Starting issues - Batteries or charging

[Chaz]

  Ok, yet another little snag. 
  I have brand new start batteries in my 4108 (8V71) and am having issues with charging, I think. It seems to me that it may be an intermittant problem.
  History:
  Bought the bus, had to jump it. Put in new batteries.
  Drove it, ran out of fuel, ran the batteries down. Charged them back up.
  Took it to IL. and the next morning after we got there, they were down again. Did a little messing with a VOM and charging and they seem to be charging again. (It seemed like the generator had lost polarity and jumpering it across got it back (?) )
  Drove it a time or two since and it's been ok.
  Drove it to my mechanic and when I went to get it, he had to jump it. Drove it home.
  Went out this morning after I had the motor plugged in over night and she barely made a grunt.
 
  So, now I need to charge them back up but only have a 12v charger. (it's 24v) Previous chargings were by other people.
  What is it that I need to do? I assume I should put the charger on the + of one battery and the - of the other one but not sure. Or should I dissconnect them and do one at a time. I have a good charger with low, med, high, start settings.
  Then what can I do to find my problem?
     Thanx again from a newbie billed as a full member!! 
            Chaz

[Len Silva]

You can charge the batteries one at a time without disconnecting them.  Just hook the charger up as you normally would on one battery, charge it, and do the other one.

However, you have got to find your charging/discharging problem soon.  These batteries will only take a few complete discharges before they are junk.

Be sure the batteries are disconnected when ever you leave the coach for any lenght of time.

Len

[Melbo]

Chaz

I only drive my bus short distances so my batteries never get charged from driving. I always put two twelve volt chargers one on each battery and plug in the block heater this time of year.

Just part of my starting routine in the cold.

Melbo

[Buffalo SpaceShip]

Chaz, did you ever put your VOM on the batts after you got it started? You need to know if the alternator is putting out charging voltage... somewhere in the neighborhood of 28v is required to keep them charged whilst driving.

You might just not be driving it long enough to charge them back up... esp. if you're having trouble firing it off. Check all of those starting circuit cables and connections, if you haven't already. A few hours with sandpaper and protectant goes a LONG way towards having reliable starts. A 24v starter, charged batts, good connections, and a warm engine should fire the high-compression DD off instantly... not even one revolution.

Use the batt. disconnect every time you stop/ park it. You can keep the batts on "float" (a special charger, 3 or 4-stage, for keeping batts "topped off") OR just charge your batts once a month with a dumb charger. Use two 12v chargers or get a 24v charger from BatteryStuff.com (like this one)

HTH,
Brian B.

[Kwajdiver]

Chaz,

You may have something draining your batteries, even when your not running.  Look for a short or some switch that is on.

My two cents,

Bill

[n4rsn]

I use a small solar panel, that I throw up in the windshield, when the bus is parked for a long time.  It keeps the batteries toped off.  If I park for a month or so, They will run down on thier own.     You will need 2 solar panels. One on each battery.
Steve

[Chaz]

Thanx for the help guys. I'll do my checking tomorrow. Is there any other checking I can do?? I can tell ya, the connections on the battery and cables are very good!! I went to great lengths to get good connections.
  The solar panels sound interesting. Any info on what to get or where?
 
   Let me know of any other things I should look for when I'm checking things out (voltages in different places, etc.)
  Thanx.

    Low on electricity,
       Chaz

[Sammy]

Hey Chaz, check your e-mail, sent some suggestions for you.
Good luck.
Sammy 

[bobofthenorth]

What Brian said - throw the disco EVERY time you shut it off until you get it figured out.  Your batts are too valuable to risk destroying them by repeated deep discharges.  It should be possible to eliminate the bus electrical phantom loads such that you can shut off the bus without having to throw the disco but you will have to spend some time doing that.  In the meantime take the sure route & throw the disconnect.

[Buffalo SpaceShip]

I can tell ya, the connections on the battery and cables are very good!! I went to great lengths to get good connections.

Chaz, OK... but did you check the other end of the cables:

• where the positive #2/0 connects to the starter solenoid
• where the positive #2/0 connects to the alternator
• where the negative #2/0 connects the starter to the engine block
• where the negative #2/0 connects the engine to the chassis AND (hopefully) back to the batts

These wires are critical to the system, and a small amount of corrosion can lead to a huge amount of starting problems. BTDT.

HTH,
Brian B.

[DrivingMissLazy]

Chaz, have you seen the post(s) that tell you how to check to see if you have a small phantom load, like a small light that stays on all the time, and it is out of sight so that you do not see it?
Richard

[gus]

Amen to the battery disconnect, I have them on all batteries. They saved my bacon once when the starter stuck on!

"(It seemed like the generator had lost polarity and jumpering it across got it back )". I hope you didn't do this to an alternator. Polarizing is for generators only-not for alternators. It is also called "Flashing the field". NEVER do this to an alternator.

[Stan]

gusc: Why would you not use the same procedure on an alternator as on a generator?

[DrivingMissLazy]

. Polarizing is for generators only-not for alternators. It is also called "Flashing the field". NEVER do this to an alternator.

I have to respectfully dis-agree with Gus on this.

All generators and alternators get started charging by using the residual magnetism present in the laminations of the device. It is a very low voltage developed, usually less than 10 volts, but it is what gets the units started producing power. Anytime a device is dis-assembled it is possible for it to lose its residual magnetism.

I worked with these devices for over 40 years, especially alternators, and many times I had to flash the field to get an alternator producing power.
A few times on units that has sat for many years, but generally after a unit had to be disassembled for diode or bearing  replacement.

On an AC alternator it really does not matter which way it is flashed. In other words it does not matter which lead the positive potential is applied and it can even be flashed with an AC source of power, but there are occasions when it actually must be flashed.

Richard

[Stan]

Richard: I agree with you, and I have also flashed many alterntor fields but I assumed that gusc must have some valid reason for saying to never do it. Maybe it it is another urban myth.