BLACK+DECKER STC1840EPC vs STC1820

Both of these are 18V PowerConnect grass trimmers from Black & Decker’s homeowner range, and both are built for lawns and tidy edges rather than anything woody. What separates them is less about raw power and more about what you get for your money: the BLACK+DECKER STC1840EPC is the fuller kit with a bigger battery and a wider cut, while the BLACK+DECKER STC1820 is the lighter, more basic entry point into the same battery system. If you’re choosing between two trimmers from the same brand, this is really a question of how much trimmer — and how much included — you actually need.

At a glance

	BLACK+DECKER STC1840EPC	BLACK+DECKER STC1820
Power	18V PowerConnect	18V PowerConnect
Sold as	Complete kit — 4.0 Ah battery and fast charger included	Usually sold bare — battery and charger extra
Cutting width	30 cm	Narrower, domestic-lawn swath
Cutting equipment	Line only, no blade fitting	Line only, no blade fitting
Weight	~2.55 kg with battery fitted	Light — among the easiest B&D trimmers to swing
Best for	Buyers starting from zero on batteries who want the bigger cut	Small lawns, light edging, minimal fuss

What’s actually different between them

On paper these two look like siblings, and they are — same 18V PowerConnect platform, same E-drive style operation, same line-only head with no blade option. The gap opens up in two places: what’s included in the box, and how much grass each one clears per pass. The STC1840EPC is pitched as a complete, ready-to-go kit, with a 4.0 Ah battery and fast charger bundled in, plus a 30 cm cutting width that’s genuinely a little wider than most trimmers in this class. The STC1820 strips that back to a simpler, lighter tool, in most listings sold as a bare unit, and with a narrower cutting swath better suited to small, tidy lawns than bigger plots.

Battery and charger: kit vs bare tool

This is the detail that most affects the real price you pay. Buy the STC1840EPC and you’re set from the moment it arrives — the 4.0 Ah battery and fast charger are in the box, so there’s no second purchase before you can start trimming. The STC1820, by contrast, is commonly listed bare, meaning the battery and charger are a separate cost on top of the trimmer’s own price. If you already own a PowerConnect battery from another Black & Decker tool, that gap barely matters — the STC1820 becomes the cheaper option outright. If you’re starting from nothing, though, the STC1820’s lower sticker price can end up costing about the same, or more, once a battery and charger are added.

Cutting width and weight

The STC1840EPC’s 30 cm cutting width is the more capable of the two for covering ground quickly, useful on a medium lawn where fewer passes means less time spent trimming. The STC1820 cuts a narrower swath, which is perfectly adequate for small gardens and edging work but means more back-and-forth on a bigger plot. Weight runs the other way: the STC1840EPC sits around 2.55 kg with its larger battery fitted, while the STC1820 is noticeably lighter thanks to its smaller battery and simpler build. For long sessions of overhead or awkward-angle trimming, that lighter weight can matter more than a few extra centimetres of cut.

What neither one can do

Neither trimmer is built for anything beyond grass. Both use a line-only head with no way to fit a metal or plastic blade, so brambles, woody stems, saplings, and dense scrub are out of reach for both models. If your garden regularly produces growth tougher than grass and light weeds, look past this entire comparison to a proper brush cutter — these are lawn-and-edge tools, full stop, regardless of which one you pick.

Choose the BLACK+DECKER STC1840EPC if…

• You want everything included — battery, fast charger, trimmer — in one purchase
• You have a medium-sized lawn where the wider 30 cm cut saves real time
• You’re starting from zero on PowerConnect batteries and want the bigger 4.0 Ah cell
• A little extra weight is an acceptable trade-off for more cut and more runtime

Choose the BLACK+DECKER STC1820 if…

• You already own a PowerConnect battery and charger from another B&D tool
• Your lawn is small, and edging or light trimming is the main job
• You want the lightest possible trimmer to swing for long sessions
• You’d rather pay less upfront and aren’t fussed about the narrower cut

Which should you buy?

If you don’t yet own any PowerConnect batteries, the STC1840EPC is the more sensible starting point — it removes the guesswork of sourcing a compatible battery and charger, and its 30 cm cut genuinely covers more ground per pass. If you’re already inside the PowerConnect ecosystem, or your garden is small enough that a narrower swath won’t slow you down, the STC1820 is the lighter, cheaper way to get the same basic job done. Neither trimmer touches brambles or scrub, so whichever you choose, keep it for grass and tidy edges — and look elsewhere for anything woodier.