Can not explain it

[StillRunning_60]

Never have had this happen before but was Packed and ready to head south Sunday morning with a night of temperatures in teens when my alt charge light would not go off. Had used my engine heater switch on all night which I can’t ever remember using before. After several attempts at trying different solutions I final disconnected from shore power and to my amazing eyes but light with out. Someone explain what happened.

[waterskier_1]

It is a know anomaly that when running the main engine alternator charging combined with charging from another source, usual the generator operating A/C going down the road, but also when connected to shore power, and occasionally Eben solar power.  The Alternator Sense circuit gets confused.  There is no damage. 

[gburgman2000]

When we run we always turn on our headlights then we never get the alarm as there is enough drawn to offset the over current alarm. 

[bikedavem]

My solar system will charge both the house and chassis batteries. When en route the alt light will come on once the voltage and/or current from the solar charge controller meets all of the needs that the alternator would normally be meeting. This serves me as a secondary indication that my batteries are fully charged. I'll usually turn off the solar system at the nest stop so I don't keep seeing the alt light.

2002 HR Endevour

Edited February 23, 2021 by bikedavem

[96 EVO]

14 hours ago, waterskier_1 said:

It is a know anomaly that when running the main engine alternator charging combined with charging from another source, usual the generator operating A/C going down the road, but also when connected to shore power, and occasionally Eben solar power.  The Alternator Sense circuit gets confused.  There is no damage. 

I've heard of this happening, but never seen it myself.

[Ivan K]

1 hour ago, 96 EVO said:

I've heard of this happening, but never seen it myself.

Me neither and I know my alternator light works. 200 amps LN and theoretical 1000w solar. Gen or not, have not seen it yet.

[Larry Laursen]

The event we are discussing here depends on the coach model and year.  On the early Sig, Dynasty, Exec. and Navigator 2000-2003 or 04 Monaco installed Cole-Hersee battery isolator devices on these units.  The battery isolator was a solid state device that was connected to the engine alternator and the 2 outputs went to the house and chassis batteries.  Thus there was no hard connection between the house and chassis batteries.  The voltage regulator got it's signal from a separate sensing wire to the chassis batteries.  These units use a DUVAC equipped alternator.  This system was changed at different times so the model years may not be totally correct.  My reference is the wiring diagrams for 2003 Sig, Dyn, Sig and Nav.  Newer models used a variety of systems, so in-house developed and some with purchased components.

On units built in Indiana the system was totally different.  On these units they installed an interconnect relay either a White-Rogers or Trombetta that was controlled by the Intellitec interconnect relay delay (IRD) device.  On these units the house and chassis batteries are hard wired together through the interconnect relay after the chassis batteries reach about 13.2 volts.  Thus, when you start the engine and have it running for a period of time the relay is closed and the alternator is charging both sets of batteries.  If the generator is running or you are connected to shore power the house batteries are being charged by the inverter/charger.  When this voltage exceeds the charge voltage of the alternator set by the voltage regulator you will get the warning light.  The warning light is triggered by the field voltage on the alternator and the voltage regulator controls it.   On some units such as mine there is another relay in the system that disables the interconnect relay when the generator is running.  This means the chassis batteries are not being charged by the generator and if you dry camp for a period on time you may discharge the chassis batteries.  I installed another relay so the interconnect relay is disabled only if both the generator and engine are running.  The Windsor and Imperial models used the dual battery system from about 1998 - 2004.  

So again what you have on your individual unit may or may not apply to what someone else has.  🤔🤔

[dl_racing427]

My 93 Dynasty has the battery isolator, but no separate sense wire to the alternator. 🤯
The alternator output is adjusted approx. .6v higher than normal to compensate for the diode drop in the isolator.

My genset also has a battery charging alternator, which was only connected to the chassis battery.
I added a relay that closes whenever the genset is running to connect the battery banks together, which greatly reduces the time needed to recharge the house batteries.

[Larry Laursen]

David,

I don't doubt that your 93 Dynasty doesn't have the sense wire.  This just points out the value and challenges of this group.  The value is that we have a wide range of experience in the group to cover the wide range of units.  We are covering about 30 years of time and a broad range of models that have much different prices ranges.  The units also have many different options and accessories.  Thus, when making a somewhat broad statement as I did, there are always some exceptions.  I did give a age range outside of your unit by several years.  I am not familiar with coaches that go back to the era of your coach, so I try not discuss anything earlier than 2000.  The original poster had a 2002 Windsor which had the dual charging system installed at the factory.  Others were giving their experience with coaches that had a much different charging arrangement.  I was just trying to say, to the OP you don't need to look for some of the parts others were suggesting because his was different. Also many coaches have had modifications after leaving the factory so it's nearly impossible to state exactly what's on an individual coach.

All input is good from everyone.

[dl_racing427]

Larry,

I wasn't calling you out, I was just illustrating what you said, that different coaches, from different eras, can have quite different configurations.

Thanks,

David

[Rikadoo]

So heres my 2cents worth, when i was in the working world my job was a Mechanic for ford, i focused on electric issues. I discovered like it was said earlier that the voltage regulator “OEM parts” have two events that trigger the light to come on... One is when battery voltage falls below operating voltage an the other is when the operating voltage goes over the set voltage. Even with leese neviel alternators on ambulances an fire trucks if it still had the OEM regulator the “warning” lights worked the same because both situations can be a problem if left unattended. Where all that falls appart is in the aftermarket parts... they know there “less than perfect” parts cost more if they put in all the safegaurds, thats how they can be competitive.

[Mel S - '96 Safari]

On 2/26/2021 at 9:34 AM, Larry Laursen said:

David,

I don't doubt that your 93 Dynasty doesn't have the sense wire.  This just points out the value and challenges of this group.  The value is that we have a wide range of experience in the group to cover the wide range of units.  We are covering about 30 years of time and a broad range of models that have much different prices ranges.  The units also have many different options and accessories.  Thus, when making a somewhat broad statement as I did, there are always some exceptions.  I did give a age range outside of your unit by several years.  I am not familiar with coaches that go back to the era of your coach, so I try not discuss anything earlier than 2000.  The original poster had a 2002 Windsor which had the dual charging system installed at the factory.  Others were giving their experience with coaches that had a much different charging arrangement.  I was just trying to say, to the OP you don't need to look for some of the parts others were suggesting because his was different. Also many coaches have had modifications after leaving the factory so it's nearly impossible to state exactly what's on an individual coach.

All input is good from everyone.

David

Well said 👍 because (No 2 Coaches are the same)