Community Forums

Notn2bars · 10-18-2021, 10:17 AM

We are still on our trip. Took the DW to Niagara Falls, had a great time. Now close to South Bend, Michigan. Looks like our alternator is taking a dump. Noticed the house batteries are not being charged as we go down the road. In addition, the solar panel is not charging the batteries either. Took readings at the isolator and the chassis batteries. The Chassis batteries showed 12.84 volts before starting the coach. After starting the coach, the voltage dropped to 12.63 volts. When we left our dash gauge showed output of a constant 14 volts. Now showing 12.5 volts. Center terminal on isolator with motor running 13.1 volts, bottom terminal 12.70 volts, top terminal 12.85 volts. Not sure what this means. Is it possible that both the alternator and the isolator are bad? All input is appreciated. If the alternator needs replacement, what is a good alternative or should we have it rebuilt? Any reputable and reliable rebuilders in the area? Thanks for any help. God Bless, Ed

153stars · 10-18-2021, 10:27 AM

I think there is a fuse to excite wire from batt to alt.. Check for fuse and condition of wire connections crimps ect.
There's many threads on how to convert to different alternator like Delco 28SI that is easier to get in more location, personally I would use the higher brushless version . Also use other type of battery isolators from diode. to Bluesea MTL ACR.

jacwjames · 10-18-2021, 10:30 AM

My alternator died ~6 years ago, I was at home though and got the name of a rebuild shop. They got it done in a day, cost was $185.

Not sure on your charging system, mine used a BIRD and Isolation Solenoid for charging while driving and a Lambert to maintain chassis battery while parked. I started to question the Lambert and decided to change out all of the above with a Bluesea ML-ACR system. Here's a post I did on my change out but a number of other chimed in and show there install also. https://www.irv2.com/forums/f115/win...ck-540763.html

To get by you could jump across the house and chassis batteries and run your generator to keep chassis charged and engine running.

Your alternator most likely is a Leece Neville Duvac type, the most common recommendation is to rebuild. People have had success changing to a none Duvac type alternator but I hear of more problems then not when doing it. I'm sure others will comment.

jacwjames · 10-18-2021, 10:32 AM

Quote:

Originally Posted by 153stars

I think there is a fuse to excite wire from batt to alt.. Check for fuse and condition of wire connections crimps ect.

Yes, there is a fuse labeled DUVAC, may be in your rear electrical compartment, mine is in a separate fuse holder.

8.3Oilbuner · 10-18-2021, 10:59 AM

Good morning Notn2Bars; If you want to know if the alternator has any output check the voltage at the terminals +&- on the back of the alternator. This, to me, is the first step in knowing if your alternator is putting out voltage! This is a simple test to start with. If no output, at least 13.8+ volts, then you need to move down the line. Also make sure you come off of idle to get a reading. Sometimes at idle the alternator will not start to charge until you get up to 800 to 1,000 RPM's. Give this a try and let us know what you find. As Jim mentioned there is the DUVAC fuse to check and also if the alternator is bad, rebuild is the best way to go.

twinboat · 10-18-2021, 11:16 AM

Seeing a drop between the center terminal and the two sides on the isolator is normal.

Whats not normal is that your only getting 13 volts at the center.

Check with higher RPMs and then the wire connections on the back of the alternator for corrosion , including the ground. Belt tension too.

Otherwise probably have a failing alt.

Timaz · 10-18-2021, 11:34 AM

Quote:

Originally Posted by Notn2bars

We are still on our trip. Took the DW to Niagara Falls, had a great time. Now close to South Bend, Michigan. Looks like our alternator is taking a dump. Noticed the house batteries are not being charged as we go down the road. In addition, the solar panel is not charging the batteries either. Took readings at the isolator and the chassis batteries. The Chassis batteries showed 12.84 volts before starting the coach. After starting the coach, the voltage dropped to 12.63 volts. When we left our dash gauge showed output of a constant 14 volts. Now showing 12.5 volts. Center terminal on isolator with motor running 13.1 volts, bottom terminal 12.70 volts, top terminal 12.85 volts. Not sure what this means. Is it possible that both the alternator and the isolator are bad? All input is appreciated. If the alternator needs replacement, what is a good alternative or should we have it rebuilt? Any reputable and reliable rebuilders in the area? Thanks for any help. God Bless, Ed

Does your electrical bay behind the rear axel look like mine? Look at the picture of the Dual Battery Isolator and see if you have a crack in it like mine did. That is why my batteries stop charging with the engine running. Remove the cable on the isolator marked ALT and bolt it to the one marked chassis and see if your charging the chassis batts with the engine running. If so you found it, just replace it. Easy to find at auto parts stores.

Notn2bars · 10-20-2021, 07:46 AM

Thanks to 153stars, 8.3Oilbuner, Twinboat, Jim and Tim for taking the time to look at the post and offer your help. Cleaned all the connections at the alternator and was able to take readings. Could not locate a fuse labeled DUVAC. Readings at the alternator were: 1. Idle--13.17, 2. 1000rpm--13.42, 3. 1300rpm--13.70. Readings at the isolator during idle 1. House--13.05, 2. Alt--13.18. 3. Chassis--12.66. At the batteries during idle: 1. House--13.05 2. Chassis--12.64. Looks to me like the house batteries are charging but the chassis batteries are not getting enough charge. However the house batteries are being drained while traveling with the inverter running the fridge. The solar controller is not showing any charge going to the batteries. So, is the alternator up to snuff? Is the battery isolator toast? Any additional suggestions? Thank you for your input and expertise. Sorry it took so long to respond. God bless all of you and your families, Ed & Sylvia

windsorbill · 10-20-2021, 07:56 AM

Quote:

