery drains by itself when vehicle is parked (parasitic draw)

A 1998 Jeep Grand Cherokee has gone through 3 batteries in the last 3 months. While they have all been replaced by warranties, it'd be nice to get the problem solved permanently. I've tested the ...
11
votes
3answers
32k views

Why should I connect the red/positive terminal first when jump starting?

So, it's fairly popular consensus online that it's red/positive clips to the positive/red posts, then the black/negative clip to the frame One site mentions sparks, but you'll still get a spark when ...
41
votes
3answers
19k views

Jump starting a dead battery: Connect black wire to negative pole of battery or grounded metal?

Most of the advice I've seen for jump starting cars instructs to connect the black wire to a bare piece of metal on the car with the dead battery. However, I've always just hooked up both poles to the ...
25
votes
6answers
41k views

Is Start & Stop technology good or bad for my car? (Alfa MiTO)

I was recently in the lucky position to obtain an (almost brand new) Alfa Romeo MiTo, Progression. Like many new cars coming out these days, it has "Start & Stop" technology that turns the engine ...
5
votes
3answers
58k views

Interpreting AC Delco's manufacturing date for car batteries

I understand that AC Delco encodes the month of manufacturing a car battery using two digits and encodes the year by one digit. The battery I just purchased, for example, is labeled P124R, which, ...
3
votes
5answers
17k views

how much water can be safely added to a battery?

My 2008 Jetta SE 2.5L has the battery as follows: ENERTEC EMC // 1J0 915 105 AD // 12V 61 Ah 330A DIN // 540A EN/SAE. It would appear that the battery can no longer hold the starting charge after an ...
6
votes
4answers
10k views

Technique to test an alternator - fact or fiction?

A friend explained that the following is a simple way to test an alternator to see if it is working: Turn on the vehicle. While it is running, carefully remove one of the 12V battery leads. See if ...
56
votes
6answers
7k views

How to maintain a sometimes-used vehicle?

My daily commute changed from 9 miles to 9 feet when I started working remotely. That means I very rarely drive my car much. After a particularly hectic month, I didn't drive for about 4 weeks and ...
11
votes
4answers
25k views

How to assess battery charge level and alternator performance?

What diagnostics can be done to to assess battery charge level? I'm interested both in one-off tests like can be done in car service and also continuous monitoring during normal use. Car panels ...
21
votes
4answers
5k views

Replace car batteries with capacitors?

I recently watched this video on YouTube which basically shows the guy replacing a larger capacitors with some smaller capacitors which he had bought. The larger capacitors were actually in place of a ...
8
votes
2answers
8k views

Battery Light Won't Go Off Since Changing Battery

I just changed the battery on my 98 Mazda 626 and now the battery light comes on and stays on after starting the car. I checked the battery and it's reading 12.8v with the engine off, and 13.8 with ...
4
votes
3answers
18k views

What happens if I disconnect the battery while the car is running?

There are some comments on the question Are there any modern diesel engines that require electricity to continue running? suggesting that disconnecting the battery while the car is running can damage ...
4
votes
4answers
23k views

Should I use coca cola or baking soda + water to clean my battery clamps?

The clamps that are attached to the car battery are corroded, I was told either of these liquids will work. Which one is better? Is there a how to guide on the exact steps I need to take? With my ...
4
votes
3answers
42k views

Getting information from manufacturing code on Exide car battery

If you can help me decode the following manufacturing code on EXIDE EA640 battery, especially which production plant has made it what was the date of manufacturing Code: 3EC28K5 Perhaps 28K means ...
27
votes
6answers
403k views

What causes battery terminal corrosion?

I put a new battery in my car about 8 months ago. After a problem starting a couple days ago, I found that there was massive corrosion under the battery terminals, so I cleaned them out and ...
19
votes
6answers
24k views

Adding a additional battery to car

I have purchased a brand new Toyota Innova. I need to install a a mac mini, 2 laptops and make this car a mobile office. I need to know if I can install another car battery in parallel, and will ...
11
votes
3answers
30k views

how fast does the alternator charge the battery?

