-
Chassis voltage
Should the chassis alternator put out
13.5 Volt measured at the battery? I assumed the voltage should be around
28.6 volts when engine running. Any feedback would be great.Also where is the
voltage regulator for the chassis located, and is the same regulator works for
both house and chassis?.Hish
-
19 Replies
-
. What does your Tech Link display ?
I’am using a picture that displays both systems on Marathon Tech Link . Engine was at idle taken when I had a “261” display which was due to faulty donut cable reader in the house battery compartment. It’s my understanding all voltage regulators are housed internal in respective alternators
-
Hish,
What is your pro driver saying on the dash? 13.5 is about right.
Later
bv -
Al
The Techlink is only showing the house battery voltage and house alternator output voltage.
Bernie
The Pro Driver is at 26.5 while the engine is running one would think it should be at 28.volts.
Hish
-
We have to be wired different Hish. Mine runs at 13.3 to 13.7
-
Bernie
But shouldn’t be 14.4 volts when the engine running, the chassis batteries are lead acid filled batteries just like the car batteries.
Hish
-
According to the Prevost service manual the voltage regulator should be set to a voltage of 27.5 volts so with the engine running the voltages under normal conditions should be 13.7 or 13.8 and 27.5 volts.
The engine electrical monitor will display hi or lo voltages if the voltage exceeds 30 or is less than 24.
-
Jon Can I adjust the voltage regulator to 13.7 volt, and where is the chassis regulator located is?
Hish
-
Hish,
First, check the voltage at the battery bank. Then make sure you don’t have Lifeline chassis batteries. If you do, then 13.5/27V is good. If you don’t and read the same 13.5/27V then adjust regulator after first checking each battery in the bank’s voltage at rest. Each should be 12.8V or higher. If one is lower you may have a bad or failing battery.
-
Hish,
Your voltage regulator should be on the bulkhead above the chassis batteries.
However, not all our coaches are set up the same way and not all of our alternators are for the same purpose so keep in mind any information here may not apply to your coach or others.
The Prevost service manual presumes your 50DN is a 24 volt alternator and it is used to charge the chassis. Your converter may have used it to charge the house batteries because it wanted its large output to handle running some air conditioners through inverters. In that case it is possible you have a smaller second alternator for the chassis, and those smaller alternators typically have internal, non-adjustable voltage regulators.
To add to the confusion, some coaches have 12 volt 50DN alternators for the house.
I have no experience with how your coach is set up so if your problem is related to the chassis make sure you understand how your converter has set up your coach to keep the chassis batteries charged.
If you only have the single 50DN alternator you can adjust the voltage regulator but keep in mind it is charging the house batteries and you do not want to deviate from the charging voltages the house battery manufacturer calls for.
-
Jon
Thanks I do have both
the chassis Delco Remy 75 amps and house alternators one is a DN 50 270 amps.
The Delco Remy 75 amps that charges the chassis battery may have the internal
voltage regulator. I will check with Marathon on this issue.Gil
All of my engine
batteries are lead acid, the house batteries are Lifeline and charge on these
should not exceed 28.4 volts. -
Hish,
I am almost certain the small alternator is for the chassis and that you have the internal non-adjustable voltage regulator.
If your chassis voltage is somewhere around 27 to 28 it is working fine and you don’t have to do anything, but if not you might want to pursue that problem.
-
Hish,
Okay, you have 2 alternators and your house bank is 24VDC.
That should mean that the monster 50DN is for the house bank and it has an external regulator, almost always adjustable. The really smart converters on late model coaches may have went to the expense of installing a smart 3 stage regulator to ensure your Lifelines are charged as they would be from your inverter/charger. I have seen this on one coach. Lacking a smart regulator, it should be set for 26.4-26.8V. This is Lifeline’s float voltage. Your automotive alternator should never be set for a voltage greater than float voltage for your house bank. The reasoning is that your engine may be running for a much longer duration than your Lifeline would like above float voltage.
Your smaller alternator should be for the chassis batteries as the current requirements are not very demanding. The only exception would be for those that have Prevost OTR air as it’s powered from the chassis batteries or it was when sold by Prevost. As Jon, said, it should have an internal non adjustable regulator. With that said, there are smaller alternators that are used in marine applications that can be coupled to adjustable or smart regulators. I haven’t seen one of these used on a coach, but there’s no reason they couldn’t be.
There should not be a 12V alternator or regulator on your coach if the house battery bank is 24V. 12V demands are satisified through a battery equalizer that should supply 12V, actually supply half of what ever the 24V side is actually producing. This is not adjustable.
-
Hish,
What Gil is talking about is where it get’s confusing and I’m glad he explained it.
I have a 100 amp for chassis and a 270 amp for house and both are 24 volt alternators, the battery equalizer gets me 12 volts on the chassis side. Tell me if I’m wrong guys but that is the way I believe it works.Later
bv -
Actually if your converter has provided a 24 volt house, it is likely that in addition to the equalizer provided by Prevost for the chassis there is a second equalizer for 12 volt conversion loads such as the dash radio and multiple other 12 volt devices that the converter installed.
This entire topic gets confusing because each converter seems to have created the house electrical system in their own way. Hish has one such approach using the 50DN primarily because he likely does not have OTR and his converter set up the house electrical system to run one or two house air conditioners through the inverter.
Other converters have used the 50DN as the sole source of alternator, using an isolator or some device to separate the house and chassis so one system could not draw power from the other. Usually when this happens the coach has OTR and the 50DN output is needed to satisfy the current draw on the OTR.
Some have used a 12 volt 50DN as the house battery alternator on a pure 12 volt house coach. The separate alternator for 24 volts would handle the chassis which would not have OTR.
I know batteries do not like to get a heavy dose of excess voltage, but I have never had any issues with my house batteries that saw the same voltage as the chassis batteries for extended periods.
-
Hish…From your questions I have one. When charging issues are posted here and based on wanting to adjust charging rates…I’am reminded of this…
Have you checked your batteries each one separately ? I know it’s a pain but this is where to start.
A weak battery in the group can be the source of charging issues. Chassis batteries live in a very harsh environment.
Log in to reply.