Battery Bypass / Disconnect Switch

[CableDawg6]

Good day everyone, 

I have a Heartland Big Country 3950FB 40' 5th Wheel RV.  I have been issues with my Lippert Leveling system.  I flipped / turned the Red Knob today and suddenly the Jacks seemed to work just fine.  However, before that turn - my Jack Motor was getting power, and it was not turning enough.  It was working as hard as possible to spin.  But, again, as soon as I turned the knob Jacks immediately raise and lower the 5th Wheel.  I think that I am having an issue with the batteries but not 100% sure.  If anyone has any advice would greatly appreciate it.  We are planning on traveling this weekend, so just wanted to make sure I get everything running smoothly before I roll out. 

Thanks Chris

[TXiceman]

Is the Red Knob the battery disconnect?   

Is the trailer hooked up to shore power?

Have you checked the battery voltage?

Are the jacks mechanical or hydraulic?

What motor is spinning?

Ken

 

 

[CableDawg6]

Good Day TXiceman - 
Yes the Red Knob is the Battery Disconnect (apologies for not elaborating)

Trailer is on 110 Shore Power 

Don't have a voltmeter sadly ... will be getting one this weekend 

Jacks are Hydraulic - Lippert Brand 6 Point Contact 

The motor that I mentioned is the same motor that controls the Hydraulic Jacks

[Will B.]

My immediate thought was:   The batteries are connected to things that aren't turned off by the cutoff switch, namely the jacks.  You have things drawing on the batteries when the switch is closed (or "connected").  Therefore, when you turned the cutoff switch "off", you disabled the other draws on the batteries, thereby giving sufficient power to the leveling jacks.

If I'm right, that'll at least help explain the circumstances, though I don't know about correcting anything, if necessary.  Other than having more batteries / power available.

[bipeflier]

 

Best guess, with the batteries "ON" you have sufficient amperage available to run the jacks.  With the battery switch "OFF" the shore power is trying to supply the necessary 12 volts but the converter does not have sufficient capacity to supply the necessary amperage.

You should definitely be ON to run the jacks!

[Kirk W]

3 minutes ago, bipeflier said:

Best guess, with the batteries

That would be my guess as well. Without the battery on the output of the converter is also being used by things like the appliances, charging the battery's, and everything else that uses 12V.

[Chad Heiser]

Typical OEM installation of a battery disconnect switch isolates the batteries from the 12 volt power panel and the converter.  The jacks and slides are typically wired directly to the batteries and do not pass through the shutoff switch.  With the shutoff switch off, you can still use the jacks and slides, but interior lights or other 12 volt items in the 12 volt power panel won’t work because the batteries are isolated from them.  If shore power is active, the converter will energize the 12 volt power panel even if the batteries are disconnected from the system (so interior lights will work without the batteries).

If you are not sure which way the shutoff switch works (which way is on and which way is off), disconnect from shore power and try an interior light.  If the light works the disconnect switch is active and passing battery power through.  If the light doesn’t work, then the disconnect switch is off and not allowing battery power to pass through.

The circumstances you describe are probably caused by low batteries.  With the disconnect switch turned off, the jacks are relying on the batteries alone to power them.  With the jacks barely running or running slowly when activated, it indicates the batteries are low.  When you turn the disconnect switch on, now the converter is also in the circuit with the batteries and it is supplying additional 12 volt power to the batteries (via shore power being converted to 12 volt).  The combination of the converter power and the low battery power is now enough to properly power the jacks and they function properly.