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Old 01-11-2020, 09:52 PM   #1
2 Rivet Member
2019 28' Flying Cloud
Dripping Springs , Texas
Join Date: Dec 2019
Posts: 85
Trojan T105 install, Blue Sea switch

Completed my first major AS mod today! Installed a couple T105 batteries along with a Blue Sea switch.

I was stumped when I realized I couldn't use the automotive type connectors with my Trojans. Scoured the web for ideas and finally went to my local auto parts store and bought two types of connectors: soldered 3/8 rings and bolt-on 3/8 rings. Ended using the soldered version since the others would not have fit inside the Blue Sea.

For the switch I went to Home Depot and found a 4x4x2" plastic junction box. I decided to use the existing 1.5" opening in the AS battery box for passing my cables. This worked ok but the junction box ended up being rather congested. My wife had to pull the cables from one side while I bent and pushed on the face of the box, it was very tight. I'd go with a slightly bigger box next time (blood was shed )

The T105 batteries fit perfectly within the stock AS battery box, this is on a 2019 model and the box is 12" high. At first I modified the factory plastic tray and intended to place the batteries in the original location but one of the bolts from my switch box interfered slightly. I didn't want to risk creating a hole in the battery over time so I threw away the tray and moved the batteries back. I stuck a piece of 2x4 in there to make sure they don't slide around (ie. 3.5 inches of gap at the back of the box.)

Thanks to wulfraat for his excellent wiring diagram! I modified as follows:
- 6v series instead of 12v parallel
- Inverter on "1", camper on "2". This way I never actually use the "1" position, it's either OFF, camper only [2] or inverter & camper [1+2] as I twist the knob clockwise (Blue sea 4-position switch.)

Bolt cutters to remove old connectors

Soldered connector. Smeared some 'Goop' on exposed piece of copper wire after the soldering.

Empty box

Junction box and hardware

Back of switch, installed in junction box face

Junction box installed, waiting for switch & face

Switch in place! (By far the hardest part due to stiff cables)

Completed installation


Kalashnikov is offline   Reply With Quote
Old 01-12-2020, 11:14 AM   #2
3rd one is the charm?
pcskier's Avatar

2014 23' Flying Cloud
Park City , Utah
Join Date: Aug 2015
Posts: 1,459
Originally Posted by Kalashnikov View Post
Completed my first major AS mod today! Installed a couple T105 batteries along with a Blue Sea switch.

Nicely done. Get some paint on that box and you’ll be finished

I did the exact same thing a couple years ago, same switch and all and a homemade box. Moved the switch inside trailer last summer when I did my solar upgrade. It’s nice to know the inverter is truly ‘off’ and really nice to take the batteries offline so easily between trips.

Your gonna love those batteries. Kick the tar out of the Interstates.
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