Battery Charging Question

[JEZ.S320L]

Assume that the battery you have, is of average condition. The charge it holds, is JUST enough to start up with.

Question:

How many miles would need to be covered - again, assume a motorway - before the battery becomes FULLY charged again?

Over to you ..................

 

[rf065]

I would imagine the size of battery, the output of the alternator, a petrol or diesel engine & it's cubic capacity, and even the outside temperature would make it extremely difficult to give an exact answer that would relate to everyones car.

Russ

 

[television]

Its a fixed issue or sum we say that a car used 30 amps for the engine and 30 amps for the consumers, so with a 70 amp alternator there is 10 amps spare.

You cant give amps, but you can give volts, amps (current is drawn)

the car battery is 12.5 volts and the car runs at 13.8 so you have the difference that is of 1.3 volts to charge the battery, when the battery is good but low say 10volts, then you have 3.8 volts to charge the battery. these figures are added to the battery.

If in the car above with the 70 amp alternator, if it was raining and cold and every thing turned on, there is not much left to charge the battery.

alternators are not designed to charge flat batteries and they should not be used for this.

If the battery has a high resistance cell then it will be fine while topped right up, but after an overnight stop it could be US again until charged again. A short circuit cell pulls the running voltage down.

Hope this helps

 

[colechelle]

we was always taught that a average start would require a 5 mile run to replenish the battery, that was the old school of teaching!!!

 

[television]

we was always taught that a average start would require a 5 mile run to replenish the battery, that was the old school of teaching!!!

Actually Cole it was not so long ago that the engines turned over quite a bit before the fired up, these days its instant and they start on the first turn

 

[Xtractorfan]

Once again too many outside factors to give a precise answer, but I've always found a healthy battery will charge with a 10 min tickover or as cole suggests a five mile run.. on the other hand jez's (average) battery will always be struggling to maintain a full charge..so change it..

 

[jibcl500]

The running voltage on my CL was 13.4 which was never enough to keep the battery topped up, replaced the regulator on the alternator and it now has arunning voltage of 14.2 and the battery is always charged and ready.

jib

 

[television]

The running voltage on my CL was 13.4 which was never enough to keep the battery topped up, replaced the regulator on the alternator and it now has arunning voltage of 14.2 and the battery is always charged and ready.

jib

And there you have it Jib, Ohms law is something that no one can argue with, its basics and fact

 

[mattkh]

it now has arunning voltage of 14.2

Hi
What is the maximum safest running voltage ?

 

[television]

Hi
What is the maximum safest running voltage ?

14.2 volt is the max that you want to run at, anything over and the bulbs and ECU's are not too happy

 

[David Nock]

2nd car does very low miles so when it goes out I make sure that it does 12 to 15 miles at least before coming home. I'm not sure thats enough so in the winter I also use a supplementary charger to boost the battery every month or so.
Something inside says 5 miles is not enough.

 

[television]

2nd car does very low miles so when it goes out I make sure that it does 12 to 15 miles at least before coming home. I'm not sure thats enough so in the winter I also use a supplementary charger to boost the battery every month or so.
Something inside says 5 miles is not enough.

The same with me David and the SL,,I have to once a month give it a good charge..it does work wonders

 

[FIBAMAN]

The same with me David and the SL,,I have to once a month give it a good charge..it does work wonders

That is good practice if you dont want to get caught out (always happens when you dont need it happening).
Remember in the winter dark nights, more lights, cold + more use of heated screens +heavy load on your system= more strain on batteries. A little attention pays dividends my old C180 got 9.5 years out of first battery (about 185,000 miles) but went down overnight when it was minus 6. I couldnt really complain about performance like that.

 

[stumpy]

I was told to do a lap of the M25 to charge a jump started battery. But that could take a few days so not really feasible

 

[television]

I was told to do a lap of the M25 to charge a jump started battery. But that could take a few days so not really feasible

Quite possible but in all fairness if the battery is very low or virtually flat and you jump start,and then drive, the only thing holding down the voltage is the alternator regulator, normally the battery takes much of this load, so if the regulator packed up you could say goodbye to all of the lamps and ECU's on the car.

It is possible to put 30 volts into a flat battery until the charge picks up