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Battery Drain - Advice Please

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I own a 2005 (55) Focus 1.6 diesel (89500mls) which has been rock solid (apart from the usual wear and tear bits) since I got it.

Due to work arrangements I spend one week driving long distance (1hr drive start to stop morning and evening) then the next 2 weeks short (10 minute drive from start to stop morning and evening). This has been routine since I owned the car and has never caused a problem before. About 3 months ago I noticed that during my 2 weeks of short trips the battery started to struggle in starting the car to the point where one morning all it gave was enough juice to light up the dash and no more. I thought it was the battery and replaced it, I was then back onto my long week driving and all was well.

Due to holidays, trips etc it's been fine with long journeys quite often.

However, it started to get sluggish again over the past 2 weeks to the point on Saturday where it was completly dead and I was convinced it was the battery so had it swapped for a new one (put it in yesterday) but I decided after fitting the battery to test the current draw and alternator.

Below is what I found. I'm not sure if this amount of idle current draw is too high or normal or what to do next.

Battery idle - 12.49v

Alternator running - 13.89v

All lights, heaters, fans etc on - 13.86v

Above results seem OK to me with regards to the alternator doing what it should.

engine off, everything off and doors closed - 0.37amps

Unfortunatly I do not have a clamp meter but have a multimeter inline on the positive terminal - This therefore reset the system when i put it in place 'waking' up the car.

I hooked up the multimeter and left it an hour - These are my results:


Pulling - No 46 - Central Fuse Box - drops from 0.18amps to 0.13amps

I can not get it to drop any lower than 0.13amps and with what i've read this is exceptionally high for an idle parked up car.

I only removed the mini fuses, I did not touch the big bolted in fuses in the aux box as it was getting dark.

Any advice would be greatly appreciated.


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Youre alternator has s fault idle is fine but otherwise it should be 14.4v so i would book it into a ford garage to have the smart charge looked at also what battery have you hsd fitted if its not a silver calcium battery and you have a lead acid one thats youre problem

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hi there,

I fitted a Bosch S5 100 battery (74ah, 750CCA) - This is Silver Calcium

Your another person that's mentioned 14v off the alternator! - Yet my local garage has said 14v or above is an overcharge

Should it be 14.4v running idle or does that kick in when on a higher rpm?

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Youre garage knows nothing to be honest ford uses a smart charge system which when on a dead battery can put 18v through 14.4v is what it should be at idle from cold 13.8 on a fully charged battery with a warm engine .

silver calcium is needed as 14.4v would fry a lead acid battery the voltage you have means it may have reverted to a standard alternator so wont charge the battery properly it should be 14.4v from idle on a cold engine it can go down as the battery electrolyte temperature increases the fault is either the alternator bearing or the 3 wire plug that goes into the alternator for these issues take it to a ford dealer as they understand the system


check peter cooper car repairs ford smart charge

I hate mechanics who dont have a !Removed! clue check the voltage via the dash test on a stone cold engine

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