ALT/CHARGE light while generator runs?

[USAFFlyer]

Hello All,
I had an interesting situation come up yesterday when I went to run/drive our 1996 Monaco Dynasty. My standard MO is to go and start our coach every weekend, and then drive it every 2 weeks. This was a “drive around” week, so I went and started both the big Cummins 8.3 and the generator, let them warm up and got on the road. The generator was powering a 1500 watt portable heater (for a load). As I began to drive I noticed the ALT/CHARGE light flickering on and off on the dash, and the tachometer dropping to zero then jumping back up to normal RPMs. This sporadic show lasted for 5 minutes, (about 1/2 way through the drive). I then shut down the generator and the problem stopped. Now, I know the tachometer gets its feed off the engine alternator, and I strongly suspect that shutting down the generator “fixed” the problem. But I’d like to know for sure, can anyone offer any information/advice on this issue. Thanks in advance. - Tom

[DriVer]

Quote:

Originally Posted by USAFFlyer My standard MO is to go and start our coach every weekend, and then drive it every 2 weeks.

Tom, I feel that whatever was going on with the generator should not have any bearing on the main engine charging system.

In regard to your opening comment. Personally, I would retire the strategy of starting the machine every weekend and only start and drive the machine every other weekend like you have been doing.

There is more downside than benefit in allowing the machine to simply sit and idle.

If you are going to start the machine - run in on the highway. This brings all the power train devices up to operational temperatures and it will not promote condensation and or any other anomalies from not being completely and totally warmed up, boiled off or ejected.

[Rex]

Tom it is not a good idea to run the engine unless you also drive the coach around 25 miles so the engine is completely warmed up. The Alt light most likely came on due to the batteries being low. You should run the generator once a month for at least 1 - 2 hours to keep the batteries fully charged. If they are low and you start the engine first it puts a strain on the alternator and can cause the light to come on.

[Robi.1014]

Tom,
WRT the ALT light (and perhaps even the tach) acting unpredictable, I think it's because there were two sources attempting (or "fighting") to charge the chassis batteries at the same time.

Here are my assumptions:
1) You have an Inverter/Charger (as most of us do) that will charge the house battery bank when the genset is running.
2) Your rig has the "electronics" that energizes the "Battery Boost / Charging Solenoid" while the main engine is running. If you need more info on #2 here, let me know.

So..........
This solenoid is instructed (via the "electronics" I mention) to activate (close) and thus there is a charge-path from the alternator to the house batteries...and vice-versa: from the Inverter (powered by the genset) to the chassis battery bank. The alternator's regulator doesn't know what to do under this condition and its state of confusion is shown to you via the ALT dash light acting erratically.

[walt2137]

Tom I have heard of that happening before and the solution was to turn the headlights on probaly for the reason that Robi stated

[USAFFlyer]

Thanks guys, it's always nice when folks are willing to share info! - Tom