dual batteries

  • Any here running dual batteries, either a kit or DIY? If so, what are you using? Looking at getting a dual battery tray (likely the M.O.R.E version) soon and eventually a second battery and isolator, just haven't decided if I want to do it myself or use a kit.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

  • This may sound weird but there are some nice dual battery kits packaged for boats. I would look in that direction.


    I installed one last year in one of my boats and they are packaged with an auto charge relay and a switch. The auto charge relay bridges the batteries together when the voltage of one of the batteries climbs to 13+ volts. This indicates the battery tied to the alternator is charged and couples both batteries together to allow them to be topped off by the alternator. When the motor is off the battery voltage drops and the batteries uncouple.


    The boat kits don't use isolaters but use a dedicated isolation switch in combination with the charge relay. They also have different switch configurations so you can have two isolated batteries for different purposes and couple them together if one of them dies. The thought being you have a battery for the motor and an additional battery dedicated for electronics. They only come together for emergency purposes.


    They also have switches for a system with a single battery system with a dedicated standby battery. The switch allows you to select from either battery or both.


    Boats seem to have gotten away from battery isolaters in favor of the charge relay. I assume this is done for reliability.


    This is the kit I installed:
    Blue Sea Systems Add a Battery
    It's set up for a dedicated house battery.

  • I am running a dual battery set up. My tray is Tomken Machine. It is well made and was close to $100, the down side was I ordered it from Quadratec, and it shipped from Tomken a month after I ordered it (It was back ordered) my isolator is off Amazon. I will send the link. It charges both batteries while the jeep is running, but only pulls from the auxiliary battery when the jeep is not running. If my starting battery does drain, I press a button, and I can jump from the auxiliary battery.

  • my isolator is off Amazon. I will send the link. It charges both batteries while the jeep is running, but only pulls from the auxiliary battery when the jeep is not running. If my starting battery does drain, I press a button, and I can jump from the auxiliary battery.

    Do you remember the brand or model info of that?


    After doing some research, I'm kinda leaning toward going with the Genesis complete kit since they make a very clean install for about the same price as if I pieced it together... the main difference is that theirs is a smart link where it'll only charge one battery at a time, reducing strain on the alternator.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

  • Do you remember the brand or model info of that?


    After doing some research, I'm kinda leaning toward going with the Genesis complete kit since they make a very clean install for about the same price as if I pieced it together... the main difference is that theirs is a smart link where it'll only charge one battery at a time, reducing strain on the alternator.


    Here is the link to the isolator I use.


    https://www.amazon.com/gp/aw/d…s=battery+doctor+isolator


    It seems to work well, but I have only been running this set up for a few weeks. The isolator was about $70, the dual tray was about $120, and the wires were another $50 for the good stuff. I also added a 100 amp fuse between the isolator and the auxiliary battery. The genesis kits I see when I google them are $500. Perhaps the genesis offers more features, but I just wanted to run my lights and winch without worrying about a drained starting battery. Let me know what you decide!!

  • I am just curious. What purpose does the second battery serve? The reason for boats is obvious to me. I grew up around boats, and my dad always had the dual-battery setup. Is it just for the unlikely event that you have a dead battery in a situation such that there is no one anywhere nearby (including AAA) to help jump it?


    I am not being facetious; I really don't understand. And I always carry one of these. I guess I am missing something here?

    ~ JD
    * WARNING - The above post may contain trace elements of biting sarcasm. Those with known sensitivities should avoid staring directly at it.

  • Mostly it's so you can run accessories with the engine off and not worry about a dead battery. So surfrider can listen to the radio at the beach and I can run my fridge and lights at camp. If I'm using the campsite as a base for hiking, I might not need to start the Jeep for 2 days.


    I have one of those little jump packs and it only works if the battery is slightly low. I accidently drained the battery really low one night and it wasn't enough to turn it over... Drained the jump pack and had to get a jump.


    Fwiw, this battery worked ok when I had just bought it, ran the fridge overnight in the hot Nevada desert (90* at midnight) and started strong. One year later, though...

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

  • Hey Jerry, I was recently looking at the same idea for my fridge, in case I wasn't going to be driving the vehicle every day. I haven't done it yet but here's a list of parts I have found while planning it.


    My plan was to just use a portable power pack so I could cheaply and easily go camping out of either of my vehicles (truck, sara's jeep, buggy). So it surrounded from the idea of running cables with quick connects from the car battery to the back for the "accessory" battery and plugging the fridge into the accessory battery only.


