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High Chassis voltage
I am working on adding lights in my bays and had some issues. Voltage I’m checking my voltage at the chassis battery and equalizer and note 17 volts and 33 volts, very concerned, help would be appreciated
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10 Replies
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Do not run the engine. STOP!
It sounds like you have a voltage regulator that has an issue and as a result you are getting unregulated voltage which will do serious damage to the point it can start a coach fire.
To be more specific a lot of details are required. But for now make sure the engine is not running, the inverters do not have shore or generator power, then report back with details on whether the chassis or house is getting those voltages.
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Engine is not running and I checked the inverter voltage in the house all seems normal there, the chassis battery is reading 17 volts, I have turned off the mater pier to the coach and emergency battery disconnect
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With shore power disconnected and chassis battery switches off, battery still reads 16.95 volts
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I’m guessing you have a Bosch alternator equipped multiplex coach. I am not familiar enough with how it is set up with regard to alternator control other than to guess the alternators have internal regulators, and that an equalizer is used to keep the relationship between the 12V and 24V systems such that the 12V side is always 1/2 of the 24V side, within 1/2 volt.
Your chassis batteries should be at 25.4, fully charged with the 12 volt side at 12.7, plus or minus a few tenths of a volt. Certainly no more than 27.7 Volts (13.8) with the engine running, and at rest, engine off as stated above.
Continued charging at those voltages is dangerous.
Since Prevost and the converters used multiple configurations for alternators, somewhere between 2 to 4 alternators it appears to me that one of the alternators has a faulty regulator and if you can isolate which it is and disconnect it you can proceed down the road until you get it replaced or repaired.
I would urge you call Prevost PASS and see if they can walk you through attempting to isolate the problem. Based on your previous comments it does not appear to be inverter related.
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
House butteries are reading 16 volts on the multi meter, although the inverter panels suggest 25.5 volts?
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I assume the multimeter is accurate?
The house voltage you state above is OK, but the 16V doesn’t make sense because it suggests an equalizer is not doing what it is supposed to do.
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Do you have any other charger on your chassis batteries? I would think that if your 24v batteries were actually charged to 33v, you would be seeing or smelling something rather alarming. Could your high voltage readings be from another source (like a trickle charger) sending current with the engine off?
i don’t know what all it affects on a newer coach’s computers, but I would want to disconnect the batteries and then check their voltage with no other variables.
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Many apologies guys, it didn’t make sense to my why all the voltages were so high! I used my truck as a Control to test my multi meter, my truck was reading 16 volts too!! I changed the battery in my multi meter, picked up my heart off the shop floor and all seems to be normal, regarding voltages
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
Whew! Thank goodness. Sounds like all is good.
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Thank you for the quick responses, as I was tracing the issue with my bay lights in my driver side bay to figure out the problem I ran across these ridiculous voltages and had a bit of a panic attack. I will go back to diagnostics on a simple light now!
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