Major Engineering FUBAR
 

Hello All:
My first season of camping in our new HILO has come to a close, and as we live in Northern Nevada, where our winters can become quite extreme, I didn't waste any time getting our coach winterized.
In this process, some really bothersome engineering errors came to light.
First off, the winterizing was easy-peasy, but to count on getting any really good information on the trailer from the owners manual.....forget about it! The manual for these trailers is really poor.
I got the trailer drained, and the anti-freeze put in, and today I decided that I would remove the batteries to store in the garage for the winter. I had read that you are supposed to store your HILO in the lowered position, but in a rather poor engineering moment, you cannot access the battery box with the trailer in the down position! Also, when the trailer is in the down position, you can't access the manual lifting mechanism for the hydraulic pump! What is up with that?
I had the trailer in the raised position when I removed the batteries, and then discovered that the trailer needs power to lower the top. No worries, I just plugged into shore power, and was able to lower the top. Then a sneaking suspicion hit me, and I wanted to see if it was going to go back up. But noooo.......all I get is a high pitched electrical type squeek from an area at the front of the coach. So now what the heck do I do? With the top down, you can't access the manual override! I'm really hoping that the lift mechanism is just being fluky, but I'm really worried about this issue.
I know there are some really smart HILO experts on this forum, and I could really use some input
Thank You!

Hi Pat,

I haven't heard the acronym FUBAR since leaving the military many years ago, brought a chuckle to me! On my 2007 Towlite, the battery cover is hinged which allows access to the manual override in the down position. Is your 2010 model different?

It is hinged
 

Hi Greg,
It is hinged but I really don't think it has the clearance. I'll check it tomorrow.
Thanks

On mine, I need to remove the propane cover and one of the bottles for clearance to actually raise the top. It takes about 140 pumps to raise it all the way but it's doable. You should also be able to lower it manually with the batteries removed by opening the lowering valve, much like a bottle jack.

Let us know how it goes!

If you can, reach n and get hold of the battery cables and pull them towards the front. Then you should be able to get jumpers on them and connect to an external battery, like your tow vehicle, to get the juice to raise it. Others have attached a positive jump cable to the solenoid on the lift motor and a negatve to a decent ground on the trailer. I leave my cables on the trailer so I can open the hinge and access them.

I don't see any necessity in removing the batteries unless you will not have access to an electric source for charging the batteries. I store our Hi-Lo in my friend's storage shed and hookup my Battery Tender and leave on for the winter. The batteries are always fully and not over charged and ready to go in the Spring. As long as the batteries are kept charged there should be no danger of them freezing. If the batteries are in good shape you can put a charge on them maybe once a month an be okay. Make sure the master switch is turned off so you have nothing like the LP detector draining the battery.

On my 2805C there is a slot in the front of the battery box to put the jack handle thru to pump up the top. You have to lay down on the ground in order to pump it up, but once up about a foot you should be able to get a jumper cable hooked up to finish the lift. There is no hinged top on my battery box. To improve on this system I got the jumper cables and plug that came off a parted out light aircraft, installed the plug on the outside of the battery box, and connected it to the battery. Now if the battery is low I just plug the jumper cable into the plug, connect to the truck and up the top goes.

Why won't plugging the trailer into shore power make the pump work?

Hi, Pat. The voltage converter/battery charger in the trailer limits the 12V charging current to the battery (what would feed the pump motor) to a relatively low Amperage (possibly 8 Amps max) so that the battery will not be damaged. The pump motor needs maybe 50+ Amps to operate, and a fully charged battery can supply that for a short period of time.

You can send the needed Amperage to the motor directly from your tow vehicle battery through a set of jumper cables as long as they are heavy gauge (4-6 gauge) wire. The poor little 10 gauge battery charging wire to the trailer plug and 30 Amp fuse in your tow vehicle will not supply enough power for the motor either.

Hope I'm making sense here.

