Shore power not enough?

[Jgraham14813]

Ok you guys have helped me get power to the slide now just wondering why is shore power not enough to close my slide why do you also need a fully charged battery to close it I’m just confused on this as I know the shore power is supplying a constant 12+ volts to the slide motor or st least should be. Granted I have a 25 ft house cord attached to the 30 amp supply cord and on a 15 amp breaker but nothing else is on or running

[JRTJH]

The 12 VDC shore power converter/charger is nothing more than a stepdown transformer and a bridge rectifier circuit. That device is simply not capable of maintaining the load required without "backup additional power" from the battery. That's why there's a "BIG RED/WHITE WARNING" on the wall next to the slide switch that says, "Do not operate this switch without a fully charged battery connected to the circuit"

Ignoring that warning is a great way to find out exactly how much a replacement converter/charger costs... It likely won't happen the first or even the second time, but every time you push that switch without a battery, you melt some of the insulation off the transformer windings, Once you've damaged enough of the windings, it stops working and the spiked output blows a transistor in the bridge circuit and your lights get dim (permanently) until you replace the converter charger....

[Jgraham14813]

I don’t have that warning on mine lol

[ChuckS]

Your converter will run everything in the rig that requires DC power with the exception of the slides/landing gear...

You need the reserve capacity in amperage from the battery to operate hyd pump motor for slides and LG.. or electric motors for slides/LG

Another example to illustrate need for good battery is.. your car is dead ...disconnect the cables from battery and connect to a 75 amp charger and try to start the engine..
.. engine won’t turn over and charger will hum loadly and hopefully tripmits breaker..

And on my 2014 Alpine there is NO warning anywhere regarding operation of slides or LG without having battery turned on... I’m guessing Keystone firgures dealership would explain this to buyer ....yea right....

[chuckster57]

Decal/sticker seems to be hit/miss on pretty much every RV.

[JRTJH]

With a 2001 RV that was previously owned by someone else, who knows what might have happened with decals, or for that matter, switches, circuit breakers, fuses, wiring, etc.... Owners have some very different ideas on what stays, what looks bad and what needs to go. Some even question why there's a red/white EXIT decal over the only door leading outside... Hmmm :cool:

The owner's manuals from as far back as are published on the Keystone website have a warning about not operating the slides without a fully charged battery connected to the circuit. The manuals don't explain why, they just say, "Don't do it"...

Here's a few photos I picked up from the internet:

[Laredo Tugger]

Whenever I operate the slides or LG in a non powered mode, battery only I connect the trailer to the TV for extra battery power, so I thought.
Am I correct on this or does it not make a difference?
Thanks
RMc

[JRTJH]

I don't think it makes a hill of beans difference whether the trailer is connected to the truck, shore power or is disconnected from both. The only "end result difference" is the battery charge level at the end of slide/LG operation. If connected to the tow vehicle (and it's running) you'll "pull a little amperage" from the TV's alternator via that 12/14 ga charge line. If you're connected to shore power, you'll pull "a little amperage" via the converter/charger. If you're disconnected, you won't pull those "few amps"... but as soon as you do plug into shore power or the tow vehicle, either of those systems will work to recharge the battery. So, an hour or so after opening the slide, whether the truck/shore power/solo battery is used, you'll be "about the same status.

About the only "consideration" I use is that if I'm going to be dry camping, I try to leave the tow vehicle connected during setup. That's only to delay the need to start the generator for a few hours longer than if the tow vehicle was not connected. Otherwise there's not much difference.

[hankpage]

Whenever I operate the slides or LG in a non powered mode, battery only I connect the trailer to the TV for extra battery power, so I thought.
Am I correct on this or does it not make a difference?
Thanks
RMc

If the TV is running , yes, it helps.

[sourdough]

Our '14 has the red/white tag right beside the slide rocker switches.

[Steveo57]

I would say it depends. There might be slides that draw more than the converter can supply?

My slide motor is max rated at 30 amps and is fused with a 30 amp fuse. I haven't seen what it draws while in operation but I know its not going to be over 30 amps or it will blow the fuse.

The converter in my rig is rated for 55 amps so I don't see any reason why it wouldn't operate the slide without a battery. As long as I didn't have a bunch of the other DC loads on there should be more than enough capacity to operate the slide.

