The generator and the alternator

[Joel Ashley]

I know enough to make sure my house batteries are charged up before driving away from camp, and the reason is to save wear and tear on the alternator.

But after a rare several days of dry camping recently, and anxious to hit the road, I naturally wondered just how far along the state of charge should be before one can expect little alternator hardship.  This came from keeping an eye on the inverter panel for a couple of hours of running the generator.  Obviously, cranking up the CAT while the charger is in a state of Bulk Charge isn't advisable, whereas Float Charge is a safe status to drive off in.

In between is Absorb Charge, where the voltage is well over 14 and the amps drop from around 90 as time passes.  But do I really have to wait for the charge rate to drop to Float, or is there an earlier point during Absorb where I could begin my day's trip without worrying about overworking my alternator?

Joel

[Edward Buker]

Joel,

90 amps would need to be furnished by the the alternator if not being supplied by the generator. It may be somewhat less depending on the regulator charging profile but not vastly different. In that case just run the generator along with the engine and alternator for awhile and drive. Assume that each source is supplying half current and when you reach maybe 30 amps on the inverter feel free to shut it down. The alternator can handle the approx 50-60 amps continuous that will be required. These are approximate values and the cooler it is out, the better the alternator can tollerate higher current output. If it was very hot out I would maybe run the genereator a bit longer.

Later Ed

[Dick Simonis]

Joel, while I don't know much about the specific generators installed on our engines, it's unlikely they are equipped with a 3 stage regulator....most likely a simple voltage sensing device that cuts back the charging current once the set point is reached.  More like the bulk charge feature on the inverter.  As such, if your charging voltage has reached the absorption rate you should be good to go as the voltage is already in the 14V range.

Still, a lot would depend on the alternator installed on your engine and how much house power you're using which is additive to the battery needs.  One would think that if you have a 160A alternator, it should easily supply 80 to 90 amps without overheating.

I routinely ran my high output marine charging system a full capacity without problems, but, as has been explained the air circulation on out diesels is much less efficient.  Still, I would think the it should safely run at 50-60% of max rating.

[Joel Ashley]

Not being in the habit of running the genset at the same time the CAT is guzzling fuel, it didn't occur to me I could simply do that when I'm late getting under way... Duh.  A little extra fuel is cheaper than a new alternator.  In this midwest heat, the buscuit burner has occasionally talked me into running the generator and roof AC while on the road anyway, since the dash air is minimally effective at speeds over 35 mph.

Though it would be tough to see the inverter panel from my seat, I reckon driving down the road I could guess when the genset had been on long enough and the alternator out of harms way.  Or pull over briefly to take a gander at the panel and charge progress and status.

Thanks fellas.  I really appreciate your input.

Joel

[215]

Joel
[justify][/justify]
On my coach the Magnum planel does not indcate a charge from the invertor/charger when running the generator while driving.  On examination of the BIRD, the Bi-directinal Isloator Relay Delay-Diesel 2 located in the battery compartment does not have a wire connected to the generator pole.

According to the manual I downloaded from Intellitec, "A Gen Set lock-out is provided to isolate the batteries to prevent conflicts if both the  converter/gen-set and alternator are trying to charge the batteries at the same time.  When this conflict occurs, it can cause the dash alternator light to illuminate in error and may cause 12 volt circuit breakers to trip.  If the Gen Set is running, the chassis battery and coach battery will be isolated.  In this case the chassis battery will be charged by the alternator and the coach battery will be charged by the Gen Set.  In the event that the chassis engine is not running, the chassis battery is isolated and will not be discharged by auxiliary loads."

Since the Bird is not receiving a Gen Set signal I assume this is why the Magnum charger is blocked from charging.  I was wondering if your's and others Gen Set pole is bare and if anyone knows why Monaco would not have connected the Gen Set pole.

Dennis

[Brad Burgess]

Hello All

I posted about this BIRD issue in the past - search for BIRD on this board.  What Intellitec doesn't realize is that there are parasitic loads on the chassis battery when the coach is idle, whether in storage or not.  By isolating the batteries if there is a voltage sensed on the generator tap of the BIRD it becomes impossible to charge the chassis battery by running the generator when shore power is not available.  I discovered this when my 03 Monterey was in storage with no shore power available.  Disconnect the wire from the generator tap on the BIRD and you can now charge both battery banks with the generator when shore power is not available.

NOW, my 06 Monterey is like dennis' - no wire on the generator tap.  There is a second wire going from another tap (can't remember which one right now) that goes to a relay that controls I don't know what.  I do know that when the engine and generator are both running the Big Boy is combined.  I will check tomorrow to see if the Magnum shows a charging state when both are running.

I used to be concerned when there were two charging sources going to a battery bank but I have done it for years on cruising boats and coached with no ill effect.  I believe that Intellitec is wrong in trying to prevent this at the expense of being able to charge chassis batteries with the generator.

Kindest Regards,

Brad Burgess
06 Monterey