Anybody ever connect an external battery?

Yes, and Torklift makes a holder for one as well. Take a look here. http://www.torklift.com/index.php/products/auxiliary-battery-storage/hiddenpower

X2 on Torklift - manufactures very solid products.

I've looked at that Torklift box, but I think my installation will be more humble to begin with. Probably just in a std battery box and shoved under the truck when camping to begin. I may a cut ally install the box on my running board at some point. I have enough room there.

I'm trying to keep the cost moderate and that Torklift box is about $175 shipped. That's 2x the cost of a group 27 at Costco.

jmcgsd wrote:
The Lancer 880 only has room for one battery. I'm thinking of connecting a second one and using jumper cables to the main battery. Has anybody ever done this?

Jumper cables would be a poor choice . the battery/s cables should have a solid connection , wing nuts or bolted clamps . Many have added extra batteries secured in front or behind the wheel wells in the truck bed . Remember to cover the cable ends if the extra battery is not being used , they will be live if still connected to the camper battery .

Jumper cables work just fine if properly choosen and installed.
I had external battery on my travel trailer that I kept in dry storage at the lake.
I could not charge the battery there, so I had small (older) battery in the trailer compartment for brakes and occasional water pump use, while the big battery was traveling in my SUV for full recharge at home.
That set also would allow me to recharge the external battery while taking SUV for sightseeing. Small wire plug into cigarette lighter with alligator clips for the battery and all sitting in cargo space of SUV with plug there.
Sure for inverter use you will need good cables and bolted terminals, but for lighting and water pump no worry.

I don't exactly want to look like Jed on the Beverly Hillbillies, but I'm looking at cheap fixes to the power problem while I decide whether to keep both the TC and the trailer. If I sell the trailer then I'll spend some bucks upgrading the TC.

The other issue is recharging the battery or batteries in a reasonable time. I know I'll need to upgrade the old Magnatek with the PD replacement, but in the meantime I plan to use an external charger running off the genny to get he batteries back up in a reasonable amount of time.

I'm spoiled by my trailer. It has a massive 4D AGM battery and an auxiliary 30A Samlex charger to bring it up to capacity quickly.

I do want to do some cold weather boondocking with the TC however and that one group 27 with the Magnatek just won't hack it unless I run the generator all night.

My Fleetwood has battery box w tray that fits 2 of 110 Ah batteries.
It even fit 2 golf cart batteries there with room to spare.
I do not camp in extreme cold, but having 2 batteries in my Powerstroke I was considering use them as well overnight.
With generator and 2 computerized chargers can recharge everything pretty fast.
Also solar panel is good for topping batteries up during the day.

My old Citation camper had a generator compartment that was pre-wired. I connected another battery in there.

I put my 2nd 12 volt in the bed ahead of the driver's side wheel well. I got this external charge terminal from Summit Racing. Put in the battery, load the camper, attach the leads to the back bolts of the terminal.

It also works well with a stand alone battery charger plugged into your genny. Charges up much faster.

I agree that jumper clamps would be a poor choice. You might use them while stopped, but then there would be no charging when under way. And leaving jumper clamps on while under way would be a really bad idea, since they could vibrate loose and short circuit. Proper ring terminals are not expensive.