Voltage, well regulated, please...

[phorner]

Just to add to the mix, how does the generator battery get charged?

Also, the bus was disconnected from shore power with the engine running, when the inverters displayed the "over charging" condition. I tried shutting them off, then back on, in an effort to reset them, but it made no difference.

[Joe Cannarozzi]

If there was no a/c current being supplied to the inverters and they still displayed overcharge that would lead me to believe you have an inverter fault of some kind, that's just a guess. That is not to say that you don't also have another issue.

These are the most fun, simultaneous failures in a common system.

Your gen battery should be getting charged by the gen. alternator.

Our control panel also includes a second equalizer switch, but 12 volt, that enables us to charge the 12 volt bank of house batts. with the gen. alternator or use the house to jump start the gen. if need be.

If a/c current is being supplied and the inverters are on we can also send a charge to the gen. battery from the inverter by engaging the 12 volt equalizer switch.

This is all stuff that I had to figure out on my own through time and experimentation. Even though we received a full set of converters manuals many of these functions were not discussed and our converter, Hickox, is no longer around.

[Jon Wehrenberg]

Joe, you are 100% correct with respect to your coach. We still don't know from Paul if he has 2 alternators so to answer his last question we need to make educated guesses so I try to remember to phrase my answers in that regard.

I think his generator battery is charged via the inverters when connected to shore power, and via the generator alternator as you suggest when the generator is running. This is a real gray area for me and I am speculating. I believe he has an isolator that separates that battery from the house, so the house battery condition does not adversely affect his generator start battery.

I think his engine charges both sets of batteries independently so I question his common 15 volts on each set of batteries.

Paul, Two alternators? What is actual voltage at batteries with engine running? With engine running and inverters connected to shore power what is the voltage at the two sets of batteries and the generator battery?

You should be able see slight changes in voltage at the batteries as you change conditions, such as engine off, inverters off, etc. because each regulator probably is set up for slightly different voltages. Divide the 24V side of the chassis by two.

[dalej]

The system that I have allows the generator battery to receive charging by

1. The Detroit running, is charging the house, cables connect house batts. to gen. bat. thru an isolator.

2. Generator is running, invertors are charging the house batts feeding current to gen. batt. like in #1

3. Shore power is charging house batts thru the inverter and feeding gen. batt. like #1

Note: a isolator allows current to flow in only one direction so the gen. batt. doesn't drain when the
house volts go down.

[bill&jody]

1. The Detroit running, is charging the house, cables connect house batts. to gen. bat. thru an isolator.

so, does that mean defective (old and tired) gen batt could pull down the house batts, eg. when boondocking?

wmm

[Jon Wehrenberg]

Unlikely Bill,

There should be an isolator. But with a battery tester it is easy to find the condition of the generator battery, or just take it off line by disconnecting it.

Almost 100% of the investigative work can be done with a multitester and some time. Back in the dark ages when I had issues, I would just isolate things one at a time until the problem showed up.

I don't have a clue as to how the generator battery is isolated in all coaches, but on my old coach the "isolator" between the chassis and house batteries for example was nothing more than a big solenoid (relay) that closed when there was charging current from the alternator. If the alternator was working, the house and chassis batteries were joined by the closing of the circuit through the solenoid (relay). As soon as the alternator stopped functioning such as turning the engine off, the solenoid (relay) opened and both sets were separated from one another. Classic simplicity.

I am sure there is some means of isolating the generator battery from the house as soon as charging of the house batteries stops so the generator battery and the house batteries can not adversely affect one another.

[dalej]

Bill, just when you are starting the generator. That is the intent of the cross over, to charge the gen. bat. and to use the house batts if the voltage in the gen. bat. is lower then the house batteries when starting the gen.

[phorner]

As an up-date, there are 2 alternators that are used to charge the batteries on my coach. With the engine running, and disconnected from shore power, the chassis batteries are measuring 27 volts, which sounds fine to me.

However, under the same conditions (engine running and disconnected from shore power), I am measuring 15.2 volts at the cigarette outlet in the dash, which is the only place that I could find to measure voltage directly. Additionally, my analog dash gauge for the house batteries also reads slightly in excess of 15 volts, which kind of confirms to me that the house batteries are being slightly over-charged when the engine is running.

Does this sound like a reasonable conclusion?

I have also found 1 voltage regulator, located on the bulkhead by the chassis batteries and the chassis battery disconnect switches which is adjustable, but I believe that this regulator adjusts voltage to only the chassis batteries, which appear to be OK, reading 27 volts.

Any ideas or comments?

[garyde]

My Alternator provides power to chasis and coach batteries thru the regulator. When the engine was running, and I had a bad regualator, the voltage to my coach batteries went way up into overload. At the same time, my chasis batteries were reading low voltage .

[Larry W]

I am not certain, but I think the lighter may get it's power from the 12V side of the chassis battery system, the same as the 12 volt chassis lights.
On my coach the engine alternator will charge the house batteries at about 15 volts when the engine is first started. As the engine run time increases the charge will decrease slowly to 13.8 volts. The timing seems to be tied to the batteries state of charge. It never seems to stay high for more that 15 minutes max.