Battery Tender Plus 12V Battery Charger and Maintainer

AGM compatibility is confirmed on the Battery Tender Plus manufacturer compatibility chart (image[8]) alongside standard flooded lead-acid and GEL. The 4-stage charging algorithm (initialization, bulk, absorption, float) is appropriate for AGM chemistry, and no overcharge complaints on AGM batteries were found in the 21,000+ review corpus. The manufacturer specifies a float voltage of 13.2V per label claim — which is at the conservative low end of the acceptable range for 12V lead-acid chemistry (13.2–13.8V). For AGM specifically, 13.2V may be slightly conservative; some AGM manufacturers recommend a higher float voltage in the 13.5–13.8V range. Community-measured float voltage on an actual AGM battery has not been independently retrieved — if float-voltage accuracy on AGM is critical for your application, confirm with independent forum reports before relying on this unit for long-term AGM maintenance.

No. The Battery Tender Plus (ASIN B006590ADM, model 021-0128) does not support LiFePO4 or any lithium chemistry. The manufacturer compatibility chart lists Standard (Sealed or Flooded Lead Acid), AGM, and GEL only — lithium is explicitly absent. The sibling 800mA model explicitly markets a Lithium mode as a differentiator; the 1.25A Plus does not have this mode. Do not use this charger on a lithium battery.

The Amazon product specification table lists 'Specification Met: CE, ETL, FCC' for this product as of May 2026, indicating ETL certification. ETL (Intertek) is an OSHA-recognized Nationally Recognized Testing Laboratory equivalent in authority to UL Listing for the US market. However, the specific ETL listing number was not independently verified in the Intertek certification database during this review. CE is a European self-declaration mark (not independently tested to US standards). FCC Part 15 covers electromagnetic compatibility. The ETL mark — if confirmed in the Intertek database — is the relevant independent US safety certification here.

The Battery Tender Plus specifies a float voltage of 13.2V per manufacturer label claim. The correct maintenance range for 12V flooded lead-acid and AGM batteries is 13.2–13.8V, so 13.2V is at the conservative low end of this range — adequate for flooded lead-acid storage and unlikely to overcharge. The 4-stage algorithm switches to float mode after full charge, making the unit safe for indefinite connection on a maintained battery. Community-measured float voltage (independent multimeter reading) has not been retrieved as of this review — the 13.2V figure is the manufacturer's stated value, not an independently confirmed measurement.

Both. The Battery Tender Plus will charge a battery from a depleted state and then automatically switch to float/maintenance mode when the battery reaches full charge. The 1.25A output is appropriate for batteries in the 14–100Ah range; it charges slowly by design — this is not a rapid charger. A car battery at 50% state of charge will typically take 6–12 hours to reach full charge at 1.25A. If you need to recover a deeply discharged battery (below 5V), note that this unit does not have a documented recovery or desulfation mode — batteries that have been discharged to near-zero may require a separate recovery step or a charger with an explicit recovery mode.

No. The CPSC recall database was searched on May 15, 2026, and no active recall was found for the Battery Tender Plus model 021-0128 or ASIN B006590ADM.