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Old 12th January 2016, 14:55   #106
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Default Re: Car Battery: Dos and Don'ts!

Why is the vaseline on the terminal important? My car came back from service today and I did not see any petroleum jelly on either of the terminals? If it is really important, I plan to do it myself. Please suggest
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Old 12th January 2016, 16:18   #107
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Default Re: Car Battery: Dos and Don'ts!

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Why is the vaseline on the terminal important? My car came back from service today and I did not see any petroleum jelly on either of the terminals? If it is really important, I plan to do it myself. Please suggest
It is to avoid corrosion. Smear it yourself if it is not already done by the service technician.
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Old 12th January 2016, 16:34   #108
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Default Re: Car Battery: Dos and Don'ts!

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Why is the vaseline on the terminal important? My car came back from service today and I did not see any petroleum jelly on either of the terminals? If it is really important, I plan to do it myself. Please suggest
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Originally Posted by techiecal View Post
It is to avoid corrosion. Smear it yourself if it is not already done by the service technician.
Get a proper Battery Terminal Coating spray. It isn't expensive nowadays.

Car Battery: Dos and Don'ts!-img_20151206_202957.jpg
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Old 13th January 2016, 09:26   #109
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Default Re: Car Battery: Dos and Don'ts!

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Why is the vaseline on the terminal important? My car came back from service today and I did not see any petroleum jelly on either of the terminals? If it is really important, I plan to do it myself. Please suggest
Vaseline - I have not used Vaseline on my car battery for a long time. I just make sure the battery is not overfull or being overcharged. But lately my car's service technician (it goes only to the ASC) applies a coat of anti corrosion spray to the terminals/clamps. That helps of course but is not necessary IMO.

If you see a white/green coating on your battery clamps and terminals please check as follows:

The biggest cause of corrosion is overfilled battery cells. The water/acid bubbles up from the vent holes and battery terminals and coats them. The acid is corrosive and will damage the clamps and wiring over time. So, make sure you NEVER overfill the cell. Like with many other fluids in a car those Max and Min lines are there for a reason, please follow them.

Secondly, make sure the battery is not being overcharged. higher than recommended voltage will 'boil' the electrolyte causing leakage and damaging the plates. Check your alternator charging voltage - it should be between 13.8 to 14.4 VDC at idle. Any lower or higher, get the alternator's voltage regulator checked.

Thirdly, make sure your battery case is not leaking anywhere especially from the terminals and all the cell caps are fitted tightly. Many technicians have a habit of tapping or hammering the clamps into place with a spanner or hammer, which if done carelessly can cause miniscule cracks at the base which may cause a leak or which in turn causes corrosion. If you see your tech doing this, tell him to stop, loosen the clamp a bit more and fit it by hand pressure. He can then tighten the clamp nuts to recommended torque settings.

Four - keep the battery and clamps clean and free of oil/grease and dust.

Last edited by R2D2 : 13th January 2016 at 09:28.
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Old 8th April 2016, 23:07   #110
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Default Re: Car Battery: Dos and Don'ts!

Hi all,

i left the car keys of my alto in the ignition at ON position and forgot about it for 3 days! the stereo was on at low volume.
The battery is completely dead now. Nothing works, stereo, headlights, not even the odometer.
The battery was replaced two years ago and should be good.
Will it run if i try to push start it or do i need to take the battery and get it charged at a battery shop?
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Old 9th April 2016, 06:57   #111
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Default Re: Car Battery: Dos and Don'ts!

@guptavis; Modern cars need some juice for the ECU, so push start is unlikely to work. I suggest you get a friend to give you a start using a set of jumpers. Remember the drill - start donor car, connect jumpers - line and then earth, and then start your car. I suggest you wait for say two minutes for some juice to flow in. Once started disconnect jumpers, earth first. If you drive the car round for say, 20 minutes or so you will be in business, though it will take longer to get the battery fully charged.
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Old 9th April 2016, 09:23   #112
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Default Re: Car Battery: Dos and Don'ts!

