Most portable power stations are built around a 120V inverter, with 12V as an afterthought. Comvolt's stations work the other way round. Each one is a 12.8V LiFePO4 battery first, with a 120A Anderson port and two 12V sockets for your DC loads, and a pure sine inverter on top. That is why a Comvolt power station can stand in for an RV, van or trailer house battery, and it changes how you size one.
Start with what a day costs you
List everything you run on a typical day away from hookups, with its watts and the hours it runs, and multiply. Here is a worked example for a small travel trailer or van. Your numbers will be different, so read the labels or measure with a battery monitor.
| Load (example) | Watts | Hours a day | Wh a day |
|---|---|---|---|
| 12V compressor fridge (average draw) | 45 | 24 | 1,080 |
| LED lights | 20 | 5 | 100 |
| Water pump | 60 | 0.5 | 30 |
| Roof vent fan | 25 | 8 | 200 |
| Phones and a laptop on a 12V charger | 60 | 4 | 240 |
| Furnace blower (cold nights) | 50 | 4 | 200 |
| Total | 1,850 |
Every load in that table is 12V, so on a Comvolt station it runs straight from the Anderson port or a 12V socket, with no inverter in the way. The station's USB-A and USB-C ports are rated at 18W each. That's fine for phones but slow or too weak for most laptops, which is why the example charges the laptop from a 12V charger.
Turn rated capacity into usable capacity
Comvolt rates the 2200 at 2,201Wh, the 4200 at 4,200Wh and the 6000 Pro at 6,016Wh. You won't get every one of those watt-hours back, so we plan on about 85% of the rating, which allows for conversion losses and a small reserve. That 85% is our planning assumption, not a Comvolt figure.
| Station | Rated | Usable at 85% | Days on the 1,850Wh example |
|---|---|---|---|
| Comvolt 2200 | 2,201Wh (12V 172Ah) | about 1,870Wh | about 1 |
| Comvolt 4200 | 4,200Wh (12V 328Ah) | about 3,570Wh | about 1.9 |
| Comvolt 6000 Pro | 6,016Wh (12.8V 470Ah) | about 5,110Wh | about 2.8 |
Those are days with no charging at all. Very few RVs live like that, which brings us to the part that matters more than size.
Refill matters more than size
A big battery you can't refill is just a slower way to run flat. Every Comvolt station charges three ways.
Solar
The 2200 and 4200 each have one XT60 solar input rated 20–45V and 400W max, and an MC4-to-XT60 adapter is included for third-party panels. The 6000 Pro has two XT60 inputs at 400W each, so it takes up to 800W. Our rule of thumb, not a Comvolt figure, is panel watts × sun hours × 0.75. With 4–5 good sun hours, 400W puts back about 1,200–1,500Wh a day and 800W about 2,400–3,000Wh.
Against the 1,850Wh example, 400W of solar slows a 2200 or 4200's drain without stopping it. The 4200 then lasts several days instead of two. Fill both inputs on a 6000 Pro and good sun covers the whole day.
Alternator
Every station includes a 30A DC-DC charger that plugs into one of the XT90 inputs and charges from the vehicle while you drive. At roughly 12.8V, 30A works out to about 380W, so an hour on the road puts back something like 380Wh before losses. That's our arithmetic; Comvolt doesn't publish charge times. Wiring it is covered in installing a Comvolt station in a van or trailer.
Shore power or a generator
The 2200 and 4200 come with a 500W wall charger that feeds an XT90 input. By our arithmetic (Comvolt doesn't publish charge times), that refills a 2200 in about 4.4 hours (2,201Wh ÷ 500W) and a 4200 in about 8.4 hours, before losses. The stations have two XT90 inputs, and Comvolt's manual says multiple chargers can be used at the same time to double the charging speed. It also notes that slower charging helps battery life. The 6000 Pro's box lists a wall charger cable, but Comvolt doesn't state a charger wattage for it.
Size the inverter for your biggest 120V load
The 2200 and 4200 have the same inverter ratings: 1,600W sustained, 1,800W nominal and 3,600W peak. The 6000 Pro is rated 2,500W sustained, 3,000W nominal and 6,000W peak. Plan anything that runs for more than a few seconds around the sustained figure. A coffee maker, microwave or hair dryer often draws well over 1,000W, so check the input watts on the label, not the cooking watts. If you want 120V cooking and a 120V rooftop air conditioner, look at the 6000 Pro. Our inverter sizing guide walks through typical RV loads.
A 12V DC air conditioner skips the inverter entirely and runs from the 120A Anderson output. The numbers for a DC unit are in how much battery runs a Nomadic DC air conditioner.
When to add an expansion battery
Comvolt makes two packs that add storage to a station: the 4000 Expansion Battery (12V 320Ah) and the 6000 Expansion Battery (6,016Wh, 12V 470Ah). Neither has an inverter or outlets. Each connects through the station's rear Anderson port with the supplied cable, plus an RJ45 network cable so the station and pack can share status.
Comvolt's manual says the voltage difference between the batteries must be under 1V before you connect them, and that each battery needs its own battery ID when they're linked by RJ45. Comvolt doesn't publish a maximum number of packs, so ask us before you plan a large bank. Add a pack once you can refill it. If your station runs flat every day, more solar usually helps more than more battery.
Quick picks
- Van or weekend trailer, 12V loads only: the 2200.
- Boondocking a few days at a time, mostly 12V: the 4200, which has the same inverter ratings as the 2200 and about twice the battery.
- 120V cooking, air conditioning or long stays: the 6000 Pro, ideally with both solar inputs filled.
The three are compared side by side in Comvolt 2200 vs 4200 vs 6000 Pro.
FAQ
Can a Comvolt station replace my RV's house battery?
It can do the same job: it is a 12.8V LiFePO4 battery with a 120A Anderson output for 12V loads. How it ties into your RV's existing 12V wiring and converter depends on the rig. Have a qualified RV technician do that wiring, or send us your setup and we'll talk it through.
How do I check my real daily use?
The station's screen and the Comvolt app (over Bluetooth) show input and output power and state of charge. Note the state of charge at the start and end of a day off hookups and you have your real number. Our RV solar and battery calculator does the sizing math for you.
What warranty do the stations carry?
Comvolt covers its batteries and power stations for 5 years and its accessories for 1 year.
Not sure which one fits? Tell us what you run and we'll check the numbers with you, or browse the full Comvolt range.