Strange... Need some advice...

[cgaskins]

Hi. I have a 2015 Heartland Big Country 3650RL. After our weekend trip today, I went to park the RV in its storage space and I could not get the landing gear to go down fully. Both front feet extended until they hit the ground then all I heard was a clicking sound. I was still plugged into my truck so I should have had plenty of 12 volt power. However, they would not extend. I ran an extension cord over plugged into 120 volt and all worked fine. I know my batteries are getting weak but I don't understand why the truck wouldn't power it. I went inside the RV prior to plugging into the 120 volt outlet - while plugged into the truck with the truck running and pressed the battery meter button and I got all 4 lights light up. My Big Country has the original deep cycle batteries that came from the unit. I am using a new truck - 2017 Super Duty. This never happened with my 2011 Super Duty no matter how weak the RV batteries were. Any ideas?

Thanks,
Chris

 

[danemayer]

Hi Chris,

Compare the size of the wire to the hydraulic pump to the hot wire coming through the umbilical cord from the truck. With weak batteries, the truck is going to have a hard time pushing enough power through that tiny wire to sub for your trailer batteries pushing power through the fat wire.

When you test the battery, you're reading voltage not amps on reserve. So you may see 4 lights because the truck is supplying 14V DC, but it's not an indication that there's enough juice to run the hydraulics.

When you plug into shore power, you're getting the output of the Power Converter added to the batteries. You probably have an 80 amp Power Converter pushing power through a wire the same size as the wire for the Hydraulics. There's a 50 amp mini-circuit breaker on the buss bar that is the limiting factor.

 

[DougS]

Is it possible the battery switch was off. Plugged into the truck you may not be getting enough amperage through RV plug.

 

[cgaskins]

Is it possible the battery switch was off. Plugged into the truck you may not be getting enough amperage through RV plug.

Nope - checked that. Battery switches were to green / on.

- - - Updated - - -

Hi Chris,

Compare the size of the wire to the hydraulic pump to the hot wire coming through the umbilical cord from the truck. With weak batteries, the truck is going to have a hard time pushing enough power through that tiny wire to sub for your trailer batteries pushing power through the fat wire.

When you test the battery, you're reading voltage not amps on reserve. So you may see 4 lights because the truck is supplying 14V DC, but it's not an indication that there's enough juice to run the hydraulics.

When you plug into shore power, you're getting the output of the Power Converter added to the batteries. You probably have an 80 amp Power Converter pushing power through a wire the same size as the wire for the Hydraulics. There's a 50 amp mini-circuit breaker on the buss bar that is the limiting factor.

All good points Dane. So do you think my new truck is supplying less power to the trailer or do you think my batteries were that weak?

-Chris

 

[danemayer]

My first guess is weak batteries. But we've seen some posts about trucks where a fuse has to be installed to get power to the trailer. Might be time to check whether any power is getting to the trailer batteries from the truck. Pin #4 in the one o'clock position on the truck connector.

 

[cgaskins]

My first guess is weak batteries. But we've seen some posts about trucks where a fuse has to be installed to get power to the trailer. Might be time to check whether any power is getting to the trailer batteries from the truck. Pin #4 in the one o'clock position on the truck connector.



View attachment 50585

Yup - time to get out the voltmeter...

-Chris

 

[TedS]

Hydraulic power will draw up to 50 amps or more. Electric landing legs will draw up to 30 amps. That truck feed may be good for 10 amps, not enough. The trailer battery alone should handle the draw unless it is bad and not capable of holding a full charge.

 

[cgaskins]

Hydraulic power will draw up to 50 amps or more. Electric landing legs will draw up to 30 amps. That truck feed may be good for 10 amps, not enough. The trailer battery alone should handle the draw unless it is bad and not capable of holding a full charge.

Ok. Maybe need some new batteries for the new camper.

 

[jimtoo]

Check the fuses in the truck, under the hood. If new truck it probably does't all the fuses installed to power all the trailer wiring.

 

[wdk450]

Check the fuses in the truck, under the hood. If new truck it probably does all the fuses installed to power all the trailer wiring.

Charging a battery is like filling a big water container with a hose. The bigger the hose (cable and circuit amperage capability) the more water per minute (amperage) can be delivered to the water container. Running something with a battery is like putting a drain line in the bottom of the water container. The bigger the power load, the bigger the drain hole and tubing is, and the more water volume (amperes) is drained out of the container.

Small input hose and large drain hose equals a drained water container (discharged, low capacity battery). A small input hose connected for a long time without much draining load equals a battery getting a charge, like being plugged into the truck's charging connector, or being on the shore powered converter overnight.

BTW, the charging connection from the truck is mandated by the highway safety people for the specific purpose of keeping SOME charge on the trailer battery for the electric emergency disconnect braking system (lanyard), so that the trailer brakes DO engage when there IS a disconnect. The trailer emergency brakes wouldn't come on with a dead trailer battery. I don't believe the standard truck trailer charging circuit was intended to charge up a trailer battery for landing gear, lights, slides, etc. I have seen where some truck owners have modified their trucks with heavy cables directly from the truck battery (with a ground cable from the battery area, too) to a heavy duty tow truck jumper type electrical connector connecting to the trailer, and more of the similar heavy duty wiring in the trailer directly to the trailer battery.