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@guptavis; Modern cars need some juice for the ECU, so push start is unlikely to work. I suggest you get a friend to give you a start using a set of jumpers. Remember the drill - start donor car, connect jumpers - line and then earth, and then start your car. I suggest you wait for say two minutes for some juice to flow in. Once started disconnect jumpers, earth first. If you drive the car round for say, 20 minutes or so you will be in business, though it will take longer to get the battery fully charged.
Thanks for the quick reply sgiitk.
Wish id read it earlier though. First thing in the morning i tried push starting the car and made a big fool of myself lesson learnt. dont try push starting with zero battery. atleast i got some excercise.
Dont have jumper cables. Guess ill just take the battery to the shop and get it charged. The voltage on removing battery was 7.8V!! didnt know it could get that low. Hope battery hasnt suffered any major damage.
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Old 9th April 2016, 09:42   #113
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Default Re: Car Battery: Dos and Don'ts!

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Dont have jumper cables. Guess ill just take the battery to the shop and get it charged. The voltage on removing battery was 7.8V!! didnt know it could get that low. Hope battery hasnt suffered any major damage.
Modern cars should not be push started.

Buy a set of good quality jumper cables off eBay or any accessory store and store them in your car - always. Treat them as emergency essentials - just like you would your spare wheel and jack.

If your battery voltage is down to 7.6V it's probably dead due to cell failure. But I hope not & it can be recovered after a bench charge. Get it charged and then load tested ASAP.

The longer you wait i.e. more than 24 hrs sulphation sets in and that reduces battery life and performance.
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Old 9th April 2016, 10:52   #114
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Default Re: Car Battery: Dos and Don'ts!

@guptavis; I agree with R2D2 that you should get a set of jumpers pronto. Just watch out (I and some others) bought jumpers from a Trivandrum chap, and while the connectors were excellent, there was almost no copper in the cables. I ended up replacing the wire with 10mm copper lines. I keep them in both cars, but then I have both ATs as well. Today many people carry jumpers so you should check with your friends.
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Old 9th April 2016, 18:08   #115
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Default Re: Car Battery: Dos and Don'ts!

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... start donor car, connect jumpers - line and then earth, and then start your car. I suggest you wait for say two minutes for some juice to flow in. ...
It is always a good idea to gun the donor car (keep at high RPM - say 2500RPM; not redline) till the other car starts. Once the other car starts, keep it at a high RPM for some time.
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Old 9th April 2016, 18:59   #116
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It is always a good idea to gun the donor car (keep at high RPM - say 2500RPM; not redline) till the other car starts. Once the other car starts, keep it at a high RPM for some time.

Not so sure about that. It should make little difference in todays modern cars with regulators that keep electrical output at constant levels of voltage in order to charge your battery with regulated current. During starting itís the battery that provides the actual power (volt/amps) to crank the engine, that alternator on the donor car isnít going to contribute much if any at all.

Technically, if an alternator spins at a rate where its voltage is being regulated then there is little to no improvement in spinning it faster. So, no matter how fast above that number of RPM the engine turns, the charging current will increase very little. From that point on the current is determined by the voltage difference between the fixed alternator output voltage and the battery voltage divided by the resistances of the alternator and battery in series. As the battery voltage rises, the chargeing current gradually decreases.

But if it makes us feel better by all means go ahead. Hundreds of posts on as many car forums the world over suggest you should do this, so why should Team BHP think differently?

Jeroen
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Old 9th April 2016, 19:27   #117
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Default Re: Car Battery: Dos and Don'ts!

