Minimalist Design - Ecoflow with DC 2 DC converter and 12v secondary battery question

[YotaTrail]

I just bought an ecoflow delta 2 portable battery that I will have in the back power my fridge and other camping accessories. At the same time I bought the ecoflow DC 2 DC (alternator charger they call it) that can charge the ecoflow delta 2 battery at 800w by running off the main battery/alternator. This DC 2 DC charger can be controlled via phone app to also reverse charge the car battery in case it dies. and also as a battery maintainer I also have an ecoflow deployable solar panel as a backup incase all systems get drawn down, (car battery and ecoflow delta 2)

This is my opinion is a good minimalist approach and can be moved from vehicle to vehicle. Now, I want to add a Lifepo4 12v secondary battery under the hood that will power my lights, winch etc. Do you think I need another DC to DC charger or can I somehow hook into this ecoflow system ?

 

[YotaTrail]

I guess the question is, do they make a product that's like a switch to charge the 12v backup battery instead of the main ?

I think I may use something like this

https://www.amazon.com/100-240A-Integrated-Wireless-Disconnect-Isolator/dp/B0BLH9VMW6

 

[shermantank55]

How about a switch:

https://www.bluesea.com/products/6007/m-Series_Mini_Selector_Battery_Switch_-_Red

I'd be cautious with putting LiFePO4 under the hood. I understand they don't like heat:
from redway battery: (Redway Battery - China Lithium Ion Battery Manufacturer - https://www.redwaybattery.com/)

Optimal Operating Temperature Range for LiFePO4 Batteries​

LiFePO4 batteries are designed to operate within a wide temperature range, typically from -20°C to 60°C (-4°F to 140°F). However, for optimal performance, safety, and longevity, it is recommended to maintain the battery within a narrower range of 0°C to 45°C (32°F to 113°F). Operating outside this optimal range can adversely affect the battery’s efficiency, capacity, and lifespan.

Effects of Temperature on LiFePO4 Battery Performance​

Temperature fluctuations can significantly impact LiFePO4 battery performance:

• High Temperatures: Elevated temperatures can accelerate self-discharge, reduce cycle life, and increase the risk of thermal runaway—a dangerous condition where the battery overheats uncontrollably.

 

[Shoredreamer]

First thing you’re gonna wanna look into upgrading is your alternator. If the DC to DC eco flow kit pulls 800w (60-65amps) out of your 80a alternator, things aren’t gonna work too well.

Second, there’s no real point in adding a second engine bay battery if you already have your eco flow for aux (parked) power use. Add all your engine on (driving) accessories like driving lights, radio, compressor, winch directly to your start battery.

Also, you can’t parallel connect a lead acid and lithium battery together. A different option may be to add a second engine bay battery that matches type, size, and chemistry with your start battery and wire those in parallel to double your CCA and capacity. It also can protect you from a dead or damaged start battery.

There’s lot of combinations of setups for additional power use. Some seem simple but in reality are complex, some seem complex and turn out to be dead simple. I don’t love portable power stations in vehicles, especially if you’re relying on it in the backcountry or on trips without easy service. They are designed more for backup power in homes meaning they lack a lot of 12v ports and the ports have low amp limits, they have rather limited operating temps, you can’t troubleshoot anything if something goes wrong and you spend alot of money and space on the 110v features in these boxes that don’t get used a lot out camping.

I’d recommend a diy battery box with a LiFePo4 battery and decided dc to dc charger around 25-30amps charge, with distribution built in to get the best of both worlds. I’ve built a ton of these for people and they work great.

 

[Nad Aitch]

First thing you’re gonna wanna look into upgrading is your alternator. If the DC to DC eco flow kit pulls 800w (60-65amps) out of your 80a alternator, things aren’t gonna work too well.
View attachment 3683105

800w is the max, but it's adjustable via the app. It's quite a slick bit of kit if it does what they say.
It can also go reverse / charge your starter battery.

I'd probably just run a single bat under the hood and watch things closely. You might not need anything else.

 

[YotaTrail]

Thanks for everyone's input. I will skip the extra 12v under the hood and just have everything wired to main battery

 

[Nad Aitch]

In theory you could slap a solar panel up and even if your starter battery and power station died, you could solar charge the power station, transfer that to the starter via the app and make it home.

But that's all theory
I'd monitor things closely and experiment before a solo trip to BFE.