I am close to putting my second in. The tray is there. I have the hold down bracket.
Here are my powered items
Warn M8000
eventual fridge
will hardwire an inverter (already have the 750w inverter)
So what I've been uncertain about is what kid of battery for the second. do I get a Marine battery? A Deep Cycle? Or another starting battery?
I'd like it to be wired for self jumping, but not if it limited me from powering a fridge.
So with that in mind,
what should the second battery be, and any tips on where to wire the power items?
Should the winch remain on the main battery, and put the inverter and fridge on the secondary? I basically never winch, and when I have, I've been running the truck and using the hand throttle.
A Marine type battery is a decent choice. It will likely be cheaper than a true deep cycle battery and in a pinch can be used as a starting battery-ie built in redundancy. I use the Costco Marine batteries for this-$90 or so, 100 Amp-hour capacity, decent for the $$. It's only a 3 year battery but I've had them go 5 with care (BatteryMinder charger when not in use). A deep cycle battery will also work well for this type of use.
I would not use a regular starting battery-they do not tolerate any appreciable discharge and repeated cycling to 50% charge (which is typical) will kill it quickly.
Wiring for self jumping is possible but over-rated. Since the (-) grounds are already joined, all you need to do for a jump is to jump the positive terminals of the battery. That's not too hard. It's a rare event in any case.
I can highly recommend the Blue Sea ACR type voltage sensing relays. I have them in 3 trucks. THe 7610 will work well for an 80. If you also want to self jump with a switch, get the Blue Sea add-a-battery kit which comes with the 7610 ACR and the combiner switch. The Larger Blue Sea 500 amp ML-ACR can do this without the external switch, but it's a bigger more expensive unit and not as easy to mount. Still a good choice though.
I would not hard mount your inverter. In fact, evaluate if you really need an inverter. They are huge power hogs and waste up to 50% of the input power. Even with no loads, they still consume power. If you must have one, at least put a switch in the (+) lead you you can disconnect it from all power when not in use.
Winch should remain on the main battery.
Your second battery will be your "house" battery, so all of your auxiliary loads will come off of it-like your Fridge, your inverter, Ham radio, camp lights, etc. The best way to do this is mount an interior fuse panel inside the cabin. Then run a heavy gauge FUSED wire from your house battery to the panel, then run your house loads from the panel.
Most important advice-Fuse any wire coming from the positive terminal of the battery at the battery or immediately adjacent. This will keep you from burning down your truck in the event of a short.
Give a serious look at the Blue Sea ACRs. They are excellent and a good deal too. The 80 alternator makes 100 amps, so the 120 amp Blue Sea SI-ACR works perfectly. You can get more bells and whistles with the Blue Sea ML-ACR.
My standard approach (now that I have 3, I have a standard approach!):
Blue-Sea SI-ACR 7610
2 gauge wire (use good marine cabling with marine type heat shrink on the terminals).
ANL fuses for the cables at each battery that go to the ACR
Maxi fuse (60A) for the 8 ga wire that runs to the interior panel
Blue Sea 6 circuit panel under the passenger seat
I went a slightly different route than Cruiserdrew.
The second battery is a Odyssey 2150. From this I run the 1000 watt inverter, aux power panel and winch. I left the main battery to be used only for engine starting and accessories that I use when driving.
For battery charging, I used a Blue Seas 7622 system. Allows you to use both batteries for starting if needed with the push of switch.
The major difference is the winch. My reasoning is that it can easily drain a battery when in use. Drain the aux battery, no problem with starting the engine. I can start the engine and drive off. Drain the main - not going anywhere unless you can jump start it. You can read about my installation and battery monitoring system and reasoning at Cayman Islands FZJ80 DIY build-up
Well, how often do you winch with your engine off? It's extremely unlikely you would drain your main battery to the point your truck would not continue to run.
7622 = good stuff. Just more than most need with typical Land Cruiser alternators/charging. A very good option though.
Odyssey batteries I'm not sure are good stuff. They require almost impossible charge profiles and seem incompatible with our 14 volt charging systems.
Thanks for this guys. It gives me some homework on getting a few parts and getting to the next stage of implementing the upgrade.
On the inverter, it gets use while camping quite a bit, from running aux lighting (14w CFL or LED bulb in a drop light for light near the truck for cooking and such) to charging phones, various other power chores that require a 120v outlet over a battery connection.
Thanks mmajsw- gonna read your linked post shortly.
