Skip to main content ↑ ↓
Topic: Voltage problem (Read 756 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Voltage problem

Yahoo Message Number: 67009
We are having issues with the voltage coming up on our 1997 Country Coach Intrigue with a Cummins big block 325HP Engine.
When we first turn the key, of course, the "wait to start" light comes on. During this delayed start time, if the voltmeter reads 12V or under, after the engine starts, the voltage will never go above 12V, it stays at 12. This was intermittent at first but the last several months the guage will not go above 12V.
For awhile if we used the Battery Boost switch, SOMETIMES, the voltage would be very slightly above 12V while the wait to start line is on, and after starting the voltage would come up normally as long as you hold the boost button down for 30 seconds or so after the engine starts. The last few months even this trick hasn't been working.
Now the only thing that seems to work if we let the engine heat up by driving a short distance and stop and re-start, then voltage has been coming up to 13.8V normally.

So it appears there is some issue with heating up the engine.
When the gauge is 12V after startup, I have gone out and checked the voltage at the battery with my voltmeter and confirmed the 12V is accurate. We have had the alternator replaced, with no improvement. We have also removed and cleaned all battery connections several times.
I am thinking the 2 likely culprits are a bad chassis battery, or an engine heater that is not dropping out either from a bad relay or some other reason. I did have the chassis battery tested at a local auto shop, and according to their tester, it was ok. I am not sure how reliable those testers are, and if the large battery size might throw them off?..

Any suggestions from anyone out there?

Happy New Year from cold and windy Minnesota!

Sandy

1997 Intrigue 10468

Re: Voltage problem

Reply #1 –
Yahoo Message Number: 67011
A faulty voltage regulator might be a third possibility.

Don Seager
2004 Allure

Re: Voltage problem

Reply #2 –
Yahoo Message Number: 67012
Once you start your main engine and the oil pressure comes up an oil pressure operated switch activates the solenoid that connects the positive poles of both battery banks just like manually activating the "battery boost" switch on your control panel so activating the "battery boost" switch after the engine is running should really have no effect. The manual switch on your control just bypasses the oil pressure switch. This is based on my coach installation and wiring diagram.

You can verify that the battery boost switch/solenoid is actually connecting the batteries by running your generator set which turns the charger section of your inverter/charger on whether or not the inverter is turned on. Then the reading you get on your voltmeter will reflect the output of the charger to the combined in parallel house and coach batteries. The inverter/charger usually starts with a relatively high saturation voltage (around 14.4 VDC) so you can note this on the voltmeter almost immediately. Alternators usually put out around 14 VDC or a little less depending on how adjusted and vehicle loads (lights, fans, etc.)

It sounds like either your alternator or regulator is bad and/or one or both battery banks (or one battery within a multi-battery bank) are going bad. Since manually activating the battery boost switch produced changes another possibility might be that your oil pressure switch that activates the battery boost solenoid or the solenoid itself are not working properly.

Jim M

'02 Intrigue #11410 ISL 400
 

Re: Voltage problem

Reply #4 –
Yahoo Message Number: 67020
On my SOB the alternator requires a 12 volt INPUT wire in order to output charging voltage voltage. If that wire is broken or absent you may have the symptoms you describe. Mine was corrected with a rebuilt alternator. I would check and be sure your NEW alternator is functioning properly.

Bob Wexler
SOB