Verdict
It’s compact and appears constructed to take a couple of knocks, however the WAI PPS-400 has a restricted vary of ports, crammed into two small panels. Regardless of a surprisingly excessive battery capability and good discharge effectivity, it’s quite sluggish to cost and isn’t particularly confidence-inspiring to make use of. General, this can be a low-cost approach to purchase a mains energy financial institution with an honest capability, however I’d quite spend a bit of extra on one thing that feels extra reliable.
Professionals
- Mild and compact for this capability
- Vary of charging choices
- Good output effectivity at load
Cons
- Crowded management panel
- Not the very best port choice
- Unreliable at greater hundreds
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A small-medium energy financial institutionThis compact energy financial institution packs a powerful 426 watt-hour battery – sufficient to energy a pc for a couple of hours -
A variety of portsEnergy mains and USB units by a variety of ports – however not probably the most complete we’ve seen.
Introduction
WAI is finest identified for its vary of automobile equipment, however its PPS-400 is an all-purpose moveable energy financial institution.
It’s compact and light-weight in comparison with the competitors, but it packs in a 426Wh battery, giving it a bit extra oomph than you may count on for its measurement.
The port choice contains two USB-A and two AC sockets, with the latter able to supplying 400W between them – that’s a reduce above entry-level units, making this a compelling energy financial institution for the cash. Nevertheless, I discovered it to be unreliable at greater hundreds, so it might be price spending a bit of bit extra elsewhere.
Design and options
- Mild, compact and rugged
- Cramped and unimpressive port choice
- Very primary show
Whereas many moveable energy provides look extra like a stereo than a battery, the WAI PPS-400 appears to be like like one thing a mechanic may use to begin your automobile. Certainly, it’s a part of the corporate’s new EV vary, which additionally features a collection of EV charging cables. I’m not completely clear the way it suits in – it’s far wanting the ability you’d must high up an electrical automobile’s battery.
The PPS-400 might look drab, but it surely’s impressively compact. It’s barely narrower than a loaf of bread, and weighs solely 3.7kg – the identical as Anker’s PowerHouse 521, which has solely simply over half as a lot battery capability. On high there’s a retractable deal with, however the 4 lengthy sides are in any other case featureless aluminium – all of the necessary bits are crammed into the 2 small, sq. ends.

That’s not nice. The enterprise finish combines AC and photo voltaic inputs, a lamp, show, two USB-A ports and two 12V DC ports, alongside switches for the lamp, DC and AC ports. Add in contemporary air vents and it’s a cramped house with a reasonably arbitrary structure.
The sunshine is vivid and directional, which is nice for locating your approach, however much less so for studying in a tent at evening. The switches function with a nice click on, and the plastics appear robust.

On the again finish are two AC ports, plus followers for lively cooling.

Right here, the small panel poses one other downside: the ports are organized horizontally and oriented 180 levels from one another. Some top-heavy energy adaptors received’t match with out blocking the second port, whereas common energy plugs are near the sting of the machine.
This implies cables mission from the facet, with little means to flex in the event that they’re knocked. Together with the loose-fitting multi-region sockets, it’s too simple to knock a plug unfastened.

The WAI PPS-400 has a really primary show, exhibiting solely the battery cost share. It’s off until you activate the DC or AC circuits, and doesn’t present any indication of incoming or outgoing energy, or how lengthy the battery will take to cost or drain.

