Two matching batteries installed side by side in a cordless mower

What Two Batteries Do on a Cordless Mower

ByKen

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What do two batteries do on a cordless mower? In short, the manufacturer rates the mower for a longer run, and on some models the two packs also change how charging works. Five manufacturer pages we opened give two-battery run time ratings from 75 to 90 minutes, each with its own conditions. The pages describe the second battery in different words, and some do not describe it at all. This guide sets out those statements and what they leave out.

Quick answer

  • Manufacturers rate two-battery mowers for up to 75 to 90 minutes on a single charge, under stated conditions.
  • EGO says its dual battery port combines the power of two batteries, and its dual port charger can charge two EGO batteries at the same time.
  • DEWALT’s figure assumes both batteries are used in succession, which is the page’s own wording.
  • Treat every rating as the manufacturer’s claim, because grass, cutting height and terrain all affect the result.

What a second battery does for run time

Each of the five pages gives a run time figure that depends on having two batteries. For the voltage and amp-hour side of the same question, see the lawn mower battery voltage and amps guide on this site. EGO’s 22-inch Select Cut kit is rated for up to 90 minutes on a single charge with two included 6.0Ah batteries. EGO’s 30-inch dual-motor kit is rated for up to 75 minutes on a single charge with two included 6.0Ah batteries. EGO’s 21-inch self-propelled mower with Peak Power technology is rated for up to 80 minutes with two included 5.0Ah batteries. DEWALT’s 21-inch RWD kit is rated for up to 80 minutes using both included batteries in succession. RYOBI’s 40V 21-inch mower is rated for up to 80 minutes using two 40V 6Ah batteries.

None of the five pages gives a run time with one battery in the text we read. That means these sources do not show how much a second battery adds to the run time. The ratings are the most the pages state for the two-battery configuration, and they do not say what the mower does on one pack.

Reading a single-charge rating

A single-charge rating describes the run time from one full charge of the batteries in the kit. It is not a promise for every lawn. EGO’s wording is “on a single charge,” and DEWALT adds a footnote that the figure is based on mowing one third of the grass height, at height setting 6, using both fully charged DCB210 10.0Ah batteries. That footnote is the most specific mowing condition on any of the five pages.

The conditions matter because a taller or thicker lawn, a lower cutting height or rougher terrain can all change how long the batteries last. The pages we opened do not give figures for those conditions. Use the ratings to compare kits, not to plan a single mowing session down to the minute.

What a second battery does for charging

Charging is where the pages differ the most. EGO’s 22-inch kit lists a Dual Port Charger and gives an approximate 90-minute charging time for the two included 6.0Ah batteries. EGO’s dual port charger is described as able to simultaneously charge two EGO batteries of any size, and the 30-inch dual-motor kit includes a Dual Port Charger with the same description.

EGO’s 21-inch dual battery mower works differently in the listing. It gives about 50 minutes of individual charging time for each included 5.0Ah battery on the POWER+ Rapid Charger. That wording describes one battery at a time, so it is a per-battery figure rather than a total for the pair. EGO also states that all of its chargers charge all of its batteries, which is a general statement about the EGO range.

Charging in a DEWALT kit

DEWALT’s 21-inch RWD kit lists a charger as included and gives the charger count as two 4A chargers. The page does not say how long the charging takes for two batteries, and it does not say whether the two chargers run at the same time. Read the kit listing before you assume a single charger will serve both batteries.

Charging in a RYOBI kit

RYOBI’s 40V listing shows a two-battery and charger option, labeled as (2) 6Ah Batteries/Charger, next to a Tool Only option. The page gives the run time for the two-battery configuration, but it does not state a charging time or say how the charger handles two packs. If a pack will not take a charge at all, the lawn mower battery that will not charge guide on this site is the better place to start.

How the two batteries work together

EGO uses the phrase “combines the power” in its descriptions. Its 22-inch page says a dual battery port combines the power of any two EGO 56V ARC Lithium batteries for long runtimes and efficient power draw. Its 21-inch page says the same thing in shorter form, and it refers to any two EGO 56V ARC Lithium batteries rather than a specific pair. The EGO statements are about EGO batteries only.

DEWALT takes a different approach in its wording. Its run time figure is for using both included batteries in succession, which means one battery after the other. The page does not say whether the two batteries are used at the same time. RYOBI’s listing gives the two-battery run time without describing how the batteries are used, so that detail is not stated.

Two-battery figures side by side

The table below puts the manufacturer statements for each two-battery listing next to each other. Where a page does not state the item, the table says “not stated.”