It would appear that the common word of wisdom is that car alternators provide 50A of output. I actually looked at the supposed specs for my 2008 Jetta 2.5L on the internet -- a compact car -- and it ...
9
votes
1answer
3k views

Why the different the colors of terminal corrosion on the battery?

I have a 2001 Ford Windstar. When I went to clean the battery terminals: the one with the RED cover over it was a bright blue color; the other had normal white corrosion. I do not know why the this ...
7
votes
3answers
5k views

How should I prevent my battery going flat when I leave my car alone for a month?

I will be leaving my Focus alone for around a month in (scottish) winter weather. Ordinarily I would make sure to take the vehicle out at least once a week to prevent the battery going flat in the ...
7
votes
1answer
324 views

how do i know if my lead-acid battery has been resurrected?

The OEM battery in my 2008 Jetta SE 2.5L has been nearly fully discharged one month back (had insufficient surface charge after a prolonged use without the engine running, but leaving it idle for 20 ...
4
votes
2answers
27k views

What is the difference between a normal battery and a maintenance free battery in a 2 wheeler segment

What is the difference between a normal battery and maintenance free battery. Is a maintenance free battery really free of maintenance or just it requires less no of charge cycles. I currently own a ...
4
votes
0answers
111 views

Negative surface charge?

At about 20°C, there has been a situation that the OEM battery in my '08 Jetta was not capable of starting the car at all (virtually no movement of the starter at all), after being used for at ...
3
votes
3answers
4k views

why does the VW dealers in NA have a different battery than OEM?

My 2008 Jetta 2.5L SE came with the following OEM battery in North Carolina: e ENERTEC EMC 1J0 915 105 AD 12V 61 Ah 330A DIN 540A EN/SAE (Note that some appear to come with VARTA as the OEM vendor, ...
1
vote
2answers
1k views

Faulty Motorcycle Regulator?

I am on my second 12v motorcycle battery in a couple of weeks. Will a faulty regulator, ie too higher volts, cause this? Also I have upgraded my ct110 to a 160cc, all works well for a few days, then ...
0
votes
0answers
42 views

Why did car go quiter and cut out after fuel change?

I did a fuel change and during it was concerned that I may have put diesel in my petrol car because it wasn't clear which pipe was which. However the handle was green and said unleaded so I guess it ...
9
votes
4answers
64k views

What precautions are needed when charging a car battery in an apartment?

Suppose a car owner lives in an apartment building and parks his car nearby. He wants to detach the battery, bring it home and charge it with a mains-powered charger indoors. How to properly handle ...
40
votes
3answers
71k views

Is there a way to put Prius with dead battery into neutral?

I own a 2010 Prius. It has a dead battery, front facing forward in my garage. I do not have long enough jumper cables. I’ve searched the Internet. Did Toyota really create a car that cannot be put ...
8
votes
1answer
10k views

How to track down an intermittent battery drain?

I know there are several questions on here about finding the source of a battery drain (like Battery drains by itself when vehicle is parked (parasitic draw) ). However I don't think the answers ...
5
votes
4answers
58k views

How do I know when a car battery was produced?

I have a hard time finding when my car battery was produced - can't find any defintive information. The battery is Bosch Silver with the following data printed: 5EN in huge letters and two rows of ...
20
votes
4answers
45k views

Can a weak battery destroy an alternator?

I've heard a story that a weak vehicle battery can destroy an alternator or cause an alternator to fail early. Is this true, or is it largely fiction?
8
votes
4answers
7k views

Will an auxiliary battery hurt a vehicle's alternator?

I am going to be road tripping and living out of my SUV for a while. I need a way to power a tiny portable cooler/fridge 24/7 and would like to be able to power my cell phone, laptop, and maybe a few ...
8
votes
1answer
3k views

Battery tender vs trickle charger

I understand battery tenders are used to keep batteries charged for long term storage, and trickle chargers are.... also used to charge batteries? What are the differences between these two devices, ...
7
votes
2answers
4k views

Starting using a deep-cycle battery

This weekend, during a camping trip, the starter battery on my 2001 VW Eurovan camper started to show signs of weakness - cranking was much slower than usual and took about 5 attempts to get the ...
6
votes
2answers
2k views

Should I get a battery tender for a car not used for long periods of time?

