Best Power UPS Batteries

What is Best Power?

Best Power Technology was a Wisconsin-based UPS manufacturer that produced FERRUPS, Fortress, Patriot, Axxium, and Unity product lines through the 1990s and early 2000s. Best Power was acquired by Invensys, which subsequently sold UPS assets to Eaton. The Best Power brand and associated UPS models are discontinued, but many units remain in service, especially in industrial, telecom and medical sites.

UPSPLUSBATTERY.CA stocks compatible aftermarket replacement cartridges for the legacy Best Power UPS line. Full UPS battery catalog at all UPS replacement batteries.

Legacy Best Power families covered

Aftermarket disclosure

Replacement cartridges UPSPLUSBATTERY.CA stocks for legacy Best Power are compatible aftermarket, matched on voltage, capacity (Ah), terminals and connectors. They are not OEM Best Power / Invensys / Eaton parts. 1-year UPSPLUSBATTERY full-replacement warranty.

For most pre-2000 Best Power UPS, OEM replacement cartridges have been discontinued for years. A compatible set matched on voltage, capacity and connectors is the practical replacement.

How to identify the right cartridge

Method 1: unit label

Side or rear of the Best Power UPS lists model number and battery configuration. Older FERRUPS units often have battery specs etched on a metal plate.

Method 2: existing cell

Open the cabinet: cell label lists V, Ah, terminal. Most use 12 V SLA blocks in series; the string voltage depends on the model.

Method 3: model-number lookup

Send the Best Power model number to our team, we maintain cross-reference for the legacy catalog.

How long do Best Power UPS batteries last?

SLA: 3–5 years rated in 20–25 °C climate-controlled environment. Most legacy Best Power UPS predate impedance-based battery monitoring, schedule routine load tests every 2–3 years on aging units.

How to replace

Fortress, Patriot, Axxium, smaller Unity: front-access cartridges, similar to other commercial UPS. Larger FERRUPS and Unity: site-specific procedures, qualified service typically required. Always reference the original Best Power user manual.

Warranty and support

1-year UPSPLUSBATTERY full-replacement warranty on every aftermarket Best Power cartridge. Coordinated through our Canadian team. Shipped from Canada.

FAQ

Is Best Power still made?

No. The brand was discontinued after Eaton acquired the legacy UPS portfolio.

OEM Best Power batteries?

Generally no for pre-2000 SKUs. A compatible set matched on voltage, capacity and connectors is the practical replacement.

Should I keep my Best Power running?

FERRUPS and Unity electronics from the 1990s often remain serviceable. If the UPS still passes self-test, replacing the battery is usually the practical choice. If electronics show signs of failure, step up to a current Eaton 9PX or 9SX equivalent.

FERRUPS specific?

FERRUPS used a ferro-resonant transformer design, robust against utility disturbances but power-hungry on standby. Battery strings vary widely by VA. Send model number for verified cross-reference.

Battery warranty?

1-year UPSPLUSBATTERY full-replacement.

Disposal?

SLA cells: municipal hazardous-waste depot, Call2Recycle, or ship back to us.