Dual Battery Setups! Let's see them! Multiple Batteries Thread!

Yes, but the ml-acr and others connect the batteries together when charging. Automatically disconnects when the voltage gets below a set point. Using the switch or manually, you can force the connection open or closed. Some uses wound be self jump, protecting a battery during winching, sharing the winching load.

 

ah okay makes sense.. thanks guys for the info bout to pull the trigger on Offgrid engineering's set up
edit: also would a scan guage replace the function of the red button indicator?

 

No. The ml-acr has 5 or so small wires coming off the main body that goes to the red button.

If you don’t care about remotely controlling the unit you don’t have to connect the switch. In my case, I did not like the switch and only hooked up 1 of the wires. Mine runs in auto most of the time and when I push my switch it forces the connection (ie self jump or both batteries for winching)

 

The scan gauge connects to the OBD2 port. It has nothing to do with the ML-ACR and no way to connect to it.

 

If you're going to buy the OGE kit why not just get the button too and the wire harness. i bought the ACR, wiring harness, and switch from OGE and I couldnt be happier. I had thought to myself I can make the harness but the ease and time savings of pulling it our of the box and fishing it through the firewall WITHOUT having to really even think about it was very rewarding. Especially after I got a dud ACR off Amazon and lost an entire afternoon trying to save like $20, needless to say it was not worth it. But you know what was worth it? buying from OGE.

 

You can have OGE wire the ACR (or do it yourself) to not have the in cab button. I did that because the button really serves no purpose and just complicates the install. The ML-ACR will automatically latch the two batteries together anytime the truck is running and disconnect anytime the truck is shut off (assuming correct voltage increase/decrease of course).

 

The button is nice if your start battery dies and you’re too lazy to pop the hood to manually latch the 2 batteries.



It doesn’t look too out of place paired with a Peak DBI voltmeter next to it. Ditched the clutch bypass switch by jumping it at the plunger on the pedal, left everything still plugged in, just tucked the oem switch up under the dash.

 

Really, it works however you decide to wire it. You could have the alt battery not connected to anything, and just a reserve. Then close the solenoid to jump the truck from the reserve battery. Most people use the alt battery for "house" functions or to run winches or other items that might run down the battery when the trick is off (or on) leaving you unable to crank.

So your reasons for forcing the solenoid open or closed may vary. The ACR works by closing the solenoid when it detects charge voltage (alternator running) and then opens when there is not charge voltage. Of course you can override that behavior with the switch, or with the manual override on the solenoid itself.

 

Anyone have a good leads on a 27F battery tray? (other than the plastic toyo one)

 

All of this ML-ACR talk motivated me to dig into my switch issue again. The LEDs never lit up on mine. Ripple checked the install. The harness. Pulled the switch all apart. Blah blah blah.

Checked the harness and pin outs again. Everything was right. Bench tested the switch. LEDs worked on the work bench w/ powere & ground to the LED pins. Put it back together. Still nothing.

De-pinned the switch plug at the ML-ACR. Connected just the pins together. FINALLLLLLY the switch lit.

There is some play where yellow pin 7 off the switch plugs in. It looks seated when it’s not plugged into the ML-ACR side of the plug but when they’re connected, there’s enough slop in it it doesn’t make a connection. Tweaked the pin and plug so it seats better and stays seated. Everything works.

Lesson of the day, even if you think the pins are seated, double check them.


Glad it’s sorted out.


Now my question is....

When the batteries are either automatically or manually latched, both LEDs light correct? When they are locked out, both LEDs go out, correct?

 

Correct. Lights are on when linked. Lights are off when disconnected. It does not matter if it is auto or manual linkage or disconnect.

 

Awesome.

 

What size batteries fit in the stock location behind the headlight without any sort of modification to the fusebox, battery mounts, etc?

 

What year is your truck?

 

Oops. It’s an 09 TRD. The nice big spot by the passenger side firewall is already occupied. Don’t need crazy deep power reserves. I know I can go lithium, but I’m also trying to stay remotely budget oriented.

 

Group 27F is the stock size IIRC. I've read of some using a Group 31 in the stock location without modifications.

Someone with a 2nd gen should chime in here to confirm.

 

Dual 31’s definitely need modification. At a glance it looks like dual 27’s still kind of look like they might. L

 

With both batteries linked via ML-ACR and needing to help someone jumpstart his dead battery, do I have to disconnect my batteries at the switch first or can I just hook up the jumper cable normally?

 

I would just hook up the jumper cables to the starting battery

 

2nd gen trucks came with either a 24F (base) or a 27F (if you have the tow package). Either of those are a drop in replacement in the factory location.

Dual 31s, 27Fs etc will not fit. Group 31s for example are huge: 13 x 7 x 9.5 inches (roughly). With that being said, it is possible to get dual 35s in the factory location. But its tight from what Ive seen.