Temporary Battery

[gus]

As Lin says, the big batts were there to support the AC/heat for the GMs huge blower motor. Up through the 4104 there was a separate engine for the AC compressor but that blower still had to be powered.

The amount of power (watts) used by bus systems is the same regardless of voltage, just simple math. Higher voltage allows the use of smaller wires but the power used is the same.

[luvrbus]

I got Lin that sucks ,Gus if your theory is right isn't a starter a motor ? I don't where the watts came from but a Delco 42 starter can draw up to 1650 amps @10.40 hp the same Delco 42 in a 24 V can draw up to 800 amps@ the same 10.40 hp go figure I just don't buy into the HVAC is the reason for more battery JMO but I have been wrong before

[Jriddle]

We made the trip with very little problems. One thing that happened halfway through the trip is the Not Gen light came on. The light started to come on intermittently and eventually stayed on. It did become intermittent again at the end of the trip for a short period of time. I could hear a clicking sound from under the floor. My gage never came off 28 Volts. I had no problems with the head lights. I really don’t need to fix this problem on this bus but thought it would be good to do some research in case it happens on the other bus and may be good for others to learn. The only thing I didn’t have working was the coach heat. It got a little cold heading north into Montana. I did some trouble shooting but decided that I needed to get going and put on a heavier coat. Any thoughts on this would be good. The bus is a 1980 MC-9.

John

[Jnbroadbent]

We made the trip with very little problems. One thing that happened halfway through the trip is the Not Gen light came on. The light started to come on intermittently and eventually stayed on. It did become intermittent again at the end of the trip for a short period of time. I could hear a clicking sound from under the floor. My gage never came off 28 Volts. I had no problems with the head lights. I really don’t need to fix this problem on this bus but thought it would be good to do some research in case it happens on the other bus and may be good for others to learn. The only thing I didn’t have working was the coach heat. It got a little cold heading north into Montana. I did some trouble shooting but decided that I needed to get going and put on a heavier coat. Any thoughts on this would be good. The bus is a 1980 MC-9.

John

Doesn't the Not Gen light come on when there's zero load? Don't trust the gauge, pull out the multimeter and check.

[TomC]

Unless my alternator (50DN) has a load on it, the No Charge light will come on. I found when the batteries are charged, the light will come on. Hence I run down the road with my headlights and clearance lights on. It keeps the warning light from coming on and it is just safer to have lights on all the time. Good Luck, TomC

[Ed Hackenbruch]

I usually run with my headlights on for the same two reasons as Tom, but if i know that i am getting close to a stopping point for the nite i try to remember to shut them off for about the last 1/2 hour, (i try not to run after dark), to make sure that the batteries have a full charge for starting the next time.

[Jriddle]

When I turned on the heater motor the gauge fluctuated. The heater motor would not come on until the Not Gen light was off. When the Not Gen light flickered that is when the volt gauge fluctuated with heater motor on and I could hear a noise under the floor. What about Air pressure switch?

[gus]

Watts is amps x volts. 746 watts = one HP. and etc. I'm just saying how it works, I didn't design it! This problem doesn't happen with a 100-150 amp truck alt conversion.

A starter motor operates two seconds or less, an AC/heat motor operates hours and hours.

Tom, Ed and Jr - as I said the load is too little and it shuts down many times a minute. My switch didn't stop that but it stopped the AC/H solenoid from clicking itself to death!!

What is the noise specifically? I'm not familiar with MC9 layout so your AC/H solenoid may be under the floor. I'm not sure what an air press switch has to do with this setup but then MCs and GMs are definitely different!!

This is all about a grossly over capacity alt trying to stabilize with our light loads.

[Jriddle]

Thanks Gus

After reading this and looking at two or three recent threads we may all have the same problems. My converted bus had some clicking noise that I could never figure out. It probably all boils down to this A/C heat solenoid. My converted bus never has the Not Gen Light on. I might have to check the bulb. LOL I believe on the MCI the air pressure needs to be above 100 PSI to have the heat or A/C to work.

John

[luvrbus]

You guys ever look at the DD manual the alternator and voltage regulator rebuilding it shows the 50D for all applications,the OEM of the bus screwed the charging system up IMO 

[gus]

The system was fine for its intended purpose, it was never intended for our light loads.

As I said, the AC/H solenoid switch solves the clicking problem, but not what goes on between the alt and reg.

It would seem to me that this constant on/off would overwork both the alt and VR, but maybe not?

My 4104 was converted to a standard 105 amp truck alt and had none of these problems.