here`s one i was told.about starting and charging

somone said it takes about 7 miles befor the charge goes back into the battery......
what do you think?

sounds about right to be honest

it obviously depends on the size of both the alternator and the battery, but a "normal" car then yes thats about right

is that 7 miles with all the lights,blower etc on a dark frosty morning after the 2.5 diesels been stood for a week in sub zero temps , or seven miles on a warm summers afternoon when the fiat 500 started first flick of the key ?

As ricc says. Its a difficult one with many variables.

If you have lights, heaters etc etc on it will take time to recoup the charge used. Depends on the age of the battery, condition of wiring and accessories etc etc.

Is it not the case that it takes about this time/distance for the charge used in the initial starting to return to its previous charge level? Surely the alternator will start to charge the battery as soon as it starts spinning.

BIG_GINGA_BEARD said:

As ricc says. Its a difficult one with many variables.

If you have lights, heaters etc etc on it will take time to recoup the charge used. Depends on the age of the battery, condition of wiring and accessories etc etc.

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Yes, like you say it will take this time to recoup the charge used.

My Doris' car gets started then driven 1.5 miles, 10 times a week and that's it.
This time of year that's with lights, wipers, blower, HRW radio etc.
Never have a problem with the battery going flat.

Trewey said:

My Doris' car gets started then driven 1.5 miles, 10 times a week and that's it.
This time of year that's with lights, wipers, blower, HRW radio etc.
Never have a problem with the battery going flat.

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Same with my Missus, she works 2 miles away, works on average 5 times a week, gets the odd 30 mile round trip for messages, no problems with the battery. However, I have disconnected my alternator on my Landy while I work on the chassis. I start it up, drive it out of the garage and onto the driveway and back into the garage when I am finished for the day. I only get about 4 or 5 starts before it needs charging again.

our 2.8td fourtrak usually does less than 2 miles on a journey , never had a flat battery problem

it can more or less recoup the charge it used when starting straight away i.e. less than a mile, if its a good starter that is.

whenever i get called out i generally tell any customer that once the vehicle is started it would be best to give it a short run for approx 1/2 hour as good practice to get plenty of charge into the battery. This goes for cars, vans, trucks etc treat all the same.

have to agree with above post as do the same when called out to a dok/flat battery

I have always worked to a 20 min run to recharge what a start takes out.

I agree with Mr Prime there. Does depend heavily on the condition of the battery and the drain on it during driving though. If the alternator is sub standard then it won't be shoving as much back to the battery as it should.

I monitor battery levels on about 20 motors... someof which are 24 volt. Lots of them only deliver 25 volts when they are running! Won't take too many goes with the tail lift to drain them feckers - the good ones are getting 27 volts delivered and the 12 volt systems usually 14.8.

Having said all that - I have a voyager that has about 10 internal lights. Leave the boot open so the interior lights are on for half hour and the battery is too flat to start the car. It is generally ok after about 10 miles or so though.

I usually advise a 20-30 min run after I've jump started someone.

My truck charges at 28v when running. If I do loads of flat batteries (especially ones on diesels) I end up with one of my batteries getting pulled down to 11.5 volts and the other bugger overcharging at 16.5 volts. I have to have 3 batteries for my truck and switch them over regularly to ensure they charge equally. The one that is off gets charged up on a battery charger in the workshop and replaces whichever one is getting low. I then charge up that one and the cycle continues.

My landy kicks out 14.5 volts and even with the urn and 300w heater going it generally charges at 14.2 volts. I'm thinking about switching the single 017 battery for 2 075's instead as I can get genuine vauxhall ones for peanuts at the moment. If I do switch, I'll put em one a twin switch so I can choose between battery 1, battery 2, both batteries or neither battery at the flick of a switch.

does it still charge at idle?

goonarmy said:

does it still charge at idle?

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A battery will still charge on idle. If you drag down a single battery on a 24 volt system it takes a long time to-recharge.

so,if i fit a second battery and loop it to the other one.will that help?
not so it split charges.

no - it will get yu the worst of both worlds - the good battery will be drained by the bad one . that why split charge systems were invented.

i was always told about 20 mins of engine running to replace the charge used by starting