Battery Platforms
This is the decision that quietly sets the cost of every cordless tool you buy for the next decade. The tool is a one-off purchase; the platform is a subscription paid in replacement packs, spare chargers and bare tools that fit nothing else. Almost nobody calculates it in advance, and it is entirely calculable.
What a platform actually is
Voltage class
Nominal voltage — typically 12 V, 18 V or 36 V/2×18 V — sets the power ceiling. Note that “20 V max” and 18 V nominal describe the same 5-cell string: one is the off-load peak, the other the working nominal.
Capacity
Amp-hours measure stored charge. A 5.0 Ah pack holds roughly two and a half times a 2.0 Ah pack, and usually contains more cells — lowering the current each cell must supply, which reduces voltage sag and heat under load.
Pack format and rail
The physical mount and electronic handshake that decide what fits what. Rails almost never cross brands, and within a brand a higher-voltage line usually needs its own packs and charger.
Charger class
Standard, rapid and multi-bay chargers differ by hours, not minutes, on a large pack. When a job needs more energy than your packs hold, charger speed stops being a convenience and becomes the constraint on your day.
The five-year cost of lock-in
Start at the usual entry point: a combo kit with two tools, two mid-capacity packs and a charger. Over the following years the collection grows to five or six tools. Two of those — a saw and something from the outdoor range — draw hard enough that the original packs are inadequate, so you buy two high-capacity packs. A spare charger follows. Around year four the original packs reach the end of their cycle life and get replaced.
Count that up. The batteries and chargers on a mid-size collection routinely cost more than the most expensive single tool in it, and frequently more than the two most expensive combined. This is not an edge case; it is the normal trajectory of anyone who keeps buying into the platform they started with.
| Year | Typical additions | Battery-related spend |
|---|---|---|
| Year 1 | Combo kit — 2 tools, 2 mid packs, 1 charger | Most of the kit premium over bare tools |
| Year 2 | Saw or trimmer added bare | 1 high-capacity pack — existing packs sag under load |
| Year 3 | Mower or blower added | 1 more high-capacity pack, often a second charger |
| Year 4–5 | No new tools | Original packs replaced as cycle life ends |
A platform with cheaper packs and a wide bare-tool range can be the better long-run buy even when its tools have less impressive headline specifications. Lock-in compounds. Headline torque does not.
How to run the number before you commit
You do not need our figures for this — four honest inputs and ten minutes will do.
- Tool count. How many cordless tools will you own in five years? Most people undercount, because each purchase feels standalone.
- Draw profile. How many are high-draw — saws, mowers, blowers, chainsaws? Each pushes you towards high-capacity packs and a spare.
- Pack price tier per brand. Compare tiers rather than exact prices. The spread between the cheapest and dearest mainstream platform is wide enough to dominate the calculation on its own.
- Bare-tool availability. A platform selling most of its range bare lets you add tools without buying batteries you do not need. One that mostly sells kits forces a pack purchase every time — which is where lock-in gets expensive fastest.
Multiply through and you have a five-year platform cost. Compare it between two brands and the ranking often inverts against what a tool-by-tool specification comparison suggests.
Ah, voltage and the things people misread
Amp-hours do not increase power. A 5.0 Ah and a 2.0 Ah pack of the same class supply the same nominal voltage; the larger simply stores more charge and, holding more cells in parallel, sustains high current with less sag. That secondary effect is why a big pack can make a saw feel stronger without changing the tool’s rating.
Watt-hours are the honest cross-platform capacity measure: nominal voltage multiplied by amp-hours. An 18 V 5.0 Ah pack stores 90 Wh; a 12 V 6.0 Ah pack stores 72 Wh despite the larger Ah figure. Comparing amp-hours across voltage classes is a common category error.
Cycle life decides replacement timing and is rarely published clearly. Lithium-ion packs lose capacity through cycles and through calendar ageing, so a lightly used pack still degrades. Battery warranty terms frequently differ from the tool warranty and often require registration within a short window — check both.
Which platform should you commit to?
Two or three light-duty tools and nothing more: a 12 V platform is smaller, lighter and cheaper to feed, and entirely adequate for drilling and driving. A general kit including saws: an 18 V platform with a broad bare-tool catalog and mid-tier pack pricing is the safest long-run choice. Significant garden equipment: prefer a brand that runs high-draw outdoor tools on two 18 V packs over one requiring a separate higher-voltage line — a second pack family idle all winter is the most expensive lock-in there is.
- Drills & Drivers — usually the first purchase, and the one that sets your rail
- Saws — where pack discharge capability limits the tool
- Outdoor Power Equipment — the heaviest sustained demand
- Measuring & Layout — where platform choice barely matters
- Comparison Methodology — how this cost model is built
See the battery platform spec comparison — pack voltage, capacity and weight across 62 listings, with the fields we removed and why.
