whilst driving today in traffic my engine died when i went to turn over was as dead as a dodo nothing managed to jump it and drove fine till in slow traffic and died again i watched the volts drop on dial on dash when called rac he said it was not charging and said should have a battery light on dash with ignition feed and a live feed off to spade connector on engine electrics so can charge when below 3000rpm as when above 3000rpm u get something called Excite which charges battery when got home on drive volts dropped but when took above 3000rpm the volts went back up now i have never had a battery light or anything to this spade connector on engine is there anyway to solve this problem or do i have to add a battery light to dash and live feed to engine
Cant make head or tail of that but it sound a right load of cobblers i think he has got confused with something more moden the old type as fitted to our van do not use a excite curicuit. The alternator should charge the battery at tickover you should get at least 13v at the battery with the engine ticking over. On the dash you should have a warning light in the dash along with the outher waring lights (oil, turn, mainbeam) how this light works is with the key in the lock and turned on but without the engine running the light is on as it has a live feed and earths through the alternator. With the engine running and the alternator charging the light will go out as the alternator starts charging it becomes live so the warning light now has a live and live so goes out If the alternator is not charging at low speed there is a problem with the regulator or the brushes in the alternator. Depending on the type you will have a external regulator (box with wires behind the air filter) or a internal regulator built within the alternator.
^^^WHS^^^ Sounds like either the regulator is shot or there is a bad connection to the regulator. Check for a bad connection first, I speak from personal experience on that one. :-[
Could it be that the RAC man meant that if the warning bulb is blown that the exciter current is not generated and therefore the alternator never starts generating any current? maybe worth checking that lamp too
^^^ that's right. Our alternators aren't self exciting like modern ones and need an initial load to start charging. (pain in the arse if you want to use solid state blocking diodes for split charging). on a train, get back to you about what to do ifsomeone hasnt already later Cheers S
^ this. The alternator isn't self-exciting. If the bulb's not working, the alternator may fail to start charging.
there has never been a dash light and when i start and ticks over at 8 to 10 volts when i rev it the needle goes up to 12v when stop reving drops down i am asuming the issue is with the live feed as when he run a piece of wire from 1 connection to another it was charging on tick over and when revved and as soon as piece of wire was taken from equation it stopped charging on tick over but charged when revved
12v is not charging you need 13.5 to 14.5v Did you take the readings at the battery? Do you have a external regulator box behind the air filter with 2 wires that go to the alternator? The charge system is very simply on these vans. A large wire goes from the alternator through the regulator to the starter then onto the battery. The neutral goes through the metal work of the engine through a earth strap at the gear box to the chassis then to the battery vie the battery lead. that's all you need for it to work. I would check these connections then test the voltages if still no joy look at replacing the alternator
the charge light on the dash absolutely affects whether the battery charges or not. You need to get your wiring looked at and see what's been removed
Hi, back again. Was going to write something up but frankly the page below is the best you're gonna get: http://www.ratwell.com/technical/ChargingSystem.html He gets a bit techy bottom line is this: You switch the engine on, the alternator warning light goes on (called an ignition light sometimes) The alternator warning light is connected to the voltage regulator which connects to the Df and D terminals internally (blue wire) and then to terminal D+ on the alternator (red wire from VR to alternator). With the light on power flows to alternator field coils in the stator magnetising them When the engine starts the alternator rotor rotates in the magetic field and starts to generate electricity. A current flows through the B+ terminal (connected to the battery) and the D+ terminal. Faster the rotation the more current generated. When the current exceeds that needed to light the alternator warning light (1.2w same as instrument lights) (watts = amps x volts, ie .1amps) the alternator light goes out and the VR starts to control the current output by regulating current to the field coils. The more current in the field coils the stronger the magnetic field the more current generated at the stator. (PS if you have a mechanical regulator do yourself a favour, junk it and get a solid state one, far more efficient and reliable, £36 at Custom and Commercial) The value of the alternator warning light bulb is important as this will effect when the alternator starts delivering current. I've not bothered to explain about the diodes or alternating current, Ratwells article does that better than I can if youre interested. The value of the alternator warning light bulb is important as this will effect when the alternator starts delivering current. Ratwell's article explains all the testing. Bottom line, you need an Alternator warning light in circuit for your alternator to work. (Caveat, you may get some current out of our alternators without the warning light because of residual magnetism in the alternator but it wont be much..) Good luck with it. Cheers s
Just had a look in your rides nice van by the way Has the problem started since the wiring and dash have been heavy modified. I see you have volt meter, depending on the type of gauge and how it is wired it could be your problem as it will be giving a diffrent resistance that a warning light would and that is coursing the the alternator not to charge until a higher RPM. As the wiring is so modified i would get someone who knows to have a look or start from basics using the link above.
ERK!!!, just read thru" Stevesplatto and other"s write up on elec"s >specifically, gennies and warning lamps , my lamp has been out a couple of wks and i cannot find out why , methinks the very loose bulb holder ? (i"m clutching at straws here ) so i was relying on my voltmeter to keep me informed ! oh oh >tomorrow it"s out wiv the multimeter and elec.screwdriver , thanks guys!
