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]

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?

I would look at a 12v to 12v DC Charger from Renogy. The Isolator works, but the Renogy will make sure the 2nd battery is ONLY receiving power when it needs it.

I have this, 40a on both a timer (5 minute delay, want start battery to have first dibs and sometimes I have to just slightly move my rig) and a switch (basically, just interrupts the signal from the timer) so I can turn it off for that normal life mode when the house battery isn't being used... but my house is a LiFePo4, so I don't Want it constantly topping off.

Anyway, bought the Renogy in ~2019 and it has just flat worked from the start. More than happy with the product. Their support was a Touch slow (2 weeks?) when I contacted them about something in the manual, turned out they were revising the manual at that time and sent me (digital first and paper in the mail) the correct version once they had it.

So you're going to power your winch from the rear battery? What size wires are you going to need for that long of a span that will support the amp load from the winch?

This is probably a better solution (and would allow different battery chemistries to be used for starting vs. house) - but you do lose the ability to jump start the starting battery from the house battery.

If you are doing solar, do you just run it to charge the house battery and not the starting battery?

-Charlie

You can still jump, just takes planning ahead (vs having it built in). The risk of forgetting the disconnect and draining down the start battery is higher IMHO. There are some automatic disconnects out there though, if this just seems like the better option.

Solar is.. well, lets say if you travel anytime it's hot, you're usually looking for shade, right? I went from solar to dc-dc charging because solar was such a huge letdown. Vastly more expensive for significantly less charging. It has its time and place, mostly in long-term camping while out in the open... but then you have to deal with food and water running out before your power.

If you drive daily, a dc-dc charger will simply be cheaper and more reliable source of energy. Heck, my 100ah is good for roughly 4 days, I can only carry roughly 3 days worth of food and water. I do have to be engine-on for 2 hours to go from 20% SoC (LiFePo4) to 100%, but I'm usually 40% of more SoC after 3 days and don't tend to drive less than several hours when leaving a camping spot. It's the right choice for *MY* use... solar was very, Very wrong (South East, lots of trees and always seeking shade) and it's no wonder the batteries I inherited with the solar were completely toast despite being only 1 year old.

Knowing your use is very important here. But I talk to a LOT of DIY van conversion folks (since I'm in one, others always love talking about theirs), and nearly none in the past 6 years have had dc-dc charging. But roughly 80% have said they regretted going solar (from cost, damage to the equipment, leaks from difficult installs, simply not living up to the power hype for their needs, etc...) and most were Very keen on the dc-dc setup once I talked about how and why I went that way.

Just trying to say, solar is instgram worthy, but is it really the Best option?

Do you have a write up and links? I'm curious how this would work in my intended use case/battery chemistries.

EDIT
2/0 AWG can carry 250 AMPs up to 15' so that's the plan for positive and the frame for negative.

Solar would be secondary charging for the starting battery and potentially emergency charging for the house battery.

Sorry, no. I do but don't document. The basics of it are:

Alt to start battery and Renogy 40a dc-dc (parallel).
Renogy has a "trigger" of 12v, not sure what I used, but any switched 12v source works for this
Ran that switched 12v into a 12v delay timer like this:
Amazon.com: DC12V Delay Timer Time Relay H3Y-2 0-60S Second & Base Socket DPDT (DC 12V) : Tools & Home Improvement

with the output running through an on/off switch before hitting the Renogy unit.

Output of the dc-dc charger then runs to the battery. With this particular dc-dc charger, you can run any of the battery chemistries (changed via dip-switches). Want SLA right now and LiFePo4 later? No worries.

If you're going to haul around solar though, there are Other options out there that allow for solar input AND dc-dc charging. I think ctek, yup check out the D250SE & SMARTPASS 120S.

I don't know any reason why you Couldn't use LiFePo4 for a winch, but I'm not a battery geek either. Just enough knowledge to be dangerous, that's my motto.

That's awesome, thank you!

Sent from my Pixel 4 XL using Tapatalk

What about a relay like this Blue Sea Systems ML-ACR 12V DC 500A Automatic Charging Relay with Manual Control instead of an isolator?

FWIW, Solar is not part of my requirement at all. It was suggested by the Antigravity guys as a backup/secondary charging source

Still an isolator, just has a built in relay that trips with 12v switched ~ I'd mentioned these as an option up above... not Specifically this one, just the general class. Might be cheaper options from the car-audio side of things rather than the marine. You can DIY something similar too, though it's more single components to have to deal with.

And looking at that link to the timer, that specific one is 0-60 seconds, they come in all sorts of time ranges and I opted for ~5 minutes to give the engine less stress in cold-start environments (below freezing). Point is, if you want to delay-start something, you can and pick the time that suits you most.

I have a True battery isolator on my Polaris RZR. Works great and only charges the secondary battery if the primary is charged. They make kits for larger batteries also.

True Amalgamated, Inc. | 12 Volt Battery Isolator Relay | SwitchTrueAm Dual Battery Isolator System

I would keep the winch on the engine battery if it were me.

Seems like renogy and redarc both make nice stuff that would do what your wanting.

I too am mulling around a storage system, but I want it light weight. I haven’t quite figured out how to do it lightly yet.

This is the one i run.

I have my solar panels run on a long extension cord so I can camp/park in the shade and still charge my system. I love my solar system and its a great mod and has been extremely reliable allowing 24/7 use of ARB fridge for wks straight without starting the 4runner and charges both the house and vehicle batteries. I run a gaming system at times, play my vehicles music that runs off 4 ch and 1ch mono amps on rest days when camping, keeps the batteries changed sun up to sun down, while the music is still playing (this is in good sun). I run all my solar and inverters off Victron controllers.

What's the value of the customized delay?



Sent an email to Redarc about their SBI12/212 isolator

Check out Antigravity deep cycle for storage, 28#
DC'-'100'-'V1 Lithium Deep Cycle Battery – Antigravity Batteries



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