DorsetStrider
|
| posted on 29/11/05 at 03:16 PM |
|
|
HELPPPP!!!!!!!!!!!!!!!
Hiya all.
I'm having a few problems and was hoping someone can steer me in the right direction, or at least confirm my suspicions.
My everyday car is having a problem starting in the cold, in the wet it's fine but the colder it is the less it want's to start. When I
turn the key it turns over but seems to be struggling like there's not enough power coming from the battery. I've had to get a friend to
give me a jump twice now. Both times it's worked for about a week then the problem resurfaces. Would you say that this is a problem with the
alternator not charging the battery? Or just a duff battery?
I'm thinking it's the alternator because this has happened with 2 different batterys (ok one of them was out of a donor car but appeared
to be almost new) the other was about 9 months old.
Who the f**K tightened this up!
|
|
|
|
|
flak monkey
|
| posted on 29/11/05 at 03:20 PM |
|
|
Duff battery....
Stick a meter across the battery terminals, then put a load on the batt. (Something like full beam headlights or heated screen or something). The
voltage shouldnt drop below 12V. If it does the battery is knackered.
To check the alternator is charging ok, start the car up and check the battery voltage, it should be about 14volts (give or take 0.5volt).
New batteries are crap. Just put a new one on my sisters car, was only dated 2003, and that was a proper Ford one.
David
Sera
http://www.motosera.com
|
|
|
David Jenkins
|
| posted on 29/11/05 at 04:00 PM |
|
|
Find a friendly local motor factors - the sort of place where you'd buy a new battery - and ask if they are able to test your battery.
They'll probably have one of those probe thingies that you poke onto the terminals to check the voltage under load. Charge it before you go, to
give it a fair chance.
One of the cheapest places I found to get a new battery for my previous Toyota was the local Toyota garage! It's well worth shopping around,
and worth paying a bit extra if you're going to keep the car for a while. Even Halfrauds keep a range of batteries from cheap to expensive
(sorry - expensive to even more expensive) and they give a decent warranty, if you keep the receipt.
Dj
|
|
|
dave-69isit
|
| posted on 29/11/05 at 04:27 PM |
|
|
starting problem
what is your car petrol or diesel
|
|
|
britishtrident
|
| posted on 29/11/05 at 05:42 PM |
|
|
You need to do some basic checks then test the battery alternator underload
(1) Check the battery connections are clean and tight.
(2) Check the connections at the back of the alternator are making good firm contact --- espcially important if you have the 3 Lucar spade block
connector.
(3) Check the aternator drive belt is tight enough and not worn.
(4) Check the main earth connection between engine, body and chassis.
For the next test you need a 0-20 voltmeter or cheap digital multimeter DMM.
(1) Check the battery voltage if less than 12.5 volts before going to test (2) charge it untill it reaches 12.8 volts off charge.
(2) Connect voltmeter acrosss battery, with all loads off run engine to 2500 to 3000 rpm and check out put voltage.
13.3 volts or under --- fail not charging at all.
15 volts or over --- fail over charging.
13.4 to 14.8 volts OK to proceed to test #(3)
(3) Switch on heated rear window and headlight dip beam repeat test #(2)
13.4 to 14.8 volts OK to proceed to test #(4)
(4) With engine still at 2,500 to 3,500 rpm switch off head lights, heated rear window and other loads if voltage climbs above 15 volts Fail
overcharging
Pass on Alternator tests (1) to (4) alternator is usually good but won't always indicates alternator is OK
The following tests are needed when the engine is cold best done in the moring following following tests 1 to 4.
(5) Battery voltage test ----
Put voltmeter accross battery if reads below 12.5 either the battery or the alternator diodes are gubbed or there is curent drain.
(6) Battery load test -- cranking voltage test.
Connect voltmeter across battery and try to start car.
Drops to 10 volts --- pass battery is OK
Drops to 6 volts then rises slowly to 9 volts -- dead (gassing) cell in battery
Drops to 9 volts --- suspect dead cell.
(7) If battery drain through alternator diodes is suspected disconect alternator overnight and reconnect in the morning before starting -- if battery
hasn't drained with the alternator disconnected suspect battery or drain through something switched on in car such as a boot light.
[
[Edited on 29/11/05 by britishtrident]
|
|
|
zzrpowerd-locost
|
| posted on 29/11/05 at 06:24 PM |
|
|
quote:
Originally posted by flak monkey
Duff battery....
Stick a meter across the battery terminals, then put a load on the batt. (Something like full beam headlights or heated screen or something). The
voltage shouldnt drop below 12V. If it does the battery is knackered.
To check the alternator is charging ok, start the car up and check the battery voltage, it should be about 14volts (give or take 0.5volt).
New batteries are crap. Just put a new one on my sisters car, was only dated 2003, and that was a proper Ford one.
David
hmmm.....every 12v battery i have ever tested gives out around 11.5volts without engine running, 13.6volts engine running!
|
|
|
flak monkey
|
| posted on 29/11/05 at 06:33 PM |
|
|
BT's way the the proper way to do it. 
If you look at the figures he posted (13.4-14.8V) it ties in with my 14V give or take 0.5V.
With a relatively small load such as headlights or a heated screen the batt shouldnt drop much below 12V. When I last changed a batt it was so dead
that it dropped to 4V with just the headlights on.
Cranking is a different matter and really pulls the voltage down!
Sera
http://www.motosera.com
|
|
|
JamieG
|
| posted on 29/11/05 at 06:44 PM |
|
|
I had the same problem last winter, battery turned out to be falling below that 0.5v tollerance i changed the starter motor and alternator (started
making weird noises) as well as the battery and all was fine after that.
Hope you get it sorted before it gets any colder  
|
|
|
britishtrident
|
| posted on 30/11/05 at 01:39 PM |
|
|
quote:
Originally posted by zzrpowerd-locost
snip
hmmm.....every 12v battery i have ever tested gives out around 11.5volts without engine running, 13.6volts engine running!
Older styles of batteries 11.8v off charge was regarded as at least 3/4 charge, these days batteries types have changed and 12.5v off charge with
no load is the norm but becuase modern everyday cars are so electronic laden there is always a load so 12.4 is more representative.
The actual charging voltage depends on the the car bigger electronic laden cars with high amp alternators and bigger batteries charge near 15 volts
-- for example these numbers are fairly typical
Rover 214 -- 13.4 volts
Rover 75 1.8 -- 14.4 volts.
Rover 820 -- 14.8 volts
|
|
|
David Jenkins
|
| posted on 30/11/05 at 03:23 PM |
|
|
This is all getting too complicated!
Start with the most likely and simplest task - get the battery tested under load. they only have a finite life. Then go on to harder stuff if
that's OK.
As an aside, also check all major power connections - battery live, battery to chassis, engine to chassis, live to starter. Strip them down, then
brush/scrape them bright and shiny before replacing them.
rgds,
David
|
|
|