- Jack

Thanks Jack

I'm still trying to make sense of it. Electrical systems are not my forte' (obviously).
What confuses me about the converter/shore power thing is that to run the A/C unit, you need to be on shore power, or a strong generator. Whereas the pump for the hydraulics (which isn't as big of a draw as the A/C) is isolated from that power source. It would make sense to me that all of the coaches power needs such as A/C, 110 power, fridge, and the hydraulic pump would be in the same line, and the items that need reduction such as lights and battery charging, would be separated.
My confusion is in the fact the hydraulic pump is in the wrong power scheme lineup. Can somebody explain to me how the power goes from the plug in the garage, through the cord, into the trailer, through the converter, and makes the A/C run, but NOT the hydraulic pump.
I'm sorry if I'm being dumb on this subject, but I really don't understand this.
Either way, this weekend I'll hook up one of the batteries via jumper cable to the trailer and see if that powers the pump.

The airconditioner is in the AC circuit and is protected by a 15 amp circuit breaker. So it pulls no more than 15amps. The AC power cord that you plug into the house is sized for 30 amps AC. The hydraulic pump is 12V DC and pulls 100 to 115 amps depending on the size of the top (weight) and age/ware on the lift system. As Jack stated the converter can only supply a small DC amprage to recharge the battery and at best the tow vehicle will supply 30 amps. If the battery is low there is not enough power to raise the top. The AC and DC circuits are two completely seperate circuits with each having it own limits on power output. If I have been towing for 6 or 7 hours with the fridg on DC, I know my battery will be low when I set up. When I park the first thing I do is plug into shore power then crawl into the RV and turn off the fridg. By the time I get unhooked and level the RV the battery has been boosted up enough to raise the top. Hope this helps.

Pat- Others will explain it better but:

When you are hooked up to 110 there are certain things that are wired specifically FOR that. The AC is one. A couple receptacles in the trailer are the other. You can plug a microwave or hairdryer etc into those. So- power is directed to those receptacles. Power is also sent to the converter/charger. The converter part CONVERTS that power to 12v- and so your lights inside, the pump, the bathroom fan, etc, are operating on 12v. The hydraulic motor is also 12v-. I know you get that and I'm not trying to be condencending ( I think out loud-even when writing) Think about it- if the hydraulic pump was wired for 110 you would only be able to raise it or lower it when hooked to 110, which , with all do respect, really WOULD be FUBAR in respect to making the trailer go up and down be a handy procedure under most circumstances. WHY it must be wired thru the battery is a bit above my pay grade but I think jack must of nailed it. But I certainly understand why I would want 12v on that the majority of the time.

Rick

Hi Pat, I'll try again - I know I'm not always clear on these things.

As Rick said, you'd want to be able to raise the top when your trailer is all by it's lonesome in the woods, not even hooked up to a tow vehicle. So, as both Rick and Jim said, the hydraulic pump motor has to get ALL its power from the trailer battery, a 12V source. The motor is a DC motor, so it should not be powered by AC.

AND, as Jim said, that motor pulls a LOT of power. He said it can be as high as 100-115 Amps, and I believe him, but have never measured it.

IF, you're plugged into shore power, the converter's charging output will "help" the battery, but if the battery is drained, or missing, this little 8 Amp boost is like trying to support your weight on a 1x2 plank of wood. You really need a working battery in the circuit to handle the draw.

As Jim said though, if the battery is low after a long trip, you might restore enough power to it by disconnecting the refrigerator from DC and plugging in to shore power long enough to replace some of the depleted charge. This may actually take several minutes or even a significant part of an hour to bring the battery back to a sufficiently charged state. And, when you finally raise the top, you are not getting the actual lifting power from the shore power source. It's coming from whatever has been stored in the battery.

But, as long as you can connect ANY 12V battery that's big enough and in good condition directly to the battery cables in the trailer, the top should go up without problems. So, you could attach jumper cables to a battery on the ground, or to the battery in your tow vehicle.

