Dometic PLB-40 Review: Solidly Not Right for Us

I don’t enjoy writing critical reviews. I try to see the best in everyone and everything, and that extends to businesses that produce products designed to make my life more enjoyable. Unfortunately, sometimes a product doesn’t live up to the expectations, and it’d be irresponsible for me not to talk about it. So that’s what we’re going to do — break down the good and bad of the PLB-40 battery system from Dometic, and explain why it wasn’t a good fit for us.

On paper the Dometic PLB-40 is awesome. It’s a compact, lightweight, all-in-one battery solution that features a lithium battery for powering your adventures on-the-go. There is a built in solar charger, allowing you to connect the PLB-40 to a solar panel to re-charge it mid-adventure. The lithium battery is rated for thousands of lifecycles, so you’re getting a product that will last many years. And the plug-ports on the battery are specifically designed to mate with the power cords found on Dometic fridges, which are the most popular options in the industry.

If you have a Dometic fridge, the PLB-40 looks like a no-brainer. Which is largely why I opted to go with it. I wanted a battery solution that was compact, powerful, solar compatible, and suited for travel on-the-go. I spent a lot of time watching YouTube videos and reading about all the options for 12V power before settling on the PLB-40 battery as the right choice for me. Which is probably why I was so disappointed when I discovered the limitations with the system that no one bothered to mention. (Keep reading and I’ll let you in on the limitations!)

The PLB-40 mounted on top of my Goose Gear drawers. You can see the fridge plugged inot the middle output socket.

Who Should Buy the PLB-40?

If you are an overland traveller or camper who is doing short trips, or someone who intends to park and unfurl a solar panel at your campsite, then this battery is perfect for you. It’s compact, lightweight, and easy to use. No fuss. Plug a compatible solar panel in and recharge the battery while keeping your fridge and beer cold.

Car campers who want an easy battery option to power a portable fridge or other 12V accessories, and who prioritize portability, should seriously consider the PLB-40. The size and form factor makes it ideal to toss into the car for a quick weekend camping or fishing trip. Weekend warriors who live in temperate climates can also benefit from the ease of the PLB-40.

The other group of folks who should consider the PLB-40 is anyone with literally no awareness or comfort with basic wiring. If you can connect a positive wire to another positive wire, then there are other options for you, but someone who is afraid to do any DIY wiring should eyeball the PLB-40.

The PLB-40 sitting in our Jeep

Who Should Not Buy the PLB-40?

If you intend to use this battery pack connected to a permanently mounted solar panel, and are hoping your solar panel can charge the battery while you are on the go, then this battery pack is NOT for you. Or if you are a semi-serious / serious overlander who wants to be off-grid for more than a day or two, you should look elsewhere. Why?

One of the oversights with the PLB-40 software is that it errors out whenever the solar panel input voltage drops, and it won't reset itself when the voltage returns. In other words, imagine a scenario where you have a solar panel mounted to the top of your rooftop tent. You plug in your solar panel and start to drive.

The first part of your drive is in sun, so the battery charges. But then a cloud passes overhead. Or you drive underneath an overpass on the highway. Or a tree casts a shadow on the road. Any one of these things will cause the solar panel input to drop, and triggers the PLB-40 to error out.

What does it mean to error out? It means the battery will start to beep and will not stop. Ever. It also means the battery won’t reset once the input voltage returns. So that quick bit of shade over your panel causes the PLB-40 to freak out, and it’s not smart enough to stop the freak out when the sunlight returns.

Said another way, the PLB-40 is incompatible with permanent / hard mounted solar panels and travelers who expect to charge the battery from solar while on-the-go.

As an overlander with a solar panel mounted to the top of my tent, this was a hard discovery to make. Why? Well, for starters, nothing in the PLB-40 literature or instruction documents articulates that this could be an issue. So until you buy the battery and experience this problem, you don’t know that you effectively purchased a battery that is incompatible with most overland travel. Although you can hard wire the battery using the Dometic Hard Wire Battery Kit to your alternator and charge the battery while driving, this option is a little dicey because you have to be sure you don’t accidentally drain your starter battery when charging the PLB-40. I have done this wiring option, but do not recommend it, as I’m constantly juggling cords and am at high risk of draining my starter battery if I space out and forget to unplug a cable. I cannot risk getting into my car in a remote wooded area and finding it won’t start because I was too busy charging my fridge.

Bottom line: If you expect to get regular use from your battery system, and you want something that integrates with solar for charging on-the-go, then you’re better off looking elsewhere.

The Good News

Like I said up front, I don’t like writing negative reviews, so before I come “internet bash” a company, I want to give them a chance to talk me through the problem and help me resolve it. This is where Dometic crushed it. We reached out to them and wrote a long letter explaining the issues we were encountering. Dometic is a top-notch company, and we heard back from the US Regional Sales Manager on our issue a few days later. They generously tried to help by sending me a software patch that was designed to fix the problems with the solar charging, but after months of back-and-forth with Dometic, we never got it to work correctly. Still, hats off to Dometic for the amount of time and energy they spent trying to improve their product and to help me out. It speaks volumes about who they are as a company, and is one of the many reasons I choose to purchase from reputable companies.

In the end, we made the decision to sell the PLB-40 and get another solution for our Jeep build. Hopefully Dometic will continue to improve on the design and a Version 2 of the PLB-40 will resolve some of these issues.

Most importantly though, we had a great experience with Dometic trying to help out, and although we cannot recommend this product for others who want to use it like we did, I would not hesitate to recommend Dometic as a brand or buy a Dometic product again. I love their fridges!