Good morning,
It is a combination of my inexperience with Prevost ownership coupled with the converters desire to create a better mousetrap. The trap is created when the converter changed the regulator battery lead to monitor the house as a primary monitoring source and not the chassis. In a perfect world the Vanner balancing device would keep everything in check, but there was no provision made for an Isolator failure that also housed the jump start solenoid.
The isolator (long blue cylinder with fins) on my bus had 3 lugs and 2 smaller lugs for the jump start, a House lug, an alternator lug, a chassis battery lug and a 2 wire jump start lug for emergency starting. The isolator had the capacity to open the current flow in one direction, from the house side across to the chassis side for a period of seconds while depressing the switch inside the bus. I took a look at a few other buses while at Prevost to check out other installs, and found that some had a simple Solenoid that had both house and chassis at either side separate from any other isolator for this purpose.
My decision after viewing what happened was to replace the isolator with one that could not allow for the jump start feature, in other words it cannot pass (should not) current across from either source. This way I should not be able to fry my chassis batteries in the future. I plan to install at another date simple solenoid and provide a connection from the house and chassis batteries for this purpose, as I retained the 2 wires from the switch inside the bus.
When I do go to Prevost car for service and pay the long dollar, I try and get an education when possible, spend the entire day right next to the mechanic, as his grunt, holding, fetching, and asking questions and taking notes. I even ask in advance if they do not mind if I tag along and stay close at hand for the day. It does add a few minutes to each hour, but I figure that the investment allows me to add Prevost school credits to my education as an apprentice.
Here is one I learned. Did you know that the lugs on all terminals for the batteries, all ground wires to the chassis are required to be torqued to 13 LBS?? I did not and was told that it is the case. At each connection the mechanic would take a razor blade and scrape the metal and make sure the contact was clean on both sides before replacing each wire.
Battery condition: I was always under the impression that if each battery, disconnected from the rest of the bank read lets say 13 volts they were ok. Not so, there is a meter that reads the condition and the ability to maintain a charge and readout if the battery is either dead or on its way. I have been wrong about this for my entire life, no clue.
the final take away from the whole deal is that when you have low voltage you get high amps, and based on our buses and the power demands one should look at the batteries first. The next issue is a short to ground that causes an increase in current, wiring harness for the brakes or bulbs that are shorting out to the chassis.
Finally when driving down the road without the genset operating and all converter power coming from the house batteries the alternator will come on at some point to maintain voltage to the house batteries. I did notice a slight increase in the voltage from the chassis side .2/10's, .5/10's maybe as the ride continued along 4 hours or so. I have decided to knock back the regulator output by .5/10's volt today. I do not want to see the output exceed 28 volts from the chassis side.
The other solution is to add a second alternator, dedicate the big old beast, 270 amp alternator to the house and include a smaller one for the chassis. Not a small operation and not cheap, will stay where I am for now.
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Originally Posted by 0533
