2001 HR Imperial House battery charging issue

[floydfowler]

On 4/23/2019 at 11:09 AM, wolfe10 said:

kriscaughey,

Welcome to the FMCA Forum.

So, the alternator IS charging the chassis batteries but not the house batteries?

If so, you need to check your battery isolator-- may be diode-based or solenoid based. Follow the large gauge wire from the alternator B+ terminal to find the battery isolator.

I am having the same problem on my 2001 Holiday Rambler. I have tried to find the isolator but the large guage wire from the battery post on the alternator disappears into a mass of plastic wire loom and I have yet to be able to locate the isolator.  The inverter is pulling about 36 amps with the refrigerator running but the alternator is only showing about 12 to 14 amps at 14 volts with the engine at idle so I don't think the house batteries are  getting charged.  I checked the voltage on the Duvac terminal with engine off but ignition on and it is showing  12V. I found a good 20 a fuse in the duvac circuit and a battery isolator lockout relay but I think that is for the battery isolator relay which is activated by the battery boost switch on the dash and used to combine house and chassis batteries for starting with weak chassis batteries. I don't know if it is also used for the duvac . I have a wiring diagram for the coach and it shows the ign. and Duvac wiring but only a post for the battery connection and no wiring diagram! 

So, at this point I am stumped and would appreciate any suggestions.

[dickandlois]

The Green box in the picture is the isolator !  They do fail. It is a diode circuit and it is a lot smaller then most I have seen. 

Your system is using an isolator  relay and It could be caring most of the charging current.

A diagram would be easier to fallow then the pictures. Do you have one?

Hope what I have offered helps.

Rich.

[kaypsmith]

I believe this system is an isolator lockout system, it uses a diode based unit and transistors that actually engages the relay in the picture to engage the charging circuit from the coach alternator when it sees current from the coach alternator, if current is present, this will engage the relay to allow charging while coach is charging. I would start with the relay to make sure that it is functioning, if so, then the next place is the chassis wire to the alternator, if no 12 V there while the coach is running, either broken wire or bad connection to the alternator, if not that that, then the circuitry within the alternator. The three black boxes to the left of the green box is either transistors, or relays, all three work in conjunction with each other to cause the the circuit to work. Hope this helps.

[floydfowler]

1 hour ago, DickandLois said:

The Green box in the picture is the isolator !  They do fail. It is a diode circuit and it is a lot smaller then most I have seen. 

Your system is using an isolator  relay and It could be caring most of the charging current.

A diagram would be easier to fallow then the pictures. Do you have one?

Hope what I have offered helps.

Rich.

I thought that device was a battery maintainer (Lambert 415) that trickle charges the batteries while on shore power.

Here is a wiring diagram from panel door and my wiring diagram drawing.

[floydfowler]

1 hour ago, kaypsmith said:

I believe this system is an isolator lockout system, it uses a diode based unit and transistors that actually engages the relay in the picture to engage the charging circuit from the coach alternator when it sees current from the coach alternator, if current is present, this will engage the relay to allow charging while coach is charging. I would start with the relay to make sure that it is functioning, if so, then the next place is the chassis wire to the alternator, if no 12 V there while the coach is running, either broken wire or bad connection to the alternator, if not that that, then the circuitry within the alternator. The three black boxes to the left of the green box is either transistors, or relays, all three work in conjunction with each other to cause the the circuit to work. Hope this helps.

I thought this was the "combiner relay" that was used to boost the chassis battery with the house because it clicks in when I push the aux start switch. I guess it has more than one function.  The alternator is keeping the chassis battery charged while running but not the house batteries with the inverter drawing 36 to 38 amps.

That chassis wire from the alternator is the one I can't find. I have checked the amperage and voltage at the alternator but don't know where it goes from the alternator.

Not sure if I am stepping on any toes by using this thread. Should I start a new one?

[dickandlois]

Floyd, No problem regarding the use of a post that is somewhat relevant to the OP. So many different OEM setups.

From the wiring diagram portion you attached, it looks and the inscription mentions battery maintainer. That holds water because wire gauge is to small to carry a high current load one would see in the charging circuits. So the larger wire (#2  or 4 gauge ) would go directly to the chassis battery from the alternator. 

Could you attach a picture covering more of the drawing on the right ?

Does your coach drawings show the invertor / charger wiring ? The coach batteries are not getting a high current charge from the alternator only about 5 to 10 amps from the green colored module in the picture.

Rich.

  

[floydfowler]

1 hour ago, jleamont said:

floydfowler, what year and model is your coach? 

