EcoFlow's Alternator Charger is a device you install in your pickup truck, van or RV to charge the huge power plant you carry around to keep all your equipment running.
While your vehicle is running, the generator charger produces up to 800W. That's about eight times more power than you can normally get from a 12V cigarette lighter, and it's enough to charge EcoFlow's new 1kWh Delta 3 from zero to full in just over an hour of driving. If you're driving EcoFlow's larger 4kWh Delta Pro 3, it takes five hours.
It's also clever enough to reverse the flow of electrons and use the power station to provide a trickle charge to your starter battery or bring it back to life. When you get home from the job site or vacation, these giant portable batteries can be hooked up to EcoFlow's $200 solar balcony kit to offset your electric bill and provide backup power in the event of a power outage.
EcoFlow's alternator charger is far from an industry first, using proprietary connectors that only work with Ecoflow's own batteries, but the company brings simplicity, elegance and a superior user experience to a product typically designed for electricians and mechanics.
After 6,000 km of testing, I can say that the $599 generator charger could be a game changer for many. It allowed my wife and I to live and work in a Sprinter van this summer with ease, with all the modern conveniences that come with so much power on demand.
RV builders often retrofit DC-DC chargers to a vehicle's alternator. They're incredibly good at keeping multiple batteries charged for home use to power off-grid luxury appliances like e-bikes, projectors, 3-in-1 fridge/freezers with ice makers, coffee makers, and air conditioners. Some basic chargers are cheaper and others are more powerful than EcoFlow's, especially when built around a secondary alternator – but these offer fewer features and require professional installation.
To avoid overloading the vehicle’s alternator, the EcoFlow charger regulates itself so that only excess Power, which may be less than 800W, is sent to the power plant. (The generator charger can draw a maximum of 76 amps.) In my case, the Sprinter's powerful generator has enough capacity to easily provide 800W almost continuously, even when the air conditioning is running and the wipers and lights are on.
I also travel with 420W solar panels on the roof for extra boost, resulting in a simultaneous real-world charge of just over 1,100W when driving on sunny days. This combination also works when the van is parked and idling, in case I ever need the Sprinter as a backup diesel generator.
installation
Installing EcoFlow is a DIY project for many edge Reader, in my case, however, I turned to an expert: Fabian van Doeselaar, who already equipped my standard van with his Solo interior and previously helped me with my test of the EcoFlow Power Kit.
EcoFlow offers some helpful videos showing the generator charger being installed in a Ford F150 pickup truck and another showing the installation in an older Sprinter based RV.
To install the alternator charger, it must be connected to the starter battery, not the alternator itself. The exact steps vary for each vehicle, but on my Sprinter we ran the thick, five-meter cable to the bus bar in the auxiliary battery fuse box, which meant removing the driver's seat. The cable was long enough to reach the alternator charger box, which is mounted in a cabinet in the back where I manage my power.
My Sprinter van is designed from the ground up to be powered by any portable solar generator, which is nothing more than a large power station that includes a MPPT solar panel charge controller. For this test, we hooked up my van's circuits to EcoFlow's original Delta Pro, which in turn was connected to the Alternator charger via a proprietary EcoFlow cable and adapter.
The Delta Pro keeps my laptops, phones, drones, and headphones charged, and also powers my Starlink internet, lights, fridge, water pump, induction cooktop, and roof vent, as well as the EcoFlow Wave 2 air conditioner/heater combo that I just tested. Since I wanted to live and work as remotely as possible, having a way to charge it reliably was crucial this summer.
Performance
After a straightforward installation, it was time to configure the Alternator Charger in the excellent EcoFlow app, which makes performance monitoring both fun and addictive.
The alternator charger will only send power to the power station if two conditions are met. First, the charger must be turned on using a button on the device itself or a “work start” switch in the EcoFlow app. Then, the voltage measured on the starter battery must exceed the “start voltage” threshold set in the EcoFlow app. If it stays on, it should automatically charge the connected power station while driving – but that didn't quite work with my setup.
I initially chose the app's default starting voltage of 13.0V. When starting the van, the starter battery voltage rises from around 12.6V – 12.8V to over 14V, triggering the 800W charge. However, my van is fitted with a smart generator that causes the voltage to fluctuate over time, occasionally dropping below that 13.0V threshold. This causes the generator charger to repeatedly turn off and on, reducing the Delta Pro's charging speed.
To “fix” this, I lowered the charger's starting voltage to 12.5V in the app (it's limited to 0.5V adjustments), with a predictable side effect – when I arrived and turned off the engine, the alternator charger started draining my van's battery and would have continued to do so until it reached the 12.5V threshold and stopped.
That's not the end of the world, but it's below the 12.6V resting voltage that's considered healthy for a lead-acid starter battery. While EcoFlow makes it easy to manually transfer stored energy from the Delta Pro's battery back to the Sprinter's by switching the generator charger to “reverse charge” or “100W battery maintenance” mode, it's far from ideal.
Ideally, this would all work automatically, so that every time I drive, I know that 800W is being fed back into my power station and I don't have to worry about the state of my starter battery after parking. Lacking this security, I decided to play it safe and leave the start voltage at 12.5V, but manually toggle the “start working” switch in the app every time I start and stop the drive.
Still, after testing EcoFlow's Alternator Charger, I can tell you that $599 is a small price to pay for the peace of mind of having all that power available whenever I needed it for two months this summer – rain or shine, even in the middle of nowhere. Too bad that in my case it has to be turned on and off manually and only works with EcoFlow's own batteries.
EcoFlow's products are often on sale throughout the year, and discounts are also available in packages. An $848 package that includes the generator charger and the new Delta 3 Plus for $649 looks pretty compelling for a 1 kWh solar generator that can grow with your needs.
All photos by Thomas Ricker / The Verge