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2nd Gen Dual Battery with on-board charger

Discussion in '2nd Gen. Tacomas (2005-2015)' started by seafur, Oct 28, 2019.

  1. Oct 28, 2019 at 6:49 PM
    #1
    seafur

    seafur [OP] Well-Known Member

    Joined:
    Jul 11, 2014
    Member:
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    Messages:
    115
    Gender:
    Male
    Pacific Northwest
    Vehicle:
    2014 DCSB MT TRD OR
    Sprinter bed tiedowns, Aux fuse box, AIO key, 3-way canopy light switch, 12V bed outlet, Dual Battery AGM G35, Viair OBA, Uni-filter mod
    After getting things improved as much as I could for by ARB 63 qt fridge/freezer running on the stock starting battery and still draining the battery I decided to do a dual battery upgrade. I installed over 3 months so not all the pictures have all the finished components as I took the pictures as I went.

    After doing quite a bit of research on AGM batteries I decided to install an AGM battery as my aux to deal with charging and the non-ideal "charging" characteristics of the alternator I decided to install an on-board DC charger and a simple solenoid to be manually controlled to allow me to start the truck on the aux battery if ever needed. I decided against a smart isolator or manually controlled isolation since the alternator is not a charger as it doesn't control current and although I was initially concerned about the alternator running too high of a voltage for float conditions on the AGM battery but it turned out the alternator is too low (mine measured 13.9-14.1V) to get the AGM battery in bulk charging. I know there's a diode trick to use on the Alt-S circuit but I decided against that for other reasons, if you want more info on that search TW for Alt-S. I know a lot of folks use the alternator to charge AGM batteries, either dual or single and there are several threads where that's been discussed at great length. I'd rather keep this thread to parts, technique or Q&A on this approach so those that choose this method can exchange ideas.

    The X2Power AGM battery is mounted passenger's side against the firewall using the OGE bracket.

    OGE in truck 1.jpg OGE in truck 2.jpg aux battery in truck.jpg

    The "jump-start" solenoid is mounted on the passenger's engine compartment, I mounted the solenoid using rivnuts.

    solenoid on bench.jpg solenoid rivnuts.jpg solenoid mounted.jpg

    The solenoid has a short wire from the aux battery to the solenoid and a long wire across the upper radiator support directly to the positive clamp of the stock battery.

    aux positive clamp.jpg stock positive clamp.jpg

    The ground for the aux battery takes the same path to the negative post of the stock battery. To allow for that connection I cut off the stock negative battery clamp and installed a military-style clamp, this allowed for a clean place to connect a large conductor ground wire to the aux battery. The only thing I don't like about this arrangement is now cables are leaving the ground clamp 180 degrees apart and it's hard to move the ground clamp out of the way when it's disconnected from the battery, it wants to sit on top of the negative post which negates disconnecting it for maintenance but it can be zip tied out of the way.

    aux negative clamp.jpg stock negative clamp.jpg
    I mounted the DC on-board charger under the passenger seat. This location keeps the charger for getting too hot, keeps it clean but does make monitoring the LEDs a challenge. The other location I considered was in front of the radiator off to the side. There's plenty of room there but with good sheet metal fab skills I couldn't come up with a mounting method I'd be happy with. An Aussie company makes a bracket for the LC for a Redarc charger but they don't make a bracket for the Taco. If they made a bracket for the Taco I probably would've bought a Redarc. The Redarc with solar input is also $140 more than the CTEK which has solar input and MPPT standard. The charger is grounded to the aux battery post. The 18 gauge wire on the charger output is temporary and just there to monitor the voltage with my Fluke, yes with this wire being protected by the 80A fuse I might just burn down my Taco :(

    charger mounted.jpg

    The DC input comes from a tap behind the driver's side toe kick panel on connector IB1 that is a 30A ignition switched circuit intended to charge a battery in an RV via the 7 pin tow connector. I don't tow an RV and this circuit has a 30A in the main underhood fuse box and is controlled from a relay in the main fuse box. When IB1 is plugged in it's the top right black wire that I tapped.

    IB1 tap.jpg

    The positive post of the AGM battery has two fuses. One 80A that the on-board charger connects to and it also feeds a 50A breaker that's under my Blue Sea 12 position aux fuse box.

    aux fuse box.jpg

    The other fuse on the AGM battery post is a 200A fuse that goes to the jump-start solenoid.

    This way if something goes wrong during a jump-start once I get going I still have the 80A fuse feeding the aux fuse box. It also allowed me to use smaller gauge wire to feed the 50A breaker and eliminated the need for rather ugly in-line fuses. I bought several of the ANL fuse holders and didn't like how big they were and the lack of mounting locations.

    I also have an AC CTEK battery charger to use on the AGM for charging when I'm parked at home. I plan to connect this to the aux fuse box using an Anderson power pole connector to make it an easy hook-up to top off the AGM battery.

    Pro Tip: I used a strap between the back seat headrest and the passenger seat headrest to keep the passenger seat out of my way by leaning it back.

    seat head rests.jpg

    Plug for the AC CTEK charger when the truck is sitting in the driveway. The CTEK came with two sets of leads, one with clamps and one with ring terminals. I cut the rings off on and soldered zip cord onto it to reach my aux fuse box. I zip tied the cord close to the grill but not visible so I can feed the CTEK cord through the grill and close the hood if I want.

    AC charger plug.jpg

    Schematic
    Aux Electrical.jpg

    Battery Options PDF is attached to this post.

