Wheelchair lift issues.

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BulldogPI

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Not sure what happened.  Will have to type all that again, sigh.

I have an E450 Super Duty cutaway with a starcraft shuttlebus body on it.   6.8L Gasoline engine 2003.

Anyway, I suspect there is something wrong with my wheelchair lift circuit.  I replaced the 12.18 volt output obviously worn out 850 cold cranking amp car battery last night with a still has some life AGM 100 Amp Hour battery which read 12.72 volts after charging.  

I was able to lower the wheelchair lift a couple hours ago, and was using it for seat removal.  Then it wouldn't go back up.  Thank God for the hand crank.  The battery now reads 12.37 volts even with the engine running.  (It was 12.72 at the time of install).  I threw an exterior battery charger on the battery and it has a little meter on it showing 40% battery charge... so my guess is that the van isn't charging the battery right.  Now I don't really care about the lift and it's coming out eventually but I wanted to use it for the seat removal, and now I'm worried that the auxiliary charging circuit isn't working properly.  I wanted to make use of that circuit and the auxillary battery for "house" current, and charging off the alternator which I'm sure is how it is supposed to work.

Anyone have ideas?  I'll provide an update as to whether the battery can make the lift go after it charges for a while with my exterior battery charger.
 
By "engine running" do you mean at something more than idle? Because idle doesn't generate enough to recharge a battery.
 
the difference between 12.37 and 12.72 volts isn't enough to matter to a motor.
What does matter to a motor is being able to draw enough amps.
Either there is something wrong with the motor and it's wiring harness, or you need a fresher battery.
Voltage is like the push of the circuit.
Amperage or current is the amount of electricity moving through the circuit.
You could easily have a situation where your battery supplies 12.75 or 13.5 volts under load. But cannot deliver more than 25 amps of current, while the motor wants 50.
Of course unloading it had a gravity assist, and retracting the gate, a gravity penalty.
 
MrNoodly said:
By "engine running" do you mean at something more than idle? Because idle doesn't generate enough to recharge a battery.
Appreciated, yes it was idling.  Maybe generating enough voltage but the amps were too low?  But an Idling car will charge a battery given time, and I would think that between the bus idling and the battery the lift should of responded.
 
It's been a while and I can't remember for sure but I think the E450 I used to drive would automatically kick up the idle when you engaged the lift.

Kind of like when you turn on the AC the idle goes up.
 
Lifts are not made to work non-stop. If you had it going for long taking the seats out, the motor could be overheated, or the battery drained too much.
 
BulldogPI said:
Appreciated, yes it was idling.  Maybe generating enough voltage but the amps were too low?  But an Idling car will charge a battery given time, and I would think that between the bus idling and the battery the lift should of responded.
I cant answer as far as the lift itself but as far as idling the bus to charge the lift battery there is a big consideration there.

Yes idling the engine will charge a cars starting battery given time. It will also charge that auxiliary battery for the lift while idling given time. BUT and it's a big but it would take many many many hours of idling to replenish say.. 50 amp hours of charge to that battery.

Driving at highway speeds is where the magic happens for charging that auxiliary battery. Idling the engine is gonna be more of a trickle charge, worse most of that trickle charge is going to be going to the starting battery and THEN trickling down to the auxiliary battery.

When I first started researching all of this stuff I just assumed that if the vehicles alternator was rated at say 120 amps then it was like having a 120 amp generator on board. This unfortunately isnt the case 99% of the time except for hybrid cars like the Prius.

Some of the old farts on here who have been alternator charging for 20 years or more will tell you the same. HOWEVER alternator charging IS a thing and IS doable. But generally speaking the ones who make the best use if it are people who are always driving. Like municipal buses that have wheelchair lifts, or vanlifers traveling to that next park, or people who drive 4 hours for work a day.

Hope that helps.
 
Most likely a simple problem that involves a bad or corroded connection to a weak or under charged battery. You can simply take a known good, well charged battery and some good thick short jumper cables and connect to the lift directly to check it or run by an auto parts place and have the charging system checked to see if the lift battery is charging and how much power the lift is drawing while in use with their tester.
 
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