2001 Holiday Rambler Imperial with cummings 350 ISC

[floydfowler]

56 minutes ago, DickandLois said:

Floyd, No problem regarding the use of a post that is somewhat relevant to the OP. So many different OEM setups.

From the wiring diagram portion you attached, it looks and the inscription mentions battery maintainer. That holds water because wire gauge is to small to carry a high current load one would see in the charging circuits. So the larger wire (#2  or 4 gauge ) would go directly to the chassis battery from the alternator. 

Could you attach a picture covering more of the drawing on the right ?

Does your coach drawings show the invertor / charger wiring ? The coach batteries are not getting a high current charge from the alternator only about 5 to 10 amps from the green colored module in the picture.

Rich.

  

.The chassis wiring diagram is in two parts. Coach is all on one page.

I was expecting the alternator to charge the house batteries at about the same rate  that the  inverter was discharging them (38a).

[dickandlois]

Floyd, I understand, but the wire gauge indicts other wise . That is why I asked for the other part of the wiring. 

For the coach batteries to charge at 38 amps. There needs to be a different path between the alternator and the batteries.

Will be studying the new information for now to see what things are wired like.

Rich..

  

[jleamont]

2 hours ago, floydfowler said:

2001 Holiday Rambler Imperial with cummings 350 ISC

I had a feeling it was an Imperial, that compartment is a clone to ours. 02 Imperial, let me know if you need voltage readings from a specific pair of terminals in that rear electrical bay. 

Where did you get the wiring diagrams ? I could use those!

[dickandlois]

Floyd,  Got to keep looking, interesting thing is the Alternator is pictured; but no cable connected to the battery charging post. 

I might have missed the coach battery and chassis batteries wiring, but just getting started looking at what is offered in the drawings forwarded.

Rich.

[kaypsmith]

Same system that I worked on last fall, the green box supplies the voltage to the relay in the picture to close the relay when it sees current from the alternator. The wire that triggers it is within the wiring harness attached to the alternator not the main output of the alternator. The relay in the picture is also triggered by the aux power in the coach to combine the chassis and coach house batteries. If you push the combiner switch on the inside, then the switch activates, then the relay is ok, need to start checking the green diode box, if that is ok, the three square relays that shows battery isolation in the middle need to be tested, if all three of these are good then the wire on top needs to be traced all the way to the alternator. Pretty simple system but a little complicated as to how it works.

[floydfowler]

2 hours ago, jleamont said:

I had a feeling it was an Imperial, that compartment is a clone to ours. 02 Imperial, let me know if you need voltage readings from a specific pair of terminals in that rear electrical bay. 

Where did you get the wiring diagrams ? I could use those!

If the photos are ok for you I can send you a photo of all that I have. The wiring diagrams are in the back of the HR Manual that came with the coach.

[floydfowler]

1 hour ago, kaypsmith said:

Same system that I worked on last fall, the green box supplies the voltage to the relay in the picture to close the relay when it sees current from the alternator. The wire that triggers it is within the wiring harness attached to the alternator not the main output of the alternator. The relay in the picture is also triggered by the aux power in the coach to combine the chassis and coach house batteries. If you push the combiner switch on the inside, then the switch activates, then the relay is ok, need to start checking the green diode box, if that is ok, the three square relays that shows battery isolation in the middle need to be tested, if all three of these are good then the wire on top needs to be traced all the way to the alternator. Pretty simple system but a little complicated as to how it works.

I know the relay works with the aux power switch.  How do I check the green box?

A little more trivia.... I took it out for a test drive for about 1 1/2 hours with the refrigerator and inverter on. Inverter showed negative 38 amps.   As soon as I got it parked I switched to shore power and turned ref off.  Inverter/charger display shows Bulk charge at  + 90 amps.  In about 20 minutes it switched to Absorb charge at 60 amps.  In 10 minutes it is down to absorb at 50 amps and I read 40 amps at the house cutoff switch.   This is why I am thinking the Duvac system is not working properly since the house batteries don't seem to  be charging from the 160 amp alternator.  I know the alternator has the capacity to offset the 38 amp inverter draw.😬

[dickandlois]

Do you have a current meter with a current loop clamp? 

What is the reading?

Regarding the green box with the 3 wire removed( mark them so they can be replaced the same way they came off.)

Using the Ohm setting measure the resistance between the center connection being negative and positive to the 2 outer connections. wright down the readings for each one.

Then place the positive  to the center and read the resistance for both of them. wright down the readings for each one.

Post the readings relative to the center being negative and the readings with the center being positive.

Rich.

