8 replies to this topic

[antn0585]

hi i have a k reg cooper 1.3 spi and haveing some problems with it charging only getting 12.4v at the battey put 2 new alternators on and still the same ive had a look and have been told that the 3 wires on the back of the alternator shud be 2 of them 12v live at all time and 1 shud be 2v live when ignition is on im getting no voutage the the 2v wire and only 9v to the other 2 but when ignition is on the 2 wires that are 9 volt go to 0.24v any ideas

[JonnyBMX]

erm, as far as i know... u should either have 0v or 12v in a car as this is what the battery would output.. in order for the battery to be chraged via the alternator it must output over 12V in order to overcome the e.m.f of the battery... i.e. if they were both at 12V no charge would be incurred to the battery. when the car is running you should see a slight increase in the voltage across the two battery terminals (use a multimeter to measure them) in my expirience most electical faults on my SPI have been shorts or bad earths to it would be a start to check all the wires to the alternator as it doesnt seem to be outputting a voltage according to your above observations.

[Dan]

A healthy charging system will run at around 14.4v with the engine running and can usually take a load of as much as the headlights without dropping volts. A heavily discharged battery will reduce this voltage though. The two large terminals at the alternator should connect to the solenoid through some fusible cables. They should be at battery voltage with the ignition off, if they aren't at the same as the battery there is a fault in either the main supply or the earth. The small terminal is battery sense and charge warning, I don't know where the 2v is supposed to come from! It should be at ground potential with the ignition off . Is the no charge lamp on the dash working? Have you tested the bulb? The alternator cannot work without it.

[antn0585]

is the charge light the orrange light as when i start the car it has a rad and a orrenge light thay both go out after a few seconds tho

[Dan]

Orange is low oil pressure, red is no charge. They both sound like they are working fine. Have you had the battery tested?

[antn0585]

just put a new 1 on it

[antn0585]

well been at it today tried running a earh from battery to block and still the same found a brokn wire from alt to starter so fixed that and still te same but for around 1-2 min i got 16v from the back of the alternator any ideas as im now stumped

[Sprocket]

you cannot have 16v with a 12v batter and the engine not running. with the engine running and 16v I would be very worried that the regulator in the alternator was damaged.

It might be time to hand this over to an auto electrician before that car sets on fire.

To me it sounds like a wiring loom fault, especially considering its age.

[antn0585]

ni i was 16v wile running not done it sinse but seemed to have solved the problem got a constant 14.3 volts not on idle