Cordless lawn mower battery charging on a garage workbench

How Long to Charge a Lawn Mower Battery

ByKen

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If you are asking how long to charge lawn mower battery packs, the honest answer starts with the charger, because the charger changes the time about as much as the pack does. The manufacturer pages we opened list charge times for named charger and pack pairs, and those times run from 32 minutes to 95 minutes. Two of the listings say “as little as,” which marks the figure as a best case. This guide sets out each time with its source and shows how to plan around it. The figures come from product and charging pages for Ryobi, DEWALT and STIHL, and each one stays tied to the charger and pack it belongs to.

Quick answer

  • The charger sets much of the time. For the same STIHL AK 10 pack, STIHL gives 95 minutes on the AL 101 charger and 45 minutes on the AL 300.
  • Named times run from 32 minutes to 95 minutes. DEWALT lists 32 minutes for a 2Ah pack on its four-port charger and 60 minutes for a 6.0Ah FLEXVOLT pack on its 8 Amp charger, and Ryobi lists 40V batteries at one hour or less on average.
  • Two listings give “as little as” figures, so treat them as best cases. The sources we opened give no charge time for lead-acid mower batteries.

Charge times by charger and pack

The table lists each time that a manufacturer page states. Where a page gives no minute figure, the cell says not stated.

Charger, as named on the page Pack, as named on the page Charge time stated Source
18V ONE+ Charger 1.5 Ah battery As little as 45 minutes Ryobi product page
40V Rapid Charger 40V batteries 1 hour or less on average Ryobi product page
12 Amp fan-cooled fast charger 20V MAX and FLEXVOLT batteries not stated DEWALT product page
8 Amp fast charger 6.0Ah FLEXVOLT pack 60 minutes DEWALT product page
4 Amp multiport charger Up to four 20V MAX 2Ah packs As little as 32 minutes DEWALT product page
4 Amp multiport charger Up to four 20V MAX 4Ah packs As little as 67 minutes DEWALT product page
AL 101 STIHL AK 10 battery 95 minutes STIHL charging times page
AL 300 STIHL AK 10 battery 45 minutes to a full charge STIHL charging times page

The rows are not directly comparable. Each figure belongs to one charger and one pack, and the Ryobi, DEWALT and STIHL pages name their packs in different ways. A time from one row should not be read as the time for a different charger or pack. Match the names on your own charger and pack to the pages above before you plan around a time.

What the charger changes

STIHL says the charger has its own effect on the time: “The charging times of batteries do not only depend on their capacity – the charger also has an influence on the battery charging time.” Its example uses one pack. The AK 10 takes 95 minutes on the AL 101 charger, and it is fully charged after only 45 minutes on the AL 300. The difference for that pack is 50 minutes, as the calculation below shows, and the page does not extend that gap to other packs.

The DEWALT 12 Amp fan-cooled charger page gives no minute figure. It says only that “Fan-assisted cooling results in faster charge times and reduced downtime in the field.” If you need a number for that charger, check the manual for your model before you plan.

DEWALT names its chargers by amp rating. The 12 Amp page describes its charger as “with this 12 Amp fast charger,” and the four-port page describes “this 4 Amp multiport charger.” The amp figure is part of the charger’s name. It does not give a charge time on its own, and the 12 Amp page gives no minute figure at all, so compare the named times and not the amp ratings.

Charging more than one pack changes the wait as well. The STIHL page says: “If 2 batteries are charged at the same time, the charging time may increase depending on the battery type.” DEWALT’s four-port page states its figures with the words up to four packs, so check which pack count a time refers to before you plan a run of batteries.

Temperature is a condition on the quickest figures. The STIHL footnote for its AL 1802 MO charger reads “Charging time up to 80% at ambient or pack temperatures of 25–40 °C in combination with AL 1802 MO.” The page does not give a time for a colder pack, so for a cold garage or a chilled pack the time is not stated. For a battery and charger from another system, see the related guide on the Snapper XD 82-volt battery and charger.

A worked comparison for one pack

To compare two chargers for the same STIHL AK 10 pack, subtract the shorter time from the longer one.

Difference = 95 minutes (AL 101) minus 45 minutes (AL 300) = 50 minutes.

The two inputs are the times that the STIHL page gives for that pack. The result tells you how much longer the slower charger takes for that pack and nothing more. It does not give the gap for any other pack, and it does not say how the gap changes with temperature.

Capacity and time on the same charger

DEWALT’s four-port charger page gives two figures for one charger: as little as 32 minutes for a 2Ah pack and as little as 67 minutes for a 4Ah pack. Two short calculations use those inputs. Dividing each time by its amp-hour rating gives minutes per amp-hour.

2Ah pack: 32 minutes divided by 2 Ah = 16 minutes per Ah.

4Ah pack: 67 minutes divided by 4 Ah = 16.75 minutes per Ah.

