Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Topic: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla (Read 1806 times) previous topic - next topic

Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

December 27, 2019, 01:55:24 pm

hello everyone , just fitted a new Alternator , its working perfectly , charging all batteries vehicle and house, but I had 4 connections on my old alternator , but the new one is exactly the same fits engine , but its just slightly different it only has two connections and a black wire going into a third , the two small wires I have left and don't really know what to do with them ,one is for ign switch, so wasn't sure if I can just connect that wire to the big red terminal the same, and the other wire is supposed to go to a duvac, what is a duvac and where would it be situated and also what purpose dose it serve , il upload a couple of photos in a bit of old and new and maybe someone could advise me on this little matter, thanks kev

[fixed title typo to correct alternator brand = Leece-Neville for future searches - Michelle]

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #1 – December 27, 2019, 01:58:21 pm

What are the connections labeled on the new alternator?

Do you still have the diode-based battery isolator?

Is voltage output on the new alternator adjustable?

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #2 – December 27, 2019, 02:01:40 pm

Quote from: kevo0000 – December 27, 2019, 01:55:24 pm

hello everyone , just fitted a new Alternator , its working perfectly , charging all batteries vehicle and house, but I had 4 connections on my old alternator , but the new one is exactly
Quote from: kevo0000 – December 27, 2019, 01:55:24 pm
hello everyone , just fitted a new Alternator , its working perfectly , charging all batteries vehicle and house, but I had 4 connections on my old alternator , but the new one is exactly the same fits engine , but its just slightly different it only has two connections and a black wire going into a third , the two small wires I have left and don't really know what to do with them ,one is for ign switch, so wasn't sure if I can just connect that wire to the big red terminal the same, and the other wire is supposed to go to a duvac, what is a duvac and where would it be situated and also what purpose dose it serve , il upload a couple of photos in a bit of old and new and maybe someone could advise me on this little matter, thanks kev
Quote from: wolfe10 – December 27, 2019, 01:58:21 pm
What are the connections labeled on the new alternator?

Do you still have the diode-based battery isolator?

Is voltage output on the new alternator adjustable?
Quote from: wolfe10 – December 27, 2019, 01:58:21 pm
What are the connections labeled on the new alternator?

Do you still have the diode-based battery isolator?

Is voltage output on the new alternator adjustable?
the same fits engine , but its just slightly different it only has two connections and a black wire going into a third , the two small wires I have left and don't really know what to do with them ,one is for ign switch, so wasn't sure if I can just connect that wire to the big red terminal the same, and the other wire is supposed to go to a duvac, what is a duvac and where would it be situated and also what purpose dose it serve , il upload a couple of photos in a bit of old and new and maybe someone could advise me on this little matter, thanks kev

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #3 – December 27, 2019, 02:05:15 pm

OK, from the picture of the new alternator, two connections are clear-- B+ and ground (-).

Either from installation instructions or by doing a search for instructions for that PN, what are the other connections??? Their information is far better than our speculation based on a picture.

Need answers to the other two questions (battery isolator type and is voltage adjustable).

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #4 – December 27, 2019, 02:35:05 pm

Quote from: wolfe10 – December 27, 2019, 02:05:15 pm

OK, from the picture of the new alternator, two connections are clear-- B+ and ground (-).
Quote from: wolfe10 – December 27, 2019, 02:05:15 pm
OK, from the picture of the new alternator, two connections are clear-- B+ and ground (-).

Either from installation instructions or by doing a search for instructions for that PN, what are the other connections??? Their information is far better than our speculation based on a picture.

Need answers to the other two questions (battery isolator type and is voltage adjustable).
yes I have a blue battery isolator which I think also is a reece nevuille, the middle connection goes to alternator , and the two go to vehicle batteries and other terminal to house battery. ive checked and I have just over 14 volts going into it from alternator

Either from installation instructions or by doing a search for instructions for that PN, what are the other connections??? Their information is far better than our speculation based on a picture.

Need answers to the other two questions (battery isolator type and is voltage adjustable).

