Onan 5.5 won't run unless on jumper cables or jump box

[mineurbiz]

My hauler seemed to develope an issue Sunday am, when I went to start the hauler, I thought the batteries were dead but they were good. Used jumper cables to the positive terminal on the generator the the negative to the chassis and it ran. Tried hooking the jumper cables to the batteries and it would not run. I got home and plugged the trailer into the house for over 24 hrs and still does nothing, does not even try to start. Strange the it worked purfect, then just stopped working. Also thought that these gererators would just run without batteries, once they are started? any thoughts?

Just to ad, the batteries were good enough to get my trailer lifted off of the truck, but not start the generator?

Edited November 13, 2012 by mineurbiz

[Adam @ GTP Off Road]

sounds like a connection issue to me, i'd start with all battery cables. especially the grounds.

[mineurbiz]

I really read something on that, but thought after the gen was started, that it should continue to run, but if you remove the jumper cables or jump box, it shuts off. It is in storage so hopefully I can get a few things to try for when I go there.

[dunefreak]

So initially it didn't crank when you went to start it?

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[Adam @ GTP Off Road]

if there is a grounding issue though, the charging system won't be able to work right. it should run without a battery, but the other cables and stuff still need to be good.

If the cables are good then it must be something in the charging system. It's a weird combo to me that it won't start, and won't stay running since that seems like it would be different componenet issues.

[mineurbiz]

So initially it didn't crank when you went to start it?

It won't crank from the batteries, but when you hook jumper cables to it, the gen starts normal. I went to put it in storage and figured before making someone follow me to jump it (thinking the batteries might be shot), I decided to try them and I was able to lift the jacks no problem, leading me to think the batteries are fine? But yet you push the gen start button either from outside or inside the trailer and it won't start.

[Adam @ GTP Off Road]

are you sure the Generator battery is the same battery. I know if might be a dumb question, but i am used to Motorohomes, which can have a seperate gen battery from the other coach batteries.

[vegas style]

i would check the power cables from the batteries to the gene. sounds like maybe a bad ground. with the jumpers you are creating a new ground path. it would also explain having battery power elsewhere. just a thought.

[mineurbiz]

Good info, I will trace them all out and find the issue.

[bp-guy]

I am with everyone else on here. Sounds like a grounding issue. Once it is started then it is self powered. But the current draw on the start is a big one and a bad cable somewhere will kill it when you try to start it. Your electric jack probobly doesn't have the draw like the generator and thats why it seemed to work with no issues. Did it sound normal when you were using it? A good battery and it will move quickly and a low battery or bad ground will sound much different.

[mineurbiz]

I am with everyone else on here. Sounds like a grounding issue. Once it is started then it is self powered. But the current draw on the start is a big one and a bad cable somewhere will kill it when you try to start it. Your electric jack probobly doesn't have the draw like the generator and thats why it seemed to work with no issues. Did it sound normal when you were using it? A good battery and it will move quickly and a low battery or bad ground will sound much different.

Sounded normal while running, but only runs while on a jump box or jumped from another vehicle, but won't work from it's own batteries. I did not try the jumper cables from it's own batteries

Edited November 14, 2012 by mineurbiz

[Adam @ GTP Off Road]

The jack is probly grounded itself by being screwed down. The generator is probly on rubber motor mounts so no real (or Good) ground connection.

[JasonR]

i had the same problem at one time.. and it was a combo of two things... the first prob was that the the Gen battery was bad.. and it has to be good to work or to "switch" the isolator .. and the second thing was the isolator itself went out.. when the generator is running the isolator switches over to the "house" batteries and then runs a trickle charge to the motor battery. but if the house battery is bad it will shut down the motor.. kinda like a car with a bad battery it will run till you put a load on it try putting a known good batt. in the place of house batt.

hope this helps..

[JoeDuner]

i had the same problem at one time.. and it was a combo of two things... the first prob was that the the Gen battery was bad.. and it has to be good to work or to "switch" the isolator .. and the second thing was the isolator itself went out.. when the generator is running the isolator switches over to the "house" batteries and then runs a trickle charge to the motor battery. but if the house battery is bad it will shut down the motor.. kinda like a car with a bad battery it will run till you put a load on it try putting a known good batt. in the place of house batt.

hope this helps..

One of the batteries might have a dead cell....(grounded)

[mineurbiz]

One of the batteries might have a dead cell....(grounded)

Would that let the batteries work well enough to lift the trailer off of the truck?

I appreciate everyones input, nice to go to storage with a few idea's rather than just one or two, so thanks to all!!

[Adam @ GTP Off Road]

i would think that there is 2 battery set-ups in there. so the jack probly works off the coach batteries, while the gen works off its battery. so if the gen battery is bad the jack could still work.

the gen has to have it's own seperate battery or when the coach batteries died over night, the gen wouldn't start. Like i said though, my experience is with expensive motorhomes, and i'm not sure how your hauler is set-up.

[White Rhino]

Toy haulers usually only have one bank of batteries and if stock. Usually just one battery.

Yes a dead battery will lift your trailer. I'm betting u have a dead battery. Take it out and have the battery tested

[mineurbiz]

Yeah maybe I will just buy two new batteries and swap them out.

[bp-guy]

If you leave them hooked up long term. When you buy new batteries I wiould get a small solar charger to keep them topped off during storage. Nothing fancy just a simple solar trickle charger will do the trick.

[mineurbiz]

If you leave them hooked up long term. When you buy new batteries I wiould get a small solar charger to keep them topped off during storage. Nothing fancy just a simple solar trickle charger will do the trick.

Good idea

[bp-guy]

But if you ever get the itch to go all out. Here is a write up I did on my solar install to charge my batteries and have plenty of room for future upgrades.

http://www.dumontduneriders.com/invision/index.php?showtopic=17170&hl=solar&fromsearch=1