Battery/starting problems

[dean36014]

Ok, I'm not the best on car electrics, so a little advise please. The daily modern, grande punto, has failed to start again due to flat battery. Battery was replaced earlier in the year with a new bosch from ECP. I work nights so at this time of year its headlights on and heater on max all the way to work and on way home. Funnily enough I only get problems if the car isn't used every day. So my question is, how do I check the voltage drain using a multi meter I possess? Is it worth replacing the battery again?, the bosch has died a few times now. I can get a brand new Yuasa silver top for £48 locally and keep the bosch as a spare to jump start if needed. Are Bosch batteries crap these days? Are Yuasa any good? 

[mrbenn]

Just a thought, how far do you drive to work and back? Battery shouldn't go flat, even in winter, unless you're only doing short trips, the car isn't charging it properly or something is draining it when switched off.

 

Guide for checking for battery drain here:

 

http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

 

I guess you've checked battery voltage at rest and alternator output when running?

 

I thought Yuasa were ok but others may have different experiences. I replaced both the batteries in the moderns with Bosch 3-4 years ago. Never had a refusal to start (even though one only does ~4k per year), one of them even got me home when the alternator died and still works fine so Bosch get a thumbs up from me.

[tommotech]

I'd be checking the alternator is up to the task, how many amps are being delivered with all electrical loads on at idle speed. Don't blame the battery first off.

 

Also worth checking earth cable too.

[steve_earwig]

Yuasa always used to be very good, but then so did Bosch and my recent experience of them is they are indeed short-lived crap. Although I wouldn't bother replacing the battery until I knew it was the problem.

 

Suspect car may have one of these smart* charge systems. God help us all.

 

As above, although you can't really measure the current with a basic meter so you'll have to measure the battery voltage with it off, at idle and at idle with everything (heater, lights) turned on.

 

Current drain? There's probably an easier way (involving a clamp meter) but you could connect your meter on the 10 amp range to both sides of the battery negative terminal and measure it once the clamp is disconnected (so that there is still continuity through the meter). What could happen is whatever's causing the drain may release once the battery is disconnected (if it's a relay or similar) so I reckon it's better to do it in a way that keeps the voltage there, you just have to divert the current through the meter in order to measure anything.

[dean36014]

ok, thanks for the info. Just discovered my old gunson meter which has an alternator checking thing so will use that when battery is charged. Just need to see if I can find instructions on the net somewhere.  Travel time is around 25 minutes to get to work, stuck in traffic all the way, 8 minutes to get home in the early hours. Not the best journey for it as its dark and damp both ways at this time of year.  Car was fine when i left it on xmas eve now flat so hence me thinking battery drain or crap battery. 

[fordperv]

I had similar problems with my saph, the alternator was faulty not charging properly so when lights, blowers, stereo and heated window were on the battery was on the verge of being dead, one snowy morning it was

[Rocket88]

You should get [with the car running] approx 14.2v measured across the terminals for a healthy alternator

[dean36014]

ok, battery been on fast charge for 5 hours @6 amps. The amp guage on the battery charger has dropped down to nearly zero, and voltage is reading 10.5volts  on the digital multimeter and the reading drops  while connected? Battery wasn't totally flat to start with but wouldn't turn engine over fast enough for it to catch. Beginning to thing its a knackered 8 month old bosch battery. Will check alternator tomorrow when I hook battery back on, got a alternator check and voltage drop thing on the gunson meter.

[dean36014]

IIRC correctly you should check alternator with and without lights etc on to make sure it works under load?

[steve_earwig]

Do you mean 10.5 volts? If so I think the battery's dropped a cell.

[dean36014]

yes disconnect charger, hook up digimeter and it reads 10.5 volts.

Will leave it on charge till tonight and check again.

[djimbob]

yes disconnect charger, hook up digimeter and it reads 10.5 volts.

Will leave it on charge till tonight and check again.

 

 

It's goosed to use a festive term, but on the positive side (I'm here all week) is it not still in warranty?

[dean36014]

Ok, ignore the readings above, for some reason I decided to double check the voltage reading using another meter, 12.8 volts. This is confirmed using the analogue, needle reading on the gunson testune meter. Battery fitted to car and it fired straight up. Alternator check done, 14.2 volts with no load, 14.1 volts with everything switched on, so I'm assuming alternator is a good 'un.

Disconnected a lead and did a leakage check as per the the wiki link above. Drain is 0.5 amps. Is this excessive? Thinking my problem is 0.5 amp leakage, so thats 12 amps a day? 40 amp battery, so battery under half charged in two days. Is my reasoning correct?

[NorthernMonkey]

That's definitely excessive....try pulling fuses one by one and watching the meter. When the current drops significantly from 0.5 amps, then it's something on the circuit protected by the last fuse you pulled that's the issue. Normal culprits tend to be a boot or glovebox light staying on all the time.

[spike60]

Don't be fooled by the interior lights having a drain because you worked on the car with the drivers door open. Dunno about Fiats but E39 BMWs take 16 mins to go to sleep when locked with the zapper IIRC, it make getting a drain reading difficult. W215 Mercs take 45mins so I'm telt.

