We took our U300 to have the windshields replaced last Monday. They were going to replace it that day so we didn't turn the batteries off.
They ended up breaking one of them so didn't get a replacement till Friday.
They said they'd turn it around so we could pick it up
Yesterday but when they tried to start it it wouldn't start.
We wen over yesterday and left the generator run 7 hours and it still wouldn't start.
We went this morning and hooked a small battery charger to it and it shows batteries are 100 percent.
Any ideas what it might be?
Unless modified, the CHASSIS battery is not charged by shore power or generator.
Is it the CHASSIS or HOUSE batteries that show 100% charged. Should be the house batteries.
If so, the boost switch may provide enough amps to start. If not, leave the boost switch on and generator running. That will charge the chassis batteries.
1) Running the generator for 7 hours doesn't really mean anything unless you know where the electrons are flowing.
2) IF the chassis battery is totally discharged, something I accomplish all too regularly by leaving the headlights on, there are very few free electrons in the electrolyte. Your smart inverter-charger will throw up it's hands and refuse to do anything. Using a dumb battery charger it will take several hours before you begin to see any current flow on the charger's meter. However once the dumb charger is running at maximum capacity you can switch to your inverter-charger to complete the process over the next 4 hours or so.
3) Such a deep discharge means that your chassis battery has lost some if its amp-hour capacity.
It won't start or it won't crank (turn over). Two different problems. I'm assuming you mean won't crank.
The cranking sequence for my coach requires the following items to function properly. I don't know if your coach, with different engine, works the same way. On my coach, if any one of the items listed below were to fail, I would have a NO-CRANK situation. This would be true even if both battery banks are fully charged.
1. Ignition switch
2. Ignition solenoid (under lift-up dash cover)
3. Neutral safety switch (or relay).
4. Aux Start Solenoid (on or near the battery isolator panel)
4. Starter Solenoid (bolted to the engine starter)
Make sure you did not leave it in Drive when you parked.. I did this once...
I've never actually tried to leave our transmission in Drive. I always assumed the (electronic) Allison would default to Neutral when engine is cranked, but I could be wrong. Anybody know for sure?
To check a chassis battery turn on your headlights. If they don't go on you have and
open connection or the batteries are dead. Most modern chargers won't charge a completely
dead battery. Use the boost switch and then the charger will see voltage and start charging.
Thanks all, we went back after the charger had been 4 hours.
Bob determined the motor wasn't cranking hard enough to turn over so he sprayed ether in the air intake while I started it.
I think when we took it there the refrigerator was running on gas. The place working on the windshield had to start it to move it closer to their dock so they could reach the windshield and the refrigerator might have switched to run off the battery's then and that might have drained them.
We also have it plugged into power when we are home so it always starts when going on a trip.
What refrigerator do you have that would use 12 VDC to power a heating element.
Most refrigerators of that vintage only have propane (which takes a small amount of 12 VDC) or 120 VAC for the heating element.
Don't know what engine you have-- actually 1995 U300 had several different ones used, but be very careful (actually don't do it) using ether with any engine with an intake manifold heater. Ether and red hot wire don't play nice together. And the starting fluid would have had zero effect on cranking speed.
If chassis batteries weak but house bank charged, using the boost switch WILL help with cranking speed.
Doesn't hurt to clean up the battery connections from the chassis battery's to starter.
I had a lot of hard to start issues on my M11 and even though it acted like a low battery condition. It was actually a weak starter. New starter had the engine spinning like it was hooked up to a nuke power plant.
Is your 1995 U300 a CAT or Cummins M11? Where are the start batteries located?
Pierce
Never the mind the house versus chassis battery separation, but My Dometic RM4804 defaults to 12V only if AC and gas aren't present. My suspicion is that your chassis battery has an internal short and is self discharging, and this issue has been covered up by your coach being plugged in or driven and never sitting dry.
Unless some aftermarket provision has been made, the chassis batteries are NOT charged by 120 VAC. From the factory, only the house battery bank is charged by the converter or inverter/charger.
Absolutely, many of us have modified our coaches so both banks are charged from shore power/generator.
Have you put a voltmeter on the start battery bank? Tried charging from shore power with the boost switch on? Don't use ether on a Cummins with the heated screen as Brett posted. Have you cleaned the engine battery terminals?
Pierce
As an aside, your 12V should NOT run without the key being on. If it does, it is incorrectly wired.
Well after having our coach back home and plugged in for a week, Bob tried to start it again and it wouldn't start.
When he turns the key to start one time it showed 8 volts and another 12.
He did get it to start once, let it run about ten minutes, then shut it off and it wouldn't start again.
Our engine is a Cat 3176.
We bought it on EBay from a guy in California who had repossessed it.
I looked up the names of the previous owners and determined they were in their upper 80's.
Since it was a repo it had no manuals in it.
Luckily since it is our second Foretravel Bob knew a little about some of the systems.
It has three optima start batteries and 4 house batteries.
We had the place in California put all new (supposedly new batteries before we went to pick it up)
We picked it up in February 2020 so quite possibly the batteries might be, as some have said, not as good of quality as optimas used to be.
Bob is going to have our son-in-law take the start batteries out and test them individually tomorrow.
Anyone have recommendations for replacement batteries that might be better.
Thanks,
Susan
Check all you connections. As for being plugged all week won't make any difference to
the start batteries unless you have a added device to charge the start batteries from the
house batteries or the boost switch is left on.