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2nd AUX Battery install

JK47TheWeapon

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******* SEE POST 16 for my latest update - Redid it with Redarc DC-DC charger and tossed the ML-ACR *******

Has anyone done this yet?

I am planning on adding a AGM Deep Cycle AUX battery to run my dashcam / LED addons / custom mods. (In order to get the 2nd battery to fit, I will be swapping the CAI probably too the Vararam. )

Most of the good battery isolators I am seeing have a 200amp max limit (500amp for Blue Sea ML-ACR). With the Rams 220amp alternator / 700+ amp cranking main battery, I am worried about instances which may overload the isolator.

The 500amp Blue Sea should work in this case, but I am leaning more towards other isos.
 
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Wow you must have big power draw requirements for a long time. The battery is huge in these trucks. I do however keep the Anti Gravity starting pack charged up in the truck in case I ever need it.
 
Wow you must have big power draw requirements for a long time. The battery is huge in these trucks. I do however keep the Anti Gravity starting pack charged up in the truck in case I ever need it.

While the battery has high cranking amps, the capacity isn't unlimited. The battery should not be drawn lower than 12.4v (80% of battery max) for the health and longevity of the battery so you don't deep cycle it. Temperature also impacts the amount you can draw. Hot battery full unloaded can sit near 13v, a cold battery at 12.5v.

There's plenty of phantom draw in the system, remote start monitoring, unconnect, sensors, etc.

My dashcam (dual channel for front and back) in parking mode, is 5-7Wh of draw. I wouldn't want more than a day off draw on the main battery, and more often than not, I think it'll hit the 12.4v floor at 8-12 hours.
 
I noticed the HD trucks that I saw at the Boston Auto show had two batteries. They may have been diesel engines, but they certainly had two batteries. Perhaps you can use their mounting brackets, check the parts diagram?
 
I noticed the HD trucks that I saw at the Boston Auto show had two batteries. They may have been diesel engines, but they certainly had two batteries. Perhaps you can use their mounting brackets, check the parts diagram?


Good plan. I'll hunt around. I've seen some docs for 2018 promasters, but they have an inside fuse box made for this.

The HD trucks run dual alternators, bit different setup.
 
While the battery has high cranking amps, the capacity isn't unlimited. The battery should not be drawn lower than 12.4v (80% of battery max) for the health and longevity of the battery so you don't deep cycle it. Temperature also impacts the amount you can draw. Hot battery full unloaded can sit near 13v, a cold battery at 12.5v.

There's plenty of phantom draw in the system, remote start monitoring, unconnect, sensors, etc.

My dashcam (dual channel for front and back) in parking mode, is 5-7Wh of draw. I wouldn't want more than a day off draw on the main battery, and more often than not, I think it'll hit the 12.4v floor at 8-12 hours.
Diesels come standard with dual batteries, dual alternators are an option but not standard on HD's or diesels. Not sure about Ram but I know Ford and Chevy both offer dual batteries on gas engines as an option. We'll just have to wait until the heavy duties switch over to the new cab, then we can see if the secondary battery bracket will fit in our 1500's.
 

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I'm working on a dual battery system of sorts, but it will be a lithium ion setup. I haven't decided if I want to place it in the engine bay, behind the back seats, or in the Rambox areas. Stay tuned.
 
I'm working on a dual battery system of sorts, but it will be a lithium ion setup. I haven't decided if I want to place it in the engine bay, behind the back seats, or in the Rambox areas. Stay tuned.

It's taken me forever to find time for this, but this weekend I made lot's of progress. I designed and 3d printed a pretty rough but workable platform for the battery (Odyssey 31M-PC2150) and it's enclosure, to straighten out the area over the passenger wheel well. The 3d printed part was then filled with Smooth-On Epoxacast 670HT High Temp epoxy for strength. I'll ratchet strap the battery in place, and also use bolts to secure it.

I had the big open area from switching to a Vararam CAI in the engine bay.

I ran 1/0ga copper across the bay, and tomorrow I will run 4ga to the bed for a on|off switch/plug socket adapter/usb outlet I plan to have back in the bed for a 12v fridge. I also have a 150amp fuse to install inline to the ACR.

Also, my SPOD Bantam and touchscreen finally showed up on Friday which will be my control hub for it all. I'll 3d print a tilt bracket for inside of the cab to plug into the 12v plug on the dash.


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Diesels come standard with dual batteries, dual alternators are an option but not standard on HD's or diesels. Not sure about Ram but I know Ford and Chevy both offer dual batteries on gas engines as an option. We'll just have to wait until the heavy duties switch over to the new cab, then we can see if the secondary battery bracket will fit in our 1500's.
My buddy just got one of the new style RAM 2500s. It did come with two batteries.
 
Almost done. Spent a few hours a night this week when it wasn't raining.

1/0ga from starter battery to 150amp fuse to BlueSea ML-ACR charge relay. 2ga from Relay to new Odyssey AGM Battery. 8ga ran to a fuse box in the bed. 12v socket plug and USB outlet in bed to bed fuse box. 12v Fridge cooler connected to bed fuse box.
SPOD Bantam installed.

33737Tomorrow: I need to run my SPOD wire through the firewall gasket to the cab and install the touchscreen control. Run my dashcam and led wiring from cab to SPOD.
 
Very nice mod, is the tie down needed or have you not bolted it all down yet.
 
Very nice mod, is the tie down needed or have you not bolted it all down yet.
Straps are a short term solution until I figure out a better way to bolt it And make some mounts. Too hot out to be crawling under the truck this week.

It's a much tighter fit than I was wanting until I find a new home for the ml-acr. I had to get everything buttoned up today since the family is heading out camping in the morning.

Lots of cleanup work to do, but it's working well for now.
 
Almost done. Spent a few hours a night this week when it wasn't raining.

1/0ga from starter battery to 150amp fuse to BlueSea ML-ACR charge relay. 2ga from Relay to new Odyssey AGM Battery. 8ga ran to a fuse box in the bed. 12v socket plug and USB outlet in bed to bed fuse box. 12v Fridge cooler connected to bed fuse box.
SPOD Bantam installed.

View attachment 33737Tomorrow: I need to run my SPOD wire through the firewall gasket to the cab and install the touchscreen control. Run my dashcam and led wiring from cab to SPOD.
Is that a group size 34 agm battery?
 
Dont worry about the 200 amp limit for a continuous duty solenoid. Not sure you could ever depkete the entire system that much to call for that amperage all at once. There are liniters all through the system from the engine computer, fuses and of course wire resistance, as well as internal battery resistance in a FLA or AGM battery. Now if you went lithium, thats a different story and more conplicated.
 
So, I didn't love how I had this before. Couldn't easily integrate solar. There wasn't much room in the engine bay for the battery, ML-ACR and fuses, and I couldn't swap it out to LiFePO4 in the future due to temperature near the battery.

I've decided that I will move it to the truck bed in a battery box, switch to a DC-DC charger, and clean it up.
This is what I now have
Need to bolt the battery box into the bed this weekend. Then cable it up to the main battery.

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