Buffalo is rolling out the BMPBSA10000 series, a power bank built around a semi-solid electrolyte, to consumer electronics retailers across Japan starting in early September 2026. Until now the model was sold only through Buffalo's official stores on Amazon.co.jp and Rakuten Ichiba. The expected street price is 5,990 yen, capacity is 10,000mAh, and maximum output is 30W. A battery designed to structurally limit the risk of fire and smoke will now be something buyers can pick up and inspect in a store.
From online-only to the shop floor
The BMPBSA10000 series is a semi-solid power bank that Buffalo has been selling through its own official online stores. With this move, distribution widens to consumer electronics retailers and other sales channels. Two colors are offered, Metallic Black and Silky White, sold as BMPBSA10000BKX and BMPBSA10000WHX respectively.
Given the repeated reports of power bank fires and the way railway and airline operators have been revising their carry-on rules, it makes sense that a product built around safety claims is moving beyond mail order. At 5,990 yen, it is not unusually expensive for a 10,000mAh model either.
Gel instead of liquid
A typical lithium-ion battery uses a liquid electrolyte to carry current. That liquid burns easily, and if an internal short occurs or strong external force is applied, heat can spread quickly and lead to fire or smoke.
The semi-solid electrolyte in the BMPBSA10000 series turns that electrolyte into a gel. Buffalo explains that, unlike a liquid electrolyte, the structure keeps damage from spreading if the unit is broken or shorted. The cell type is a rechargeable semi-solid lithium-ion battery, which sits between liquid and solid rather than being a full solid-state cell.
Tested three ways: nail penetration, crush, and gas
Buffalo cites three forms of verification to back the safety claims. The first is a nail penetration test that forces an internal short. The second is a crush test that applies high pressure vertically, checking resistance to combustion under conditions that simulate damage or heavy load.
The third is a chemical test carried out with a third-party organization in Japan. Assuming a scenario in which the product is broken, the company says it confirmed that the generation of gases of concern to human health is low. Looking not only at whether the cell ignites but also at what comes out of it when it breaks is one of the more distinctive parts of the product's story. The unit also carries multiple protection functions and complies with Japan's PSE electrical safety standard.
These tests are, of course, conducted under controlled conditions. Buffalo warns users never to deliberately apply impact to the product, or to disassemble or modify it.
Roughly 210g with a built-in cable, and a 1 percent charge readout
A strap-style USB Type-C cable roughly 23cm long is built into the body, so there is no scenario where a forgotten cable leaves you unable to charge. The cable uses durable nylon fabric with a neck guard at the base to reduce breakage. The connector is slim enough to fit phones still wearing a thick case.
Remaining charge appears on an LED monitor in 1 percent increments. While the power bank itself is charging, the number blinks, and during fast charging a mark next to the number glows green.
30W output, pass-through charging, and cabin carry-on
Output is USB PD compliant at up to 30W from a single port, covering 5V/3A, 9V/3A, 12V/2.5A and 15V/2A, with PPS support as well. There are two output paths in total, the built-in cable and a USB Type-C port, so two devices can charge at once, though combined output is capped at 15W in that mode. A pass-through function charges the phone first and then automatically switches to topping up the power bank.
For low-current devices such as wireless earbuds and smartwatches, there is a low-current mode, engaged by pressing the button once. The power bank itself also charges at 30W, but no charger is included, so a USB PD charger capable of 30W or more has to be supplied separately.
Buffalo's own test results put charge counts at about 1.7 times for an iPhone 17, about 0.8 times for an 11-inch iPad Pro (M5), and about 1.2 times for a Google Pixel 10. The rated capacity is 37Wh, which allows it as carry-on baggage only when kept at hand rather than stowed in the overhead bin. It cannot be placed in checked baggage or used in flight, so anyone flying should check their airline's guidance in advance.
| Item | Specification |
|---|---|
| Battery | Rechargeable semi-solid lithium-ion |
| Capacity | DC3.7V/10,000mAh (37Wh) |
| Input and output | USB Type-C up to 30W, two Type-C outputs |
| Dimensions | Approx. 74 x 15.2 x 116mm (W x H x D, excluding protrusions) |
| Weight | Approx. 210g |
| Warranty | 1 year |
Thickness is about 15.2mm and weight about 210g, which is ordinary portability for a 10,000mAh unit. The operating environment is minus 15 to 45 degrees Celsius when discharging and 5 to 40 degrees Celsius when charging.
Summary
Buffalo's BMPBSA10000 series is a 10,000mAh power bank that uses a gel-like semi-solid electrolyte and backs its safety claims with nail penetration and crush tests plus chemical testing alongside a third-party organization. It reaches consumer electronics retailers across Japan from early September at an expected street price of 5,990 yen. With a built-in cable, roughly 210g of weight, up to 30W output and pass-through charging, the feature set is generous for the price. For anyone considering a replacement on safety grounds, being able to choose it in a store is no small change.
