My leese Neville 160 alternator was rebuilt last year. At the alternator it's 15.5 V, through the isolator it's 14.7-8 volts, so the isolator is working correctly. The only regulator I can seem to find is set at 14.2. Which is to low. Does anyone have an idea on an adjustable regulator? 13.8 coming out of the isolator would be great, 14.5/6 at the back of the alternator. I don't actually think the 14.8 will hurt my new AGM house batterys, but I'd really like to calm it down a bit.
My opinion only: I think "13.8 coming out of the isolator" is too low.
Does your alternator have a sense wire terminal?
If yes, is the sense wire connected to start battery POS terminal?
If yes, then alternator should automatically adjust itself to compensate for the voltage drop through the isolator.
You would like the voltage measured at start battery to be around 14.2 when alternator is running at idle.
Chuck, 14.4 at the house at idle, 14.8 on the Silverleaf at all times. Need to check the start batteries at idle. The sense wire is connected to the pos side of the start battery. I wouldn't mind a 13.8 volt. I have an automatic charge control relay, so my solar is going to take care of topping things off. I'm considering taking the alternator out of the house system, as I can always use the boost if necessary to charge the house. The solar seems to do a much better job charging the 3 8d AGMs.
Bruce, doesn't your alternator have the voltage adjustment screw? My factory Leese Neville 160 amp has one.
no it doesn't, in searching the internet it seem they are no longer available. Before the rebuild the old one was adjustable. My fault though for having them replace it along with everything else.
Here is one
Leece-Neville Voltage Regulator 14V New Old Stock! P/N 79000 | eBay (https://www.ebay.com/itm/363516651468?hash=item54a347e7cc:g:yT8AAOSwQJZiHR7A&amdata=enc%3AAQAIAAAA0No1VpPwz4VCF65rfaVlBqRxImxGHx7iiK9BQG946L89vvHrNMrKDrvu5NCACoMkV7NmU5DGhApcVQCvFNadaK4AkUQrZ20ioL4LM7pNyz5l1ak6YzDB1j8hPukdyiVyU%2BFtlDd4x%2BtC6F4LnrTI3Ffeucc0lofHNO2T07PZuznUxTy7PwKlBrhlhHU24MHiyv6QQjO3xifD7c3LxWlTcO0rN1nA9vdFAjeKVhrJr8nGVeiXUOX%2FOJdnVOVc3UiLRy6DS4pu3UfofUyEHAtta24%3D%7Ctkp%3ABk9SR9SUrNydYg)
Mike
Thanks Mike, I now have a back-up.
Thanks Mike, I'll see if I can find somewhere to ship it to.
Leese Neville alternators have had 3 choices of voltage regulator: variable with small screwdriver (not common), fixed voltage (never seen one), and the most popular has three internal jumpers that can choose between voltages (open up to change jumpers).
Barry, can you send me the part number for the 3 voltage regulator?
I put a Balmar external regulator on my coach so I can set the three stages any way I
want and it has a heat sensor on the alternator so I can't burn up the alternator. There
is also a place to put a heat sensor on the batteries but my batteries will take a lot more
heat than I get from charging.
Bruce,
I do not have part numbers, which I assume others may have. I did find this link: and the attached document.
http://wiki.foreforums.com/lib/exe/fetch.php?media=technical:electrical:troubleshooting_leece-neville_alternators.pdf
My leese Neville 160 alternator has the 3 set point regulator, for Lo, Medium, or Hi voltage settings. I found it was difficult to know from the diagram what the actual setting was, so be sure to measure the voltage after changing the setting. I believe the voltage settings are 13.8v, 14.2v, or 14.6. I used an analogue voltmeter at the dash so voltage could be monitored while driving. My target for the AGM batteries was 14.4 volt. With regulator set to 14.2v, I added a standard 5 watt resister to the sense wire which raised the voltage at the batteries to 14.4v. while the alternator was still sensing 14.2v
Note that I moved all the wires on the metal plate behind the driver side rear tires to under the foot of the bed, so adding a resistor to the sense circuit was easy.
Am I missing something here? If the voltage regulator is set to 14.2, how can the resistor make it kick the voltage up? Is the voltage regulator capable of increasing the voltage above the set point.
The resister makes the voltage regulator put out 14.4 thinking that it is reading 14.2
After doing a little investigation, actual voltage is 15.4 at the alternator, 14.2 at both battery banks. I adjusted the voltage on the Silverleaf to reflect the proper reading.
How do I adjust the Silver Leaf to have it tell me the actual voltage.
Govto advanced at the top, then to engine corrections click on what you want to correct, look for multiplier adjustment adjust accordingly, careful a little goes a long way.
Thanks Bruce got my son out to the coach and he got the voltage set right on the Silver Leaf
and I used a voltmeter to check the dash voltmeter and it is out also.
*potential dumb question(s)*
I also have a Leese Neville and for some reason the PO disconnected the smaller wires to it.
It was stated that the "sense" wire goes to the start battery + terminal.
