Makita BL4040 40V MAX XGT Lithium-Ion 4.0Ah

Makita BL4040 40V Max XGT 4.0Ah Battery

The BL4040 is a 4.0Ah lithium‑ion pack for Makita’s XGT 40V Max system. With roughly 144 Wh of usable energy (36V nominal × 4.0Ah), it balances runtime and weight for demanding power tools and outdoor equipment.

Best For

• High‑draw tools: 7-1/4 in circular saws, 4–5 in grinders, SDS-MAX demo hammers
• Outdoor power equipment: string trimmers, blowers, chainsaws
• Users who need strong output with a manageable pack size

Key Specs & Compatibility

• Energy: ~144 Wh (36V nominal, 40V Max marketing)
• Capacity: 4.0Ah high-output Li‑ion cells
• Charge time: ~45 minutes with Makita XGT Rapid Charger (e.g., DC40RA; dual-port DC40RB similar)
• Electronics: Tool–battery–charger digital communication for overload, overheat, and over‑discharge protection
• Platform: Fits all Makita XGT 40V Max tools; works as one of two packs on 80V Max XGT tools (tandem use)
• Not compatible with Makita LXT 18V/36V tools or chargers

When to Choose BL4040

• Choose if you run grinders, saws, or OPE where 2.5Ah packs empty too quickly.
• Choose for all‑day rotation: two to three BL4040 packs often keep pace with a single-user workflow.
• Avoid if minimizing weight is the top priority (consider BL4025 2.5Ah).
• Consider BL4050F 5.0Ah if you need maximum runtime and can accept extra weight.

Alternatives at a Glance

Model	Capacity	Approx. Energy	Approx. Charge Time	Best For
BL4025	2.5Ah	~90 Wh	~28–30 min	Lighter tools, overhead work, quick tasks
BL4040 (this)	4.0Ah	~144 Wh	~45 min	General heavy-duty use, good balance
BL4050F	5.0Ah	~180 Wh	~50 min	Longest runtime with modest weight penalty

Runtime Planning

Actual runtime depends on the tool’s average power draw. Estimate using:

Runtime (minutes) ≈ (Battery Wh ÷ Average Tool W) × 60

• Example: 144 Wh ÷ 400 W grinder load ≈ 0.36 h ≈ 22 minutes of trigger‑on time.
• Example: 144 Wh ÷ 250 W trimmer load ≈ 0.58 h ≈ 35 minutes.

Typical ranges (trigger‑on): grinders 12–25 min; 7-1/4 in saws 20–30 min; string trimmers 25–40 min. Heavy cuts, dull accessories, and cold weather reduce runtime.

Charging & Care

• Let the pack cool to room temperature before charging for best life.
• Use Makita XGT chargers only (e.g., DC40RA/DC40RB) for correct communication and thermal management.
• Keep terminals clean and dry; use the terminal cap during transport.
• Storage: 30–60% charge, in a cool, dry place (ideally 50–77°F / 10–25°C). Avoid prolonged heat or direct sun.
• Rotate multiple packs to balance wear; label packs to track cycles.

Safety Notes

• Do not use or charge a damaged, swollen, or water‑immersed battery.
• Charging is typically permitted within 32–104°F (0–40°C); outside this range, the charger may delay or stop.
• Avoid shorting the terminals with metal objects; transport with the cap installed.

FAQ

Is the BL4040 compatible with LXT (18V/36V) tools?

No. XGT and LXT are different platforms with different batteries and chargers.

Can I use one BL4040 in 80V Max XGT tools?

80V Max XGT tools require two XGT batteries used together. The BL4040 can be one of the two packs.

Can I mix different Ah batteries on a twin‑battery (80V Max) tool?

It will operate, but for best performance and balanced discharge, use two packs of the same capacity and similar state of charge.

How does cold weather affect performance?

Expect reduced runtime and charging speed in low temperatures. Warm the pack to room temperature before charging.

Does partial charging harm the battery?

No. Lithium‑ion packs have no memory effect. Frequent partial charges are acceptable and can help extend service life.