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Originally Posted by R2D2 View Post

Buy a set of good quality jumper cables off eBay or any accessory store and store them in your car - always. Treat them as emergency essentials - just like you would your spare wheel and jack.
Quote:
Originally Posted by sgiitk View Post
@guptavis; I agree with R2D2 that you should get a set of jumpers pronto. Just watch out (I and some others) bought jumpers from a Trivandrum chap, and while the connectors were excellent, there was almost no copper in the cables.
I did think of getting jumper cables when i first thought of going to kinnaur in my alto. But i didnt and luckily never faced a problem like this even on two kinnaur and one spiti trip. Car always started on first crank even after standing overnight in one foot of snow.
This is only the second battery in 8.5 years and never gave any problems. actually my dad accidentaly left the key in the on position which drained the battery. anyways will think of getting good quality cables.
removed the battery and gave it for charging at the shop. the guy checked the specific gravity with the tube in 3 cells and said its okay. i was told to collect it tomorrow morning. hopefully wont have to replace it.
i disconnected the -ve terminal first while removing. which terminal do i connect first while installing the battery? or does it not matter?
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Old 9th April 2016, 19:58   #118
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Default Re: Car Battery: Dos and Don'ts!

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I did think of getting jumper cables when i first thought of going to kinnaur in my alto. But i didnt and luckily never faced a problem like this even on two kinnaur and one spiti trip. Car always started on first crank even after standing overnight in one foot of snow.
This is only the second battery in 8.5 years and never gave any problems. actually my dad accidentaly left the key in the on position which drained the battery. anyways will think of getting good quality cables.
removed the battery and gave it for charging at the shop. the guy checked the specific gravity with the tube in 3 cells and said its okay. i was told to collect it tomorrow morning. hopefully wont have to replace it.
i disconnected the -ve terminal first while removing. which terminal do i connect first while installing the battery? or does it not matter?
I assume your battery service chap will not overfill cells. The electrolyte level should be cover the grid separators and at max reach the bottom of the filler vent. Do NOT overfill or acid may leak out when the battery goes through the charging process. Also, please ask him to do a load test on the battery before delivery.

Make sure the ignition and all accessories are switched off.

When you install the battery connect the +ve cable FIRST and tighten it sufficiently but not too much. DO NOT hammer the clamps onto the terminals. Loosen the clamp so it slides onto the terminals when pushed down and then tighten. Then follow the same procedure for the -ve terminal.

If possible coat the terminals/clamps with a thin coat of Vaseline, never grease.

Start the car. If you have a digital VM check the voltage at 2000-2500 engine RPM. It should read between 13.8 and 14.4V with all accessories switched off.

Last edited by R2D2 : 9th April 2016 at 19:59.
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Old 11th April 2016, 09:21   #119
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Default Re: Car Battery: Dos and Don'ts!

I remember once giving juice to a colleagues car which was 'dead as a dodo', I think a Swift or something. I was quite surprised that my jumpers (10mm) got warm in the transfer of juice, and the donee car could only be started after, say three to five minutes.
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Old 11th April 2016, 15:42   #120
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Default Re: Car Battery: Dos and Don'ts!

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Not so sure about that. It should make little difference in todays modern cars with regulators that keep electrical output at constant levels of voltage in order to charge your battery with regulated current. During starting itís the battery that provides the actual power (volt/amps) to crank the engine, that alternator on the donor car isnít going to contribute much if any at all. ...
It is not about the voltage, which the voltage regulator takes care of to keep in the 13.2-14.4V range. It is about the current that the alternator produces, and that is engine RPM dependent. If the load connected to it is more, the alternator will present a higher load on the engine, and the voltage will dip slightly (check headlight intensity).

At idle, about 20-50A is produced, depending on the car / alternator. By design, most of the current produced suffices for the donor car itself, depending on the loads connected at any point of time. However, since all the connected loads of the stalled car are now appearing as additional load, the current produced at idle by the donor car is unlikely to be sufficient for charging the recipient car.

In this situation, the time taken for the recipient battery to charge will be much higher than if higher current is supplied. Add to this the voltage drop across the jumper cable, which usually has a gauge governed by low cost. This is what @sgiitk has written about above (voltage drop across the jumper cable x current flowing through it = power loss which appears as heat).

Most alternators produce max output at around 2500RPM (engine). At that point, the alternator will make more current available to cover the additional load(s) of the recipient car. By doing this, one is trying to minimize the time taken to get the recipient car to a cranking state. Since the cranking current of the recipient car is being supplied by the donor alternator in all this, it is better to keep the donor alternator around the max. operating point.
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