Compare them
The finder below is already scoped to this category — 46 of the 433 tools in the corpus. Widen or narrow it from there, or open the full cordless tool finder to search everything at once. Every result is placed against the median weight for its own size class, where that class holds at least eight tools. Bear in mind that a pack’s weight is a proxy for its cell count, not for its usefulness — read it alongside the voltage class.
46 tools match
Hedge Trimmer Cordless 22" – 2 x 21V Batteries & Fast Charger, Easy to Use | 3200RPM Powerful Motor, Electric, 2.0Ah Lightweight Battery Powered Bush Trimmers for Garden, Yard Care, GT860 Green
Weight
2.68kg
Too few tools in this class to publish a baseline.
WORX Cordless Grass Shear & Shrub Trimmer, 20V 4" + 8" Bush Trimmer, WG801 | 8"& 4" blades interchangeable blades for grass and shrub trimming;2.0A battery battery & charger included; PowerShare.
Weight
0.91kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is +133% against the class median of 0.39.
AOBEN Cordless Angle Grinder 4-1/2 inch, 21V Battery Grinder Kit, Power Electric Cut Off Tool, Brushless Motor, 2×4.0Ah Battery & Charger, for Metal Cutting, Grinding, Polishing
Weight
4.82kg
Too few tools in this class to publish a baseline.
Dremel 8250-5 12V Lithium-Ion Variable Speed Cordless Rotary Tool with Brushless Motor – 5 Rotary Tool Accessories, 3Ah Battery, Charger, and Tool Bag
Weight
0.39kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is 0% against the class median of 0.39.
20V Hedge Trimmer Cordless with 2 Battery and Charger, 2 in 1 Bush Trimmer | Electric Hedge Shears, Battery Powered Shrub Trimmers with 2 Blades, Mini Handheld Grass Cutter Yard Tool, Gifts for Men, Dad
Weight
Not stated
This listing does not publish a figure, so it cannot be placed against the baseline.
DEWALT Grease Gun Kit 20V MAX with 4.0Ah Battery and Charger, Cordless Grease Gun, LED Light, 42” Hose, 10,000 PSI, Variable Speed Triggers (DCGG571M1)
Weight
6.71kg
Too few tools in this class to publish a baseline.
DEWALT DXAEPS14 2000 Amp Jump Starter with Compressor | Portable Power Station with 500W AC Power and 15W USBa & 25W USB
Weight
7.85kg
Too few tools in this class to publish a baseline.
GOOLOO A3 12V 3000A Portable Jump Starter with Air Compressor | Supersafe Car Battery Booster Pack (9L Gas/6.5L Diesel) – BOOST for Dead Battery – 150 PSI Auto-Off Tire Inflator – LED Light
Weight
1.63kg
Too few tools in this class to publish a baseline.
Makita DC18RC 18V LXT® Lithium-Ion Rapid Optimum Charger
Weight
0.83kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is +113% against the class median of 0.39.
DEWALT 20V MAX 5 Ah Lithium-Ion Battery and Charger Starter Kit (DCB205C)
Weight
0.64kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is +63% against the class median of 0.39.
Milwaukee 48-59-2401 12V Lithium-Ion Battery Charger
Weight
0.45kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is +16% against the class median of 0.39.
Ecarke 220W Portable Power Inverter Compatible with Milwaukee 18V Battery (Tool Only), DC 18V to AC 110V Power Station with 1 AC Outlet, 2 USB-A, 1 Type-C & LED Light for Camping Outdoor Emergency
- Max torque
- not stated
- No-load RPM
- not stated
- Pack
- not stated
Weight
0.31kg
Batteries & chargers · under 1.5 kg · 29 tools
Weight is -21% against the class median of 0.39.
Common questions
Are third-party batteries a sensible way to cut platform cost?
They reduce the cash figure and add risks the arithmetic does not capture: cell quality varies widely, protection electronics may not match the original, and use typically voids the tool warranty. We record what manufacturers state about warranty and compatibility and leave the decision with you.
Is it ever worth running two platforms?
Occasionally — a 12 V system for compact indoor work alongside an 18 V system for everything else is defensible, because the tools genuinely differ in size and reach. Two 18 V platforms in parallel almost never is.
Do adapters between brands work?
Third-party adapters exist. They generally void warranties on both tool and pack, and they bypass the electronic handshake the tool uses to manage current and temperature. We do not treat them as a solution to lock-in.
Why not just tell me which brand is cheapest overall?
Because the answer depends on your tool count and draw profile, and pack pricing changes constantly. The model above is the durable part; run it with current prices and it gives you your answer rather than ours.