Listing Batteries stated Run time wording Charging wording Source
EGO POWER+ 22-inch Select Cut kit (two 6Ah batteries) Two 6.0Ah batteries included Up to 90 minutes on a single charge Dual Port Charger; approximately 90-minute charging time for the two batteries EGO 22-inch kit page
EGO POWER+ 30-inch dual-motor kit (two 6Ah batteries) (2) 6.0 Amp Hour Batteries included Up to 75 minutes on a single charge Dual Port Charger included; charges two EGO batteries simultaneously EGO 30-inch kit page
EGO POWER+ 21-inch self-propelled, dual battery Two 5.0Ah batteries included Up to 80 minutes on a single charge Approximately 50 minutes of individual charging per battery on the Rapid Charger EGO 21-inch dual battery page
DEWALT 2x20V MAX XR 21-inch RWD self-propelled kit Both included batteries; footnote names DCB210 10.0Ah Up to 80 minutes using both included batteries in succession Charger included; (2) 4A Chargers; charging time not stated DEWALT kit page
RYOBI 40V HP 21-inch self-propelled mower (RY40HPLM01B) (2) 40V 6Ah batteries in the two-battery option Up to 80 minutes using (2) 40V 6Ah batteries Not stated RYOBI 40V listing

The table shows that two-battery ratings land in a narrow band, but the charging statements do not line up. EGO gives total and per-battery charging figures and a dual port charger. DEWALT gives a charger count without a charging time. RYOBI gives no charging detail on the page we opened.

Conditions behind the numbers

Each rating in the table has a condition attached, even when the page does not spell it out. EGO’s ratings are “on a single charge” with the batteries named in the kit. DEWALT’s rating has a mowing footnote. RYOBI’s rating names the two 40V 6Ah batteries. RYOBI’s page places the line “Ideal for 3/4 Acre or Less” beside its run time line, but it does not tie the run time to that lawn size or state any other condition. The other pages give no lawn size, grass type or terrain for their figures.

Real run time changes with grass, cutting height and terrain. A rating from the manufacturer is useful for comparing one kit with another under the same listed conditions. It is not a forecast for your lawn. The DEWALT footnote assumes fully charged batteries, so a partly charged pack will not match its figure.

Safety when you use and clean a two-battery mower

Charge and store each battery as the owner’s manual says. EGO’s 21-inch page points owners to the manual for complete instructions on its mower, and the same wording appears on its FAQ for other procedures. Use the manual for the charger and battery steps rather than this guide.

Remove the battery before you clean under the mower. EGO’s FAQ on its 21-inch dual battery mower says to first remove the safety key and the battery before you clean the underside of the mower. Do this before you clean under the deck, and if your mower is a different model, follow its own manual.

Use the charger the listing names with the batteries the listing names. EGO states that all of its chargers charge all of its batteries, and DEWALT and RYOBI name the charger in each kit. The pages do not say that a charger from one brand works with another brand’s batteries, so do not assume a match across brands.

What we could not verify

  • How much a second battery adds to run time on any of these mowers. None of the five pages gives a one-battery figure in the text we read.
  • Whether the batteries in a DEWALT or RYOBI kit run at the same time or in turn, beyond DEWALT’s in succession wording.
  • How long a RYOBI or DEWALT kit takes to charge two batteries. Those figures are not stated on the pages we opened.
  • Whether the ratings hold for a lawn of a particular size or for a particular grass type. The pages give no such conditions.

What the sources do not say

  • No page states a price comparison between a single-battery and a two-battery mower. This guide does not compare prices.
  • No page says a two-battery mower can run on one battery, and no page says it cannot.
  • No page describes battery life over many charge cycles.
  • No page says that an EGO battery works with a DEWALT or RYOBI mower.

FAQ

Do two batteries double the run time?

The pages do not say. Each rating is a figure for the two-battery kit under stated conditions, and none of the five pages gives a one-battery run time to compare against. Read the rating as the most the manufacturer states for that kit, not as a doubled figure.

Can I mix battery sizes on an EGO mower?

EGO says its dual battery port combines the power of any two EGO 56V ARC Lithium batteries, and its dual port charger can charge two EGO batteries of any size. That is EGO’s statement for EGO batteries. The pages do not say what happens with batteries from another brand.

Do I need two chargers?

It depends on the kit. EGO’s kits list a Dual Port Charger, which EGO says can charge two batteries at the same time. DEWALT’s kit lists two 4A chargers. RYOBI’s two-battery option is listed with a charger, and the page does not state how that charger handles two packs.

How long does it take to charge two batteries?

For EGO’s 22-inch kit, the listing gives an approximate 90-minute charging time for the two included 6.0Ah batteries with the Dual Port Charger. For EGO’s 21-inch dual battery mower, the listing gives about 50 minutes per included 5.0Ah battery on the Rapid Charger. The DEWALT and RYOBI pages do not state a charging time.

Is the second battery included in every two-battery listing?

Not always, and the listing decides. The two-battery figures in this guide come from kits that list their batteries as included. A tool-only option leaves them out, so read the included list for the exact option you are buying.

Does a two-battery mower need more care than a single-battery one?

The pages we opened do not say so. The 21-inch EGO page’s FAQ says to remove the safety key and the battery before you clean the underside of that mower, and it points owners to the manual for complete instructions.

Bottom line

Read the run time rating together with its condition, then check whether the listing includes the batteries and the charger you need. If the listing does not say how two batteries charge, plan for the charging time the manufacturer does state rather than assuming the second battery halves the wait.

How we chose

We opened five manufacturer pages on 2026-10-22 and cite all five: three EGO POWER+ mower pages, one DEWALT kit page and one RYOBI listing. We chose pages that give a two-battery run time or charging statement for a mower. We did not cite any retail listing, and we did not rank the mowers. Each statement in this guide is tied to a quoted sentence on one of the five pages.

Sources

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