1) does that cause the alternator to generate power and provide current back to the battery?
1a) isn't that the same as the large wire going between the alternator and battery?
1b) theoretically, I could jump from the alternator start battery + terminal to the sense terminal and have current produced?
2) on a TEMPORARY basis could I do 1b above and turn on the "boost" switch to charge the house battery bank?
1) No. You are confusing the SENSE wire with the EXCITE wire. The SENSE wire tells the alternator regulator the voltage at the START battery. The EXCITE wire (if required by your alternator) activates the alternator to generate power. The SENSE wire is HOT all the time. The EXCITE wire is HOT only when the ignition switch is in the ON position.
1a) The voltage on the SENSE wire would be the same as the voltage on the large wire going between alternator and battery
ONLY if the alternator is connected directly to the START battery. In other words, if you didn't have a battery isolator in your charging setup.
1b) As explained above, the SENSE wire does not activate the alternator. This is the function of the EXCITE wire (if one is required). Some alternators are "Self Exciting" and do not require the EXCITE wire.
2) IF the alternator is connected directly to the START battery, and IF the alternator is putting out charging current, then activating the BOOST switch will allow the alternator to also charge the house batteries.
So, that means because I have a boost switch, I have a battery isolator?
Can I tap into any HOT when ON (of sufficient guage) line?
Find the start battery on the isolator, run a line from that to the excite and I should be good?
Sorry for all the questions, I've never been good with vehicle electrical systems.
1. Not necessarily. You can have a boost switch with or without a isolator.
2. If asking about the EXCITE wire, yes, any source that is hot
only with ignition switch in ON position will work.
3. NO, that line would be hot all the time. The EXCITE wire is
only hot when ignition switch is in the ON position.
Ok.
1) How do I tell if I have an isolator?
3) My bad, meant "sense".
Sorry.
Does it help to mention that my alternator has two charging lines coming out of it?
One of the heavy wires will be positive the othe one will go to ground frame or engine.
1) You need to look around your coach - see if you see something like the photos below. The isolator
might be red in color, with 3 or 4 battery cable posts. It will have large diameter battery cables attached to the posts. It could be mounted in the engine compartment, or in one of your storage bays, or under the lift-up mattress platform at foot of bed, or ?
3) In that case, yes, find the START battery (post) on the isolator, run a line from that to the SENSE terminal, and should be good.
4) What would help is a photo of the back side of alternator showing all of the terminals. OR, if you can see the ID plate on the alternator, tell us the model number. We can look up the factory specs and then we'll know what you are working with.
Hi Moby!
Foretravel's original equipment is a diode isolator. This is a big heat-sink with three battery terminals and a screw for a wire. It's somewhere between the alternator and the batteries.
IF you have a Leece Neville DUVAC alternator and you have two heavy studs with 12+ on them with the engine running then you don't need an isolator -- the alternator does that for you.
A good voltmeter is your friend.
Your coach did come with a diode-based battery isolator. Likely on front wall of engine compartment. Just follow the large-gauge red wire from the alternator B+ terminal to it.
And to have the alternator properly functioning, you need both excite (only hot with ignition on) AND the sense wire connected. The sense wire is connected to any place "downstream" of the diode-based battery isolator and the chassis battery positive terminal. The lug going to the chassis battery on the diode-based battery isolator is an easy location to connect the sense wire.
No need to be sorry - we all have varying degrees of knowledge/skill - that's why this Forum is so valuable. We pool our knowledge and assist each other in areas where we may be a little "weak".
One potential "problem", when dealing with older coaches like yours and mine, is that prior owners
may have made undocumented modifications to the original factory design. That is why I resist the urge to make flat statements about what equipment another member will find on his/her coach. I like to get positive evidence (photos or model numbers) of what exactly constitutes the existing setup
before attempting to diagnose a problem or answer a technical question.
Example: We can't tell you how to repair or restore the correct wiring to your alternator until we know exactly what alternator is mounted on your engine. It might be the OEM factory installed Leece Neville, or it could be a good quality replacement alternator that is "the same as" a genuine Leece Neville, or it could be a rip-off generic rebuilt alternator sourced from a off-shore no-name provider. In any case, it may or may not have the same wiring connection terminals as a genuine Leece Neville model. Same thing applies to the isolator that you may or may not find on your coach. Perhaps a prior owner removed the isolator and substituted another device, like a VSR, or perhaps they removed it and wired the alternator direct to the start battery. Until we find out from you what equipment you currently have to work with, we can't really give you useful advice.
End of sermon.
And even if the alternator was replaced by a "professional" shop they may have not known what to do with the sense wire. Mine had been cut and tucked back into the harness. Spent four days going crazy while going to a B2B charger and dealing with a sense wire bridged to the excite wire.
Got you all.
The alternator WAS replaced, and the receipt is in the documents bag under the bed.
I distinctly remember it being a Leece on the reciept.
Model when I get it.
Time to go tracing big, fat, red wires.