MOD: National Luna Dual Battery Isolator

[teebes]

So a while back I finally got around to installing my aux battery setup. My secondary/aux circuit is intended to serve as the primary source for all my 'offroad' electronics while serving as a backup in case my good 'ol red top should croak.

Components powered via aux circuit are available for use ALL THE TIME (regardless of whether the truck is started, or key is at the run position):
-Front HIDs
-CB
-HAM (eventually)
-Rear electro cooler (coolman peltier)
-Air compressor for OBA

I tossed around a few of the isolators out there and finally decided to try out the National Luna Dual Battery setup. Note, I didn't go with the kit which includes everything for a typical install. Install I ordered up the isolator and dual battery 'monitor' as individual items from Sierra Expeditions.
- Isolator
- Optional Dual Battery Indicator and control unit


This isolator is 'Intelligent' which is handy as it allows me to be my forgetful self while out 'n about Specifically from their manual:

Features:
1. The Intelligent solenoid is designed with a 5-minute time
delay (before connecting the auxiliary battery) in order to
ensure that the main battery has a sufficient recovery/charge
period after starting.
2. The intelligent solenoid timer will automatically activate after
the vehicle has started and the alternator is charging above
13.2V.

Safety features :
1. The solenoid will not engage in the case of the auxiliary
battery being absent (not connected) or completely flat.
2. Should the auxiliary battery be incorrectly connected
(i.e. reverse polarity), the solenoid will not engage.
3. If under a charging condition, the alternator (main battery)
voltage collapses below 12.7V, the system will disconnect
the auxiliary battery.

On the dual battery monitor, it has an override feature for the 5min start window. This can be useful if I know the batteries are fine and I want to start charging the aux battery right away, etc.

The monitor also shows voltage of each battery and has an alarm warning light/buzzer, too!

Enough babble, onto the pics:

Shot of the dual monitor. Kinda hard to see, but it's showing both batteries voltage is at 12.6v, note the car is off:



Random shot of my Air Lift guage It seemed more practical than my rear wiper control as I never use it:



Overall console view, for the moment. Wires still haven't been tucked away nicely. maybe some day



Primary battery with the isolater attached directly to the body:







Nothing special on the aux battery. It's a yellow top and installed in the rear of the truck, passenger side. I'll get some pics of that setup along w/ tool storage soon.


Since installation I've had 0 issues with the new setup and it's successfully managed to keep my batteries isolated when they should be isolated and cconnected when they need to be charged. That shitty elec cooler pulls a constant ~4a and when left over night can easily drain my yellow top.

[Philberto]

I've been waiting for this... what was the cost for you?

[MrSmithsTB]

Very nice! Trivial question, but to where did you relocate the rear wiper switch? Or did you simply delete it?

[teebes]

I've been waiting for this... what was the cost for you?

Retail via Sierra Expeditions (isolator: $145, dual monitor $90). Note, the monitor is optional!!

Very nice! Trivial question, but to where did you relocate the rear wiper switch? Or did you simply delete it?

I'll never tell

Just kidding... It's gone... Whacked... Swimming with the fishes About the only time I ever used it was on dirty, dusty trails. I can't remember the last time I saw a rain cloud

[MrSmithsTB]

Now if you use the wiring that is already there for some aux lighting, that would be an awesome idea. Use the existing hole for some mid-level adjustable floods. And redirect the washer hose to squirt the cars behind you on the freeway!

[Nakashige]

What Gauge wire should I be using for this? is 2 or 4 enough

[Trail X]

Depends on if you want to be able to start off your second battery or not.

Mine is 6 gauge, but I cannot start off of the second batt. If you want to start off the secondary battery, you'll need something like 0 or 00 depending on your wire length.

Bill will be able to give you more specific direction though, since he's our resident electrical engineer.

[navigator]

I was trying to run an extension for a trolling motor for my canoe. That motor pulls pretty good amps and you run it continuous for long periods of time so I wanted a heavy cable to run it. I don't remember all the details but I found for that instance it was cheaper for me to buy a set of jumper cables and remove the clamps off of one end than to buy the wire separately. It might not work out that way for you and you might not be able to find them in the length you want but keep your eyes open.

[Nakashige]

I picked some 4 g Monster power cable today 14 feet for 20 bucks

[Nakashige]

http://www.amazon.com/gp/product/B0026J ... %20Battery any one know if this is similar to the National Luna Kit

[The Roadie]

Similar idea. Cheaper, but not so cheap as to be suspiciously bad. If I was putting one in I'd go to Sierra Expeditions, though, if I had the budget.

For wire gauge, where would your second battery go, and would you want it for emergency starting? I put mine behind the driver's seat, wired to a switch off the rear fuse block feed stud. So it's fused by the Magafuse and not suitable for vehicle starting. I have a jumper box for that.

Depending on the location, I'd trust this chart:
http://www.alternatorparts.com/wire_size_chart.htm

[Nakashige]

Battery Box in the rear. No starting i have a jump box in the TB at all times. Powering a inverter, Aux lights, Refrigerator maybe, maybe a amp