Battery drain/ fuel economy

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johnnevett

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Hi,
In the car last week and checked the battery level whilst waiting for someone and I was surprised it only had 2 bars showing. Car had been stood for about 5 days. I kept my eye on it over the next few days driving at it charged back to 100%
Car has been stood for 3 days now and the battery level has dropped again to 4 bars and is slowly charging back up with each drive I do.
I have also started to notice a massive drop in fuel economy. Just done a 32 mile round trip (motorway and 30mph roads) and it's used 1/8 of the tank. On these figure I would only get 256 miles to a full tank.
Is the battery drain normal for a car standing for 3 to 5 days?
Would the bad fuel economy be because it is constantly charging the battery on every trip?
Do I need a new battery?
Thanks
John
 
This time of year is battery killing season, that's why Halfords are advertising battery fitting on commercial radio.
My wife's car and son's bike have both needed batteries since the first frost.

But it may be worthwhile getting it checked over for current drain while stood and running, I have a clamp on current meter which is useful for testing charging and discharge current.
 
Zafi said:
This time of year is battery killing season, that's why Halfords are advertising battery fitting on commercial radio.
My wife's car and son's bike have both needed batteries since the first frost.

But it may be worthwhile getting it checked over for current drain while stood and running, I have a clamp on current meter which is useful for testing charging and discharge current.
Click to expand...
I don't have a clamp on meter.
Where could I get the battery tested? Do halfords/ kwik fit do it?
 
Halfords and Kwik Fit will both be able to test the battery and I wouldn't be suprised if they both told you that you needed a new one, they are in that game. If you ask them to look at the brakes they will probably condem them.
How old is the car ?, what size is the engine ?, when you do journeys how long are they ?.
It seems the alternator is charging OK but as you say there may be an issue with the car where it's causing a drain on the battery.
As said above cold weather is a battery killer, the slightly duff battery that has got you through the summer will fail because of the extra load from lights, heater, glow plugs, more current when starting and lower capacity due to being colder.
Where abouts are you in the country ? Maybe somebody could suggest a place local too you.
I have enabled the battery status indicator on my 2008 car which has the original battery. It's permanently on 100% , I have never seen it any lower than that.
Karl.
 
desertstorm said:
Halfords and Kwik Fit will both be able to test the battery and I wouldn't be suprised if they both told you that you needed a new one, they are in that game. If you ask them to look at the brakes they will probably condem them.
How old is the car ?, what size is the engine ?, when you do journeys how long are they ?.
It seems the alternator is charging OK but as you say there may be an issue with the car where it's causing a drain on the battery.
As said above cold weather is a battery killer, the slightly duff battery that has got you through the summer will fail because of the extra load from lights, heater, glow plugs, more current when starting and lower capacity due to being colder.
Where abouts are you in the country ? Maybe somebody could suggest a place local too you.
I have enabled the battery status indicator on my 2008 car which has the original battery. It's permanently on 100% , I have never seen it any lower than that.
Karl.
Click to expand...
Hi
Car is a 2008 2.0tdi 143 with 82,000 miles. I have owned the car for about 18 months. I have had a works van for the past 6 months so my brother has been using my car for work. (10mile round trip) but since I've had it back I do 60 mile round trip twice a weekend and a few small drives in the week.
Would a draining battery cause poor fuel economy with the alternator having to work hard constantly
I had facelift rear lights fitted about 6 weeks ago. Could these cause any issues?
 
My 2009 A4 needed a new battery this year. I would imagine yours if it's the original battery has come to the end of its life. Earlier in the year my car was stood Monday to Friday due to using a train for work when working away. This drained the battery. The car would then recharge and all would appear fine again. However one hard frost was too much for it and killed the battery. I was trying to hold out for its next service which at the time was two weeks away. Anyway my advice would be get it checked. If it's 6 years old id personally change it anyway. Trust me no jump leads trying to realease the electronic parking brake to bump the car is a real pain when I was 100 miles away from home. As for poor fuel economy it could be a a number of things, cold weather, trye pressures?, last service etc.. I can imagine using slightly more fuel to recharge your battery but alternator charge is relitive to engine speed. So unless at idle your car is reving considerably more I'd doubt it's down to low battery levels....
 
Just buy a new battery, not worth the hassle of it letting you down.
The jump lead point is just in front of the windscreen under a plastic cover if you need it, connect the +ve lead to that, then the -ve to a solid metal part of the engine.
 
With the battery being 6 years old and the intermittent nature of it's useage it's probably not the best for a battery however you would like to resolve the problem if there is one. Typically this time of the year fuel economy drops as the engine takes longer to warm up and the electrical load for lights, heater etc does load the engine and battery more.
I am not sure about the rear lights I wouldn't have thought there should be an issue but if the problems you are seeing are recent than you can't discount the fact that they may be linked. be interesting to see how much current is being drawn from the battery when the car is closed and locked.
 
You won't ever see me defending kwik fit, but on the weekend I got a quick check on my battery. They were frankly honest and supplied the attached print out. 6 year old 143 tdi s line.
9bd722fa2158aaf2881c3b6f3ec0d292.jpg


Reason I went cus a couple of weeks ago I left my lights on by mistake.

Also Carl, the battery meter on the dash is not factually correct. Must use vcds as there are multiple values to monitor.
 
Some concert and symphony systems, you'll need to vcds and code the battery meter.
 
Thanks for the replies guys.
Where is the best place to source a decent battery from at a good price?
Cheers
 
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Reactions: johnnevett and Kalashnikov
Them car battery meters are incorrect,dont bother,also when you fit a new battery it needs coding to the car or it will go dead again,if its faulty that is.
 
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