Sir Nibble Posted February 7, 2017 Report Share Posted February 7, 2017 I probably did. Link to comment Share on other sites More sharing options...
Mikexx Posted February 7, 2017 Report Share Posted February 7, 2017 Delta to star. Done it before with an A127 and cut in speed reduces dramatically. Max current is of course reduced by the same factor. (root 3). Just looked up and the A127 is indeed a Delta stator so can be converted. Most alternators I have come across have been star, and on rare occasions have another pair of diodes connected to the star point. I'm left wondering how compatible a 24V alternator is and whether a 12V regulator could be fitted for super low cut-in? Link to comment Share on other sites More sharing options...
Mikexx Posted February 7, 2017 Report Share Posted February 7, 2017 Going to renew the battery lead to the alternator this weekend. The battery says 140 ah on it what size mm thickness cable would I need I don't see any reason why you can't connect a short wire to the Starter +ve lead. That is how mine is wired and in common for cars. It saves a lot of faffing about. The alternator cable size is more dependent on charge current and length. I don't have a feel of what voltage drop is acceptable for an alternator. Thicker, of course, is better as is shorter. Link to comment Share on other sites More sharing options...
bizzard Posted February 7, 2017 Report Share Posted February 7, 2017 We here also have an open ex-ships GRP lifeboat which we use as a workboat. It has a Lister ST2 which also drives its alternator from the camshaft. It has the small standard pulley, the engine is mounted low down with a structural beam below the pulley so no room for a bigger one. The alternator is an old ACR with a 5w warning light bulb. A bit of a rev puts the light out and starts the charge, which is quite adequate for just charging an engine start battery. Originally the SR range of engines used dynamos before alternators came on the scene, You had to rev those right up to make the cut out cut in to start the charge if they had the small diameter pulley, but again they were adequate for just charging a start battery plus horn, lights and binge pump. Indeed a great many early pleasure cabin boats only had this simple set up too. I still have the charge rate voltage adjusting key for Lucas RB control boxes. A screw driver adjusted the earlier 2 coil control boxes. Not used the key for many moons though. Link to comment Share on other sites More sharing options...
Sir Nibble Posted February 8, 2017 Report Share Posted February 8, 2017 Just looked up and the A127 is indeed a Delta stator so can be converted. Most alternators I have come across have been star, and on rare occasions have another pair of diodes connected to the star point. I'm left wondering how compatible a 24V alternator is and whether a 12V regulator could be fitted for super low cut-in? Quite a few machines, A127 included, use the same winding in delta or star for 12 or 24V. A 24V stator in a 12V machine in effect. Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 8, 2017 Report Share Posted February 8, 2017 I don't see any reason why you can't connect a short wire to the Starter +ve lead. That is how mine is wired and in common for cars. It saves a lot of faffing about. The alternator cable size is more dependent on charge current and length. I don't have a feel of what voltage drop is acceptable for an alternator. Thicker, of course, is better as is shorter. If this is a boat such as Biz suggested without domestic batteries then that is fine BUT if it has a domestic bank then it is not. Split charge diode systems need the charge to the diode first and the higher voltdrop suggests one may be in use. Split charge relays and VSR systems need the alternator output to be connected to the bank that is the more discharged more often than the other so that means the domestic bank. If you wire such systems in the way you describe the system will work but you risk premature relay failure, especially if on of the more readily available relay makes is used. Link to comment Share on other sites More sharing options...
Roxylass Posted February 11, 2017 Author Report Share Posted February 11, 2017 I don't see any reason why you can't connect a short wire to the Starter +ve lead. That is how mine is wired and in common for cars. It saves a lot of faffing about. The alternator cable size is more dependent on charge current and length. I don't have a feel of what voltage drop is acceptable for an alternator. Thicker, of course, is better as is shorter. Short wire to the starter positive lead other end to where Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 11, 2017 Report Share Posted February 11, 2017 I think he was talking about the main alternator output (B+) so the cable would run from the B+ terminal on the alternator to the main battery lead terminal on the starter SOLENOID but if you have split engine and domestic batteries please read and understand my last post. Link to comment Share on other sites More sharing options...
Roxylass Posted February 16, 2020 Author Report Share Posted February 16, 2020 Got another warning light lucas SBP 354 but it doesn’t give the amps on it its for a classic Land Rover certainly bigger than the one I have this should do away with the exciter switch or should I just stick with the exciter push button decisions decisions Link to comment Share on other sites More sharing options...
Flyboy Posted February 16, 2020 Report Share Posted February 16, 2020 1 hour ago, Roxylass said: Got another warning light lucas SBP 354 but it doesn’t give the amps on it its for a classic Land Rover certainly bigger than the one I have this should do away with the exciter switch or should I just stick with the exciter push button decisions decisions If you remove the bulb it will have the wattage on it. If you want to know the amps , divide the watts by the volts. From memory it will be a 2 watt bulb so will draw 0.167 amps. Link to comment Share on other sites More sharing options...
Roxylass Posted February 16, 2020 Author Report Share Posted February 16, 2020 Took the bulb out nothing on it couldn’t see anything on it at all even using the jewellers loupe here is a pic of it Link to comment Share on other sites More sharing options...
