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Battery preservation tips?


Kristin77
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I forgot to also say @TomsFocus that my Mk2 was a bit like your Golf. It sat unused with its 10 year old battery for a month before I sold it and it started no problem.

I had bought my Clamp Meter during that time and the parasitic draw was tiny, though I can't remember how much and how long after opening I checked it. Happier days. 

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I overstretched myself a bit this weekend, had to cut this afternoons activities short!

Couldn't wait for voltages to stabilise for readings, but what was very interesting is the voltage at idle...both the Golf & Focus idling together.  Focus at a steady 14.8v, Golf barely managing 14.0v!

So perhaps the Focus is better to run...and the Golf better to charge! 

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15 minutes ago, TomsFocus said:

voltage at idle...both the Golf & Focus idling together.  Focus at a steady 14.8v, Golf barely managing 14.0v!

That ties in with my very long post earlier that people probably lost the will to live if they read it to the end😁 I think that is how our cars at set up to work.

It also ties in with what @unofixsaid about how Alternators work for the Golf and the Mk2 and a lot of other older cars. I'm sure that there is nothing wrong with your Golf either, it is just different.

All your hard work has not been in vain though, I'm now sure there is nothing wrong with the charging system on my car.

 

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1 hour ago, Tizer said:

I'm sure that there is nothing wrong with your Golf either, it is just different.

Well here's the interesting thing...  The Golf has had a charging fault every winter since I've owned it.  Cold idle for a few minutes or put the rear screen heater/aux heater on and the battery light comes on and shuts off all unnecessary equipment.  It's fine after being driven for a few minutes, and up until I stopped driving, the battery never died, even with one  short shopping trip a week during lockdowns.

The battery did eventually die after a couple of months without use, and I've just been jumping it occasionally since.  And that's when I found out it's a got standard battery, not the start stop battery it should have.  So that's done well to last 5 years.  Stop start worked fine too.  But I am wondering if the variable charging doesn't work because of having the wrong battery...  So the cold charging fault could be cured with the correct battery.  Not really relevant to this thread, but still interesting!

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4 hours ago, StephenFord said:

I've tested the Maypole voltage reading with my multimeter, and with me, they are entirely in sync.

I should clarify, I'm not suggesting the Maypole is necessarily wrong.  But because it only shows a charging voltage, and doesn't charge in a linear way, the voltage it displays is largely irrelevant until it's finished.  There's no way of knowing how 'full' the battery is while being charged, or how much longer it's likely to need to finish the charging cycle.

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Just now, TomsFocus said:

I should clarify, I'm not suggesting the Maypole is necessarily wrong.  But because it only shows a charging voltage, and doesn't charge in a linear way, the voltage it displays is largely irrelevant until it's finished.  There's no way of knowing how 'full' the battery is while being charged, or how much longer it's likely to need to finish the charging cycle.

Interesting comment. I must admit that I have taken a multimeter reading numerous times during a charging cycle, and it has exactly matched the Maypole reading at that instant. Maybe I'm not getting what you mean? (quite possible, brain isn't what it use to be, and it was never that sharp to begin with LOL)

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4 hours ago, Tizer said:

then I would say it would be at least 1/2 hour before the current draw settles down to its sleeping state whether it is locked or open and in that time frame it should not matter if the Ignition has been on or off before the time as long as nothing is opened or switched on during the wait.

Yes that would be right. The very quickest the car will go fully back to sleep is 20 minutes but it can take up to half an hour depending on what the car has just been doing.

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Just now, StephenFord said:

Interesting comment. I must admit that I have taken a multimeter reading numerous times during a charging cycle, and it has exactly matched the Maypole reading at that instant. Maybe I'm not getting what you mean? (quite possible, brain isn't what it use to be, and it was never that sharp to begin with LOL)

It shows the voltage that it's putting into the battery, so the readings will be the same at that instant.  But that's not the actual battery voltage which will remain after the charger is removed.  A 12v battery will never hold 14 volts for example...but may show that at one point while being charged with a 14.5v supply.