Quote from: kevo0000 – December 27, 2019, 02:01:40 pm

the same fits engine , but its just slightly different it only has two connections and a black wire going into a third , the two small wires I have left and don't really know what to do with them ,one is for ign switch, so wasn't sure if I can just connect that wire to the big red terminal the same, and the other wire is supposed to go to a duvac, what is a duvac and where would it be situated and also what purpose dose it serve , il upload a couple of photos in a bit of old and new and maybe someone could advise me on this little matter, thanks kev

there just uploaded two photos , see what you can work out from that thanks kev

Quote from: wolfe10 – December 27, 2019, 01:58:21 pm

What are the connections labeled on the new alternator?

Do you still have the diode-based battery isolator?

Is voltage output on the new alternator adjustable?

I don't think I can adjust the output , its putting out around 14 . something volts I think its 160 amp , but it seems to be charging fine but just not sure what terminal on the new one to put the ign switch and duvac wire

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #5 – December 27, 2019, 02:52:20 pm

You may not be using the ign hot and DUVAC wires on the new alternator.

You measured 14 VDC where? The issue with a diode-based isolator is that you loose .7 VDC across it-- voltage at the center lug from alternator B+ reads higher than the two outer lugs that go to the battery banks. The critical issue is what is voltage at the chassis battery and house battery, not just alternator output.

Said another way 14.0 minus .7= 13.3 at the batteries. That is low.

Options:
Put up with 13.3-- likely not the best option.
Replace diode-based isolator with either relay/solenoid based isolator that does not loose voltage OR with a manual ON-OFF battery switch OR a smart battery combiner.

You have to decide how you want to do it (KISS vs $$ and automatic).

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #6 – December 27, 2019, 04:45:41 pm

Quote from: wolfe10 – December 27, 2019, 02:52:20 pm

You may not be using the ign hot and DUVAC wires on the new alternator.

You measured 14 VDC where? The issue with a diode-based isolator is that you loose .7 VDC across it-- voltage at the center lug from alternator B+ reads higher than the two outer lugs that go to the battery banks. The critical issue is what is voltage at the chassis battery and house battery, not just alternator output.

Said another way 14.0 minus .7= 13.3 at the batteries. That is low.

Options:
Put up with 13.3-- likely not the best option.
Replace diode-based isolator with either relay/solenoid based isolator that does not loose voltage OR with a manual ON-OFF battery switch OR a smart battery combiner.

You have to decide how you want to do it (KISS vs $$ and automatic).

I have about 13.7 volts showing on battery's whilst the engine is ticking over and a fraction over 14 volts coming out of the alternator, whilst I was running engine I also did a volt drop test I put the night heater on all of the interior lights and the kitchen fan , and checked the batteries again and they were ranging from 13.45 to 13.50 , so whatever I've done and connected, seems to be working fine , with plenty of amps, so I think IL just tape up the duvac wire, and forget it , not sure about the thin red ign switch wire, It seems to be hot all the time , even when ign switch is off, and just another thing , when the engine first starts there is about 20 second delay before power comes out of alternator, because earlier when I first started the engine with new alternator , I checked the voltage from big red terminal to the ground terminal and showing zero vokts, anyway I went and lit up a cigarette came back checked it and voltage was flowing lovely , anyway I turned engine off , then restarted it went and checked the volts at alternator again sure enough nothing , I must have waited about another 15 secs and then there was full voltage again , checked that the power was reaching isolated and it was also flowing out of house and vehicle battery terminal on both sides of isolater , I was thinking that maybe modern alternators all have a short delay before the power starts generating for some reason maybe

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #7 – December 27, 2019, 04:50:15 pm

13.7 at the batteries is certainly OK. Suspect more than 14.0 from the alternator, but all that really matters is what reaches each battery bank.

IGN hot should only be hot when ignition on. Of course no way of knowing how someone has wired it since leaving the factory. I would spend a few minutes tracing where that "always hot" wire comes from and suggest removing it from the source--an extra hot that may not be properly fused is not a good idea.

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #8 – December 27, 2019, 05:41:01 pm

Quote from: wolfe10 – December 27, 2019, 04:50:15 pm

13.7 at the batteries is certainly OK. Suspect more than 14.0 from the alternator, but all that really matters is what reaches each battery bank.