    In terms of isolating, the quick connect is the isolator, or a manual switch for $30 from local parts store.
    Or, a voltage sensitive relay as was said, many are on amazon for $80.
    the "intelligent solenoid" sold by equipt1 is the same idea but really nice and more expensive.
    etrailer sells an ignition switched 85amp rated solenoid for charging trailer battery
    12voltguy sells a panel with 200amp rated solenoid for his dual battery kit.


    I've also found a lot of marine battery cases on amazon for this, seems group 27 is big enough for just about any and the " rv / deep cycle / marine" batteries with enough capacity are all big enough for that size. search for "marine battery box", http://a.co/i8VzqcB is an example and on the more expensive side.


    FWIW, I've found the odyssey or optima agm batteries don't offer the extra capacity for this scenario, they are probably good for replacing the starting battery and romping around on trails, and draining it lower, but not for lasting longer off the charger. And local auto zone sells their own duralast agm batteries, and their own "capacity" batteries (not for starting).


    Hope this helps, let us know what you found out and ended up with.


    I'm not sure I understand the "strain" on the alternator. I've found on forums that people said they hated their dual battery setups because they were replacing them, but there are many differently rated alternators out there and I'm not clear where the constraint is. If you're looking for "shore charging" for an extended week, "Iota dls" is a product that converts 110v to 12v and available on amazon.


    And P.S., 12.8v is 100%, 12.2v is 50%, I try not to bring the normal car battery below 50%.


    And P.P.S., the 6 volts have 215ah, for golf carts, and of the ones I've found their dimensions are taller instead of longer, in case that is better.

  • I bought one of those little jump packs at BJ's. Package says it will start up to a 4.0l engine. I tried it on my Scrambler at it started it without any trouble. I have a 401 (6.6 liter) in it. Needless to say, i was impressed by it.


    Sent from my SM-J320P using Tapatalk

  • Get a solar charge controller, attach a 100w panel to the top of the Jeep and you have unlimited power (*weather permitting).


    I have two.


    When I park my trail rig, I plug one into the 12V socket and put the panel on the dash. Prior to doing this, if it would sit for a month (or sometimes more ;( ), it would often be dead. Now with the solar panel, it always starts right up.


    I have a deep-cycle marine battery in my trailer box, which powers the breakaway, the electric tongue jack, the electric winch, and the spotlights that I mounted on the trailer. The battery has a charge feed from the tow vehicle, but it never seems to be quite enough. So when I park it, I hook the clamps from the solar panel to the battery terminals, and just set the panel on top of the box. The constant trickle charge keeps the battery at full charge.

    ~ JD
    * WARNING - The above post may contain trace elements of biting sarcasm. Those with known sensitivities should avoid staring directly at it.

  • Fwiw, the portable fridges need 200w panels and 7 hours of sunlight to keep up. Plus, if you park in the sun the fridge will be running more often. I think solar is exciting, but not convinced it is always practical. Maybe in the desert. It's hard to dodge the sun out there.



    Sent from my iPad using Tapatalk

  • Thanks for the input guys!


    A little followup... I was able to replace the battery under warranty. After running errands in the Jeep and having it running for 2 hours, it was at 12.5v when they checked it, and 380 cranking amps. The warranty process requires charging for several hours, so pulled the battery and left it with them overnight. 13.1v and 390 cranking amps. The battery was also swollen, so it clearly had some internal issues.


    I guess the jump pack just doesn't like my JK. I used it yesterday to jump the XJ, battery was so low the lights didn't even turn on (I think the subwoofer amp is drawing power). Waited 10 seconds on the jump pack and it fired up.


    The portable battery is a nice method for multiple vehicles, even for just one, but I really don't have any space to spare in the back of the Jeep.


    I wanted to get solar panels for the trailer, but the full-size 100W panels won't fit efficiently and I don't want to pay for the folding ones right now. The little dash panel things might work to help trickle charge the Jeep, but that's a little annoying for me to deal with... I have to jump into the Jeep and run pretty often for the firehouse.


    My fridge is inside the Jeep, so it doesn't really run that often, 200W and 7 hours is way more power than it would draw in 24 hours. It runs at 65W but normally only runs for a few minutes. It triggers a few degrees above the thermostat and runs down to a few degrees below so it doesn't cycle on/off constantly. I'm going to make or buy an insulation blanket to help it even more.


    I think for the short-term, I'm going to add a 4-10A onboard battery charger like I have on the trailer (and need to plug back in). I have jumped off of that battery before, just trying to avoid hurting the deep cycle using it as a starting battery.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

  • Jerry, I was also looking at the genesis dual battery tray. now that I've added a winch I need a better battery to run it, I like everything about the genesis except the price. I would like to hear from someone who has one though, I hope if someone has one they reply.

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