How to choose a power tool battery: platform, volts and Ah

A power tool battery works only with the platform it was built for: an M18 does not fit an M12 tool, nor a DeWalt XR a Makita. So first look at the designation and voltage on the tool, then choose the capacity. For light work 2-3 Ah at 12 V is enough; for drills, grinders and everything that works under load you need 18 V and 5 Ah or more. If you work a full shift, keep two batteries, one charging and one in use.

The types

• Platform lithium batteries. Li-Ion packs for the Milwaukee M12 and M18, DeWalt XR (including FLEXVOLT), Makita, Husqvarna and Efco systems for garden and site machines. They are available from 2 to over 8 Ah.
• Dual-voltage and high-output batteries. Packs that serve several voltages, such as the FLEXVOLT, or that deliver more current, such as the M18 High Output or MX FUEL.
• Kits with batteries and chargers. The kits contain from 1 to 4 batteries, in many cases with the charger: they are the choice when you are starting from scratch with a platform.
• Chargers. Standard, rapid, multiple and simultaneous; some for two systems together (for example M12/M18), others for vehicles, such as the Milwaukee M12-M18 car charger.
• Adaptors. Used to run batteries from one platform on appliances from another. Always check that the manufacturer provides for them.

How to choose by job

The features to look at

• System. This is the platform designation (M12, M18, MX FUEL, XR). It must always match the designation of the tool and of the charger.
• Voltage. In the data: 12, 18, 20, 36, 40, 54-56 V and 64 V. More volts means more power at the tool, not longer run time.
• Capacity (Ah). From 2 to 8 Ah and beyond. The high value gives more run time but weighs more; the low one is better for short jobs or awkward positions. An 18 V 5 Ah pack is worth about 90 Wh.
• Cell type. Li-Ion in the vast majority of cases; a few older models are NiMH, which is now rarely found.
• Weight and dimensions. From about 0.2 to 2.7 kg across batteries and charging stations: consider the balance of the tool, especially overhead.
• Batteries supplied. In kits from 1 to 4: two is the minimum for working without stopping.

Common mistakes

• Assuming "18 V" is valid for everyone. It is the voltage, not compatibility: what counts is the platform.
• Charging a battery that is still hot. Let it cool down before putting it on charge.
• Leaving batteries on site in the rain or in the sun. They must be kept sheltered from rain and extreme temperatures.
• Carrying on using a pack that has been dropped or is swollen. It is put aside and disposed of.
• Buying only the "bare" tool and finding out afterwards that the charger is missing. Check what the kit contains.

Frequently asked questions

Can I use a battery from one brand on a tool from another?

As a rule, no. You need an adaptor provided by the manufacturer or the same platform.

Is one 5 Ah battery better, or two 2.5 Ah?

For the same total Ah the run time is similar, but with two packs you can work while the other is charging.

What happens if a battery is dropped?

Put it aside and check it: if it is damaged or swollen it must not be recharged again and must be disposed of.

How do I store batteries in the warehouse?

Partly charged, in a dry place that is neither too cold nor too hot.

Which charger should I choose for a crew?

A multiple or simultaneous one, such as the Milwaukee M18 simultaneous super-fast charger, which charges several packs at once.

You will find batteries, kits and chargers in the Power Tool Batteries and Chargers collection: to match them to your tools, request a quote or ask the AMES technicians for advice.