My Lance 815 is running down my truck batteries- any tips?

Those 5W and 10W solar things are a waste of time, space, and money. They don't put enough back into the battery to keep up with natural self-discharge unless they're in full desert sun with 100% exposure from dawn to dusk. If you've got it propped up in the windshield on the dashboard, you're only getting a fraction of its output.

What you're seeing now is just that the detector draw is almost negligible, as it should be.

I wouldn't leave it for weeks on end, though. When I park mine, the camper umbilical gets unplugged and/or the camper's shore power gets plugged in.

Any kids know what's good for them if they mess with the cord, and they know that getting electrocuted is the less painful of the two options.

Fixed! And it wasn't the Lance! It was a short somewhere with either my dome lights or radio- they're on the same circuit in my truck. After doing a parasitic draw test, I had a 3A draw on that fuse. Gads. I pulled that and no problem. I went through the courtesy/dome/glovebox lights and couldn't find anything obvious, so it's probably the radio (the original one! with the two head units/EQ and all) that will be replaced this summer anyway. Until, no biggie to just leave the 20A fuse out and only plugged in when I'm driving the rig. Beats the alternative.

And my new 10W solar panel and charge controller seem to be keeping everything up and running day-in and day-out now, with the Lance still plugged in. I'm installing the 200W solar system this weekend with a 30A charge controller, so that'll isolate the front battery bank (two DuraLast Golds in the truck) from the back battery bank (two Optima blue-tops in the camper). I'm also upgrading the circuit breaker in the Lance (tiny little thing) with a 60A breaker designed for a marine outboard motor (Minkota?). The camper battery bank is going to be (re)located in the cabinet under the booth seating by the back door- extending the wires from the battery box to there. And trying to think what I'll use the old battery box for...

I have always wired in a relay that only connects the truck battery(s) to the camper when the ignition switch is on. That fridge or other current draw can sure kill a battery in the truck fast!

Wow, you guys are awesome. So many great replies, not enough space to quote them all. I'll get cracking on these suggestions in the right order (will be referencing back here) in the next couple weeks when I have time to tackle it. I really appreciate the outreach to a newbie here- many thanks. And more shortly!

First add the isolator inside the engine compartment so it is in line with the power feed to the camper. This will protect the truck battery or batteries which is your primary concern.

Disconnecting the camper battery with the switch will keep them from rapidly draining from anything inside the camper. They will loose roughly 10% of their charge each month when sitting unused inside the camper. You can periodically charge them back to 100% or add a trickle charger or add a solar panel to the roof. Solar is the perfect trickle charger.

Pulling the battery and taking it to an automotive supply store for testing can tell you whether the battery needs to be replaced or not. With a flooded type low water level will also keep it from charging or holding a full charge properly.

The isolator is a good idea for long term making sure the TC doesn't drain the batteries, but you definitely have a problem some place.

Start with Sleepy's recommendations on isolating the problem first. After you have isolated the problem, report back.

Sending a pm with more info.

AnEv942 wrote:


The light wiring issue I believe is seperate (not causing drain) but a lot of possilbilites. One being there is a short in camper sig/brake wire-which CW should fix. Could be as simple as a stray wire strand in one of the umbilical plugs, corroded light socket. Verify 1st its not the truck wiring to the plug.

I would start with the BU light that is not working . Could be a shorted bulb or a broken wire . You are working with a 20 year old truck , wiring gets fragile . Check where the connections where made for the TC plug .

The charge wire on GM's is hot all the time , as mentioned many times , it needs an isolator/solenoid .

Here is what you are looking for. Your local auto parts may have one for around $15. Make sure they don't sell you a starting solenoid which is not continuous duty rated.

It allows the charge line to be hot when the engine is running but breaks the connection when the ignition is off. Its purpose is to prevent drain on the starting battery.

Sentinelist wrote:
I'd agree that CW should resolve, but I'm pretty far away from even my closest one and time is scarce. I'm nearing the limit of 'well if I can just fix it myself for a few bucks then OK', as I'm down $160 for a turn signal stalk, $15 for a relay, and counting. The battery isolator and or solenoid will be my last attempt- thanks for the personal knowledge on that, 'traveler. I'm going to check out your links as well. Cool to find another 815'er out there.

Btw, otherwise, I'd trust CW with my dog as well! Every one of them at both of the locations I've been to now have been great folks! Perhaps a mistake was made, but I'd still buy the guy a beer.

You'll find there are several of us Lance 815 owners in the TC forum, jefe4x4 Lance 165s is physcally the size as our 815.

Over the years, I have made it a practice to unplug the camper from the truck, EVEN if I have an isolator. I had one short out a long time ago. I just got into the habit of unplugging the 7 wire from the truck and sticking it in the gas/fuel filler cap. That way when I jump in the driver's seat, I can see it stuck in the gas door.
Like Sleepy said, by disconnecting the camper from the truck, it will cut the diagnosis in half.
And if I missed it, the only other thing is to check the condition of the batteries. I have had an occasion where the camper battery was shorted out and would wear down the truck battery if I did not disconnect the camper from the truck.