IGN hot should only be hot when ignition on. Of course no way of knowing how someone has wired it since leaving the factory. I would spend a few minutes tracing where that "always hot" wire comes from and suggest removing it from the source--an extra hot that may not be properly fused is not a good idea.

Yeah your right there , as far as I can see , I think I've already done a continuaty test and it seems to be attached to the battery booster relay , I don't know why or for what reason it's doing there yet , IL check that tommorrow or Sunday

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #9 – December 27, 2019, 05:48:17 pm

I know it is getting late on the other side of the pond. Tomorrow is a good day.

The battery boost relay/solenoid is a terrible place for an "ignition hot" lead, since one lug goes to chassis battery, the other to the house battery. NOTHING to do with ignition hot source. Certainly wired that way by what we in Texas would call a BUBBA.

Re: reece nevel alternater on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #10 – December 27, 2019, 06:53:45 pm

Quote from: wolfe10 – December 27, 2019, 05:48:17 pm

I know it is getting late on the other side of the pond. Tomorrow is a good day.

The battery boost relay/solenoid is a terrible place for an "ignition hot" lead, since one lug goes to chassis battery, the other to the house battery. NOTHING to do with ignition hot source. Certainly wired that way by what we in Texas would call a BUBBA.

Ha ha , yeah a big bubba I wreckon , it doesn't seem to be serving any purpose whatsoever , IL find out for sure when I disconnect it , if everything else still works then IL know it's ok to lose it completely ,

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #11 – December 27, 2019, 06:54:58 pm

Quote from: wolfe10 – December 27, 2019, 05:48:17 pm

I know it is getting late on the other side of the pond. Tomorrow is a good day.

The battery boost relay/solenoid is a terrible place for an "ignition hot" lead, since one lug goes to chassis battery, the other to the house battery. NOTHING to do with ignition hot source. Certainly wired that way by what we in Texas would call a BUBBA.

Brett, he said the wire is hot all the time even with the ignition off. If it is hooked to the chassis side of the boost switch could it have been a sense wire?

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #12 – December 27, 2019, 06:59:57 pm

Quote from: craneman – December 27, 2019, 06:54:58 pm

Brett, he said the wire is hot all the time even with the ignition off. If it is hooked to the chassis side of the boost switch could it have been a sense wire?

YES, that is exactly how the SENSE WIRE would be connected.

Again, if no sense terminal on the alternator, better to disconnect it at the boost solenoid than leave an unfused hot wire in the engine room.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #13 – December 27, 2019, 09:34:10 pm

When does the fourth wire get power? Maybe someone switched the ignition and sense wires at the alternator so that they could have been hooked up wrong.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #14 – December 28, 2019, 10:23:10 am

It's most strange , I'm up here now , engine running I've got 14.07 volts coming from the alternator on big red terminal, 13.3 at batteries all of them , I've got 3 banks of house batteries and two banks of vehicle batteries all with 13.3 volts which I'm quite happy with, but yesterday I thought their was some sort of delay in the output of the alternator , but it seems that everytime I switch engine off , and restart their is no output voltage from alternator , and what I have to do is touch the small red wire which originally went to ign switch against either of the two Mt terminals on alternator , not connect it just touch very quickly and the alternator starts producing power at the big terminal,. Those two spare terminals when I put volt meter on them ,each one is producing 7 volts, I know it's strange but then that is electrics for you, I've just noticed in the box that the alternator came in that their is a small yellow jumper wire with two red connectors , it says on the packet jumper from stator to trio input, but then their is a red warning saying this alternator has a regulator that doesn't require a diode trio, so I presume it's not necessary, the volt meter on the dash is all working showing 13.20 volts , I've uploaded a couple more photos , I can't help but think that maybe one of these two wires either ign switch or duvac which I'm still trying to find out what is a duvac ,should be connected to one of these terminals, IL try and find a wiring diagram for this alternator , I don't think this is a Reece Nevile genuine part it's probably aftermarket but other than the difference of wiring it's identical , it will be something simple why the alternator doesn't start producing power , it's like I have to switch it on seperatly after starting ,

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #15 – December 28, 2019, 11:06:46 am

That wire is "exciting" the alternator which some alternators require. You will need to find out if the excite wire can be 12 volts all the time, and if so it needs to be hooked up to the ignition.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #16 – December 28, 2019, 11:16:01 am

Yes, you will need to follow the instructions for your new alternator, not the old one.

