Battery/starting problems

[tommotech]

Although you've confirmed that the alternator is regulating voltage ok at 14.2V you don't know yet how many amps are being produced by it. This could be the crux of the problem.

[twosmoke300]

That stepping down is normal its the Can Bus closing down . 

On a grande punto the eps takes loads of current when you are steering too - try and drive home in a straight line 

[billyboy406v6]

8 mins home journey = buy a bicycle ??

[steveo3002]

while driving about in the dark with all the lights n heater full on wont help , i think it should still cope if its all in good order

 

after all why does it start after work but not after a couple of days , i think i would maybe try another battery or get it tested

 

if im making lots of short trips , i try to do the last couple of miles with the main beams off and heaters etc off or on low

[Andrew353w]

May I also suggest a battery cranking test? The charging voltage of 14.2-14.4 volts is about right but what you need to also check is what the battery can deliver under load, not just the voltage it shows at rest. Most decent garages will do this for you & it takes 5 minutes. I have a cranking tester & it's useful for spotting a battery on the way out, as it simulates the cranking load (i.e.; the load needed to power the starter motor) & shows how much oomph (in layman's terms) the battery can deliver. Anything much under 9.5 volts under load means the battery's not in the best of health. If this is higher than this the battery's probably good.

[mrbenn]

I once read (can't remember where) it takes 4 miles of driving without lights etc just to replace the charge taken out of the battery to start the car up.

[dean36014]

its 7 miles to work, 5 miles home! The joys of working at an industrial estate only accessible from one side of a dual carriageway meaning I have to go 1 mile passed the place, turn round and come back! Might get a battery cranking test done, the problem doesn't happen all the time, about once a month. The trouble is all my driving is with headlights on, wipers when its raining, which has been nearly every day for the last month !And its cold so heater blowers on too. Can't cycle there everyday as I have arthritis in my feet and spine, so enjoy a leisure ride but everyday is out the question. Thanks for all the help and advice, been very helpful.

[cobblers]

4 miles to recharge is a fairly "worst case" scenario but it's not a million miles off correct I reckon, I did the maths.  A 300A starter motor, cranking for about 5 seconds works out at about 0.5AH.

The alternator will generally (ignoring any other load especially EPAS which takes shitloads at peak) be able to chuck 40A into the battery fairly comfortably, theoretically charging the battery back up in about 45 seconds. That's an ideal scenario ignoring losses both for the discharge and the recharge, so let's double it and call it 90 seconds to recharge.

 

On something older with a weak alternator, spindly wiring etc then 4 miles driving probably about right.

 

However, the electric power steering pump on my Ibiza can draw up to 100 amps - I regularly see the battery voltage drop to 12.2v when parking. I would say on average it's about 15-20A in general driving. Assuming you have a 90A alternator, subtract a steady 20A for the PAS, 12A for your lights, 12A for the blowers, 12A for the rear demister there's only 34A left to charge the battery.

However, that 90A output is a bit of an optimistic figure in my experience, and ends up being more like 70A once you account for voltage drop etc etc.

The 90A alternator on my van will only muster 58A max, into a bank of dead flat leisure batteries.

 

 

I reckon your short run to work and back in the dark is not properly putting a good charge back into the battery. Running a battery in a fairly discharged state most of the time does it no good at all, so it'll begin to lose what capacity it does have meaning it'll struggle to take a good charge even when you do take the car for a longer run or put it on a charger. Every time you fully discharge a lead acid battery it will lose a decent chunk of it's total capacity due to sulfating on the plates - 5% each time is a rough rule of thumb, more so if it's dead dead flat and left that way for any appreciable amount of time.

 

 

I'd personally want to be taking a good hard look at all the "high current" wiring on the car. It only takes a slight amount of corrosion on a connection to cause enough resistance to limit your peak charge current quite considerably. Technically your alternator should be able to keep the battery topped up properly with your usage, but it doesn't take much to prevent that happening

 

One good way to check the wiring is to turn some loads on with the engine cold and off - Maybe put the headlights on for 15 minutes or something to knock a bit of charge out of the battery, so that the alternator will be charging as hard as possible when you do start the car. Now start the car and let it run for a few minutes leaving all the lights and blowers on, then have a feel at all the main chunky connections - engine earth strap, battery earth to body, battery positive and the wiring from the alternator to the battery (sometimes this goes via the starter motor)

If any connection is significantly warmer than another then that's likely to be causing an issue. It's also worth having a feel at the wire as it goes into the connectors - they can often wick water up inside and get the "black death" while looking absolutely perfect on the surface.

 

If you can borrow a clamp meter (£20 on ebay if you fancy buying one) you'll be able to clip it round the main battery earth and see what it's actually getting.

 

[steveo3002]

my work is 3-4 miles , no bother with charging issues

 

for the good of the car though , you might want to take it for a run to get it up to full temps and clear its pipes once a week  

[alf892]

Although you've confirmed that the alternator is regulating voltage ok at 14.2V you don't know yet how many amps are being produced by it. This could be the crux of the problem.

This!!!!!.......checking voltage is not a reliable way to check charging

[hauserplenty]

Check the battery cables for corrosion. Load test. I forgot to mention that, as no proper diagnosis is possible without it.

[dean36014]

so if i buy a clamp meter can i find out how many amps the alternator is producing? seen them on ebay for a tenner upwards and might be useful for other purposes.

[cobblers]

Yup, Make sure you get one that can do DC amps too.

 

It'll only show what the alternator is "currently" producing, and it'll only produce what is being drawn from it by the battery and all the loads.

