Cordless tools · Which one do I need
DEWALT 20V MAX battery sizes: 2Ah vs 5Ah vs 6Ah, runtime and size trade-off
Adding DEWALT 20V MAX batteries: small 2Ah packs, 5Ah or 6Ah? What the amp-hour figure changes, worked out.
Quick picks who each one fits
We earn a commission if you buy through the Amazon links on this page, at no extra cost to you. Commissions never decide which products are listed or how they are described.
-
DEWALT 20V MAX four-pack: two 2Ah and two 4Ah batteries (DCB324-4)
Mixed sizes: light packs plus mid-size packs
- Platform: 20V MAX
- Voltage: 20 V
-
DEWALT 20V MAX 5Ah two-pack with charger (DCB205-2C)
Two 5Ah packs plus a charger
- Platform: DEWALT 20V MAX*
- Voltage: 20 V
- Batteries and charger: 2 x 5 Ah, charger*
-
DEWALT 20V MAX 6Ah two-pack (DCB206-2)
Longest runtime per pack here: 6 Ah
- Platform: DEWALT 20V MAX*
- Voltage: 20 V
- Batteries and charger: 2 x 6 Ah (DCB206), no charger listed*
Figures are as stated in each product's current Amazon listing; * from the maker's own spec page (see Sources). Yes or No: whether the listing or maker names the feature.
On this page
What we compared and why
- Capacity in amp-hours (Ah). At the same voltage, Ah is how much charge the pack stores. On the same tool doing the same work, runtime scales roughly with Ah.
- The tool it goes on. A drill or impact driver used overhead feels every ounce of battery; a saw, a vacuum or a light on the floor does not. Size the battery to the tool.
- Platform fit. All the packs here are DEWALT 20V MAX. DEWALT gives 20 volts as the maximum initial voltage and 18 as the nominal one, so they all fit the same tools and chargers.
- What is in the box. Battery listings come as single packs, two-packs, mixed packs and kits with a charger. Count batteries and chargers, not boxes.
The models compared
| Model | Platform | Voltage | Batteries and charger | Amazon link |
|---|---|---|---|---|
| DEWALT 20V MAX four-pack: two 2Ah and two 4Ah batteries (DCB324-4) | 20V MAX | 20 V | Not stated in listing | See on Amazon |
| DEWALT 20V MAX 5Ah two-pack with charger (DCB205-2C) | DEWALT 20V MAX* | 20 V | 2 x 5 Ah, charger* | See on Amazon |
| DEWALT 20V MAX 6Ah two-pack (DCB206-2) | DEWALT 20V MAX* | 20 V | 2 x 6 Ah (DCB206), no charger listed* | See on Amazon |
Read at this page's build and converted to one unit by us; sources as in the key above. "Not stated in listing": the listing does not give it. "Listing gives two values": it states two, so we show neither.
DEWALT 20V MAX four-pack: two 2Ah and two 4Ah batteries (DCB324-4)
Who it fits: You want light packs for the drill and impact driver and mid-size packs for the saw, in one box, per the listing.
Skip it if: You need a charger; the listing for this pack does not name one, so check the box contents first.
DEWALT 20V MAX 5Ah two-pack with charger (DCB205-2C)
Who it fits: You are starting on 20V MAX, or your only charger is tired, and you want two long-running packs and a charger; DEWALT lists (2) 5Ah batteries and (1) charger in the kit.
Skip it if: Your tools are mostly a compact drill and impact driver used overhead; smaller packs keep the tool lighter.
DEWALT 20V MAX 6Ah two-pack (DCB206-2)
Who it fits: Saws, grinders, vacuums and other tools that run continuously, where the longest runtime per pack matters more than weight; DEWALT lists (2) DCB206 6 Ah batteries.
Skip it if: You have no charger yet; this pack contains batteries only, per DEWALT's includes list.
What the Ah figure changes
Every DEWALT 20V MAX battery has the same voltage; DEWALT's footnote gives 20 volts as the maximum initial voltage without a load and 18 as the nominal voltage. What changes between a 2Ah, a 5Ah and a 6Ah pack is the amp-hour figure: how much charge the pack stores. On the same tool doing the same work, a pack with more amp-hours runs longer before it needs the charger. It does not make a drill turn faster or a saw cut harder in DEWALT's statements on these pages. This page is research-based, from DEWALT's own pages and the current listings; we have not run the packs against a timer.
The runtime arithmetic
Runtime on the same tool and job scales roughly with amp-hours, so the ratios below are a fair first guide. They are ratios, not minutes: how long any pack lasts depends on the tool and how hard it works.
| Swap | Ah ratio | Rough runtime on the same job |
|---|---|---|
| 2Ah to 4Ah | 4 / 2 | About 2 times as long |
| 2Ah to 5Ah | 5 / 2 | About 2.5 times as long |
| 2Ah to 6Ah | 6 / 2 | About 3 times as long |
| 5Ah to 6Ah | 6 / 5 | About 1.2 times as long |
| One 6Ah against two 2Ah packs used in turn | 6 / (2 + 2) | About 1.5 times as long, with no mid-job swap |
DEWALT makes the same 3-to-1 point itself: an image caption on its DCB206-2 page describes the 6Ah pack as three times the capacity of its DCB203, which DEWALT's own page for that model lists as a 2 Ah battery.
The last row is the one people miss. If you already own two 2Ah packs, one 6Ah pack still outlasts both together, but two 2Ah packs on two chargers or two tools give you a spare while the other charges. Which matters more depends on whether your jobs stop for a battery swap anyway.
Size and weight: what we can and cannot say
A larger-capacity pack is a larger pack, and on a compact drill or impact driver held overhead you feel it. DEWALT's own product pages for these batteries, as we read them, list capacity and voltage but no weight, so we do not give per-pack weights here. The listings' weights are for whole multi-packs or kits with chargers, which tell you little about one battery in your hand. If weight decides your choice, weigh a pack in a store or check the spec label of the pack you already own.
Which size on which tool
| Tool | Size that usually fits | Why |
|---|---|---|
| Compact drill/driver, impact driver, used overhead or on a ladder | 2Ah | A smaller pack keeps the tool light; swaps are quick |
| Drill or impact driver for long sessions at bench height | 4Ah or 5Ah | More time between swaps where weight matters less |
| Circular saw, reciprocating saw, grinder | 5Ah or 6Ah | Continuous load drains small packs quickly |
| Vacuum, light, fan, radio | 5Ah or 6Ah | They run for a long time and sit on the floor or a shelf |
Which listing if...
- You have tools but only one or two small packs: the DCB324-4 four-pack gives you light packs for the drill and impact driver and mid-size packs for the rest, per its listing.
- You are short of a charger as well as batteries: the DCB205-2C kit, the one listing here with a charger in DEWALT's includes list.
- You run saws, a vacuum or a grinder: the DCB206-2, for the longest runtime per pack in this table.
DEWALT's FLEXVOLT packs also fit 20V MAX tools; how they fit together is on our FLEXVOLT page. If you are still choosing a platform, see DEWALT 20V MAX vs Milwaukee M18.
Reading the table
A figure with a mark comes from DEWALT's own page for that pack, linked under Sources. The four-pack row shows listing values only: DEWALT's page for that model did not load its contents for us. "Batteries and charger" counts what is in the box, which is the figure that differs most between these listings.
What this page does not tell you
We have not timed these packs. We give runtime as a ratio of capacities, not in minutes, and we do not compare charge times or cold-weather behaviour. Battery care and charging instructions are in DEWALT's manuals.