I would venture a guess that those stickers are just stuck on every unit because the boss said to. My sticker says "Battery hookup required for slide operation". So does that mean don't operate the slide without a battery or does it mean that the slide won't operate without a battery?

I'll have to do some experimentation this spring when I open it up and put the battery back in.

[sourdough]

I would say it depends. There might be slides that draw more than the converter can supply?

My slide motor is max rated at 30 amps and is fused with a 30 amp fuse. I haven't seen what it draws while in operation but I know its not going to be over 30 amps or it will blow the fuse.

The converter in my rig is rated for 55 amps so I don't see any reason why it wouldn't operate the slide without a battery. As long as I didn't have a bunch of the other DC loads on there should be more than enough capacity to operate the slide.

I would venture a guess that those stickers are just stuck on every unit because the boss said to. My sticker says "Battery hookup required for slide operation". So does that mean don't operate the slide without a battery or does it mean that the slide won't operate without a battery?

I'll have to do some experimentation this spring when I open it up and put the battery back in.


I think your question was answered in the previous posts. If you think the converter is more than able, despite the warnings from the stickers the manufacturer placed (because the boss said to) and warnings from others, maybe you should just leave the battery(s) out and operate the slides until "something" gives or you are satisfied, that would probably answer your question - the good thing is that converters are cheap....:D

[JRTJH]

I would say it depends. There might be slides that draw more than the converter can supply?

My slide motor is max rated at 30 amps and is fused with a 30 amp fuse. I haven't seen what it draws while in operation but I know its not going to be over 30 amps or it will blow the fuse.

The converter in my rig is rated for 55 amps so I don't see any reason why it wouldn't operate the slide without a battery. As long as I didn't have a bunch of the other DC loads on there should be more than enough capacity to operate the slide.

I would venture a guess that those stickers are just stuck on every unit because the boss said to. My sticker says "Battery hookup required for slide operation". So does that mean don't operate the slide without a battery or does it mean that the slide won't operate without a battery?

I'll have to do some experimentation this spring when I open it up and put the battery back in.


You can certainly do whatever you wish with your equipment. But, to put the part you don't understand into an example you might find easier to believe.....

If you're around here, you know you can walk carefully across a lake with 2" of ice on it. If you try to "jump across that 2" of ice" you're going to get wet and cold.

Now, your 12 VDC converter can support the "slow gradual buildup" of demand to around 50 amps (if you have a 55 amp converter). But if you try to "jump on the ice" by slamming an immediate 30 amp load on the windings of the transformer and the transistors in the bridge circuit, it will not sustain that abuse (yes it's a demand greater than the design so it's abuse) for very long before it will "crap on you"....

The reason for having a battery connected to the circuit is to prevent the slide motor from "jumping on the thin ice".... However, experiment this spring and run your slide in and out 5 or 6 times without a battery, then reach behind the power center and see if you can hold your hand on the converter casing. My bet is you'll have blisters from the case being hotter than, well, just try it and you'll see.

[Steveo57]

I think your question was answered in the previous posts. If you think the converter is more than able, despite the warnings from the stickers the manufacturer placed (because the boss said to) and warnings from others, maybe you should just leave the battery(s) out and operate the slides until "something" gives or you are satisfied, that would probably answer your question - the good thing is that converters are cheap....:DThe inrush current on these little motors will be high for a very short time but I would think the converter would handle it. And there's no doubt that the converter can handle the running amps. I just like to have an understanding of the reason for these types of warnings.

I know back in my Navy days we had a big DC motor for emergency propulsion on my submarine and to get it going we would slowly rotate a manual handwheel which cut out starting resistors as the motor came up to speed. We had a really big battery to operate it!

[Local150]

If I am dry camping I run the slide before I unhook power from tv,,,in shore power camping I don't move slide until shore power is connected. It helps leaving tv hooked up

[cmg1]

If the risk is that big why isn't there a breaker or a fuse on the circuit going through the transformer?

[dpankowski]

I keep my 5th wheel in storage for the winter. I remove the batteries and keep them on a battery tender all winter in the garage.

