Electrical problem???? prevost XL

[jgm]

Everytime my condensor fans kick on for the bus A/C my voltage drops from 30volts to around 26volts for a split second and this causes my speedo to start the test just like when you first turn the key to the on position And my detroit diesel drivers display resets also just like when you would first start the coach..   And sometimes cause my trans to jerk for a split second..    And now my Trans is shifting funny from 2 to 3rd almost like it is slipping..  I'm thinking its an electrical issue..   Maybe a bad Battery???  I'm going to start working on it tomorrow.. Any ideas would be great..  It is a series 60 and allison B500
Thanks Jamie

[Brian Diehl]

Jamie,
It most likely is dropping your voltage much farther in order to cause resets on your electronics.  The first thing you should do is validate all wire contacts from the batteries are clean and tight.  Also verify all ground wires are clean and tight.  It would be a good time to take each connection apart and clean up the contacts so they are bright.  Do this with every connection starting at the batteries all the way to the AC condencer and evaporator fans.

The other thing to check is the wiring to the voltage regulator.  On my MCI I had to run new heavy guage wires directly from the battery to the voltage regulator so that it would regulate the alternator accurately and fast.
-Brian

[jgm]

cleaned all battery connections and it fixed the issue..
Thanks

[Hartley]

You shouldn't be seeing 30 volts on your 24 volt system.

Maybe 27 while under full charge. Unless you have a battery going bad
causing the load to swing wildly.

Your alternator is surging at the 150+ amp load of the a/c blowers and there
is a slight delay until it ups the charge current. A bad battery will cause that drop and surge.

Dave.....

[buswarrior]

Is the "30 volts" being read on a dashboard gauge?

Check with a proper volt meter to be sure, but I expect it's just the usual wonky calibration and the voltage will be fine.

OEM dashboard gauges are NOT precision instruments.

Use your volt meter, infrared heat gun, etc, to identify the reality point on your particular gauges.

Be aware, my daughter reports that quite a hurricane comes up through the floor access while shooting the coolant output from the engine at highway speed...

happy coaching!
buswarrior

[Don4107]

"Be aware, my daughter reports that quite a hurricane comes up through the floor access while shooting the coolant output from the engine at highway speed..."

A little bit of noise accompanies that wind too!!!  They don't call them "Screamin Jimmies" for nothing. A pair of ear muffs are a good idea.   On the trip home with the 4107 as an insulated and sheeted shell, it made a real good echo chamber when the hatch was in place.  When the son opened it at speed without warning me I thought we had a BIG problem.

Don 4107