Anker sells the Solix C300X at 288Wh and the C1000X at over a thousand. Nearly four times the battery, and most of the buying guides I read compare them on exactly that: hours of runtime. That framing has sent a lot of people home with the wrong box.
TL;DR: The C300X is a 300W device and the C1000X is an 1800W-class device. That six-fold difference in continuous output decides more purchases than the capacity gap does, because a load your inverter cannot start does not run for any number of hours.
Watts Before Watt-Hours
Two numbers on every spec sheet, and buyers read them in the wrong order.
Watt-hours are stock. Watts are flow. The C300X carries 288Wh of LiFePO4 behind a 300W continuous inverter with 600W of SurgePad headroom. The C1000X carries 1056Wh behind 1800W continuous and 2400W of surge. Anker's own pages carry both figures, and the second pair is the one that determines what you can plug in.
Here is the test I use, and it takes about a minute. Write down the single largest thing you intend to run. Not the total, the largest. If it is a kettle, a microwave, a hair dryer, an induction hob, a heat gun, or a coffee machine with a boiler, you are already out of C300X territory before you have thought about runtime. Those all live between 1000W and 2200W.
If the largest thing is a laptop charger, you are fine at 300W with room to spare, and buying four times the battery to run a MacBook is money spent on a handle you will curse carrying.
What Each One Actually Covers
| Load | Typical draw | C300X (300W) | C1000X (1800W) |
|---|---|---|---|
| Phone, tablet, headtorch | 10-30W | Yes, dozens of charges | Yes |
| Laptop | 60-90W | Yes, roughly 3 charges | Yes |
| Wi-Fi router and modem | 10-20W | Yes, a full day | Yes, days |
| CPAP without humidifier | 30-60W | Yes, one night | Yes, several |
| Domestic fridge | 100-150W running, high inrush | Unreliable, and short | Yes, most of a night |
| Microwave, kettle, hair dryer | 1000-2200W | No | Yes, in bursts |
| Induction hob, space heater | 1800W+ | No | Borderline, and brief |
The row that changes minds is the fridge. It sits well inside the C300X's 300W continuous rating once it is turning, which is why the arithmetic looks fine on paper. Compressor inrush is what breaks it, and a 600W surge ceiling is right on the boundary where the answer depends on the specific appliance rather than on anything you can look up.
The Naming Is A Trap
I need to flag this before anyone goes shopping, because the names are close enough to trip up a careful reader.
The C1000, the C1000X and the C1000X Gen 2 are three products. The earlier C1000X holds 1056Wh, weighs 12.9kg, offers six AC outlets and expands to 2112Wh with a second battery. The Gen 2 holds 1024Wh, lifts continuous output to 2000W, and takes no expansion battery at all. Same family name, opposite upgrade paths.
So a review that praises the expandability may be describing a unit that no longer expands. Check the generation on any figure you plan to spend money on, including the ones in this table, and check it against Anker's own documentation rather than a retailer listing. For the original C1000X that now means the refurbished listing or the manual, because the new-unit page is gone.
Solar Input Is The Other Split
Capacity is a budget. Solar input is an income, and it changes the whole calculation for anything longer than a weekend.
The C300X takes up to 100W of solar. The C1000X takes up to 600W. On a decent day that is roughly 400Wh in versus 2.5kWh in, which means the smaller unit tops itself up and the larger one genuinely refills. If your use case is a week off-grid rather than a night in a car park, the panel ceiling matters more than the battery, because you are living on the daily income and treating the battery as overnight float.
That is also the case for pairing rather than choosing. A C300X plus a 100W panel is a self-sustaining electronics kit at a fraction of the weight, and there is no rule saying the answer has to be one box.
What I Would Buy
If the largest load is under 200W and you carry it on your back: the C300X, every time. It is roughly a third of the weight, it fast-charges to 80 percent in around 50 minutes from a wall socket, and the two-way 140W USB-C port means it doubles as an oversized laptop bank. Anker lists it at $299.99, though you may have to buy it refurbished for now (see below).
If anything with a heating element is on the list, or you want the thing to be useful during a power cut, the C1000X. Not because of the extra hours. Because 300W will not start it.
And if you are buying for outage backup specifically rather than portability, read the home battery sizing guide first. A portable station that lives in a cupboard eleven months a year is a worse answer to that problem than most people expect, and considerably more expensive per usable kilowatt-hour. Priced per kilowatt-hour, a wall-mounted pack such as the Enphase IQ Battery 5P is in a different league entirely, and it powers circuits rather than sockets.
There is one more variable worth naming, because nobody puts it on the box: noise. Bigger inverters need bigger fans, and a station that hums quietly under a 40W load will start audibly working somewhere north of a few hundred watts. Reviewers of the C1000X have flagged this specifically. If the thing is going to sit two metres from where you sleep, that fan matters more than the last two hundred watt-hours of capacity, and no spec sheet will tell you so.
Can You Still Buy Either One?
Availability shifted after this comparison went up. Here's what Anker's US store showed on 29 September 2026:
| Listing on Anker's US store | Price shown | Status |
|---|---|---|
| C300X, new | $299.99 | Sold out |
| C300X, refurbished | $263.99 | In stock |
| C1000X (original), new | None | Product page returns 404 |
| C1000X (original), refurbished | $359.99 | Sold out |
| C1000 (1056Wh, 1800W) | $469.99 | In stock |
| C1000X Gen 2 | $699.99 | In stock |
So the original C1000X has more or less left Anker's own shop. Retailer listings still turn up in search, but I haven't confirmed stock at any of them.
The refurbished C300X page has a wrinkle. In bold, it says the purchase is backed by a 6-month warranty. A few lines down it repeats the new unit's 5-year line. Which one do you actually get? Ask Anker before paying, and keep the answer in writing.
My read: if your load list says C300X, the refurbished unit is the cheapest way in right now, as long as that warranty answer comes back better than six months. For the bigger box, the live choice is now the C1000 against the Gen 2 covered above. Treat every price here as a dated snapshot, not a quote.
Summary
Watts decide, watt-hours only describe. The C300X is a 288Wh unit behind a 300W inverter: phones, laptops, lighting, routers and a CPAP, but nothing with a heating element. The C1000X sits above a thousand watt-hours behind an 1800W inverter, enough for almost any household plug in short bursts and a fridge overnight. Pick by the largest single load, confirm the generation on any spec you quote, and check stock first, since Anker's own store had the new C300X sold out and the original C1000X delisted in late September 2026.