Two Issues at Start Up?

[reubenray]

I had two different issues happen yesterday as I was getting ready to go fuel up my motorhome. I am leaving in a few days for a month long trip and if I have an issue I want to fix it before I leave.

The first one was a light came on the dashboard while starting the engine about a low battery. It started OK, but why did this do this. I keep my motorhome plugged up to 50 amp power and I check my control board all the time for the voltages. Every thing has been OK. I only had to drive about 5 miles to the diesel station and when I restarted the engine to come back home everything was fine.

The second issue was when I put the motorhome in gear after releasing the brakes a loud sound was made like the jacks was being raised or lowered. My jacks was already up and I have been parked that way for weeks on the tires and not the jacks. I put it back in neutral, re-engaged the brakes and checked the jacks and they were all up. When this happened it depleted the air pressure. Once it built back up I was able to drive away with no issue.

[DrPhil]

Was the low battery issue due to the brief period of time wherein the glow plugs are warming and nominally depleting the starting batteries? I think if you try to start at the same time before this cycle completes, the battery will experience an abnormally high current drain. Just guessing, but this may pull the voltage really low, and set off the sensor. On the loud sound, was it like a ‘bang’? My old FL chassis would do this when the brakes were engaged for a time - especially through changing weather. I don’t know for sure, but I was told that it is the drum brake shoes disengaging from the drums with a bang. Have never heard with my Spartan K2 - disk brakes all around.

[ewlee]

Your low battery was a result of the air intake heater grid being on due to the outside air coming in being cold. NOT TO WORRY.

The bang from releasing the brakes could have been the brakes releasing especially if you have gone trough warm spells, cold spells cycles. When you said it dropped your air, how much did it drop? Could have been your brakes or an air bag popping.

[Winemaker2]

Agree
I get low batty warning frequently when doing cold starts.
Also agree bang likely brakes.
I'll bet you won't hear it again while using it regularly.

[twinboat]

The low voltage is the grid heaters in the intake manifold of the engine. When you start a cold diesel, they can smoke. The heaters warm the air going in, to limit the smoke. They draw a lot of power and at idle, the charging system is a bit overloaded for a short time. Very normal


The noise was probably the brake shoes breaking free from being rusted to the drums. The brake shoes have some metal in the compound and over time, can rust to the drums.
Parking them when wet or in humid weather can cause this but again, not a big deal, as long as they break free.

[NealC]

As others have said, low voltage - ignore.

What you may want to do after the coach is sitting for a bit even with jacks up is press the all retract so the jacks can ensure they are in the up and stowed position securely, even if visually up. I had my system come on once while driving and I think it detected a slight creep down so they were resecuring in the up position.

[reubenray]

Several responses mentioned cold starts may be the issue. The temperature was in the mid 40's when I did this.

Would the brake pads responses deplete the air pressure?

[DrPhil]

Preheater will be running at that temp for sure- maybe all temps, but I’m not sure. From where to where did the air pressure drop? Front, rear or both?

[Damion]

How old are your batteries?
Have them load tested before you hit the road!
Most auto parts will test for free and most will check charging system at the same time.

[twinboat]

You said you checked the levelers. If you cycled them and the suspension drops before they deploy, when you switched back to store, the suspension would use some air from the tanks.

You also set and then released the parking brake, that will use some air also.

[reubenray]

Originally Posted by DrPhil

Preheater will be running at that temp for sure- maybe all temps, but I’m not sure. From where to where did the air pressure drop? Front, rear or both?

Both

[reubenray]

Originally Posted by twinboat

You said you checked the levelers. If you cycled them and the suspension drops before they deploy, when you switched back to store, the suspension would use some air from the tanks.

You also set and then released the parking brake, that will use some air also.

I checked by looking which is part of pre-drive inspection.

[reubenray]

Originally Posted by Damion

How old are your batteries?
Have them load tested before you hit the road!
Most auto parts will test for free and most will check charging system at the same time.

About a year. I am scheduled for FL service in a week.

[DrPhil]

Originally Posted by reubenray

Both

That’s puzzling...