Could you clarify a bit?
Have you also been charging your valence battery as well as running your fridge off of it during these 36 hours?
And which DC to DC converter?
And finally, how is it wired in?
Sorry for all the questions!
I’m stuck in analysis-paralysis on how to power my fridge.
My existing dual battery setup uses a
Redarc BCDC. My secondary Odyssey AGM in the engine bay powers my fridge and camp scene lights. Setup has worked great for years. However, I did several trips last year and the year before where the truck would be parked for 2-3 days at camp or at a hotel. If outside, I used a solar panel to top off but didn't have that option inside a hotel parking garage or outside during foul weather. During the last two camping trips this past fall, the secondary battery was good for about 24 hours or less with the truck parked for days and 2 x 100w solar at camp. It use to last 48 hours or more.
Occasionally I will take a Goal Zero Yeti 1500x power station with me on longer trips and if I plan on needing an inverter to power AC devices (e.g. Nespresso, blender). Another forum member turned me on to the Victron DC charger which can operate in charger mode or power mode. I have another power run from my engine start battery to the back cabin. This gives me flexibility. I can easily switch the fridge power over to the main battery if needed using an Anderson connection. (I do keep a big NOCO jump battery in the truck for backup
I can use that power connection with the Victron DC charger and it will charge the Goal Zero power station while driving. I could also connect the Victron DC charger to this little Valence lithium battery (selecting the right profile on the phone app) and do the same. If I don't need an inverter and want more space and less weight, the Goal Zero stays home.
Putting all that aside, I'm playing with other power options for my fridge. The AGM's are heavy, pricey and you have to be careful about discharging them too much. I'm exploring LiFePO4 options in the cab. Seem to run longer, much lighter and last more years than an AGM. LiFePO4 can be less expense than AGM depending on brand.
If I'm out traveling (wheeling or going from one camp area to the next) and the truck is being driven each day, no issues with batteries & powering the fridge. It's those few occasions where the truck sits parked at base camp or a hotel for a few days that I'm looking at other options so my fridge doesn't unexpectedly run out of power.
I did the dual battery build out 5 years ago. It's worked great, my starter battery has never left me stranded and I have never had any spoiled food in the fridge. Given newer options on the market today, you have more choices and flexibility in run time, less weight and less expensive.
That little Valence 40 Ah LiFePO4 ran my fridge for 48+ hours before I disconnected it. I don't know how much longer it could have run as I'm still learning how to measure SOC on these. Its BMS protocol is proprietary and I don't know how else to accurately measure what's remaining on it.
@linuxgod there is a developer who contributed some Python code to interrogate the Valence BMS but it's limited. You mentioned a coulomb counter to measure charge on another thread. What's your recommendation?
