BLACK+DECKER BM3B Fully Automatic 6V/12V Battery Charger/Maintainer

AGM compatibility is claimed in the Amazon listing and spec table ('Compatible Devices: Vehicles and equipment that use 6V or 12V AGM, GEL, or WET batteries'). The fully-automatic float-mode handoff is the right architectural feature for AGM chemistry. However, no independent community instrumented test confirming correct AGM termination voltage was found during this review. AGM batteries require a tighter termination range than flooded lead-acid; if AGM charging accuracy is critical for your application — for example, maintaining a high-end AGM battery in a luxury or performance vehicle — confirm with independent forum reports before relying on this unit for extended AGM maintenance.

No. The BM3B listing claims compatibility with AGM, GEL, and WET (flooded lead-acid) batteries only. Lithium chemistries — including LiFePO4 — are not on the compatibility list. Do not use this charger on a lithium battery; the charging algorithm is designed for lead-acid termination voltages and would not safely terminate a lithium charge cycle.

The Amazon product specification table lists 'Specification Met: ETL' as of May 2026, indicating ETL certification is claimed. The feature bullets also state 'ETL certified for performance and safety.' However, the specific ETL listing number was not independently retrieved from the Intertek database (intertek.com) during this review. A listing claim in the spec table is not the same as a confirmed entry in the Intertek certification database. This is noted in the safety certification quality score (score 6, provisional) and is a confirm-at-next-regen item.

The feature bullets describe automatic stop-on-full-charge with a handoff to a float-mode monitoring stage — the correct architecture for indefinite connection on a stored vehicle. The 1.5A output is appropriate for slow maintenance use rather than rapid recovery. However, the specific float voltage is not published in the Amazon listing or the instruction manual, and no community-measured float voltage was found during this review. Float voltage is the critical number for long-term battery health — the correct range for a 12V lead-acid battery is 13.2–13.8V; a charger holding 14.4V indefinitely would damage a battery regardless of its float-mode label. If long-term float accuracy is critical, confirm the measured float voltage via independent forum reports before committing this unit to an extended storage application.

The BM3B is a 1.5A trickle charger and float maintainer — small, encapsulated, with both alligator clamp and O-ring eyelet harness connections included. It is designed for slow top-off charging and long-term maintenance on a stored vehicle, motorcycle, or seasonal equipment. Larger BLACK+DECKER chargers (higher amperage units, some marketed as the BC series) are intended for rapid recovery of a deeply discharged battery and engine-start assistance. The BM3B is the right choice for storage maintenance; a higher-amperage charger is the right choice for fast recovery.

No. The CPSC recall database (cpsc.gov/Recalls) was searched on May 22, 2026 for 'BLACK+DECKER BM3B' and 'Baccus Global battery charger' — no active recall was found.