Flyboy Posted February 16, 2020 Report Share Posted February 16, 2020 16 minutes ago, Roxylass said: Took the bulb out nothing on it couldn’t see anything on it at all even using the jewellers loupe here is a pic of it In that case, if you have a multimeter you could connect the light in series with the meter set to amps, then connect to your 12v battery. This will give you the current and from this you can work out the wattage. Volts x Amps = Watts. Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 16, 2020 Report Share Posted February 16, 2020 That might even have an LED or grain of wheat (dolls house) bulb in it, neither will energise a typical alternator. You should be able to slide the bulb holder out of the body and bezel, if you can't then there is every chance it is still a low wattage bulb/LED. You say you took the bulb out, was its base about the size of typical Christmas tree bulbs of the type used before LEDs became popular, either a screw fitting or a push in one. (LES or LB base) if so it will be a maximum of 1.5 watts and again not high enough to energise many alternators. The "oil pressure" tag tells me that the wattage of the light source is not important for that duty s it may well be a very low wattage. If you like the lamp you bought hen you can connect a resistor across the two terminal to increase the energisation current flowing. Sure someone will be along to give you the resistance and power rating. Link to comment Share on other sites More sharing options...
Roxylass Posted February 16, 2020 Author Report Share Posted February 16, 2020 Traced back to where I got it from Land Rover series 2 2a3 illuminated oil pressure warning Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 16, 2020 Report Share Posted February 16, 2020 That "bulb" looks nothing like any I have seen before. The base cap is too fat and the glass envelope too small for the base. I think it may be an LED but the photo is too small to see a filament if it has one. If it is a filament bulb I would expect it to be about 1.5 watts. Link to comment Share on other sites More sharing options...
alan_fincher Posted February 16, 2020 Report Share Posted February 16, 2020 3 hours ago, Roxylass said: Took the bulb out nothing on it couldn’t see anything on it at all even using the jewellers loupe here is a pic of it What you are picturing are a bulb holder and the box that is supplied in. Ig you Google the part number it is supplied without a bulb. The specified bulb for it at 12 volts seems to be called a 281, and these generally seem to be a 2 watt bulb. So the current it takes will be about 0.17 amps, (or 170 milliamps,put another way). The bulb in there should look like this....https://www.ebay.co.uk/itm/LUCAS-BA7S-281-MCC-CAR-DASH-PANEL-GAUGES-CLOCKS-SPEEDO-LIGHT-BULBS-LAMP-12V-2W-/153031068501?var= Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 16, 2020 Report Share Posted February 16, 2020 That was the bulb I was expecting Alan - or the LES alternative and I don't think it is one. Link to comment Share on other sites More sharing options...
bizzard Posted February 16, 2020 Report Share Posted February 16, 2020 If that is genuine old new stock I doubt LED bulbs had been invented. Land Rover series 2 through to 3 was from 1959 to 1985. I don't think any of them used a red lens for the oil pressure light, either green or amber. Those were the days when red was always ignition charge light and almost always green for oil pressure, sometimes amber. Link to comment Share on other sites More sharing options...
Tony Brooks Posted February 17, 2020 Report Share Posted February 17, 2020 The box says "Pack date 20/17" so I very much doubt its genuine old stock. I think a close up photo of the bulb may help see if it has a filament plus something to gauge the size by - like a 1p coin. Link to comment Share on other sites More sharing options...
Roxylass Posted February 17, 2020 Author Report Share Posted February 17, 2020 Get a pic taken when I get home Link to comment Share on other sites More sharing options...
Roxylass Posted February 17, 2020 Author Report Share Posted February 17, 2020 Here’s a couple of pics tried a few motor factors none of them seem to have a 5 watts biggest they have is a 2watt Link to comment Share on other sites More sharing options...
bizzard Posted February 17, 2020 Report Share Posted February 17, 2020 1 hour ago, Roxylass said: Here’s a couple of pics tried a few motor factors none of them seem to have a 5 watts biggest they have is a 2watt They wouldn't put a 5 or 6w filament bulb into that small unit, the heat would probably melt it, 2.2w is the maximum I think. That unit is the usual standard size for those warning lights. The 2w bulb should be enough to excite the alternator as lowish revs. If you want to go to 5 or 6w bulb then the holder and lens will be twice the size, needing a bigger hole in the dashboard. Link to comment Share on other sites More sharing options...
Roxylass Posted February 17, 2020 Author Report Share Posted February 17, 2020 I will certainly try this one at the weekend if it doesn’t come on when i turn the key dont wish to sound a defeatist think i will carry on with the exciter push button also check the thin wire bizz pointed out in one of the pics it does look rather tight Link to comment Share on other sites More sharing options...
bizzard Posted February 17, 2020 Report Share Posted February 17, 2020 (edited) 20 minutes ago, Roxylass said: I will certainly try this one at the weekend if it doesn’t come on when i turn the key dont wish to sound a defeatist think i will carry on with the exciter push button also check the thin wire bizz pointed out in one of the pics it does look rather tight I've just realised you still have the small diameter pulley on the camshaft driving the alternator. In which case I think your going to need the 5w bulb and holder to excite the alternator into action at reasonable engine revs. Edited February 17, 2020 by bizzard Link to comment Share on other sites More sharing options...
Roxylass Posted February 17, 2020 Author Report Share Posted February 17, 2020 As you can see by the pics of the engine it has to be the smaller pulley the way the engine cradle sits on the engine mount these are original the boat was built by Viking marine then cheverton took them over number inside the boat 69 68 which denotes it was the sixty ninth built in 1968 all is original in it and I dont wish to alter anything think that would be a shame you couldn’t point me in the right direction where to purchase 5watt warning light Link to comment Share on other sites More sharing options...
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