As long as voltage to the two battery banks is not too low due to loss across the diode-based isolator, you will be OK. If voltage is too low, you will have to choose a "Plan B" for battery isolation that does not have voltage drop (my post above).

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #17 – December 28, 2019, 12:34:18 pm

well, if that is all I need to excite the alternator into producing power, I could run a switch , a spring switch similar to battery booster switch between this red ignition wire with say a 5 amp fuse and then connect to one of the two terminals that seem to be the excite terminals , so after I start engine I just depress the switch once for a fraction of a second and it excites the alternator into producing power, I know in theory that should work , I don't want to risk making it a permanent connection as like I said earlier, these two terminals on alternator just below the one with black wire are actually producing 7 volts each while alternator is turning but there is 12 volts on ign wire, so it may damage alternator in some way by connecting it direct but if it is switched with a fuse just to make the alternator work and it does seem to work, I always put fuses where ever I think might need one , you can never be too carefull with electrics, im still trying to work out where this duvac is situated and what it does ,

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #18 – December 28, 2019, 12:36:42 pm

oh and also im gonna have to find fitting instructions on line for this model alternator because there was no fitting instructions contained in the box when I received it

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #19 – December 28, 2019, 12:45:05 pm

Quote from: kevo0000 – December 28, 2019, 12:36:42 pm

oh and also im gonna have to find fitting instructions on line for this model alternator because there was no fitting instructions contained in the box when I received it

ABSOLUTELY. This will be the key to making sure it is properly wired. Far, far better than our speculation on how your alternator is supposed to be wired.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #20 – December 28, 2019, 06:41:20 pm

Just found a topic called what is duvac on the forum a year ago by moby, lots of interesting replies , haven't finished reading it all yet , but I'm learning alot , apparently the ign wire that normally goes on the small terminal is the exite wire , so as soon as ign is turned on then it excites the alternater into starting , in that case I will get the same effect by connecting the small red ign switch terminal to the big terminal on the alternator, , the duvac wire is basically a sense wire that tells the voltage regulator when to decrease and increase voltage to the batteries , so until I can get the correct diagrams of this alternator as to what terminal to fit the duvac wire for sure IL leave everything as it is and excite it manually , just for now , I'm like that whenever I get to something that can be akward IL leave it go and crack on with another job and come back to it , I wonder if any one out there would have a wiring diagram of this particular alternator, it's just unusual that their are no markings on the two terminals that put out 7 volts , they have got to be for something ,

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #21 – December 28, 2019, 06:48:28 pm

Very unlikely that your new (and different) alternator will use a sense wire.

Excite wire-- only determining how your new alternator should be wired will give you the answer.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #22 – December 29, 2019, 08:19:28 am

Your alternator needs to be modified INTERNALLY to run dual voltage with the isolator. You need to find a qualified electric shop that knows what DUVAC is for this.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #23 – December 29, 2019, 08:41:17 am

Maybe the best thing would have been just to have the original alternator rebuilt.

Re: Leece-Neville alternator on my 8.2ltr detroit, 1990 foretravel granvilla

Reply #24 – December 29, 2019, 12:37:45 pm

Quote from: kevo0000 – December 28, 2019, 06:41:20 pm

I wonder if any one out there would have a wiring diagram of this particular alternator, it's just unusual that their are no markings on the two terminals that put out 7 volts , they have got to be for something ,

The proper wiring diagram for your new alternator IS available online. There must be a data plate or decal on the alternator that shows the model number or part number. None of your photos (clearly) show this info, however, so we can't help you. You can either post a photo of the model number on the alternator, or simply search for the wiring diagram yourself. Just do a Google search for the alternator model number and you will find the diagram.

DO NOT connect a "always hot" wire (or a ground wire) to any small terminal on the alternator until you have found the correct wiring diagram. Blindly connecting wires to alternators is a good way to let the smoke out.

Those 3 small posts on your alternator are most likely AC terminals. They are not marked because no wires are normally connected to them. They are only used when testing the alternator or adjusting the internal voltage regulator output. See photo below:

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