Vehicle Battery Thread

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Hmmm... I had gone for a small ride yesterday, and i forgot to switch of the fog lights(head lights - that which's at the front of vehicle) in the place where i halted for few hours. The fog lights seem to use high current. So it completely drained my vehicle battery. And when i came back, i was not able to ignite/start the engine. Neither pushing the vehicle to some distance helped.

1) How can i know whether the battery is ok/gone(I mean using a multimeter/so)? One battery, which i had earlier had an indicator green/white/red to indicate the state of battery. That seemed to wow to me.

2) I checked the voltage using a multimeter and it showed 11.8*V (12 V Battery). Battery voltage decreased to a very low extent, and the headlight were able to work with quite low light. This means that ignition sys uses high power. Any idea how much it uses?

3)Maintenance, i never maintained the battery, and it's also been some time i've sent it to garage. What maintenance should i do? Like adding stuffs like Distilled water and so. I don't know why a battery requires distilled water, because some of the rechargeable batteries that i use wont req distilled water. Pls also tell me how freq it shd be.

4) The battery is a LdAcid battery, and the workshop person said he will change the acid. Why should we change the acid?

5)How much max current do they give? Can i use an old battery for my electronics testing/working a radio?

6) Most of the time it starts when someone pushes the vehicle, and ignite it on the run. Why this did not work yesterday?

7)How can i know to what extent the battery is charged in the garage, whether its charged for 1 hr or completely charged?
 

Its only in discharged state, otherwise it is OK. No need to change acid. He is only trying to gain some money from you. As it was deeply discharged, it even could not supply enough current to ignition coil which is quite less as compared to current needed by starter. You need a battery charger to use it indoor. This battery can provide more than enough current you will ever need. For example testing car audio booster amplifiers, UPSs or transmitters. Battery is charged with constant current until it is reached at certain level (14.4V),then current is reduced and voltage is maintained( float charging 13.8V). In simpler cases, charging is cut when voltage of battery is raised to predetermined full charge voltage.
 
ALERTLINKS said:
Its only in discharged state, otherwise it is OK ....
charge voltage.
Click to expand...

Now, i said to change the acid, will it cause any problem? It was a new battery.
Hmmm... i think i need to buy a charger now.

Can you/anyone please answer all the Q's in my first post?
 

Most probably he will not change because it will not make a difference, otherwise it does not matter. You can make a charge yourself, its simple and cost less as compared to commercial units available.
The battery is checked for capacity by first fully charging and the discharging by constant current and observing time until battery voltage drops to 10.5V. The gravity of acid is checked by hydrometer which is also an indicative to charge in battery cell.
Visit the link below
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Are there any equipment to measure max output current of the battery? And how can one know it's current capacity without the experimental procedure that you said.
 


ElectroEnthusiast said:
1) How can i know whether the battery is ok/gone(I mean using a multimeter/so)? One battery, which i had earlier had an indicator green/white/red to indicate the state of battery. That seemed to wow to me.
Click to expand...

This sounds like the built-in monitor that is like a hydrometer. It shows state of charge. However it doesn't necessarily tell you whether the battery is 'gone'.

There's no quick and easy test to tell battery condition. A voltmeter only tells part of the story. A hygrometer is a step better.

Anyway if the battery will crank an engine, then it's okay. If not then try charging it for a while and try cranking again.


11.8 V is pretty much discharged. I believe headlights use between 3 and 6 amps. With ignition 'on', the draw is about 4 amps. (Ballpark figures)

To turn over an engine can take 100 to 300 amps. The bigger the engine the more amps.


Automotive batteries have become ever lower maintenance. And they have become harder to open. My present battery might as well be sealed because I don't know where to open it. I used to be the type to unscrew the caps frequently and check whether the acid was low.

De-ionized water is sometimes used in place of distilled water.

4) The battery is a LdAcid battery, and the workshop person said he will change the acid. Why should we change the acid?
Click to expand...

Never heard of this being necessary. The mechanic may have thought it's a last resort type of thing to try. Especially if he thought there had been leakage, odd chemicals/ enhancers/ boosters being added to the acid, etc.

Moreover, the acid is altered chemically by the charge/discharge process (PbSO4, etc.). I believe the plates are different as well. Changing the acid will disrupt the battery chemistry.

I imagine it might be okay if it's discharged completely (to become plain acid), then gets new acid, then is charged again.

5)How much max current do they give? Can i use an old battery for my electronics testing/working a radio?
Click to expand...

You can still get a few amps out of an old battery if it's just old and not seriously ailing.

6) Most of the time it starts when someone pushes the vehicle, and ignite it on the run. Why this did not work yesterday?
Click to expand...

There's a chance the battery sucked up all the juice which the alternator created. It may have worked if you had disconnected the battery.

7)How can i know to what extent the battery is charged in the garage, whether its charged for 1 hr or completely charged?
Click to expand...

Often mechanics have a high-current charger which can also start an engine. So your battery gets a big boost just after several minutes.

And even if you use a little 5 amp charger for 1 hour, that amount of charge often gives a (normal but partially discharged) battery sufficient boost so it can start an engine that it failed to previously.
 
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No, red was for replace battery, white was for recharge it and green was for 'OK' condition. i dont know what they used, probably some chemical reaction with the indicator or so. pH value?? Don't know.

11.8 V is pretty much discharged. I believe headlights use between 3 and 6 amps. With ignition 'on', the draw is about 4 amps. (Ballpark figures)
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So the vehicle to be running, it requires some current... for ballpark plug to ignite the fuel, am i right?

To turn over an engine can take 100 to 300 amps. The bigger the engine the more amps.
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Huge, requires 2-3kW of power to start an engine! Enormous.

You checked acid/water? Because i think you can see water there, btw why the requirement of water?

