Current draw for running a petrol fuelled car

To save me having to root out a DC current probe and get my hands dirty has anyone got a feel for ballpark figure for battery drain on a injected petrol
fuelled vehicle 'in use'
Assume 4 pots 1.6L, closed loop emissions, no gizmos like electric power steering, no headlights, no heater fan, no radio, no wipers just the basic engine and indicators / brake lights and with zero alternator contribution, all you have is a battery in reasonable condition.
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On 09/06/2019 22:24, The Other Mike wrote:

It's not possible to give this figure as battery will be charging to recover from starting.
In use there should be no battery drain. The alternator regulator keeps output above the battery voltage 13.5-14.7V is typical. A fully charged battery is 12.7V so while running it should be "on charge".
All charging tests I've seen use system voltage to determine alternator health.
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wrote:

It won't without an alternator :)

Yes agreed, normally their shouldn't be any battery drain but this is not normal

The voltage would be falling by the second.
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On 10/06/2019 08:06, Peter Hill wrote:

Are you sure it's just 12.7V? Where did you get this figure from?
A stable float charge is generally 13.7V
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13.8v here. ;-)
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On 11/06/2019 00:33, Dave Plowman (News) wrote:

A fully charged 6 cell lead acid battery has a voltage of 12.7V. Maybe 12.9V immediately after taking it off charge.
As I said on charge it's 13.5 to 14.4 volts.
But I missed the bit about him running this battery in total loss on a race car.
If you are running around the pits with a battery cart it's completely obvious that the car doesn't have functional charging system. The race organiser needs a rule change banning battery carts from pit/start lane. Or scrutineers to test for self starting and > 13.5V running.
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Both my cars, one old, one newer, stabilise at 13.8v engine running battery fully charged. It's the textbook figure.
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On 14/06/2019 14:05, Dave Plowman (News) wrote:

It will take hours to charge a lead acid beyond 80% capacity at 13.8V Does the charging voltage start higher and then drop off?
Mine also increases voltage when cold. The hotter the battery the lower the charging voltage needed.
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Of course. That's why I phrased the above as I did.

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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On 15/06/2019 15:32, Dave Plowman (News) wrote:

I gather, deviously so. Fully charged can mean so many things to different people given its a level that can never actually be reached.

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<snip> >Fully charged can mean so many things to

Eh?

Eh?
We are talking 'real world' here right?
Cheers, T i m
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On 15/06/2019 22:07, T i m wrote:

I suspect you might consider that a battery is "fully charged" where for a 70Ah battery the charging current has dropped below?
If you have a look at figure 4.28 of http://www.microhydropower.net/mhp_group/portegijs/firefly_bm/ffbm_4_9_5.html
your level might be 100%, but when you can still put a further 10-20% into the battery the term "fully charged" becomes blurred.
You may also see that time here is measured in hours. How many journeys do you make that last several hours? Most of mine are generally less than 1 hour and I volunteer that is the norm.

I can assure you asymptotic behaviour is real life. Pulling a vacuum with a pump is another I frequently come across, a vacuum is something you never quite achieve however hard you try.
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No, I'd consider a battery fully charged when my quality smart charger tells me it is (when it finishes all it's tests and goes into maintenance mode)?

What you seem to be doing here is quoting some specific example as if it reflects what actually goes on in the real world and for 'most people'.

Eh?

But the scenario you quoted isn't how I (or 'most people') would use, charge or determine a battery to be fully charged.

Now you are changing the subject?
'Most people' would determine a rechargeable battery to be fully charged once it no longer accepted any charge (or appeared to be but was liberating that excess charge in gas or heat etc). Now, given that most rechargeable have some level of self discharge, as you say in your theoretical world, it would be difficult to find a rechargeable that was *still* fully charged, once taken off charge.
But that wasn't what you said.
I could tell when my electric Moke was fully charged with my nose. ;-)
'Hmm, there's nothing like the smell of hydrogen in the morning'.
Cheers, T i m
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Doubt it was the hydrogen you were smelling given that it’s odourless...
Tim
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Ok, 'Hydrogen Sulfide' then? ;-)
Cheers, T i m
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It goes bang just the same. ;-)
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On 16/06/2019 09:09, T i m wrote:

That might well be the case for many who don't know any better. However the difference between running a generator and intermittently recharging a battery say in a narrow boat and the same in conjunction with a solar panel can be twice the battery life.
Ignorance is often bliss.

I was thinking of the real world rather than an ignorant one.
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<snip> >> 'Most people' would determine a rechargeable battery to be fully

Aww bless.

WTF are you trying to change the goalposts to now, talking about DoD / lifespan?
The chances are I have had a PEV longer that you (30+ years)?
How many LA powered EV's have you designed, built and raced?
How many LA batteries are you currently using / maintaining, OOI?
How far can your C5 go on one charge with the std spec battery?
How long does your electric outboard run on full throttle?

And changing the subject, disingenuous.

It appears you weren't, eh.
Now, try again with some real facts and without trying to squirm out of it.
Cheers, T i m
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Just meant that the voltage had stabilised. It never drops below that - except with a heavy load that the alternator can't balance at low revs.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On 16/06/2019 00:22, Dave Plowman (News) wrote:

I understand. The battery will still be taking a charging current at the stabilised voltage and take quite a time for it to drop down to a few amps if the charging voltage is just 13.8V
For narrowboats, before solar cells became the norm, it was often said with limited time charging, you would only recharge up to 75-80% capacity. That also meant cells became sulphated more quickly than if the battery was maintained in truly fully charged condition.
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