[steve_earwig]

45 minutes makes PSA's 2 minutes look positively speedy.
 

did a leakage check as per the the wiki link above.

Eh? Oops, sorry I missed that. I disagree with it anyway, you should do step 3 before disconnecting the battery, you wouldn't have to worry about frying body control ecu's either. Even if it means wrapping a bare wire around the terminal.

 

Anyway, it looks like it's pulling fuses time for you.

 

Btw anything aftermarket (stereo, alarm etc.) would be prime suspect.

[Pillock]

A modern will sleep in stages, but yeah half an amp sounds high. If you can, rig up something so you can leave the multimeter in place outside the closed bonnet, lock the car up and check it after an hour. Fords for example shut off the fag lighter and instrument binnacle after 20 minutes, Vauxhall doesn't shut off the aux stuff until you've opened a door.

[oldford]

0.5 amps will be roughly 6 Watts, it may be a light left on somewhere.

[dean36014]

I checked all the lights and they are definitely out when doors and boot closed, dropped back seat to check boot light. So did the fusebox check, thanks fiat for putting it behind the glovebox where you can only access it with long nose pliers and non shaky hands. Found pulling fuse 3 dropped it to 0.35 amps, according to manual this covers instrument panel only. Pulling fuse 5 dropped it to 0.3 amps as well. Fuse 5 covers obd2 port, radio, and alarm. Then realised I have a bluetooth obd reader permanently in. Unplugged reader, bunged fuses back in and reading was 0.4 amps so a 20% drop. I would guess its going to be the stereo draining the system so thats first on the list tomorrow. Will also disconnect battery first thing and leave it for a few hours first and see what the drain drops to. 

Will check my daughters Grande punto next time she comes over and see what that draws as that can stand for weeks and still start.

[Felly Magic]

You did say 8 mins to get home? That isn't long enough really to top the battery back up from cranking, especially if you have lights on, heater, stereo etc

[dean36014]

I know, that was my first thought that the battery is gradually running down due to all the short journeys at night with everything on. Its the battery drain thats got me puzzled now, but I might be barking up the wrong tree as I might not be leaving it long enough for all the systems to shut down. Might get the bigger Yuasa battery as this would give me more capacity in reserve over winter.

[twosmoke300]

On a grande punto check tailgate wiring . The wires break and so does the washer tube and cause strange leccy issues

[hauserplenty]

Buying a larger battery will only make the symptoms worse I believe. I would recommend a 6/10amp or trickle charger left plugged in overnight, since modern cars don't have enough current to charge batteries even from a 10-15% discharge. Using a battery from a different group is not advisable. A larger alternator would help more than a larger battery, but FWIW, try the current test, as above, with the keys removed. I blew the 100A main fuse on a 2015 Focus because I connected a battery box with the key inserted. The computers power down 20 seconds after the door is shut-- but only if the key is removed.

Failing that:

.4 is still too much, but I would suspect the alarm first, as they often cause problems like this. If the alarm CPU has an inline fuse, you could try removing it...

Edited to add: you're on the right track, as the airbag circuits could account for most of that .4A. 30 minutes after disconnect would likely suffice.

[steve_earwig]

I've been stuffing bigger batteries in my cars here because I don't have many people to call on in an emergency. The alternator is kind of matched to the battery, so without fitting a more powerful alternator you have to accept the fact that, although it'll start out with more, it will eventually loose charge and you'll have to give it a boost now and again when you're using the most electrics.

[djimbob]

Simple solution at no cost is to whip the battery out every week or two at the weekend and charge it overnight, then at least you are keeping the battery in tip top charge over the cold spell, might be all that is required? Even once or twice a year is better than never.

[dean36014]

will do the checks tomorrow and an occasional battery top up is looking the way to go.

[beko1987]

The meriva had this issue a while ago. I gambled on battery over starting to look at other shit and won

 

For now...

[PhillipM]

0.5a is high, I'd expect around 0.1 worst case, 0.05 more usual on modern stuff.

10 minutes should be more than enough to recharge the battery from a start unless the car is shagged and takes a lot of cranking - my workshop is 10 minutes away and I never have an issue.

[PiperCub]

^^Agreed, 500mA is an awful lot to be flowing when parked, it should be well under 100mA as PhillipM says. (As 500mA at 12V is 6Watts).

 

The only things that should draw any current with the ignition off and the car in a rest/inert/parked up state should be the radio and any immobiliser/alarm will probably draw a few mA too. 

6 Watts sounds like an interior lamp left on, usual suspects are glovebox & boot (or if you're posh, under-bonnet if it has one).

[dean36014]

right to draw a conclusion to this. Been out and done some more readings. Initial current draw for about 30 seconds is now 0.4 amps. After 30 seconds that drops to 0.2 amps, then a further minute later it drops to 0.01 amps. So I'm concluding that certain electric systems are closing down normally and a battery drain isn't my problem. Looks like the combination of driving to work in the dark in traffic with all electrical systems going, then a quick dash home in the wee small hours isn't enough to keep the charge topped up. Will either have to boost battery every weekend till the lighter nights arrive or go on a good run. Might get the larger capacity battery then keep the old one charged up for quick changes if needed.