Originally Posted by octanejunkie

What's the value of the customized delay?

Originally Posted by Brian.

In theory, less engine load on cold starts = less overall wear on the engine. I picked 5 minutes to give the engine a chance to warm, the start battery 5 minutes of recovery without competition and because I've noticed that I'm either going for under 5 min or over 20. I didn't want to put short loads through the system, just don't like doing that to electronics if I can help it.



It's probably not necessary, just seemed like a good idea to me.

Originally Posted by octanejunkie

Like the title says I'm adding a winch and OBA and maybe a fridge in the future so I've decided to update my battery and charging system. Also looking to add a second battery to extend storage capacity.

One of the key things are separating loads, and better weight distribution, so I'm looking at a smaller starting battery up front, with a larger house battery in the rear.

Battery technologies have changed so I'm looking at newer batteries, like AGM and LiFePO4s. And since I'm looking at increasing capacity and reserve, I'll be updating my charging system, too.

So I've made some decisions and triggered some purchases already. I have a Deka AGM 9A34R Intimidator battery and an ACDelco Gold 335-1050 140A Alternator on the shelf along with a battery tray/hold down and a bunch of 2 AWG and 4 AWG welding cable, connectors and heat shrink.

The plan is to move 50# out of the engine bay so the Deka will go in the rear and will power the winch and compressor. I'll run a dedicated positive cable to the Deka and use the frame as the ground conductor.

On another forum I talked to a guy running an Antigravity battery as his primary (and only) battery. Antigravity makes LiFePO4 batteries with onboard Battery Management Systems that make LiPo stable and more practical, albeit not cheap.

I chatted with Antigravity today, specifically shared my goals and needs and got some good info.
Their batteries cannot be wired in series or in parallel with other battery technologies. Also, their automotive batteries cannot be used for high draw applications, like winching.

Here is what they recommend for a dual-battery, heavy-draw applications like my intent.

Primary battery, they recommend something small like ATX30-HD or a Group-51R battery.

[URL unfurl="true"]https://antigravitybatteries.com/products/starter-batteries/restart-oem/atx30-hd/[/URL]

[URL unfurl="true"]https://antigravitybatteries.com/products/starter-batteries/automotive/ag-51r-rs/[/URL]

Secondary battery, for high draw like winching, they recommend a deep cycle, I told them I'm going to use an AGM.

To separate the batteries they recommend a battery isolator, and while they don't sell one, I found several online. Example:
[URL unfurl="true"]https://www.amazon.com/dp/B08GPJG9K2/ref=cm_sw_r_apan_i_TQ5B0907JNFG35PD7E92?_encoding= UTF8&psc=1[/URL]
Attachment 396269
Anyone have experience with isolators?

For starting and general vehicle use I'm leaning toward the ATX30-HD under hood with the Deka AGM in the back and the CS144 alternator charging both through an isolator in the engine bay.
That will allow me to cable the winch drawing from the AGM via the isolator as well as my OBA compressor in the rear drawing off the AGM directly (fused).

The ATX30-HD has 4 terminals which means it will fit in any post orientation, and the "unused" terminals can be used for a solar panel (for secondary charging) or be capped off.

Heres what this project looks like, financially:

ATX30-HD battery $560

Standard Terminals $14

Battery Isolator $100 (estimated)

(already have everything below )

Deka 9A35R $200

Battery tie down $50

Delco 140A alt $114

Wire, connectors ~$120


Questions, comments, feedback?

Originally Posted by Jakeepoo3

Your plan looks legit! I see you're wanting a high reserve capacity for your off roading adventures. They make a 12v golf cart battery now days that is the same setup as 2 6v batteries wired in series/parallel with double the reserve capacity. Little more Expensive though.



100 Ah 12V GC2 LiFePO4 Deep Cycle Battery | Battle Born Batteries

Originally Posted by octanejunkie

Those are on par with LFP pricing I've seen so far. I bet in a few years lithium battery technology will be democratized and cost competitive with flooded batteries - which will probably go away as more production cars lean towards LiFePO4

I already have the Deka AGM so I'm sticking with it lol otherwise I'd probably go LFP deep cycle for house. Next time.

Sent from my Pixel 4 XL using Tapatalk

Originally Posted by octanejunkie

Those are on par with LFP pricing I've seen so far. I bet in a few years lithium battery technology will be democratized and cost competitive with flooded batteries - which will probably go away as more production cars lean towards LiFePO4

Originally Posted by octanejunkie

Very curious about this setup... do you have it documented?

Originally Posted by octanejunkie

An email exchange with the folks at Redarc and it seems their 200A isolator will also possibly work
Smart Start SBI 12V 200A



– REDARC

Putting a schematic together to validate all the segments and materials needed

Originally Posted by RAD4Runner

That simpler RedArc system should work on your 3rd -gen. DC-to-DC charger is really only needed IF you are running solar OR if you are running other than lead-acid (AGM is still lead-acid) chemistry, OR if you have "smart" alternator like the late-2000's trucks have.

I have a simple setup on my simple truck: Dual-Battery System With Voltage Sensitive Relay - YotaTech Forums

I just use a Voltage Sensitive Isolator Relay similar to that RedArc you show above. (primarily used in audio installs and looks like a knock-off of the RedArc). Connects house battery to alternator when charging voltage has reached certain level. Disconnects when ignition is off and cranking battery voltage drops below certain point (12.7V, IIRC).

The wiring between cranking and house batteries are rated only for 50 amps so if I have to jump-start with the house battery, I would have to do it the old-fashioned way - jumper cables. I just don't feel safe running cranking amps through the isolator.

I'm confident that you know that you should wire your winch directly to your house battery, not through your isolator.

Originally Posted by RAD4Runner

I believe that Redarc relay has a manual bypass switch option where you energize the relay to connect the cranking and house batteries. Therefore, IF you pick the relay, wiring and fuses to handle cranking amps, you could simply turn the bypass on and jump-start with 2 batteries combined.

Originally Posted by octanejunkie

Made some decisions
...
now I have 2 AGM batteries and no concerns about charging profiles