Could anyone please help me? I have a Honda Civic 170i car in South Africa which I keep in storage for long periods of time while I'm working in the UK. I'm going back to SA in August for 2 months &...
6
votes
1answer
4k views

What would cause a slow drain of a battery?

Have a 2002 Toyota Camry, I got a switch to disconnect the battery, but before that the battery would slowly drain if you left the car for about a week. The solution is fine for now, but how would I ...
6
votes
2answers
416 views

Why do the batteries on some cars need to be hot-swapped?

By "hot-swap" I mean ensuring that the new battery is connected in parallel to the old battery while the old battery is removed and the new one is installed in its place. The idea is to ensure that ...
6
votes
2answers
10k views

Gases from car batteries

Does my car battery emit Hydrogen Sulfide gas when charging, or just Hydrogen gas? I bought the battery around July 2014 (brand new), and because I did not drive my car for a period of one and a half ...
2
votes
3answers
18k views

Rover 25 - My battery light starts flickering on/off on the dashboard

My girlfriend noticed this yesterday and thought it was odd, it stopped but started happening again this morning on my way to work, I think its a V plate.... "as I’m driving along my battery light ...
2
votes
2answers
1k views

Can hybrid cars be driven regularly without their battery?

I really like hybrid cars e.g. Toyota Prius ... but I would like to drive them without their battery so that I can drive them only on petrol and don't have to worry about battery maintenance / ...
0
votes
1answer
2k views

Calculate car battery life using OBD parameters

I want to calculate the battery life of a car based upon OBD2 parameters like engine load, distance traveled, Control Module voltage etc. Can anyone please guide me as to how to do this? If ...
17
votes
5answers
63k views

Can I jumpstart a non-hybrid car from a hybrid or full electric car?

This morning I had starter battery troubles with my 2001 VW Eurovan. As it happened, my father-in-law arrived just at the right time in his fancy new Toyota Camry hybrid. So we opened the hoods, dug ...
15
votes
5answers
247k views

Is it possible to harm your car by giving someone a boost?

This post explains why it's a potential hazard to clip to the negative post on the dead battery when giving a boost. But I've also been told that I could damage the electronics in my own car if I give ...
12
votes
4answers
32k views

How do I apply dielectric grease to my battery?

I recently had a new battery installed in my 2006 Subaru Forester. The shop did not use any dielectric grease, just connected the leads to the terminal and that's it. What is the preferred method of ...
11
votes
3answers
17k views

When should I disconnect the battery to stay safe during repairs?

I am planning to do some car fixes and want to know what precautions I must follow in order to make it safely. Specifically, I'd like to know is for what kind of work, the battery should be unplugged. ...
10
votes
2answers
346 views

Are there downsides to making an accessory socket always live, if accessories are removed when not in use?

In some cars, the power line from the battery to the accessory outlet (aka cigarette lighter socket) is always live. In others, it's off until ignition. It seems pretty much random which cars are ...
7
votes
3answers
614 views

Battery and Alternator Pass Test - 2003 Mustang GT

I have a 2003 Ford Mustang GT, I had the battery tested and it will take a jump and start up so naturally I am thinking the alternator is bad. I take the alternator out and have it tested 3 times and ...
7
votes
2answers
580 views

Are there any modern diesel engines that require electricity to continue running?

I was reading this question about an owner checking the alternator by disconnecting the battery, which is an easy way to validate on a gasoline engine. The single answer assumes that the OP is ...
6
votes
5answers
40k views

Replace or recharge a battery after is has been drained?

The keys in my car were left in the on position for about 12 hours (and maybe the interior light left on) and the battery is drained. Is there any way to tell if I should replace the existing one or ...
6
votes
4answers
3k views

Are there alternatives to lead acid batteries?

In a previous question, I asked about using capacitors as batteries in automotive applications. Are there any other alternatives to lead acid batteries? What are the pro's/con's to these other ...