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Old 29th August 2020, 06:32   #1
operamagorum
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Default Flat battery

Hi all
I recently returned from a 3 week stay in hospital to discover that I have a flat battery. I have dash lights, but not even a click on turning the key.
The battery is brand new
Last time this happened, I got the breakdown guy to check for a drain and he assured me that there wasn't one.
Surely there must be, as a brand new battery should hold a charge for longer than 3 weeks.
Any ideas?
Thanks
Geoff
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Old 29th August 2020, 07:28   #2
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Could be duff battery.

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Old 29th August 2020, 07:52   #3
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Hi Geoff,

A brand new battery isn't necessarily fully charged when you receive it.

Recently conducted experiments show that our cars can intermittently draw up to an amp even when the ECUs are asleep.

Consider your driving style. If you make a lot of very short journeys the battery's charge will slowly decrease.

The best thing you can do now Geoff is to put it on a smart charger without delay for 36 hours.

Simon
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Old 29th August 2020, 21:37   #4
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Quote:
Originally Posted by SD1too View Post
Hi Geoff,

A brand new battery isn't necessarily fully charged when you receive it.

Recently conducted experiments show that our cars can intermittently draw up to an amp even when the ECUs are asleep.

Consider your driving style. If you make a lot of very short journeys the battery's charge will slowly decrease.

The best thing you can do now Geoff is to put it on a smart charger without delay for 36 hours.

Simon
Simon.---New batteries don't get charged.

Electricity is available from the moment the acid is poured into the battery.

However, if you do lots of miles per week you'll be OK. If not they need to be charged. The op probably started off with virtually nowt in his battery then went down hill from there.---
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Old 30th August 2020, 07:00   #5
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Electricity is available from the moment the acid is poured into the battery.
Understood Jon, but following that, what happens to the battery's level of charge as time passes when, for example, it's sitting on a shelf in a distribution depôt? Doesn't it slowly decrease?

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Old 30th August 2020, 11:43   #6
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Yes, it tries to return to a state of balance of the chemicals inside it. Even when not joined to anything.

The chemicals continue to react with one another until they finally stop. At this point, when the reactions stop, no more electricity can be obtained from the battery. ( This internal action manifests itself by a very slow discharge of heat. )

The common term being Flat.

Whilst a battery is being normally used it's in a state of un-balance. It is constantly trying to balance itself by giving out electricity. Our cars keep it in a state of un-balance by charging it.

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Old 30th August 2020, 13:10   #7
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Yes, it tries to return to a state of balance of the chemicals inside it. Even when not joined to anything.
Thanks for the "technical" explanation Jon!
The process which you've described is what I was referring to here:
Quote:
Originally Posted by SD1too View Post
Hi Geoff,
A brand new battery isn't necessarily fully charged when you receive it.
Perhaps strictly speaking I should have said:

"A brand new battery may be partially discharged when you receive it."

Would that have been more accurate?

Simon
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Old 30th August 2020, 13:39   #8
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I guess the alarm / immobiliser will take something out of a battery too, as it will be in standby mode.

A battery on the shelf won't get that.
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Old 30th August 2020, 15:05   #9
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every battery i have bought new has always only shown about 12.2 to 12.4 volts. i have a spare new battery for my wifes civic which also came new and has not yet been fitted ready for winter if needed. this showed 12.3v originally 3 mths ago. it was charged up as soon as it arrived the same day and read 12.6 and has not fallen below 12.5 volts since. almost 3 months now as i check every two weeks or so as i have a spare varta for the rover as well. so it doesnt make much sense regarding batteries which are new and how long they are in stock since they were first activated. only my observations of course as i am no expert of course !!
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Old 30th August 2020, 15:25   #10
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have you got sat nav on your car if so this will all so take something out of the battery as well
regards paul
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