Dometic PLB40 Alternative?

qrohlf

New member
For context, I have a very compact camping platform & drawer system build in my 2000 4Runner that I'm looking to add a fridge, battery, and solar to. My power requirements are pretty minimal – I'd like to have a 12v DC input for alternator charging, an MPTT input for charging off an 85W vehicle-mounted solar panel, and about 400-800Wh of capacity to be able to run the fridge for 2-4 days while parked under tree cover. I don't need any AC power, I already have a 12v to USB-C charger setup that I like for charging gadgets, since space is at such a premium in this rig, I really need something with a small footprint like the PLB40.

Unfortunately, it seems like there are very few convenient options out there that tick this box. In the consumer "solar generator" space, you're stuck with a bunch of options from brands like Yeti and Jackery that are using outdated battery chemistry, have huge footprints, and dedicate a ton of space to useless AC outlets, with the 12v outputs being limited at best (usually just 1 cigarette socket & maybe a small barrel connector). Or you're buying from a relatively unknown company like Pecron and dealing with flaky apps, customer support and manuals that aren't in fluent English, and not much in the way of a guarantee that the product's been tested comprehensively. There's a whole thread going right now in this forum on this type of option, and frankly none of them seem that compelling from my perspective.

I thought I'd found something good in the Dometic PLB40, since it's got a great, small form factor, has all the right inputs (12v in via barrel jack, 8-25v in to an integrated MPTT charger via an Anderson connector), all the right outputs (Anderson connector & cig socket), and no AC inverter or smart-gadget chaff to complicate things and add failure points. It's basically just a LiFePO4 cell, MPTT charger, and a DCDC charger in a nicely designed rugged box with input/output ports. Which is exactly what I'm after.

Unfortunately, after some back and forth with Dometic’s customer service to determine how the unit would behave when both the 12v and solar inputs were connected, I got back this response:

"I reached out to one of our technical service advisors and he has confirmed that the product is only designed for use with one input source at a time.​
We cannot say for certain what would or would not happen if both cords were plugged in together as the product has not been tested for that type of application. As such we strongly advise that only one input source be used at a time.​
There is nothing, control board wise, that would allow the unit to differentiate types of power and automatically switch to the best option."​

Seems like somehow Dometic managed to go through the whole development process with a product that has two input ports and not only didn’t design for both those inputs being used, but seemingly hasn’t even tested (!?!) to see what would happen if someone connected a solar cell while the product was plugged into wall/car power. I considered just “fixing” it myself with a changeover relay connected to an ignition-on fuse in my rig, but since I'd like to keep the number of hacks and workarounds in my rig to a minimum (and because I'm frankly pretty frustrated with Dometic's engineering that a product like this made it onto shelves), I'd love to find a superior option that doesn't require the changeover relay hack.

To recap, I’m looking for a commercially available DC power station that can:
  • MPTT charge off solar when my engine’s not running
  • DC-DC charge off my alternator when the engine is running
  • Has ~400-800Wh of LiFePO4 battery capacity
  • Smallest footprint possible
Is there anything out there the besides the PLB40 that fits these requirements?
 
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qrohlf

New member
I'm considering the DIY route (have built a 200Ah Victron + Battleborn system for a friend before that turned out great), but if you're going with high-quality stuff that's available off the shelf from Victron or Renogy or whoever, it's designed for much larger installations and higher currents and has lots of extra plastic, housing, heatsink, flanged mounting, etc which means a DIY solution is just going to be a substantially bigger footprint compared to an integrated package from off the shelf, even if I go with a really small form-factor LiFePO4 battery like one of the Battleborn 100Ah GC2s. It's just kind of a non-starter in the 4Runner, these older 3rd gen models are *small*.

Pairing a controller-in-a-box like that Dr Prepare Hub up with a separate battery is an interesting idea. Unfortunately, the sparse documentation and the maximum 10A DC output rating on the Dr Prepare Hub doesn't inspire confidence, especially since my fridge pulls 8.2A when the compressor is running, and probably has a current spike (which I haven't measured yet) that goes above 10A when the compressor initially starts up.
 

qrohlf

New member
Closest thing that I found after hours of searching is Bluetti's lineup of expansion batteries, which are also usable as a standalone, DC-only power stations:


The only problem is that they all only have one DC/MPTT input and rely on a connection to one of Bluetti's full-featured base stations for displaying state of charge, input/output status, etc.

In the end the solution I'm going with is a Jackery 700 Plus which is LiFePO4, and has dual DC inputs, good manuals/datasheets available, and a US-based support/warranty team. It's larger than I'd like at basically double the footprint of the PLB40, but the chemistry and the price were right (I picked one up from Target at $300 off, which has to be a pricing error since the thing is brand new and so popular it's sold out in most other places).
 
I'm considering the DIY route (have built a 200Ah Victron + Battleborn system for a friend before that turned out great), but if you're going with high-quality stuff that's available off the shelf from Victron or Renogy or whoever, it's designed for much larger installations and higher currents and has lots of extra plastic, housing, heatsink, flanged mounting, etc which means a DIY solution is just going to be a substantially bigger footprint compared to an integrated package from off the shelf, even if I go with a really small form-factor LiFePO4 battery like one of the Battleborn 100Ah GC2s. It's just kind of a non-starter in the 4Runner, these older 3rd gen models are *small*.

Pairing a controller-in-a-box like that Dr Prepare Hub up with a separate battery is an interesting idea. Unfortunately, the sparse documentation and the maximum 10A DC output rating on the Dr Prepare Hub doesn't inspire confidence, especially since my fridge pulls 8.2A when the compressor is running, and probably has a current spike (which I haven't measured yet) that goes above 10A when the compressor initially starts up.
I have used my Dr. Prepare with my Dometic CFX3 55IM without a single issue. Also powered the ridge while using the USBs for other items.
 

pluton

Adventurer
These are some pre-wired battery boxes.


I have had a National Luna PPP (the gray one with the small panel) for 11 years. It only gets used when I go camping, which varies from 1 to 7 times a year, so light use. It has never failed in any way and I'd buy another one. Put my own AGM batt in it and rigged extra leads directly to the battery terminals for an external solar panel with charge controller. The "user interface" is switches and indicator LEDs. No bluetooth which eliminates having to deal with some crummy app while enjoying the great outdoors.
 

mep1811

Gentleman Adventurer
100 AH Lithium battery Cig plug, USB plugs and pigtail for DC-DC /Solar charger. I also installed external terminals to charge and also attach an inverter if needed.
 

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