Starter Alert warning light

[J_E]

I discovered that if I let the bus sit for a week without being started, there is a drain that pulls the batteries too low to start the engine.  I had the master off, the drain appears to be on a 12v inverter located in the battery compartment.  I discovered this Wednesday.  I went ahead and pulled one of the two engine batteries, the other was still showing 12.5V. 

After charging the battery and verifying the water level, I got back out there today to try again.  With everything hooked back up, I attempted to start it from the engine compartment.  Before I tried to start it, both batteries showed an individual voltage of 12V+ and a combined of 24.4V.  It looked like I was trying to turn the engine over with an impact wrench.  It was jerky and slow, but was making complete revolutions.  Admitting that the batteries must be further gone than I had thought, I went to turn the master power off at the dash and noticed the Starter Alert warning light lit.  I haven't seen that one light up before.  Is it because I wasn't getting enough power to the starter to turn the engine over and start or is it trying to tell me that my starter is less than healthy?

I'm going to get both batteries in the morning and give them both a good charge before making another attempt.  Everything seemed to work fine and the engine started right up before I parked it for a week and let the battery go flat.  Both of my switches in the engine compartment were in the correct position for a rear start.

I'm probably missing something, just have to figure out what it is.   Thanks in advance for any help.

[gumpy]

At 24.4v, your batteries are half charged, hence the slow revolution, and, I assume, the starter warning light. You need to get them up to around 25 volts or above.

[PP]

On my 2 Group 31's I have 26.4V when fully charged. If I test them separately when they're charged, I have around 13.56 and 13.58 respectively and they're going to be 3 yrs old on July 14th. They're maintenance free, so I don't have to worry about the water level in them like I do the house batteries 
Will

[brmax]

I would keep the key or run switchs in the full off position for now. Untill fully recharged, It makes me think the starter its electrically engaged a bit, and did not properly release earlier when batts ran down.
Just a thought, i have had them contacts stick in this low volt situation.

Good day
Floyd

[Oonrahnjay]

I would keep the key or run switchs in the full off position for now. Untill fully recharged, It makes me think the starter its electrically engaged a bit, and did not properly release earlier when batts ran down.
Just a thought, i have had them contacts stick in this low volt situation.

Good day  Floyd 

     Yeah, I'm with you on that.  My rule for electrical systems has been for a long time -- "the best way to kill your start batteries is to have a bad starter, and the best way to kill your starter is to have a bad (set of) start batteries", but I have to add that *phantom loads* that drain a perfectly good battery just sitting there are a pretty effective way of killing batteries, too.

[J_E]

Oorahnjay, you forgot to mention that cold weather will kill low/flat batteries surer than anything also.

Don't know the age of this pair, but they were in the bus when Houston got snowed on a few years back.  I suspect that I will be in the market for batteries before too long.  I will get them both charged up over the weekend and go from there.   On a side note, I had an old 6.2L Detroit that would turn over and start as long as I could give it at least 23V, but that was a different beast.

There is still almost all of the electrical work ahead of me, since we still have to remove the luggage racks and all the lighting and junk that goes with.

Thanks again for all of the feedback.

[Oonrahnjay]

Oorahnjay, you forgot to mention that cold weather will kill low/flat batteries surer than anything also.

Don't know the age of this pair, but they were in the bus when Houston got snowed on a few years back.  I suspect that I will be in the market for batteries before too long.  I will get them both charged up over the weekend and go from there.   On a side note, I had an old 6.2L Detroit that would turn over and start as long as I could give it at least 23V, but that was a different beast.

There is still almost all of the electrical work ahead of me, since we still have to remove the luggage racks and all the lighting and junk that goes with.

Thanks again for all of the feedback.