    Parts:
    X2Power Group 35 from BatteriesPlus $298 - $20 rebate = $278
    OGE bracket $200
    Military-style battery clamps 2 sets $10 per set
    Battery terminal covers $11
    CTEK 2505A charger $230
    200A Continuous-duty solenoid, local parts store $80, cheaper on Amazon but I went to local parts shop, better company there :)
    Solenoid terminal boots $7.50
    CTEK (56-353) MULTI US 7002 k (56-353) $108
    Blue Sea MRBF fuse holder $22
    Blue Sea 80A fuse 2 pk $10
    Blue Sea 200A fuse $9
    Blue Sea 12 circuit with ground bus $40
    Ancor 10AWG wire for charger input and ground
    2AWG wire for jump-start wiring and ground $46
    Various crimp connectors
    Hydraulic crimping tool $37
     

    Attached Files:

    Last edited: Oct 30, 2019
  2. Oct 28, 2019 at 6:50 PM
    #2
    ramonortiz55

    ramonortiz55 Not A Well-Known Member

    Joined:
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    Ramon
    Texas
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    2015 DCSB Offroad 4x4
    stock
    Sex. So much sex.
     
    Bastek, ready6delta and Hobbs like this.
  3. Oct 28, 2019 at 7:18 PM
    #3
    Jacked Burton

    Jacked Burton Well-Known Member

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    That link for the OGE bracket doesn't work.
    I definitely like this Idea cause I have a (2nd)120 amp agm behind my passenger seat on the floor board for my system.
    This would undoubtedly be a better way of setting mine up.
     
    Hobbs likes this.
  4. Oct 28, 2019 at 7:50 PM
    #4
    seafur

    seafur [OP] Well-Known Member

    Joined:
    Jul 11, 2014
    Member:
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    Messages:
    115
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    Male
    Pacific Northwest
    Vehicle:
    2014 DCSB MT TRD OR
    Sprinter bed tiedowns, Aux fuse box, AIO key, 3-way canopy light switch, 12V bed outlet, Dual Battery AGM G35, Viair OBA, Uni-filter mod
    Thanks, tried to fix the OGE link but every time I edit the link in the editor it replaces ************** with ********* when I save it so I changed it to a LMGTFY link.
     
  5. Oct 29, 2019 at 4:41 AM
    #5
    topcathr

    topcathr Well-Known Member

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    You should be proud, thats a real pro install job.
     
  6. Oct 29, 2019 at 4:45 AM
    #6
    69L46Vert

    69L46Vert Well-Known Member

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    Awesome job seafur! Very professional.
     
  7. Oct 29, 2019 at 5:10 PM
    #7
    seafur

    seafur [OP] Well-Known Member

    Joined:
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    2014 DCSB MT TRD OR
    Sprinter bed tiedowns, Aux fuse box, AIO key, 3-way canopy light switch, 12V bed outlet, Dual Battery AGM G35, Viair OBA, Uni-filter mod
    Added schematic and a PDF I made while doing battery comparisons to the first post.
     
    Bastek likes this.
  8. Dec 5, 2019 at 3:20 PM
    #8
    ready6delta

    ready6delta REGULAR GUY

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    Finally back in the PNW! Lake Stevens/ Olympia
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    IT NEVER ENDS..........
    sub a dub nice work man!
     
  9. Feb 6, 2020 at 9:25 AM
    #9
    Bastek

    Bastek Member

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    OVtune, plastidip, radio knobs and some stickers
    I'm sooo glad I came across this!
    :bowdown:
    This ia a great write up! And it looks like a great idea. Expensive, but great! Really appreciate time and effort you put into it, with all the links for us. T.hanks :hattip:

    OGE has been banned from TW, maybe that's why links turn to ***
     
  10. Feb 6, 2020 at 10:07 AM
    #10
    andrew61987

    andrew61987 Well-Known Member

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    I have a similar setup. I'll share a few things about it.

    1. I'm one of those people who just uses the alternator. Batteries are directly paralleled during charging.
    2. Batteries are automatically paralleled 5 minutes after the ACC circuit goes live. I did this by routing the activation wire from the solenoid through a bosch-style relay, then running the hot-activation wire from the bosch relay to a 5 minute delay relay which was in turn activated by the ACC circuit. The ground wire from the bosch relay goes to a switch in the cab.
    3. Resulting operation is two modes: Auto and Off, depending on the cab switch position. In Auto, batteries parallel themsevles 5 minutes after ACC circuit goes live. The batteries therefore automatically isolate during cranking because the ignition switch cuts ACC power during crank, this was my primary reason for using the ACC circuit. I did not want to crank off my deep cycle under any circumstance. This also allows a 5 minutes buffer between engine starting the batteries paralleling. I just pulled this number out of thin air, but I felt like it was good to allow the engine to warm up a bit and systems to stabilize for 5 minutes before dumping the charging load of the deep cycle on the alternator.
    4. I didn't bother with the "self jumping" ability. It seems cool to just have a dead battery, press a button, and start, but it's a lot of extra work and extra parts for a situation that's extremely rare. If I'm ever in such a tough spot that I need to try and jump off my secondary battery, I will pop the hood and jump the batteries together with a pair of jumper cables. The amount of time it would have taken me to wire up self-jumping ability exceeds the time it takes to manually jump with cables at least 100-fold, and I realistically see myself needing to do this maybe twice in the lifetime of the truck.
    5. It's been working flawlessly for 2 years now.
     
    Last edited: Feb 6, 2020
    Bastek likes this.
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