My question is can I connect the TV and keep it running and operate the slides without reinstalling the battery?

This is the first winter i've had to put the trailer in storage, usually i keep the batteries installed and leave the unit plugged into a/c servie.
thanks

[Local150]

I keep my 5th wheel in storage for the winter. I remove the batteries and keep them on a battery tender all winter in the garage.

My question is can I connect the TV and keep it running and operate the slides without reinstalling the battery?

This is the first winter i've had to put the trailer in storage, usually i keep the batteries installed and leave the unit plugged into a/c servie.
thanks
Personally I think it would work, but I wouldn't do it,, on my rv I will avoid having a possibility of having to replace the converter, as it's a,,,,,,,,,, to get to

[dpankowski]

Personally I think it would work, but I wouldn't do it,, on my rv I will avoid having a possibility of having to replace the converter, as it's a,,,,,,,,,, to get to

Thanks, but I think you misunderstood my question. I don't have any a/c in the storage area and want to use the TV to operate the slides without batteries installed.

[Local150]

Thanks, but I think you misunderstood my question. I don't have any a/c in the storage area and want to use the TV to operate the slides without batteries installed.
You are right,, I did misunderstand you,, sorry,, I would think that would be ok,

[daveinaz]

Yes, it was hard to me to believe it too -- that the sliders needed battery to operate. My PO told me that all they needed was shore power to work, but he was uninformed. I had to go get a couple new batteries and then they worked just fine. But after reading what ChuckS wrote about needing the reserve amperage capacity from the batteries, it makes sense.

[Steveo57]

Thanks, but I think you misunderstood my question. I don't have any a/c in the storage area and want to use the TV to operate the slides without batteries installed.It might work, depends on what your TV line to your rig is fused at. The slide motor draws a lot and your charge line from the TV may not be able to handle it.

[WJQ]

The power converter on my 2018 Cougar is a WFCO 8955. My slide is on the small size -- about 8 ft. I have only owned it a couple of months and did not even buy batteries until yesterday. I have been running the slide this winter using my Honda 2000 as the shore power while I make cabinetry modifications. The power converter is rated for 55 amp DC output. After seeing the caution above, I checked with the manufacturer and this converter has plenty of power to operate the slide.

Note, the DC fuses are not clearly marked in my unit as to their purpose but none is more than 15 amp.

[Steveo57]

The power converter on my 2018 Cougar is a WFCO 8955. My slide is on the small size -- about 8 ft. I have only owned it a couple of months and did not even buy batteries until yesterday. I have been running the slide this winter using my Honda 2000 as the shore power while I make cabinetry modifications. The power converter is rated for 55 amp DC output. After seeing the caution above, I checked with the manufacturer and this converter has plenty of power to operate the slide.



Note, the DC fuses are not clearly marked in my unit as to their purpose but none is more than 15 amp.I have the same converter and I asked WFCO if the converter could be damaged if I operate my slide with a slide motor rated at 30 amps and all I got back was a short "Yes, it could be damaged". So I think that it's best not to do it routinely because it is overloading the converter everytime you start the slide motor but an occasional operation of the slide without a battery is not something I would worry about.

[travelin texans]

I keep my 5th wheel in storage for the winter. I remove the batteries and keep them on a battery tender all winter in the garage.

My question is can I connect the TV and keep it running and operate the slides without reinstalling the battery?

This is the first winter i've had to put the trailer in storage, usually i keep the batteries installed and leave the unit plugged into a/c servie.
thanks

Usually the charge wire from your tv is small gauge, so it might blow a fuse. I have used jumper cables from my tv to the cables on the rv to power jacks & slides & works fine.

[johnlewis]

Also, if you try to close the slides with RV battery low, relying on the TV battery to move the slides, the current draw might burn up wires in the connection from the TV. Wiring from the RV battery to the hydraulic pump or slide motor is heavier gauge wiring than from the TV to the RV battery.

[ddibon]

Ohm's Law. You likely have one a deep cycle or marine battery. It is unable to deliver the amp demand of the slides. High amp pull in the setting of "relative" low voltage equals heat. Your RV DC charger delivers 2 amps. Your slide pull will be above 30 amps. Some pull 80. Get more battery.