From the information you posted the Charger is working fine when on shore power>

[floydfowler]

32 minutes ago, DickandLois said:

Do you have a current meter with a current loop clamp? 

What is the reading?

Regarding the green box with the 3 wire removed( mark them so they can be replaced the same way they came off.)

Using the Ohm setting measure the resistance between the center connection being negative and positive to the 2 outer connections. wright down the readings for each one.

Then place the positive  to the center and read the resistance for both of them. wright down the readings for each one.

Post the readings relative to the center being negative and the readings with the center being positive.

Rich.

Yes I have a GE clamp on ammeter.  Where were you wanting a reading?  

 

[dickandlois]

Yes get a reading of the current on the 2 outside wires .

Rich. 

[floydfowler]

Positive on center post negative on lower post I read .134 m ohms. Neg on top post I read open. Neg on center and pos on lower post I  read.03 m ohms, neg on center post and pos on top post I read open.

before I took wires off, green led was on indicating charging.  Replacing wires and turning shore power back on no green light.

DW is calling me as it is almost 6;30 in Mooresville NC and she says wine time has started without me!  I will get any other readings you want i the morning.

Many thanks for all of you guy's help.

Floyd

[floydfowler]

1 hour ago, DickandLois said:

Yes get a reading of the current on the 2 outside wires .

Rich. 

Zero amp on both wires.  I guess I should have checked them before I killed the power and removed the wires.  I will turn ref and inverter on i the morning and draw the batteries down and try again.

[kaypsmith]

Okay, done more checking, the green thing called a battery maintainer, is actually a Lambert LE415, 15 amp battery charger, instead of 120 volt ac in, it uses 12 volt dc in and a sophisticated diode circuit inside and is supposed to maintain 12 volts on either side at the rate of 15 amps. If green light is on, it is supposed to be working properly, green light off not.

[floydfowler]

1 hour ago, RayIN said:

Attention Winnebago owners! You will find your specific electrical and plumbing schematics, and parts catalog links here. The only caveat is if someone has previously modified anything.

Not all motorhomes incorporate a BIRD relay into the charging system.

Very interesting information.  I wonder if I have the Bird relay.  I am going to crawl around in the underside compartment where the inverter is located to see if I can find one. 

I have noticed for some time that the alternator light on the dash flickers with the voltage about 14v.  I found that I could stop the flickering by turning on the headlights to add load and the voltage would drop to about 13.5v.  Now wondering if all of this is related.

Thanks for sharing this information.

[kaypsmith]

Floyd, here is some very important reading for you in trouble shooting your situation. https://www.dixie-electric.com/tsb/TSB_704.pdf

Your system incorporates a Duvac (dual voltage acceptance controller), this pdf covers trouble shooting very well.

[kaypsmith]

33 minutes ago, floydfowler said:

I wonder if I have the Bird relay.

The green thing is the same as a Bird relay, you need to be looking at what makes the relay activate for now.

[floydfowler]

1 hour ago, kaypsmith said:

The green thing is the same as a Bird relay, you need to be looking at what makes the relay activate for now.

Excellent information!  I am going to recheck "green relay" with ohmmeter and confirm the readings.

I was curious as to why I would have the Lambert LE 415 as a charger when the inverter seems to be doing all the charging.

[kaypsmith]

1 hour ago, floydfowler said:

Excellent information!  I am going to recheck "green relay" with ohmmeter and confirm the readings.

I was curious as to why I would have the Lambert LE 415 as a charger when the inverter seems to be doing all the charging.

It's only a maintainer designed to keep the battery charged that is not receiving a charge from either the alternator or inverter, if charge is not happening on either then it will not try to charge . If you notice in the original picture there are three small boxes side by side, the one in the middle is marked isolator lockout, the one to the right is not marked, but your schematic signifies that it is a slide lockout. Both of these are connected to the LE415 through a ground bus bar, the ground bus bar is activated by the negative terminal on the maintainer, it appears that the ground bus bar is isolated from chassis ground unless it sees ground from the maintainer. In turn, the large relay, the one with two large wires and two small wires is not receiving ground (small wire on left is normally positive) while a relay depends on both ground (small wire on right) to be activated at the same time otherwise it will not close. The closing of this relay is what causes both chassis and house batteries to combine to maintain charge when the alternator is producing current. If you notice on your schematic someone has penciled in that this same relay is also your auxiliary battery combiner (the switch inside) which actually overrides the lockout system. The lockout goes directly to a delay relay that actuates the large relay by means of signaling the ground ( - ) side of that relay. Hope this helps. Rich emailed me earlier to tell you that he has gone to doctor today and asked me to try to help with your problem while he is away.