Good evening,
I fitted a new battery and alternator to my son's Land Rover 90 a couple of weeks ago. All seemed fine, 12.6v with no ignition on, 14.4v with the engine running. Fine since then until this morning when it wouldn't start due to a low battery. Once we jump started it I tested the voltage: Battery 12.3v with the engine running at tickover, and if the revs were increased then the battery voltage dropped to below 12v. There were no lights or any electrical equipment switched on (save presumably the fuel pump).
Any ideas on what I should be testing?
MTIA
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measure the voltage at the alternator?
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roverman
What year; what engine - and are there any significant modifications from the standard wiring.
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Ponder: why was alternator and battery changed??
General Assistance:
Does the battery light on the dash light up?
If NO then check bulb. If bulb OK then check the wiring from the bulb to the alt. as some current is required to make the alt. charge. If wire OK then it sounds like the regulator (usually inside the alt. but maybe a seperate box depending on model/age) if the regulator is internal then an alt. warrenty claim??
If YES but stays on when engine is running then unfortunately it sounds like the alternator/wiring is faulty.
Check the cable from the battery (or solenoid) to alt. is not broken, check that alt. is earthed properly, check all connections for tightness and clenliness.
If still not working:
Check drive belt.(Also check that the drive pulley is actually turning the shaft).
If all checks OK then alternator is suspect!
If you need help and are near Cardiff let me know and I'll see what I can do for you.
Brian (Ex autoelectrician)
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Thanks for the replies.
It's a 1989 2.5TD with the 19J engine.
No mods, basically standard.
We changed the battery & alternator as the battery was a duffer and I suspected that the alternator was iffy also.
The plug with the wires that fits into the back of the alternator is not entirely tight fitting so we'll use the nut connectors on the back instead and see how it goes.
The charge light goes out once the engine is started.
Cheers.
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The plug with the wires that fits into the back of the alternator is not entirely tight fitting so we'll use the nut connectors on the back instead and see how it goes.
I think you solved your own case.
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The plug with the wires that fits into the back of the alternator is not entirely tight fitting so we'll use the nut connectors on the back instead and see how it goes.
As long as the nut connectors are + and {sense/ignition fed positive} (- is usually the casing but sometimes supplied as a stud fitting)
>>The charge light goes out once the engine is started.
Hmmmmm this would denote that the alt is supplying power, maybe the + to battery is faulty (the loose fit?)
When all is correct the voltage should be between 13.2 and 13.8 volts at the battery when alt is charging
I remember a 'fault' with cavliers where the alt was on rubber bushes and had a seperate earth lead, the charge light would go out but not charge if the earth was left off (many a roadside callout after a 'home alt replacement')
Also worth noting if you have air con, the relay sometimes becomes 'stuck' (on Range Rovers anyway) in the on position energising the electromagnetic clutch that drives the compressor and will drain the battery.
Sorry not to be specific to your vehicle but I have not worked on many landys but the info may help.
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Hi, I'm having the same issue with my 1989 2.5td Land Rover 90..
Battery keeps draning and I've noticed the battery light doesnt come on with the key in ignition, oil does as normal. Ive changed the bulb and checked that im getting power up to the instrument display. 12v to brown/yellow and black/white when all connected up to dash and 12v at the other end of the brown/yellow at the alternator.Both of the other cables on the alternator also getting 12v. This I assume means no break in the cable? Alternator was changed a year ago and so was the battery. Should I be checking the other end of the black/white cable..if so any idea where that would go?
Now to confuse things this happened a few moths ago. All I did then was unravel the tape back to the bulk head, clean the connectors on the back of the instrumnet panel and remove the voltage regulator on the back of the alternator to check for lose connections. one of these seemed to work but unfortunately the same not working this time.
Any Ideas what to look at next?
Many thanks
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You need to disconnect one of the battery leads and connect an ammeter in series to measure the standby current when the ignition is switched off.
Anything significant (over 100mA?) needs to be investigated. Radio not switching off when ignition is turned off, perhaps?
I had a discharge problem like this on a car many years ago. After buying and fitting a new battery the fault was still there. Disconnected one of the battery leads (as I should have done in the first place!) and found a standby current of 3 amps! After a bit of electrical detective work I found the fault was due to a faulty horn, one side of which was permanently live and drawing this large current. The horn wasn't sounding, by the way, but it had some sort of internal short.
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Hi, many thanks and forgive my lack of knowledge.. the wiring im told is quite simple on this and the radio does come on if needed without the key in but always has done.
So am I right in thinking the small cable from alternator carries current to bulb, bulb goes out after car starts telling the battery to receive charge? If so and that cable has 12v what could be stopping the bulb turning on, an internal short?
cheers
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sorry, so when you say disconnect one of the battery leads do you mean the red positive straight from the battery? then hook my multimeter up to that red cable ant the batterys neg?
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With ignition on and engine not running, the charge warning light circuit makes an earth path through the alternator.Once the engine is started ,and the alternator charges,it puts a voltage to the earth path of the battery warning light bulb and as you now have 12 volts either side of the bulb,it should extinguish.If you disconnect the small w/light wire from alternator and earth the wire (ignition on) ,the charge light should come on.If it doesn't then you have a wiring fault back to the dash.hth
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With ignition on and engine not running, the charge warning light circuit makes an earth path through the alternator.Once the engine is started ,and the alternator charges,it puts a voltage to the earth path of the battery warning light bulb and as you now have 12 volts either side of the bulb,it should extinguish.If you disconnect the small w/light wire from alternator and earth the wire (ignition on) ,the charge light should come on.If it doesn't then you have a wiring fault back to the dash.hth
Many thanks, will have a go at first light.. can I just check when you say "If you disconnect the small w/light wire from alternator and earth the wire (ignition on) " am I disconnecting the small wire, leaving the 2 battery lives connected, turning the key whist holding the now disconnected end to an earth, i.e on the chasis etc and looking for the bulb to illuminate?
many thanks
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Yes,you can leave the large wires connected.Earth the small wire to the engine block or any metal part of the body or earth point,or the alternator body.
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Morning!
Ok could be getting somewhere, small cable disconnected from alternator and earthed to body and I get the battery light.. Where next?
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So to check, the alternator is self earthing?
Also if i want to rewire the connecting plug to the alternator any hints on how to get those pins out of the plastic plug/sleeves.
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The alternator earths through the mounting bracket (unless it is rubber mounted).Sounds like the unit is faulty.Have you checked the charge rate at battery?As for the connector plug,it may be easier to cut off the old one and re-new,like this
www.ebay.co.uk/itm/A127-ACR-ALTERNATOR-3-PIN-WIRIN...2
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Connector plug perfect, Good link cheers..
I connected it all back up, started her up and getting 12.5 at battery so no charge which i guess we knew as no bulb.. Was that what you meant?
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Replaced alternator under warranty, all fine now....many thanks!!
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