
To juice up our power-hungry gear on excursions away from base camp, we added a second battery to Campbell, our Toyota Land Cruiser. The extra power will also be helpful while we are boondocking in Cocoon, our Casita travel trailer.
The auxiliary battery can charge from the alternator and solar-panels. Since we usually drive each day, we haven’t added a solar option yet.
Battery Tray

The Land Cruiser has some space in the engine bay’s front on the passenger side. There is room for a group-35 battery if you rearrange some components.
We installed the Slee Offroad 2nd battery kit. It includes everything you need to move the components out of the way and a tray for securing the new battery.
The kit is well designed, and the components are very robust. It was easy to install and fit perfectly. That battery is going nowhere!
DC to DC Charger

To charge the auxiliary battery, we installed the Redarc dual input 50-amp DC-DC in-vehicle charger. It can charge from the alternator and solar panels.
We ordered the charger from Slee Offroad along with the bracket to mount it alongside the new tray. See the links below.
Installation
First, refer to the Slee Offroad and RedArc installation manuals.
- The wiring is 6-gauge, the maximum size recommended by RedArc.
- All terminals and splices are crimped and soldered.
- All connections are sealed with adhesive heat-shrink.
- The ends of unused wires are capped with heat-shrink.
- The tray is grounded to the chassis with star-washers on bare metal.
The affiliate-free links below list the parts, wiring, and some tools you may need.
The gallery below has pictures of the installation. They should answer many questions, including wire routing and component placement.
Do you have comments about an article? I would love to hear your thoughts and ideas. Are there any problems or annoyances that you face adventuring?
Please leave a comment below.
Don Anderson
Affiliate-Free Links:
Parts
- SLEE โ 2nd Battery Tray Kit
- SLEE โ Redarc Controller Mounting Bracket
- Redarc DC-DC Charger โ 50 Amp
- Northstar Battery NSB-AGM35
- Military Spec Battery Terminal Ends
- 2 x 60 Amp Circuit Breaker
Wiring
- TEMCo WC0082-5 ft 6-AWG BLACK (some spare)
- TEMCo WC0168-25 ft 6-AWG RED ( some spare)
- TEMCO 10-Pack Cable Ends 6-AWG 3/8″ hole ( only 3 needed)
- TEMCO 10-Pack Cable Ends 6-AWG 1/4″ hole
- 6-AWG TEMCo Butt Splice 5-Pack ( upgrade RedArc splices )
- Dual Wall Adhesive Heat Shrink Tubing Kit
- Rosin Core Solder
Tools
Gallery








