Dometic Portable Lithium Battery 40Ah

Stumbled across this: Dometic Portable Lithium Battery 40Ah & seems to be something new for 2019.

I've been looking for a solution for running a compact sized 12V power efficient fridge/cooler & I plan to use a Dometic CFX-28 (with insulating cover) that I plan to stuff in the rear passenger foot well. I believe that the cooler handles have to be removed to fit there, and I'm not sure if the CFX28 can be used to support the head when sleeping at night (when the rear seat is down), but regardless, it will fit and work.

The CFX-28 uses .75Ah on 12V. This battery is 40Ah but really 32Ah meaning it should last about 1.78 days (give or take depending on real world conditions) assuming 80% Depth of discharge or DoD. But if you run it every night, it will recharge from the 12V DC cigarette lighter socket in about 5 hours. Tech support says that it supports 2000 cycles of charge/discharge, a cycle is from 100% down to 20%.

Why is this important? Because you don't want to run the car in ready mode during the day if you're not in it, since someone can break in and drive away with it (low risk sure, but not one worth taking especially in higher risk areas).

In any case, this seems to be an excellent alternative to having to wire a 2nd battery in parallel to the Toyota 12V battery, using a dedicated DC-DC charger setup, or attaching a fridge directly to the 12V starter battery which can both degrade the battery, and risk your car unable to start.

The only risks with this, imo, is that 1) it's expensive ~$850 2) If it breaks after 2 year warranty you're shit out of luck 3) If you need to charge a fridge for more than 2.22 days the 40Ah might not be enough but for most people who just need to have their Prius running a fridge for a day or two without killing their 12V starter battery, or taking up space with a 2nd 12V deep cycle Ah battery, the wiring that goes along with it, & the technical skill needed to mount/assemble it all, this is way simpler and effective imo.

The other nice thing is that you can add a solar panel to it, you don't need a controller for it to work, & you can charge from both the 12V socket AND solar panel at the same time. This way you can keep the battery topped during the day too! Now if anyone knows of any good 100-120W panels that can fit on the inside of the windshield to use this I'd love to know!

 

some people need something like this for full time prius dwelling so ice wouldn't be efficient

 

There are numerous people that live in their car full time on purpose. There are people at Google that live in their cars/vans to save on rent. It doesn't meet the traditional definition of homeless. I, for instance, am a software dev, and don't really want to burn $1500-2k a month for rent, and I'm young enough where I can do it for a few months to pay off the car. Plus it doesn't tie you down to any one place.

 

It's capped at 8A into the lithium phosphate battery -& the fusebox is 15A on the DC socket. If it's on ready mode, the traction battery will recharge it whenever the battery gets too low.

 

40 Ah/.75 Ah -> 53 hours/24 -> 2.22 days then say you have an extra 3-4 hours with the contents still cool. so say like 2.4 days.

So cracking a window, and walking away from the car for at least 2 days, the cooler will be fine.

It'a also lithium iron phosphate so it will last 2000 cycles over lithium ion batts which last only 200-300 cycles. That's 5.5 years.

The above poster mentioned $400 difference, but the setup he mentioned requires some technical know how, take up more space, and also batteries that will be replaced more often. But the biggest factor is that that setup would seemingly take up space in the rear hatch presumably. The Dometic is just a little cube that can fit in the footwell and moved around easily.

The other thing is you would need a DC to DC charger to properly switch between the 12V battery and the house battery – doing an automatic charing relay wouldn't top the 2nd battery. So this is another step in complexity.

By using an isolator is that most cars charging algorithms aren’t made to fully charge a deep cycle battery. By using the redarc bcdc 1225 you would get a charging algorithm that is specific to the needs of the battery(it has a 3 stage smart charging algorithm, and can be configured for several battery types). Most alternators aren’t set up to fully charge a deep cycle battery because a deep cycle require 14.5v to get to 100%. So while you could use an ACR, it would only charge a deep cycle battery to 80%.