Alternator Charging off and on

[clyde1949]

Started the motor today after sitting or over a month and something strange happened, I usually watch the Alt meter on the dash and it takes maybe a min for alternator to charge then stays charging. Always there is a delay for alt to kick in. Today as soon as the motor started it went charge for a few seconds then off then on then off all with in a maybe a min then stayed on after that. I did have 50 amps shore plugged in.

Just never seen it go in the charge immediately then off then on then off then stay on all in about a min

Normal has alway been no charge for maybe a min then charge and stay charge.

Problems ??? dont know

[wolfe10]

Clyde,


Sometimes two charging sources don't play nice together.


Also, quite possible you had a large electrical load from the intake manifold heater thrown into the mix.


Unplug from shore power and see what happens.

[brobox]

The discharge for the first minute is the DEF heater that really draws the amps until it turns off. If it has only done it this one time, I wouldn't not worry about it, my 14 has done that a few times. If it continues if would be the indication that the DEF heater might be going out.

[RayandWendy]

You also have the grid heater running for the incoming air, and that is a big draw.

Later...
Ray

[oldsqueezer]

Hope I'm not hijacking your post. I have what sounds like a similar issue, but it lasts for 20 minutes and the motor keeps dying. It acts like the load, (presumably grid heater), pulls the voltage down enough to interfere with the electronics and causes the engine stall. Anyone think I'm looking in the correct place, or have ideas about other things I should consided?
- Mark

[twinboat]

Originally Posted by oldsqueezer

Hope I'm not hijacking your post. I have what sounds like a similar issue, but it lasts for 20 minutes and the motor keeps dying. It acts like the load, (presumably grid heater), pulls the voltage down enough to interfere with the electronics and causes the engine stall. Anyone think I'm looking in the correct place, or have ideas about other things I should consided?
- Mark

You need to start a post for your unrelated issue. Its not the alternator.

[YC1]

Grid heaters and new to me is a def heater. Didn't know they heated that too.

And yes while plugged into shoreline you can get some strange things. My vintage rv is known for getting an Alternator fail light with the engine running and plugged into shoreline. It is not a true fault, just something that might surprise you.

Then why doesn't it do it with the generator running you say? Because mine has a sense line to separate the charging systems when the generator is running. Shoreline is not sensed by that control module.

[clyde1949]

Talked to Cummins they say its not normal have it checked. Talked to Spartan service center tech they says its normal but is going farther cycling up and down did it 14 times today before locking to on. After starting a few more times today no shore power it finally at this moment i back to normal wait a few sec before full charging again. Found out its not a cummins alt it is a spartan warranty issue if needed.
seems Cummins furnished the motor everything attached to it is Spartan.

Will let you know how it all turns out

[brobox]

If it is cycling 14 times that is not normal. Showing a discharge on startup one time is.

[twinboat]

Are you sure your house batteries were charged before you started up.

The charging solenoid ( battery bridging ) may have been closing and opening over and over again.

There should be a delay between opening and closing but I don't know your system.

The way they function is to close the solenoid and charge The house batteries once the chassis batteries reach about 13.3 volts.
If the house battery is so low that it draws the chassis battery and alternator outputdown below 12 volts, the relay will open, stopping the chassis battery discharge. That lets the chassis battery recover.
It will cycle like that over and over until the house battery charge climbs enough to not drag down the voltage of the chassis.

Just a thought.

[Gary.Jones]

So is the bottom-line here that his house batteries discharged excessively over the month that he was not using the coach and what he needs to be doing is firing up the generator and letting the generator bring his house batteries through the bulk charge phase before he tries to let the engine alternator do all that work? Or, are his Magnum chargers doing their job?

Am I missing the point here maybe, or do I have the gist of it?

The coach alternator should not be depended upon for charging a badly discharged house battery bank..... what was the house battery bank voltage before you started the Cummins?

Gary

[twinboat]

Originally Posted by Gary.Jones

So is the bottom-line here that his house batteries discharged excessively over the month that he was not using the coach and what he needs to be doing is firing up the generator and letting the generator bring his house batteries through the bulk charge phase before he tries to let the engine alternator do all that work?

Am I missing the point here maybe, or do I have the gist of it?

The coach alternator should not be depended upon for charging a badly discharged house battery bank..... what was the house battery bank voltage before you started the Cummins?

Gary

If that was the case, batteries very low, the generator would help, but the alternator can do it, as long as the system worked as designed. They build in safeguards to protect the charging system.

[clyde1949]

Originally Posted by twinboat

If that was the case, batteries very low, the generator would help, but the alternator can do it, as long as the system worked as designed. They build in safeguards to protect the charging system.

Coach is on shore power 50 amps and has been for months I'm full timing in it now

here is a video of the problem
and YES i know its side ways

after 2:35 sec it stabilizes at constant charge


My friend Ron did the Video for me
https://youtu.be/FahvB-aY5to

[clyde1949]

well the bottom line as it turned out is
Spartan says its normal or a loose wire and if it was a problem
it would set a code on the dash and it don't.