The two results are close, so on this charger the stated times scale almost in step with capacity. Put another way, the 4Ah time is about 2.1 times the 2Ah time (67 divided by 32). The page does not say that the relationship holds for other chargers or packs, and both times are “as little as” figures, so each one describes a best case for its pack.

Safety and charging steps

Follow these steps each time you charge. Each one names the page that supports it.

  1. Match the charger to the pack. DEWALT’s four-port charger page says it is “For use with DEWALT® 12V MAX*, 20V MAX*, and FLEXVOLT® 20/60V MAX* batteries.” Use the charger that the maker names for your pack, and do not assume that a charger from another brand or system will fit.
  2. Watch the indicator light. The Ryobi 18V ONE+ Charger page says an “LED Light Indicates When Battery is Fully Charged.” Wait for that light before you use the pack.
  3. Plan the time for several packs. STIHL warns that charging two batteries at once “may increase” the wait, depending on the battery type. If you charge several packs in a row, add time to your plan rather than assuming the single-pack figure applies.
  4. Charge in the stated temperature range. The STIHL footnote ties its quickest figure to “ambient or pack temperatures of 25–40 °C.” Where you can, charge the pack in a room within that range, because the sources we opened do not give a time for colder packs.

If a pack will not take a charge at all, read the related guide on a lawn mower battery that will not charge before you assume the charger is at fault. For the voltage and amp rating that sits behind a pack, see lawn mower battery voltage and amps.

How we chose

We opened six pages from manufacturer sites on 2026-10-22, and each returned HTTP 200. Three are DEWALT product pages, two are Ryobi product pages, and one is a STIHL charging-times page. The criteria were that a page had to name a specific charger and either give a charge time or say that the page gives no minute figure. Every time in this post is quoted from the saved text of the page it comes from.

The times come from product and charging pages, which state the manufacturer’s own figures. We did not use retail listings, forum answers or blog posts. No ranking was applied to the six pages, and no page was chosen for a particular result. Each page was read as saved text, and the saved text was searched for each figure before the figure went into the table. Where one page gives two figures, both are reported with their conditions, and the words as little as stay with the figure they describe.

What we could not verify

  • Charge times from the owner’s manuals. The manuals are PDF files, and the tool used for this post cannot open PDFs, so the times come from product and charging pages.
  • The charge time for your own pack and charger. Every time above belongs to one charger and one pack named on its page.
  • Times for cold packs or cold rooms. The STIHL footnote covers 25 to 40 °C only.
  • How low the pack was before charging began. The pages do not say.
  • Whether a charger’s listed times hold after years of use. The pages we opened do not cover charger wear or age.

What the sources do not say

No opened source gives a charge time for a lead-acid mower battery. The DEWALT 12 Amp page gives no minute figure, and the Ryobi 40V page gives an average rather than a time for each pack. The STIHL page’s table is hard to read in the saved text, so this post uses only the times the page states in sentences. The Ryobi 40V page also does not say whether its average covers every 40V pack, so the one-hour figure should be read as an average and not as a limit.

FAQ

How long does a lawn mower battery take to charge?

It depends on the charger and the pack. The Ryobi 18V ONE+ Charger page says as little as 45 minutes for a 1.5 Ah battery. The DEWALT 8 Amp charger page gives 60 minutes for a 6.0Ah FLEXVOLT pack. The STIHL page gives 95 minutes for an AK 10 pack on the AL 101 and 45 minutes on the AL 300.

Is a faster charger always better?

The pages show that the charger changes the time for a given pack, as the STIHL example does. They do not give a general rule that a faster charger is better for every pack. Compare the figures for your own pack and charger before you choose.

Does charging two batteries at once take longer?

STIHL says that if two batteries are charged at the same time, the charging time may increase depending on the battery type. DEWALT’s four-port charger page lists up to four packs, with as little as 32 minutes for a 2Ah pack and as little as 67 minutes for a 4Ah pack.

Why does my charge take longer than the listed time?

The listed times are for named charger and pack combinations, and the Ryobi 18V figure and the DEWALT four-port figures use the words as little as, which marks them as best cases. The STIHL footnote ties its quickest figure to ambient or pack temperatures of 25 to 40 °C. Check the charger name, the pack name and the temperature before you assume there is a fault.

How do I know when the charge is done?

The Ryobi 18V ONE+ Charger page says an LED light indicates when the battery is fully charged. Use that light as the signal, and do not rely only on the listed time.

Do lead-acid mower batteries follow these times?

The sources we opened do not give charge times for lead-acid batteries, so this post does not give one. For a lead-acid battery, use the maker’s manual for that battery and charger.

Bottom line

Use the time listed for your exact charger and pack. If your combination is not listed, check the manual for your model before you plan, and add time for each extra pack you charge at once.

Sources

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