Allwei 256Wh
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What you actually get
Allwei 256Wh is sold as a 256 Wh unit, which places it in the under 300 Wh band — the size people buy for phones, laptops and a camera. That figure is the energy in the cells, and it is a true one. It is not what reaches a wall plug.
Between the cells and the outlet sits an inverter that converts direct current to 120 volts alternating current, and it takes its cut — roughly fifteen percent. So the number worth planning around is about 218 Wh. The remaining 38 Wh leave as heat and as the inverter's own draw. On this unit that gap is about 3 phone charges.
Nobody is misleading you here: the cells really do hold 256 Wh. But size this one by the number on the box and you will be 38 Wh short of what you planned for — which you discover at the worst possible moment, not in the store.
What that runs
Working from the usable figure, not the rated one:
| Phone charges | 15 | a 15 Wh phone battery, charged from empty |
|---|---|---|
| Laptop charges | 4 | a 60 Wh laptop battery |
| CPAP nights | 0.7 | a CPAP at 40 W over an eight-hour night, no humidifier |
| Fridge hours | 4 | a full-size fridge: about 150 W while the compressor runs, cycling roughly a third of the time |
These are arithmetic, not measurements. Your own appliances draw what they draw; check the label on the back. Cold weather, a nearly empty battery and high inverter load all cut into the real figure.
Battery: LiFePO4
Allwei 256Wh uses lithium iron phosphate. That is the more durable of the two chemistries in this comparison — typically three thousand or more charge cycles against roughly five hundred for older lithium-ion, plus better heat tolerance. The manufacturer states 3,000 charge cycles.
In practice: charge it once a week and a three-thousand-cycle pack outlives the decade. That is the single biggest difference between two units that otherwise look alike, and it is the one most buyers skip past.
Ports
- 1AC outlets
- 1USB-C up to 60 W
- 1USB-A
Counts as published by the manufacturer. Where a figure is missing above, the listing did not state it separately.
The rest of the spec sheet
| Dimensions | 9.25 x 5 x 6.81 in | |
|---|---|---|
| Recharge | 240 min | To 100% of capacity · the maker quotes 3.5 to 4 h from the wall; the longer end is shown here. Not scored — makers quote it to different targets, which makes the numbers incomparable. |
| Warranty | 5 years | Stated by the manufacturer. |
What we cannot tell you
We have not tested this unit. Everything above comes from the manufacturer's own listing, and a manufacturer's number is a claim rather than a measurement.
For this unit the manufacturer does not publish: solar input. Those fields stay empty here rather than being filled with an estimate.
We also cannot tell you how it behaves after two winters, how loud the fan gets under load, or how the support desk responds. Those are the things a real test would cover, and we are not pretending to have done one.
Specifications on this page were last verified against the manufacturer listing on September 6, 2026.
Where it sits in Compact
Within the compact class — under 300 Wh, built for phones, laptops and a camera — this unit ranks 2 of 5 on our score. Capacity and continuous output are compared only against other units in the same class, so a compact unit is never punished for being small. How the score works.