Originally Posted by Notn2bars

Thanks to 153stars, 8.3Oilbuner, Twinboat, Jim and Tim for taking the time to look at the post and offer your help. Cleaned all the connections at the alternator and was able to take readings. Could not locate a fuse labeled DUVAC. Readings at the alternator were: 1. Idle--13.17, 2. 1000rpm--13.42, 3. 1300rpm--13.70. Readings at the isolator during idle 1. House--13.05, 2. Alt--13.18. 3. Chassis--12.66. At the batteries during idle: 1. House--13.05 2. Chassis--12.64. Looks to me like the house batteries are charging but the chassis batteries are not getting enough charge. However the house batteries are being drained while traveling with the inverter running the fridge. The solar controller is not showing any charge going to the batteries. So, is the alternator up to snuff? Is the battery isolator toast? Any additional suggestions? Thank you for your input and expertise. Sorry it took so long to respond. God bless all of you and your families, Ed & Sylvia

From your numbers posted, I would have your alternator checked out. Too little voltage, and it varies quite a bit with increase of RPM.

twinboat · 10-20-2021, 08:01 AM

Alternator minimum volts is 13.4.

Have it tested.

Timaz · 10-20-2021, 02:55 PM

What did your test show just bolting the ALT and Chassis battery cables together at the dual battery isolator? (not being connected to the Isolator)(voltage at the chassis battery)

Tim

8.3Oilbuner · 10-20-2021, 10:19 PM

Good evening Notn2bars; As others here have mentioned, you might need to get your alternator tested. I agree with Windsorbill that the voltages seem slightly low. For a comparison on my 01 Windsor that has the Leece/Neville 160 amp alternator that was rebuilt just before I bough the coach from the previous owner. I have a Silver Leaf monitor that gets it's info from the engine ECM and I show at 800 RPM 14.0 to 14.2 volts. One thing you might do as a test is what Tim mentioned to check the isolator. Also you might want to check to see if you are getting any output voltage of the alternator before you have it tested. I do a check on mine now and then just to make sure there is output voltage. Not sure that is the right term. What I do is when the engine is running I set my Silver Leaf to show voltage. It will show 14.0 to 14.2 volts and then I start turning on loads to see if the voltage drops, headlights, fog lights, dash heater fan and the windshield wipers. This is quite a draw on the alternator and I may only see a .01 drop in voltage. If you only have a voltage gauge on the dash this will not tell you anything as the wiring is undersized on these coaches and the voltage gauge will drop with more loads put on the alternator. You would have to check at the alternator terminals as you did earlier for an accurate reading.

You should have a DUVAC fuse in your RR electrical compartment. On the pictures Tim posted you can just barely make out all the fuse holders on the left side of the first picture he posted. You should have a diagram on the underside of the RR electrical bay door and it should identify a lot of the fuses in that bay. On my 01 Windsor it shows the location of the DUVAC fuse on that diagram. I would sure try to locate that fuse before going into a full alternator check. Someone here in the past had an alternator charging problem and was prompted to check the DUVAC fuse. It was blown and after replacing the alternator worked as it should. Sorry for the long post as just trying to throw as much info out there as possible. Good luck Ed!

Notn2bars · 10-21-2021, 07:03 PM

To all of you who have been such a wealth of information, thank you. In regards to Tims question, the voltage from the alternator to the chassis batteries increased when I took the isolator out of the equation. Went from 12.64 to 13.14. Back on the road today and now the real adventure starts. Broke down in Kentland Indiana. The tranny stopped shifting correctly then everything died. Chassis batteries down to 11.7 volts. Was intending to remove the alternator and have it rebuilt when we reached our next destination. I guess we are there

. Evidently the genny is tied to the chassis batteries. Tried to start it, nothing. 8.3Oilbuner, I failed to find a fuse labeled DUVAC, but I did pull all the fuses in the pic and they all checked good. Obtained permission to leave the MH at a busy convenience store about a block away at the intersection. Plan to pull the alternator and find a place to rebuild it. Any suggestions as to a rebuilder in the area? Also pull the batteries and have them charged. In addition find an Oreillys and pick up an isolator. Please pray for 1. sunny, dry weather so I can get this done, 2. Availability of parts, 3. Good rebuilder. God Bless all of you. Ed & Sylvia

windsorbill · 10-21-2021, 08:21 PM

Quote:

Originally Posted by Notn2bars

To all of you who have been such a wealth of information, thank you. In regards to Tims question, the voltage from the alternator to the chassis batteries increased when I took the isolator out of the equation. Went from 12.64 to 13.14. Back on the road today and now the real adventure starts. Broke down in Kentland Indiana. The tranny stopped shifting correctly then everything died. Chassis batteries down to 11.7 volts. Was intending to remove the alternator and have it rebuilt when we reached our next destination. I guess we are there

. Evidently the genny is tied to the chassis batteries. Tried to start it, nothing. 8.3Oilbuner, I failed to find a fuse labeled DUVAC, but I did pull all the fuses in the pic and they all checked good. Obtained permission to leave the MH at a busy convenience store about a block away at the intersection. Plan to pull the alternator and find a place to rebuild it. Any suggestions as to a rebuilder in the area? Also pull the batteries and have them charged. In addition find an Oreillys and pick up an isolator. Please pray for 1. sunny, dry weather so I can get this done, 2. Availability of parts, 3. Good rebuilder. God Bless all of you. Ed & Sylvia

Happens at worse possible time.

Can't you use a jumper cable between 2 sets of batteries (Positive to positive) and run generator while traveling down the road? Then you can take your time to find someone to rebuild alt.
That should keep both sets of batteries charged up.