Defender not Charging

Hope this is in the right place for some help

I have bought myself a Defender 110 TD5 to get away from the electronic pain the first and the second P38's have caused me, guess what flat battery, no problem throw in a new one 80 euros [I live in Ireland]a week later flat again, 100 miles from home, fcuk, must be the alternater so I took that off [not a ten minute job] and down to local repair shop, 100 euros please Sir. Back on with the big lump, still no joy. Did the fcucker do anything to the alternater beside's a rub with a wire brush and a coat of wheel silver, off again back to repair shop, I said things still not working did you do anything to it, I did he said its working fine you tosser,[after him showing me it working on bench test] bollocks back home tail between my legs put it back on.
Still no electrickery. Now I now how its all suppose to work and it looks like a wiring fault, the battery warning light on dash does not come on when the ignition is switched on . Has anyone had a similar experience please.
If anyone has any problems with P38's I might be able to help I have one of the Rovercom diagnostic thingy's and had all the usual problems with my 2 P38's

where u based chef (alter ya USERCP)?

[I live in Ireland]

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Think this is a clue Floppy.

Have you had a Multimeter on it? Is there 13V with the engine running? Is there a draw on the battery with the ignition off and if there is whats causing it cos I reckon thats where the problem is. Can you disconnect the alarm

oops

Heh heh heh.

Its only showing 11.5 at the battery when running. it actually went flat when I was on a trip at night useing lights and wipers ,I drove it allday to day after an overnight charge, there is no draw on battery.
Its Thechef to you

How do I get a daft picture on my profile

yu dont, souxiesue

If the dash board warning bulb has blown you wont get any charge from the alternator!!!

Cheers Steve

Really? If the bulb on the dash blows the charge from the alternator doesn't get through. Thats a bit rubbish. Are you saying that the whole output from the alternator goes through the bulb in the dash, that over 60 amps isnt it? It would have to be a 'special' bulb to handle that kind of power.

I'm not doubting you, I just don't understand how this can be?

Its Thechef to you

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Ey up Cheffy.

it actually went flat when I was on a trip at night useing lights and wipers

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Dunno if you've checked the obvious alternator belt tension bit have you.

Really? If the bulb on the dash blows the charge from the alternator doesn't get through. Thats a bit rubbish.

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Charlsey did a post about how the alternator needs a small current to excite it into producing a charge would this be owt to do with that?

Steve thanks for your reply,I have taken out the light panel as you proberbly know they are not conventional bulbs but lcd's on a printed circuit, there are two per lamp I have a feed to one side of the lcd and if I earth the other side one of the lights works.do you think there is anyway to bypass the lamp. reading the Rave manual the system works when the voltage going out of the alternator is the same as the voltage coming in it then puts out the charge light, thus allowing charge to battery I did wonder if there is another component controlling this ??.

Thanks Malcolm

Grnut, the belt tension is automatic.I have had the alternator off twice.

Thechef

the only component controlling the voltage output is the diode pack located within the alternator itself, one way of proving weather it is charging when running is to run a live direct from your battery to the smallest dia wire coming out of the alternator (the one that goes to the warning light) and start the engine and then take a voltage reading across the battery terminals, if that is showing above 13 volts you know then that the alternator is not the problem but the live "excitable" feed is at fault via your dash warning lights.

the light i beleive is connected via the diode pack, turn ignition on power goes to bulb and this earths in the alternator ..... ie light is on, as soon as engine fires and alternator produces power and the wire that earthed the bulb becomes positive and the light goes out, ie shows you are charging, if the bulb fails this does not happen and alternator gives no output, the full charge does not go via the bulb its just 'gated' by it, certainly the case on all the classic cars ive owned but a much newer electronic td5 i cant guarantee

cheers steve

also if there is no live to "excite" the diode pack it will blow the alternator as soon as it rotates

also some alternators are ' self exciting' ( bit like grunt on that score) and don't need that extra battery fed to get them started. dunno if yours is , but going by the responses from thoses in teh know i'd say not.



Self-Exciting Alternator:
Is an alternator that uses a special voltage regulator that doesn't need an ignition wire to activate it.
This type alternator only requires a battery wire hooked to it. The voltage regulator contains
circuitry that uses the residual magnetism in the alternators fields to determine when
to turn the alternator on. The regulator does this by sensing the RPM the alternator is turning,
when it gets to a certain rpm the voltage regulator "turns on". Typically you start
the vehicle, rev the motor slightly then alternator starts charging. This type alternator is
commonly used on custom cars & trucks, tractors and other non standard applications when
wiring is a factor. In choosing this type alternator you must consider, do you want
to rev your motor slightly to get the alternator to turn on. Also when using the self-exciting
alternator on tractors or other slow turning motors does the engine
have enough RPM's to start the alternator charging. This can be overcome by using a smaller
pulley or by adding an ignition wire.


One-wire Alternator:

Hi Just sorted similar problem on my series 3 16ACR alternator, charge light not on, removed diode pack from alternator and checked diodes by passing voltage through the 9 diodes either way (bulb should light only one direction) mine ok as yours is, but then removed bonnet and traced the charge wire back to ignition lamp this was broke , so as stig mentioned earlier if you bypass all the back to ignition lamp and bulb comes on hopefully fault found

Grnut, the belt tension is automatic.I have had the alternator off twice.

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Sorry Cheffers dint realise it was automatic, still don't mean that it's set correctly though, an it might not just be coincidence that you had just about all the electrical gubbins switched on an it was ****ing with rain seems a very likely situation for the belt slipping.

ebbadger said:

the light i beleive is connected via the diode pack, turn ignition on power goes to bulb and this earths in the alternator ..... ie light is on, as soon as engine fires and alternator produces power and the wire that earthed the bulb becomes positive and the light goes out, ie shows you are charging, if the bulb fails this does not happen and alternator gives no output, the full charge does not go via the bulb its just 'gated' by it, certainly the case on all the classic cars ive owned but a much newer electronic td5 i cant guarantee

cheers steve

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Wow, thanks.