NO GEN

[peterbylt]

After Staying at the Withlacoochee River Park for four days we headed home, the No Gen Light came on when I started driving.

I thought, this is bad, I know those 50dn alternators are expensive.

I also knew I had a mechanical engine and could probably make it the 75 miles home since we were already running, as I drove, I noticed that in bright sunlight the No Gen light would come on and turn off when under clouds.

I had just added an MPPT charger and put in a switch to connect two of the solar panels to keep the Start batteries charged when the bus sat for any time.

Apparently, the Solar charger and the Buses regulator don't play well together.

I tested the voltages on everything when I got back to the yard, everything seems to be working correctly when the solar charger is disconnected and the Solar works when the bus is not running.

I've updated the preflight check list to disconnect the Solar from the start Battery when driving.

Peter

[richard5933]

Good find.

This is similar to people who run their generator while driving so they can run the a/c and forget that the 120v battery charger is running. The bus's regulator won't play well with others and will decide to shut down, causing the No Get light.

[David Anderson]

Kind of makes sense they don't like to play with each other.  I have a 500 amp solenoid to merge my house batts with the bus batts/alternator.  When running the genny, the solenoid is disconnected.  When no genny, merged. 

I notice that my Trace inverter sheds its charging amps to the house bank when the genny is running which makes the alternator pick up more load.  I don't want it to carry that extra load.
That is why it is not merged when my genny is on.

Apparently your alternator/generator is shedding its load when your solar kicks in with lots of sun power. 

I lost my alternator once, pulled the belt and drove 100 miles on battery power no problem.  If needed, however, I could fire up the genny and merge the Trace inverter to the dead alternator and continue charging my bus batts going down the road.  It would not be a trip killer for me.  Redundancy has its advantages. 

David

[buswarrior]

Just to be sure for the other readers...

The coach charging system has worked exactly as it is designed to do.

Unable to pass a charge, whether the batteries are full, or wires broken, or alternator failed, on goes the "No Gen" light.

Happy coaching!
Buswarrior

[luvrbus]

You can update the regulator for the 50DN alternator, but it may not be worth the $350.00 cost to solve the problem though

[lvmci]

My 8V92 had what sounds like the same problem. NO GEN light would flash on and alternator gauge would drop dramatically and then back to normal. After months of doing that, then when the NO GEN light would flash on, then the check starter light would come on for seconds,  then they would both go off, and alternator gauge would return to 26 volts. Staurt Steven's mechanics in Denver had the experience to recognize it as a MCI recall notice, named the Dual Function safety regulator modification, Jim McClain at MCI tech support will tell you about this kit to correct the problem...

[Lee Bradley]

My charging system did the same thing. Bright sunny morning and as soon as the solar system brought the battery voltage above the charging regulator voltage the regulator shut down the alternator and the charge light came on and the tach went to zero. That got my attention but when we went through the shadow of some trees beside the road the light turned off and the tach came back. My tach runs off the 'y' connection of the alternator, so when it shut down so did the tach.

[Bill Gerrie]

I put a relay in the solar charging circuit so if the engine is running the solar is cut off. No problems since.

[TomC]

My 10kw Powertech generator is hooked to the starting batteries of the coach. We run the generator going down the road when the A/C (roof top is our only A/C) is needed. Would you believe that the tiny alternator on the generator caused the no charge light to come on the dash? I disconnected the wires from the generator alternator and problem solved. The regulator on the DN50 (I have the new digital regulator-about the size of a pack of cigs) is very sensitive. That's why also I run with my lights on. If the 50DN isn't charging, the no charge light comes on. Good Luck, TomC