The only way to get a true reading is to stop the charging cycle and allow sone voltage drop before taking a reading.  

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1 hour ago, TomsFocus said:

But I am wondering if the variable charging doesn't work because of having the wrong battery..

That is interesting, maybe the charging system is a lot more clever than we think and it can sense if the wrong battery has been fitted, I don't know. I am surprised that the Charging light came on though. Other people have said that things like their Heated Windscreen does not work when their battery is low, but I don't think they had the Charging Light.

That has never happened to me but that might be because I'm a goody two shoes when it comes to my car. I always switch the HVAC off before parking and especially on a cold morning I start the engine right away, sort my stuff out then get my scraper from the back and only then, several seconds later, will I either switch the HVAC or Heated Screens on, rarely both, so maybe that is why I have not had problems.

That might seem like overkill but the only time I have had to change or charge a battery it was 15 years old and I had done over 250,000 miles in that car and it was during a severe winter although it did not have the same Electrics that a more modern one does.   

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Interesting topic this.

Many years ago when I did my apprenticeship we had a electrical lecture from a guy who worked at Exide.

He informed us the best thing for a battery is use! Leaver it to idle and it will sulphate (the cells go white).

We spoke about charging systems, as most cars then had dynamo's, and he told us that every time you start your car you have to drive for approximately 50 miles at 50 mph to put back into the battery what you have taken out to start the car. Modern charging systems are better as we have smart alternators so this figure may be lower.

A trickle charger will keep the battery topped up but it will still degrade and have a shorter life than one that's used. 

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My bike been stood all winter without me using it or starting it. Tried it this morning expecting to jump start it and it fired up first push of the starter button. None of this trickle charger nonsense. 🤣

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7 minutes ago, iantt said:

My bike been stood all winter without me using it or starting it.

I had a similar experience last week. My petrol lawn mower had sat since last September, still half full of nasty year old petrol, 1st pull of the cord, started right up! My previous mower was 28 years old before I passed it on to a friend. This one is now 5 years old, you see, servicing only ruins them 🤣

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On 4/24/2022 at 9:51 PM, Tizer said:

That is interesting, maybe the charging system is a lot more clever than we think and it can sense if the wrong Battery has been fitted, I don't know. I am surprised that the Charging light came on though. Other people have said that things like their Heated Windscreen does not work when their Battery is low, but I don't think they had the Charging Light.

That has never happened to me but that might be because I'm a goody two shoes when it comes to my car. I always switch the HVAC off before parking and especially on a cold morning I start the engine right away, sort my stuff out then get my scraper from the back and only then, several seconds later, will I either switch the HVAC or Heated Screens on, rarely both, so maybe that is why I have not had problems.

That might seem like overkill but the only time I have had to change or charge a Battery it was 15 years old and I had done over 250,000 miles in that car and it was during a severe winter although it did not have the same Electrics that a more modern one does.   

VAG batteries should be coded in when replaced, different system to Fords.  The Golf can definitely tell something's wrong as I've had a fault code for the BMS since getting the car.  (July 2018!)  Though I'm not sure quite how clever it is...if an identical battery had been fitted, I don't know how it would tell the difference.  

Like you, I've never had to replace a battery while in regular use so far, even despite the 3 winters of battery light on the Golf.  Have lost several after a few weeks of no use though, generally while up for sale.  Oddly, a few family members have lost batteries immediately after a 15+ mile drive.  They've all been on small petrols around 8 years old.  Suggested no warning but as 'non car people' they may not have noticed a slower crank or loss of heated screen.

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On 4/28/2022 at 12:42 PM, TomsFocus said:

Like you, I've never had to replace a battery while in regular use so far, even despite the 3 winters of battery light on the Golf.  Have lost several after a few weeks of no use though, generally while up for sale.

Thought I'd quote myself here...the Mk2 battery was flat today!

Jumped it with the GB40 and let it idle for 20 minutes.  Hopefully that's out some charge in.  Moral of the story...driving cars is the best thing for batteries!

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Always handy having a jump pack to hand

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