It’s a disgrace WAI hasn’t discovered room for any USB-C ports, or a automobile output. The USB ports can present 15W every, whereas the DC outputs are good for a mixed 120W most.
Charging
- Cost from mains, automobile or the solar
- Most 70W enter
- Expenses slowly, however can cost and supply energy
This isn’t the quickest charging energy financial institution, however it’s pretty versatile. Linked to a mains enter it’ll cost at about 55 watts, that means it ought to want round eight hours to achieve full cost. Alternatively, you need to use the provided cable to cost from a automobile energy provide at a most 70W, that means you would be absolutely recharged after round six hours of driving. A last possibility permits you to join as much as 70W of solar energy, however that is restricted to a most 18V enter. The PPS-400 doesn’t include panels and I didn’t have appropriate ones, so I couldn’t take a look at this operate.
WAI’s handbook says that this energy financial institution’s cost mild turns from pink to inexperienced when it’s absolutely charged. It additionally says that the show will present 100% cost when the battery reaches 90%. In apply it wasn’t clear when it was absolutely charged – the cost mild by no means turned inexperienced, and even after greater than 12 hours the PPS-400 was nonetheless consuming round 6W with all its circuits off.
After absolutely depleting it once more, I watched the figures extra carefully. The show reported 44% cost after my meter reported it had drawn solely 87Wh – a couple of fifth of the battery capability. When the show first reached 100%, my meter reported solely 275Wh (65%) consumed, and that the ability financial institution was nonetheless drawing 60W. After round 13 hours it had consumed 507Wh, however nonetheless didn’t fairly appear full.
This imprecise and seemingly inaccurate capability reporting appears a bit uncommon by at the moment’s requirements. I couldn’t make sure that the battery was absolutely charged however, even assuming it was, my measurements recommend a cost effectivity of 84%, which is a bit of low. I also needs to point out that the cooling followers reduce out and in throughout charging, and whereas they’re not loud, their small diameter means they’re a bit harsh.
The WAI PPS-400 is supplied with a bypass circuit, that means that when it’s linked to the mains it might probably provide mains energy with out first having to transform it to direct present and again. This lets it energy mains units with out slowing down charging. Its AC enter is rated at three amps, that means that in idea it might present round 650W to plugged in units whereas charging the battery. I examined it with my microwave on its lowest energy setting, which calls for between 60-650W, and it coped high quality.
The bypass circuit means the PPS-400 wants to change over to battery energy if there’s a blackout. WAI says it might probably do that in lower than 10 milliseconds, and it was actually quick sufficient to change with out inflicting my workplace gear any issues. At an indicated 20% the show begins flashing to warn you that the battery is getting low, and at 0% it begins a really loud intermittent beep. Whereas that’s good if you need time to close down your units, this part lasted for 35 minutes in my low-load take a look at, and there’s no button to silence it.
Efficiency
- Unreliable energy output
- Good discharge effectivity on heavy hundreds
In idea, this energy provide’s average capability makes it a sensible choice for mild backup duties within the dwelling. For instance, it might probably energy my web router and community storage (NAS) drive for about seven or eight hours – superb for driving out a major blackout. I examined it by connecting up an air air purifier, drawing round 32W. It lasted for eight hours, supplying a complete of 240Wh in line with my energy meter.
Assuming the battery started with a full cost, that’s a low discharge effectivity of 56%. That’s common for light-load testing, nevertheless, the place consumption by the ability financial institution’s personal AC inverter has fairly an impression over a number of hours.

I examined the PPS-400 with a extra demanding setup drawing round 220W, which is properly throughout the vary of its acknowledged 400W AC output. It began off fairly comfortably, with the followers sometimes kicking in, earlier than it reduce out after about ten minutes. It reset mechanically and continued for a few minutes earlier than the followers reduce in once more, and about 10 seconds later it reset. I watched it repeat this cycle a couple of instances, protecting a detailed eye on the utmost energy demand as reported by my energy meter – it didn’t exceed 220W.
I reconfigured the take a look at to scale back the demand to 190W, which proved secure. If I attempted rising it again to 220W the PPS-400 would fall over inside simply a few minutes.
Examined from full to empty with a 190W load, the WAI PPS-400 lasted about an hour and three quarters, supplying a complete of 328Wh. That equates to a way more spectacular discharge effectivity of 77%. Sadly, even utilizing this the very best round-trip effectivity (cost and discharge) labored out at 65% – that means a couple of third of the electrical energy used to cost it was misplaced.
I repeated my low-power microwave take a look at with the PPS-400 working on battery energy. It coped for a couple of seconds, however the second the ability demand spiked in the direction of the 650W most it shut down. That is protected and fairly affordable, taking into account I used to be testing it properly past its acknowledged 400W output energy.
Whereas dearer energy provides use LFP batteries of the sort present in electrical automobiles, the WAI PPS-400 makes use of customary lithium-ion (Li-ion) cells, which have a shorter working lifetime of round 800 cycles, in comparison with sometimes 3,000 for LFP. Calculated primarily based on an 80% cost, this energy financial institution may retailer about 273kWh over its lifetime. That offers an total value per kilowatt hour of £1.10, round 3 times what you may count on from extra sturdy cells.
Newest offers
Must you purchase it?
You need excessive capability at a low value: This offers a superb battery capability for the cash
You want extra energy output: This battery station wasn’t absolutely dependable in my exams
Last Ideas
On paper this must be an honest energy financial institution, however in exams the WAI PPS-400 was disappointing. It was sluggish and relatively inefficient to cost, and its primary show appeared approximate. Extra importantly, it wasn’t secure when supplying properly inside its rated energy, which didn’t fill me with confidence about its high quality.
Primarily based on my expertise, it won’t show dependable in conditions when it must be. It could be good worth to be used with low hundreds, however I’d be inclined to pay extra for one thing extra strong, such because the Bluetti AC60 or, when you want much more energy, the Dabbsson DBS2300.
How we take a look at
We take a look at each battery station we overview completely over an prolonged time period. We use customary exams to match options correctly. We’ll at all times let you know what we discover. We by no means, ever, settle for cash to overview a product.
Discover out extra about how we take a look at in our ethics coverage.
We take a look at with a wide range of units to see how lengthy the battery will final.
We take a look at completely different charging strategies to see how rapidly the battery might be topped up.
FAQs
On paper, the WAI PPS-400 must be appropriate, however my expertise with it resetting means I can’t advocate it for important medical purposes.
It’s extraordinarily moveable. It’s light-weight given its battery capability, and compact sufficient to sneak right into a full automobile boot.