Beetle, You didn't say if the tow vehicle charging wire was factory installed or someone else did it. I would make sure the charging wire is of a heavy gauge to deliver sufficient current. I had this problem on and older Hi-lo and the return ground wire was the problem. Also, I am a believer in having a 2nd battery just in case the one online gets drained down. Buy a couple of battery isolators [you can get them at Walmart Automotive] and connect them to the negative battery posts. That allows you to have one battery online and the other off line for reserve power. You can then isolate either battery and alternate the useage between them and charge them alternately. It is best not to mix battery types Ie. [deep cell and starting battery] nor is it a good idea to mix and older battery with a new one if you were to leave both batteries online for normal use and charging. Hope this helps.

Jerry

Beetle, You need to give us some more info that may help to figure this problem out. What tow vehicle do you have, What model HiLo, and is this a new problem. If this is a new problem I agree with the above post that the problem is most likely no charge from the TV. I started having the same problem on my HiLo on my return trip from Alaska. Was blowing the 30 amp charging fuse on the TV and battery would run down on RV with fridg running on DC. I cleaned up every connection in the battery, lift and fridg circuits and replaced the battery and everything has worked great since. I did all this in one action so cannot say which one corrected the problem. I did find a smaller wire than required in the fridg circuit, replaced it but do not think it was the problem as the fridg had worked ok before. If we know your TV, someone here who has the same TV will tell you if it has the 30 amp fuse and where it is. Check the charging voltage as described by Jack and if it is there then the problem is in the RV. Do not assume your batteries are good. The best check is to take them to a auto parts store and have them checked with the proper equipment under load. Since fixing my problem I have put over 7500 miles on the HiLo running with the fridg on DC and everything working great. The fridg set on #3 kept the freezer on 0 degrees and fridg between 36 and 43 degrees. Hope this helps.

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Jim L & Faye
2805C
2003 Silvarado diesel crew cab
central Virginia

thanks for your responses,
i have a 03 Grand Cherokee and an 07, 17 foot hi-lo towlite and yes this is a new problem. We traveled about 300 miles and stopped overnite in a koa and everything worked well, we were plugged in and left the next morning and traveled another 300 miles with no hook-up. I think I followed the same procedure as always and had no power at all, no lights, no lift and then even plugging in with a long extention cord I had trouble lifting. the same thing happened on our return home, no juice whatsoever after driving all day,but after plugging in for a day and then unplugging I have been going out and checking power and all is fine.
Beetle

Beetle - your symptoms tell me your trailer battery is not charging while it's being towed. That means one of three things:

1. The fuse in your charging circuit is blown or faulty in the Tow Vehicle.
2. The charging circuit itself in your Tow Vehicle is faulty (poor ground, broken wires, bad connections, etc.)
3. The charging circuit from your trailer plug to the trailer battery is faulty (broken wires, bad connections, etc.) This is a DIFFERENT circuit than the one that is used to charge the battery when you are plugged into shore power.

You've checked the fuse and are certain it's the correct one and it's fine. That leaves the two charging circuits.

If you probe the 7-pin plug on the tow vehicle at 1 O'clock and 7 O'clock and see battery or alternator voltage with the TV ignition ON, that circuit is OK, otherwise, you've found the problem. (Note: you normally will not see voltage on those pins if the ignition is OFF.)

If you probe the 7-pin socket on your trailer with a voltmeter at the 11 O'clock and 5 O'clock pins and see battery voltage there, you know the tow charging circuit in the trailer is OK. If there is no voltage on those pins, there is no connection from the socket to the battery and you've found the problem.

- Jack

Hi Beetle, Another question, prior to this first 300 mile trip have you owned this RV for a period of time and was everything working ok then? First you must determine if the charging voltage is at the TV elec plug as Jack described. If not there, the problem is in the TV. You need to find out if your TV has the separate fuse for the charging circuit as most TV have. When you said that the top raised slowly with the extension cord plugged in, this is normal. If your batteries are low on charge the power supply is too small to produce enough amps to lift the top. The pump pulls upwards of 80 to over 100 amps when raising the top and at best the power supply output is under 30 amps. You must have a well charged battery to raise the top. If the voltage is at the TV plug then the problem is in the trailer. Are you towing with the master switch in the off position so there can be no drain on the battery except the fridg? Again make sure your batteries are good. You cannot check them with a volt meter unless you know how to put them under a proper load. Take them to a auto parts store and have them checked. Keep working at this and keep us informed. There is lots of info here on the forum on this problem.

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Jim L & Faye
2805C
2003 Silvarado diesel crew cab
central Virginia

Beetle, follow all of the steps that Jack just posted as well as mine. If the voltage is at the TV plug, then plug in the trailer plug and make sure the voltage is at the batteries. Disconnect the battery cables and check for the voltage on the positive cable to the ground cable.

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Jim L & Faye
2805C
2003 Silvarado diesel crew cab
central Virginia

thanks for the timely responses I will get after your suggestions, I had carpel tunnel surgery two days ago in my dominant hand so I am not moving at full speed.
thanks again for your advice.
Beetle

Thanks to all for your timely suggestions, it seems that both my marine batteries nee replacing, I hope that fixes things.
Thanks again.
Beetle

For best results you should get deep cycle batteries, they work best with the discharge and charge rates of a HiLo. They will last longer. You could go to the AGM batteries but they are much more expensive.

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Great Wife, Joyce
2010 2310H Hi-Lo
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
Amateur Radio K3EXU

If you change NOTHING, compared to camper at rest and unplugged from houes/shore power, when you hook to the tow vehicle, then IMHO, You have a problem, with trailer up through vehicle wireing IMHO. This is hard to think otherwise, as long as what you have todl us is true, no fridge turned on, etc. Plus you would think TV would charge battery while driving.

So if, Like you said, battery stays charge when not connected to TV, and or shore power, this means possibly someone could have moved the wires around in the connector? if they did thier own TV wiring, instead of following pinouts, which I have seen done thousands of times with 4 wires setups. Maybe TV has non stock wire setup, again if not factory there is the chance someone guessed at it... Sure less likely but possible, if nothing else maybe Tow Harnes on the Vehicle side has rubbed through a wire coating, or Ive seen them routed wrong, and got smashed enough that 2 wires touch or something is touching the frame (which is ground). Plus make sure ground is good, it wont charge well without ground, even though most trailers get "some" ground through the ball...

Good luck, I would think, Even with all the lights left on, the battery (single one) should be fine for several hours while traveling, hell I have boondocked for 2days one nite without helper/recharge power, and still life the roof up at least enought to get it down off safety...

Third thought, check battery voltage at rest unhooked from EVERYTHING, everything off and fully charged up. write it down, then hook to TV, check battery voltage again. While you connect the wires, be sure to feel the connector's wires, IS anything like your wires, getting warm? THen go check battery in trailer again! IF voltage drops, from faulty connection, or something, that is dicharging battery, and it should be evident right then. I dont know how long you travel and then discover that the battery dies when you get there, so less travel time, should be bigger drop in voltage when you hook up to tow vehicle...

Another thought, if you have shore power helping the battery(s) when you lift camper, the battery could have a weak cell, and it is getting just enough help and charge to not notice. I take my battery to Autozone, have it checked for starting power, since this is what you are technically doing when you lift the top, running a starter motor with significant resisstance, like an old hard to start pickup, so to speak...

Good luck checking things out. let us know what you find, most people never report back that something is fixed, and we read the posts forever wondering what if? LOL

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From Kansas: 29ft '95 5th, converted to toybox in rear, by Hilo. Pics soon, Some Here.