 

A dead flat, full or knackered battery won't draw much current at all, whereas a good but "fairly flat" battery will draw as much as you can throw at it, up to the limit of the alternator.

[dean36014]

so if i chuck a knackered old battery on it I should get the alternator producing near maximum amps? Looks like an interesting bit of kit to add to the tool collection.

[hauserplenty]

Yes, but it will be misleading without knowing how much current the battery can deliver when starting the car. A load test is essential. Knowing this first, then measuring the current will tell you what to expect from a battery in good condition. A current test now won't tell you the condition of the battery, as it will only draw more current as its condition deteriorates. The alternator current draw is an effect; the battery condition is a cause.

A shop will be able to do a battery load test and a charging system test with the same machine, saving lots of time. If you are relying on the alternator to charge the battery, most cannot--they can only maintain a full charge or a certain state of charge above 80%, +/- 10%. Clean the inside of the terminals with a round file until you can see your reflection too--it won't hurt. Also make sure you tighten them well--loose connections corrode, then cause OMGBATERYFAYLUR in a vicious circle. If you can turn them on the posts, they're loose.

How tight?

Tighten 'em 'till they break

and back 'em off half a turn!

[dean36014]

already checked the battery leads and cleaned the earth points up. ordered a clamp meter to collect tomorrow from tool station so will have a whirl tomorrow.

[hauserplenty]

You need a load test to know the condition of any battery. Without knowing the battery's state of charge, then its voltage under load, you will end up with faulty results and risk causing a problem where none existed previously.

Carbon pile load testers are $100-$200 now and they used to cost thousands. If you want to buy a bit of test equipment to learn your basics with, I suggest one of those or a digital battery/charging system tester for around the same spendage.

OMGNOMORGUESSWORK.

[dean36014]

personally i think its just to short a journey in a car with two many accessories on. i've noticed that when the battery gets low the electric power steering is heavy for a few seconds.  If I have to charge the battery every month in winter then thats the easy option. Not going to throw mega bucks at sorting it when theres an easy solution/bodge. Obviously if it gets worse then that will change. When I worked further away it never gave me any problems. 

[DSdriver]

Or... buy a solar panel type charger that plugs into cigar lighter socket and leave it on the dashboard during daylight hours. They even work on the perpetually gloomy days we seem to have this winter.

[dean36014]

Thats a good idea, but this puzzles me, they plug into your cigarette lighter socket. but if the socket only switches on with ignition will it still charge the battery?

[cobblers]

Depends on the car, some will be live all the time, some only with the ignition on, but yes - if the socket only works with the ignition on, the charger won't do owt. A "normal" size one, about a4 paper ish will give about 2AH per day, which is enough to put back in one or two starts.

 

But, like I say above the car should be able to keep the battery topped up with these journeys, my commute is 4 miles each way and I blast the heaters, demister, lights, PAS pump and a whacking great stereo both ways and never have any problems in this car, my old golf or my 106 - all of which had absolutely shit batteries.

[hauserplenty]

Let us know how you get on...

[SiC]

I'm surprised no-one has mentioned this. Why not on once or twice a week just take a big longer route home or run it around the block a bit on the journey home,etc? Then see if the problem goes away.

 

Couple of pence extra in fuel, much cheaper than new batteries, alternators or test kit

[dean36014]

hey i don't mind buying tools lol. 

[PhillipM]

4 miles to recharge is a fairly "worst case" scenario but it's not a million miles off correct I reckon, I did the maths.  A 300A starter motor, cranking for about 5 seconds works out at about 0.5AH.

The alternator will generally (ignoring any other load especially EPAS which takes shitloads at peak) be able to chuck 40A into the battery fairly comfortably, theoretically charging the battery back up in about 45 seconds. That's an ideal scenario ignoring losses both for the discharge and the recharge, so let's double it and call it 90 seconds to recharge.

 

On something older with a weak alternator, spindly wiring etc then 4 miles driving probably about right.

It's not even that bad, as although the starter may draw 300peak for a split second to start from stalled, most will only want 100-150amps after that for turning the engine over.

 As you say, healthy battery and alternator should give no problems. Could be the battery capacity has dropped as it's aged - you'd soon find out with how many amps+how long it takes to bring it up to full when you charge it if it's not starting the car.

 

 

The buggy does ~8-12 minute stages for 2 days over an event with a startup before each and that has EPAS, twin 16" cooling fans, a big 044 fuel pump to power and a high power starter - and never has an issue keeping the battery topped up.

[cros]

No-one has come up with the correct solution which is to replace the car with an Uno.

[dean36014]

Ok update time. Rear silencer was blowing so at garage having a new one fitted. Seeing they advertised a free battery and alternator check I've availed myself of there services. Battery failed the load test,but,as they've stated it's clearly the original battery on the car do I trust them lol. Battery is six months old and has the paperwork in the bag still attached to the side of it! Think I might take it back to ecp and say rac have condemned it and see what they say. Bosch batteries clearly aren't what they were!

[dean36014]

returned battery to ECP who tested it and declared it perfect! Reading was 82% on their meter, surprised seeing as the battery has been well charged up and done a few miles it wasn't higher.

[Jimmycrackcorn]

No idea if any use or not but I bought one of these a few years ago when having issues with my van and it's proved quite useful at times.

http://www.ebay.co.uk/itm/New-LCD-Cigarette-Lighter-Voltage-Digital-Panel-Meter-Volt-Voltmeter-Monitor-W6-/201248306672?hash=item2edb5575f0:g:NgUAAOSwmrlU1CnR

[hauserplenty]

82%=perfect??

Autoshite math?

Fail.

Charge battery with 10A charger, repeat test. File inside of terminals.

Drive on...