Charging Not

[mechman]

Left car at SIL whilst on winter break, Anyway wife's been in touch with daughter and he chirps in saying he had to move car for some reason or other and it seemed a bit slow starting (Been stood a month outside) so he's let it run for a while with the head lights on so it will charge faster, me, EH, Oh yeah we do it with HGVs all the time. Me, bullocks. Am I missing something here and been wrong all my life.
Norm.

 

[Ashley Burton]

I would have thought using the headlights would put more of a drain on the battery?

 

[The_Yellow_Ardvark]

Putting the lights on, is meant to give the alternator a load.
So at idle it has to replace the current drawn.

In the past, that would of been ok. Modern charging circuits this is not required.

 

[bricol]

Not sure that was even needed with older stuff - certainly never done it. Nor the strange idea of jump staring a car with the headlights on . .

Hope next phone call will not be about the disappearance of said when he next leaves it running unattended . . .

 

[ajlelectronics]

The charging battery if more than enough load, putting lights on etc is just reducing the charging current available and is daft!

 

[bourbon]

Having to jump start the girlfriends, girlfriends daughters etc. Cars Meany times. If I leave my car on tick over(750 rpm ) the dead car won't turn over, But when ,it's increased to 1500 rpm they fire straight up. I have a good quality set of Jump leads which help a lot.

 

[mechman]

Having to jump start the girlfriends, girlfriends daughters etc. Cars Meany times. If I leave my car on tick over(750 rpm ) the dead car won't turn over, But when ,it's increased to 1500 rpm they fire straight up. I have a good quality set of Jump leads which help a lot.

But you don't have the headlights on while doing it surely?

 

[ajlelectronics]

Having to jump start the girlfriends, girlfriends daughters etc. Cars Meany times. If I leave my car on tick over(750 rpm ) the dead car won't turn over, But when ,it's increased to 1500 rpm they fire straight up. I have a good quality set of Jump leads which help a lot.

Quite likely. An alternator will give some output at idle, but 1500 RPM will get it up to full capability. You wouldn't throw that away by giving it more load.

 

[brightspark]

Having to jump start the girlfriends, girlfriends daughters etc. Cars Meany times. If I leave my car on tick over(750 rpm ) the dead car won't turn over, But when ,it's increased to 1500 rpm they fire straight up. I have a good quality set of Jump leads which help a lot.

if I ever jump start someones car I rev the car up to get full power across tickovers not much cop

 

[julianf]

It sounds odd to me, but, possibly some alternator regulators don't regulate well at low amps. But then a flat lead acid would, I expect, suck up way more amps than some head lights would need to add.

Is the type of load presented different from the head lights? As in presenting the resistive load may cause the regulator to output greater amps or rise to a higher voltage than just the drained battery would?

Like I say, sounds odd to me, but there could be some sense in it... Maybe.

 

[gordon stephenson]

In a similar vein, Russian Morcovich years ago, The handbook stated turn on the headlights for a while before starting in the winter, Apparently to "warm" the battery a little to give more power for starting, Any body else heard this!!

 

[DAPPH]

Slave starting from a running vehicle ? Connect up in the correct safe sequence , run the vehicle for 45 seconds first to about 900 rpm to start the flat battery working then try to fire the dead vehicle up. But best of all is get the problems on the fulty vehicle sorted before you damage the electrics or the alternators on both cars .

The Tw*t next door a clever know it all scribble serpent borrowed the battery of his FIL's diesel Merc and tries to connect the really heavy duty truck style jump leads back to front with his terminals of his car battery whilst his wife turned the ignition key … One of the best melting terminal flashes & smoke cloud I've ever seen came from between his hands & within the engine compartment . Think he shat himself for he disappeared inside and came out a good 20 min later in clean jeans & a different sweat top .
Later that day the RAC came and try to start the car, the next morning the scrappie came to collect it .


So what does he do with is new to him secondhand 18 month old car the next week end . Wearing his Lycra Lout Lemons he only goes & ties his & his wife's racing cycles to the boot lid using string with two bit of cardboard under them to stop them scratching things . Off they went full of civil service smugness & matching outfits . He came back less than half an hour later …... no bikes and dozens of deep scrapes & scratches where the bikes had been . I could hear his missus bending his ears all afternoon about how much the new car had cost as well as losing their expensive racing bikes .

 

[DAPPH]

In a similar vein, Russian Morcovich years ago, The handbook stated turn on the headlights for a while before starting in the winter, Apparently to "warm" the battery a little to give more power for starting, Any body else heard this!!

Yes to get the plates & electrolyte slightly warmed so the battery becomes more efficient , then be used to turn the engine over without the light on . But never it's never to be done when the battery is flat.

 

[eddie49]

Modern alternators have a signal called "DFM" Digital Field Monitor which is a pulse-width-modulated indication of the load on the alternator. This signal is sent to the ECU and often causes the idle speed to be increased. So the theory may be that adding a moderate load - the headlights - will signal the ECU via this DFM wire to increase the revs, with the overall effect being more net amps for recharging the battery.

 

[DAPPH]

The old Moscovitch cars were still running on distributors and carburettors .. electronic engine management & emission control systems weren't even invented back then .

 

[DAPPH]

Modern alternators have a signal called "DFM" Digital Field Monitor which is a pulse-width-modulated indication of the load on the alternator. This signal is sent to the ECU and often causes the idle speed to be increased. So the theory may be that adding a moderate load - the headlights - will signal the ECU via this DFM wire to increase the revs, with the overall effect being more net amps for recharging the battery.

That's what the foot on the accelerator is for .

 

[bourbon]

But you don't have the headlights on while doing it surely?

No. but her daughters boyfriend did try to start it with the heater on full. He was a nightmare, knew absolutely FA about cars.

 

[octo0072000]

The old Moscovitch cars were still running on distributors and carburettors .. electronic engine management & emission control systems weren't even invented back then .

used to have a Moscovitch estate paid £25 quid for it welded front crossmember was MOT fail up ran it for a year used it to get to work on monday sat in yard till friday then home ran around at the weekend yet never had any problems with it sold it or £50 after a year
always remember part of reg no was ARV
(armored fighting vehicle )

 

[fixerupper]

Yes .. me dad always told me " when you jump start a car or start with a low battery on a cold morning (put it in neutral) and then press the clutch down "...I always press the clutch down when starting anything ...does anyone else automatically do this?When I have shared cars or vans in the past I was often nagged about leaving them in gear ...

 

[wyn]

I always press the clutch down when starting anything ...does anyone else automatically do this?When I have shared cars or vans in the past I was often nagged about leaving them in gear ...

I always start cars, tractors etc with the clutch pedal down. A lot of tractors won't start unless the clutch pedal is down.