     Yes, very true.  But (unless a battery has been frozen so badly that it warps/cracks plates or the battery case) being warmed up again will usually bring it back to "no harm done" as long as it's warmed up and fully charged soon.  And, of course, you're totally right -- if the batteries are low or flat before they're chilled, that's much worse on them.
     The most important truism is that batteries have a life.  Some people say that it's charge/discharge cycles, some that it's just age, other people think that it's a combination, but at the end of that life, the battery will not accept/hold a charge any more.  That's it - it's "dead", useless, gone.  Our job is to not kill them before the end of their natural life.
     The problem is how to implement that "not killing them" thing!

[J_E]

Figured I'd give an update.

Still don't know whether it was low voltage or something else that gave me the starter alert warning light.  The answer is possibly buried in the manuals and I'm sure it will be a head slapper when I find it.

I took both batteries home to give them a good charge.  Got a good charge on them and the bus fired right off, no warning lights or anything. 

Luckily, I wasn't wearing nice clothes when working on the bus, because, thanks to the battery acid that I managed to spill, they are now holy shorts.  Somethings you just don't remember until you are looking at a fresh set of new holes in your shorts.  Meh, it just means that I saved a pair of coveralls for another job down the road.

Speaking of  down the road...  I knew that my tag tires were due.  Heck, I have (had) two serviceable spares to shuffle around and replace them.  After I got the bus running, we decided that it was past time to take my wife and son for a proper ride in the old girl.  We were maybe 5 miles down the road from our storage lot and on the on ramp for the freeway when I check my mirror and notice some small black chunks flying.  Luckily, I wasn't totally comitted yet to getting on the interstate, so I pull off to the shoulder of the on ramp and go to investigate.  I guess today the tag tire decided that it was overdue, but better at 35 and accelerating than at 65. 

I learned a few things from this experience:
1) Don't get in a hurry when waiting for roadside service, because they wont.
2) If you order a pizza around the time that roadside service said that they would arrive, the pizza will arrive first.
3) Figure out how to open the bleepin' spare tire compartment.  There is no t-handle under the fiberglass cover in the front.  Fortunately I had a spare spare in a luggage bay.
4) I know how much roadside service in Omaha costs if they need to mount the new tire on the wheel before bolting it back up.
5) Perhaps most importantly, Pizza Hut WILL deliver to the freeway on ramp.  At least, this one did.
6) Check that your spare tire sizes match the rest of your tires.  Replacing a 315/80/22.5 with a 12/22.5 is not ideal.

Regards,

[RJ]

3) Figure out how to open the bleepin' spare tire compartment.  There is no t-handle under the fiberglass cover in the front.  Fortunately I had a spare spare in a luggage bay.

Jason -

Early "A" series MCIs had a T-handle behind the MCI breastplate letters for the front door mechanism, not the spare tire compartment.

Access to the spare T-handle was in the exterior tool compartment underneath the driver's floor, in the upper left behind the headlight buckets.  At least that's where I remember it on the brand new '85 102A3 that was in our fleet just before I left the company.

If you have an air-powered front door, things might be different.

FWIW & HTH. . .

[dbldragon]

  RJ you are correct that is where the spare handle is on my 91" a3
   Chuck

[neoneddy]

This is one reason why I like the 24v house setup as well.  I can have my house batteries jump the coach batteries, and or the house batter inverter / charger can charge the coach batteries.

Actually right now they are all the same, but it's plugged in.  Working on a starter solenoid relay for disconnecting the systems.

[Tony LEE]

I had the master off, the drain appears to be on a 12v inverter located in the battery compartment.

Didn't notice anyone mentioning it, but this is very likely to be the root cause of your problem. No simple way of preventing damage caused by running 12V gear off half of a series 24V system.

[J_E]

Thanks Tony,

I am digging through the wiring diagrams trying to figure out what will need to stay and what can go when we start yanking out the luggage racks.  I had been tempted to go hunting to find the drains, but decided to remove the passenger stuff first and go hunting for whatever, if anything, is still left.

For now, I've pulled the positive connections from both batteries. 

If I need to, I will wire in some 24V relays to switch the 12V load on and off with the master.  Everything for that is in the battery compartment, so it shouldn't be more than a half hour with a set of crimpers.  I may do this anyways and repurpose them as needed for the conversion.