- Jack

Well done, Jack, as usual. :) But now I have a question (sorry, Pat, for jumping this thread a bit but it relates....). Is there a reason for a converter to go through a battery OTHER than the fact that the battery provides the necessary amperage for many things? In other words, theoretically, if you were pulling say five watts or less- could I power that item directly via a converter? Is that not what that little transformer thing is on my doorbell-a converter that is dropping the voltage from the house current to 12v for my doorbell without running it through a battery?

Rick

Answered my own question: This from some rv answer guy on the net.

"1) When you are plugged into electricity it converts a portion of the 120 volts coming into the RV down to 12 volts so all of the 12 volt devices like overhead lights and fan motors will operate without draining the RV battery.
2) It has a battery charger built in the converter to keep the RV battery charged (topped off)."

And, this link explains it all in some more detail for those who might be approaching my level of non-clarity. :)

https://www.rvuniversity.com/article....80107175732307

Rick

Well, I don't know about anyone else but I sure am learning alot from this thread. Thanks guys!

Now if I can just retain it . . . ;)

Rick, I'm not convinced your "RV Answer Guy" has it exactly right, but, yes, there is mostly truth to what you learned. The converter is going to supply more amperage than the battery needs, in general, so it can handle both the 12V things like lights, water pump, and so on, as well as charging your battery.

But, I think the battery is also acting to "smooth out" and regulate the voltage that the converter supplies, much like the battery does for the alternator in your car. Since the converter 12V output is sent directly to the battery, it can never be different than the battery voltage. Without the battery in the circuit, the voltage would possibly vary significantly, enough to damage any sensitive electronic equipment that is powered by DC. In your vehicle, this protects your radio, GPS, air conditioner controller, vehicle computer, and so on. I know the trailers don't have much of this kind of thing, but I think the battery still acts as a "regulator".

Also, by taking the 12V supply for the trailer "off" the battery, you don't have power interruptions if the shore power is disconnected or if there is a shore power failure.

For these reasons, the converter 12V output should go directly to the battery and then anything the battery doesn't need can be used elsewhere.

- Jack

Makes sense. I guess some of the descriptions I have been reading implied that possibly the converter was directly powering 12v ---- but never explicitly said that. I know the older original converters did not include the ability to charge a battery, and that chargers were added later. And that makes me think the power didn't go through the battery- but I am making that assumption. Possibly those early converters simply did not create the required voltage to fully charge a battery. Thanks for your always informative input. You are usually correct and I am assuming this is still the case :) I'm going to keep checking though- and I'll let you know if I find anything that further illuminates this.

Rick

Ha! You give me way too much credit, Rick. *beers* :o I suspect you were right, though, in guessing the early converters didn't have enough "left over" to charge a battery. We all have to remember that in addition to supplying the 12V power to the trailer's lights, furnace, water pump, and ventilation fans; the converter still has to have enough 120V current left over to power an air conditioner, microwave, the refrigerator, water heater, and anything you might decide to plug into the 120V outlets. All told, that 30 Amp input gets split into several different destinations. And, if the 12V portion of the converter's output can't keep up, the battery is there to take up the slack. It would start getting charged again when the demand was reduced.

- Jack

Wow!
You guys are awesome! Thank you all so very much for the help and information. It is nice to be part of a helpful online community (Rick: you weren't condescending at all) Now I get the power difference. Makes sense about the pump not being 110 now that it was explained.

I got the top raised today by reaching in and fishing the battery cables out of the box and hooking jumper cables from them to one of my batteries. Voila......up it went!

I don't want to start a different thread, but I have some more brain picking to do from you guys:
Opinions on storing the trailer for the winter in the up or down position?
Should I just put the batteries back in, and plug the trailer in to shore power once a month to top them off? Or keep them in the garage and give them a trickle charge once a month?
I live in Northern Nevada and our winter lows can be in the teens, with long stretches never getting above freezing.

Thank you again to everybody for their valuable input
Pat