Portable DC Power: Dometic PLB40 and Dometic Fridge Walk-through


Dometic has taken the next logical leap in mobile/ portable DC charging with their new PLB40 Lithium Battery, and there are a few things to know about you you can use this tool to power your fridge and devices while in camp or out on the trail. 
Dometic, whose portable fridge technology was previously found in the classic ARB Fridge, has been laser-focused on solutions for the adventure travel market with their focus on mobile cooling and now DC charging. Their wide-ranging CFX line of Fridge/Freezers, a worthy successor in terms of sophistication and technology to the old ARB Fridge, boasts its own patented compressor cooling system, as well as internal WiFi and a suite of phone-based apps for monitoring and controlling the cooling process. 
In this video, Main Line Overland’s Tom Henwood demonstrates how the the Output and Input charging functions on the new Dometic PLB40 Lithium Battery in tandem with Dometic’s Special Edition CFX 75DZW Dual Zone Fridge/ Freezer. The PLB40 uses LiFePO4 or Lithium Ion Phosphate chemistry to provide DC to DC charging for boondocking at the campsite, plugging in at the jobsite, and more. 


One of the first things to know about the new PLB40, is that it has two ways of charging up: either via the included AC Plug, or via the 12V cigarette lighter-style plug with Black-colored Anderson input plug. Anderson plugs are a click-locking, 50AMP male/female direct connector with robust terminals rated for outdoor use, so it was a great choice of connection point for DC input. Anderson plugs are also common connection points in solar panels, and the PLB40 can be used as a battery/ charge controller combo with solar panels with up to 25V/ 8Amp max output. Also on the input side of the PLB40 there are two glass fuse inputs, which come with spares in the box and protect the unit from overload.


On the output side of the PLB40, there are three main functions, a traditional 12V output, a 2-Pin 12V output, which works with the screw-off top of the Dometic Fridge's DC cable, and dual USB output. 


Fun facts about the PLB40 as it compares to traditional lead acid batteries:


- PLB40s use Lithium Iron Phosphate (LiFePO 4) chemistry – more energy dense than Lead Acid.


- They have a Built-in Battery Magagement System (BMS) w/protection against deep discharge (we've seen that it will shut down at 10% or less on the indicator).


- Can be plugged into charge via AC or 12V DC while powering a fridge on the output side.


- *Deep cycle Lead Acid batteries should not be discharged more than 60% of their capacity, and last longest (3000 cycles) when only discharged 40% of capacity.


- A PLB40 will last 2000 charge cycles at 80% discharge. Discharge rate for a PLB40 battery that is sitting is 3-5% per month. These numbers far outperform Lead Acid batteries, which have a steep self-discharge rate and require solar or a trickle charger to maximize lifespan.


- A fully charged PLB40 contains 512Wh or 40Ah of energy, and will charge a CFX40 Fridge (variable speed compressor) for 40 hours. (Anecdotally we have seen fully stocked fridges go for up to 5 days on a charge—depends on ambient temp/ fridge temp difference. Also, a full fridge will cycle less often than an empty one, since the contents are more dense and hold temperature longer.)


- The PLB40 is NOT recommended for use as a jump-starting device. It can provide output to a battery source via the 12 V output though, with a max current of 15 amps.


- The PLB40 CANNOT be daisy-chained as a dual battery 


- The PLB40 is equipped with a DC/DC smart charger, so solar panels can plug directly into the Anderson input (with a compatible Anderson plug such as a Gray or Black Anderson).  *Maximum voltage for a solar panel should not exceed 25V DC and current should be limited to 8 Amps DC. We have found that Overland Solar Ranger Series panels that work with the OS PWM-style (Pulse-Width Modulation) 10AMP charge controller will work fine. 

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