When exactly should acid be replaced? i mean how does it stop helping the battery?

There's a chance the battery sucked up all the juice which the alternator created. It may have worked if you had disconnected the battery.
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Great Idea...

Often mechanics have a high-current charger which can also start an engine. So your battery gets a big boost just after several minutes.
Click to expand...
But those chargers also require some battery! especially when the vehicle is outside in some place.

And even if you use a little 5 amp charger for 1 hour, that amount of charge often gives a (normal but partially discharged) battery sufficient boost so it can start an engine that it failed to previously.
Click to expand...

Can i use a wallwart! like a 2 amp ones with some diode circuitry?, that may seem awkward, but how are chargers diff from wall warts?

BTW, these Ld-Acid batteries LEAK badly.
 

ElectroEnthusiast said:
So the vehicle to be running, it requires some current... for ballpark plug to ignite the fuel, am i right?
Click to expand...

Correct since we're talking about gasoline engines. The battery alone can power the ignition system after the engine is running. I once drove a car several miles on battery power alone, since the alternator had gone bad.

You checked acid/water? Because i think you can see water there, btw why the requirement of water?
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It was once common for a battery to lose a bit of water, mostly due to evaporation, but perhaps partly to bubbling off due to high charge rates from the alternator. Maintenance instructions recommended taking off the 6 caps every few months, and adding distilled water to any cells that were low.

Batteries don't seem to need this close watching any longer. I believe it's because they found a way to reclaim evaporated water. I've seen special 'hydro-caps' available which do that. Maybe some catalytic substance.

When exactly should acid be replaced? i mean how does it stop helping the battery?
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The acid usually doesn't go bad over the years. At least there's no specific process that has to make it go bad. As it turns out, however, by the end of a battery's useful life the acid is less acidic. It's probably because sulfation develops on the plates (although it is possible to remove it).

Several things have to do with the battery being less able to hold a charge. The causes of a battery declining are usually: the plates get crumbly, or incurable sulfated, or a high resistance develops in the connections.

I've seen an old battery where the acid had just about turned to water.

When the mechanic suggests replacing the acid, he may be thinking that overmuch water was added to the battery acid, or baking soda got in while cleaning the terminals, or one of these 'magic battery boost' chemicals was put in, etc. Acid is cheap.

However if the acid is far enough gone that it needs to be replaced, chances are the rest of the battery is far enough gone as well.

Can i use a wallwart! like a 2 amp ones with some diode circuitry?, that may seem awkward, but how are chargers diff from wall warts?
Click to expand...

1 or 2 amps is a trickle charge. Some people attach such a charge to the battery if they leave the vehicle idle for several days.

The reason is that lead-acid batteries are known to self-discharge gradually. After a month the battery may become too low to start the car. A trickle charge keeps it charged without overcharging.

To make your own 10-amp charger, you need a transformer that can put out around 15 VAC at 10 amps. Add a diode bridge rated for 10A (best use 20A rating). You don't need a smoothing capacitor. The peaks of the waveform will go high enough to push several amps into your 12V battery. You must cease charging when the battery is full.
 
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BradtheRad said:
Correct since we're talking about gasoline engines. The battery alone can power the ignition system after the engine is running. I once drove a car several miles on battery power alone, since the alternator had gone bad.
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But what happens if the alternator output is higher than the cap of battery? i mean, if the battery is complete charged/the current produced by alternator is much higher than max rating?

Batteries don't seem to need this close watching any longer. I believe it's because they found a way to reclaim evaporated water. I've seen special 'hydro-caps' available which do that. Maybe some catalytic substance.
Click to expand...

Hey, how does it evaporate? the Pb-Acid battery is sealed

Another ques: UPS(inverter), that i have in my place has not undergone any maintenance over sometime, like about 4 years. Neither the Distilled water has been changed/ not the acid or stuffs like that. It's working as NORMAL. Are there any complications/ deterioration of life due to this.
What can i do? Shall i stop using battery till i call a technician?
 

ElectroEnthusiast said:
But what happens if the alternator output is higher than the cap of battery? i mean, if the battery is complete charged/the current produced by alternator is much higher than max rating?
Click to expand...

Normally there is a regulator in or on the alternator. It raises or lowers the output according to battery volt level. It continues to produce enough to power the other systems in the vehicle.

The voltage regulation may get out of whack. This is not common in today's vehicles, but if were to happen then it can overcharge the battery. Acid can bubble away. If allowed to continue, the acid level can go down and the battery may be ruined.

Hey, how does it evaporate? the Pb-Acid battery is sealed
Click to expand...

Leaking was more of a problem when batteries had the removable caps. I can't say for sure what safeguards exist in batteries in recent years, since the low-maintenance type may tolerate overcharging better.


Does your UPS contain gel cells? These are sealed. Gel cells need no maintenance but they are less robust than lead-acid type. One overcharging of a gel cell can ruin it. And there probably is a temperature range it should be kept within.

After a few years gel cells go bad however you treat them (same as for lead-acid type).
 


I dont know the type of the battery. Technician visited today, added some distilled water to the batteries. It had been 3 Years me adding distilled water to the battery. I asked the technician the type of battery, and he replied the Brand Name. He said the acid needs to be added only at the start of the first use of the battery. So, according to him, the maintenance of battery is just adding distilled water every three months(which i can do it myself).

I wonder what would have happened to plates of the battery, it worked well all these years without distilled water inside it.
 

It's a tubular battery, it requires no acid?
how does it spoil if i don't water it?
 



You kill completly battery. You need to replace it. You cant repair that battery. This cannot be called battery anymore, rather call that lead with acid junk in plastic case.

Check alarm system, when voltage goes under some values like 7,5V there is problem and need reset.
 

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