[les korcala]

We are traveling from KS -TX-NM-AZ to California , its long trip and I noticed our engine battery showing only 12,7 Volts on the digital board & on our dash in analog gauge under 12 V

I checked battery cables and they are super tight , and cables are very clean near the clamps.
When we used Generator at rest stop the levels are 13,8 V
I tested Battery and was 13 + V right at the posts , but that was right after we stopped generator.
So , my questions is while driving is the battery should be around 13+V or under 13 Volts is normal?
Batteries are only in second season and we got them from Newell Also, I regularly check the water levels.
I also check my drive belts and they are tight!

We been on the road now 16 months and drive about every 2 weeks to every month and always battery showed fully charged ar around 13 V while driving!

[encantotom]

les,

it should be above 13v. more in the 13.6v range.

it is likely not your batteries. the ddec will be a more accurate reading than your dash gauge.

it is most likely your connections from your alternator to the battery or the voltage regulator.

i have the huge 50dn oil cooled alternator and it has a separate voltage regulator that you can adjust the output voltage on and i have done that.

the other alternators likely have an internal voltage regulator.

i would clean and tighten the cable from the alternator to the battery and and the ground cables.

tom

[les korcala]

Thanks Tom, I will try that..

[lbrachfe]

tom,
How do I adjust the voltage regulator and where is it ?? I have the same alternator as you and I assume the same regulator....

[encantotom]

it is in the electrical compartment accessible from opening the engine rear hatch. the big one at the rear. the electrical panel behind the door under the hydraulic fluid tank.

on mine, the upper left is a delco remy voltage regulator. on it will be a hex set screw. that is a cap. remove that and there is a small flattip screwdriver adjusting screw. turn it ever so slightly i believe clockwise. the engine and regulator should be warm. you can look at the voltage on your silverleaf or put a voltmeter where the alternator delivers voltage to the battery.

turn it gently.

you will not need to turn the screw very much, so start slow. when you are done, just put the set screw back in snug

tom

[encantotom]

by warm, i mean you should be running the engine for 10-15 min at high idle with the headlights on bright and dash blowers on to consume as much current as possible.

tom

[les korcala]

Okay looks like we have bad alternator ! when I pulled to the stop to check the voltage on the Battery insulator center post, my wife fired up the engine since its needs to be running in order to check for bad alternator, smoke and loud sound came out of the belts and alternator pulley, we stopped the engine!

I pulled both belts off and pulley si frozen solid!!!

We are super close near Mexico nothing around here to trust , just bunch of dust haha!!
I need to get new alternator and plan is just to cruise with out the belts on generator and make to Tucson ( 300 miles ) and get it done somewhere in AZ
Better yest I should do it self , problem the battery -alternator cables are short and way in teh back & might be bugger to get them loose! I anyway I am getting new one , not rebuild one ! dont trust it for full timing driving, we did some 18,000 miles and alternator was working like champ , but again coach is 12 years old!!

[Richard]

Les,

Before you put a wrench on the electrical connections to the alternator, disconnect the ground and pos on the chassis batteries. Make sure the merge switch is off. Those positive cables to the alternator are electrically hot. A wrench on the pos side that makes contact with other metal will cause great fireworks. It's tight back there and hard to see. Disconnect the batteries before you start.

[lbrachfe]

Thanks Tom for a great explanation....

[ccjohnson]

Les, Stewart Stevenson Detroit Diesel in El Paso is a good shop for repairs. I have also had Border Equipment in Las Cruces, NM do some work for me. I would steer away from Rush Truck Center in Las Cruces. Jimmy's RV Repair in Deming is also good and he has a good relationship with Harris Auto Electric in Deming.