20V 4.0 AH MaxLithium Battery


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Harness Even More Power

Our most powerful 20V battery--4.0 Ah delivers up to double the run time of the 2.0 Ah battery

Delivers increased runtime and powers your 20V cordless WORX tool through the entire job

Professional grade, gas-like power with none of the emissions

Efficient MaxLithium technology charges quickly and lasts longer

Compact and lightweight — helps reduce fatigue while you're working

Part of the 20V Power Share platform that lets you save money by sharing batteries among multiple 20V tools

Recommended for use with WA3742 20V charger or WA3868 20V quick charger

20V 4.0 AH MaxLithium Battery ITEM WA3578

Availability: In stock

Ships for FREE
1 Year Warranty
30 Day Guarantee
Technical Specifications
  • Battery Type
  • Rated Voltage
  • Charging Time
    ≈ 5 Hours
  • Charger Model
You're Getting
  • (1) - 20V MaxLithium Battery

Frequently Asked Questions

  • Which tools are compatible with this battery (WA3578)?

    The Worx 20V 4.0Ah battery is compatible with all 20V Worx tools – both garden tools and power tools! PowerShare lets you share the battery and save money.

  • How much does this battery weigh?

    The 4.0Ah 20V battery (WA3578) weighs about 1.4lbs.

  • How long can you trim on each 4.0Ah 20 Volt Max Lithium battery charge?

    On the Worx GT 2.0 String Trimmer/Edger/Mini-Mower, each 4.0Ah 20 Volt Max Lithium Battery will provide enough working time per charge to trim up to the average 1/2 acre yard. It’s like having two batteries in one! Actual results may vary depending on the density of the grass or weeds you’re cutting, the amount of trimming versus edging, and the age of the battery pack.

  • How long does it take to charge the 4.0Ah 20 Volt Max battery?

    It takes about 10 hours to fully charge the battery with a standard charger (WA3742), or two hours with a quick charger (WA3868).

  • Is the battery larger than previous models?

    The Worx GT 2.0 features our highest capacity battery to date. This 20 Volt Max Lithium Battery has an amp hour rating of 4.0 vs our previous models (2.0 and 1.5 amp hour rating). The amp hour rating measures how much energy can be stored in the battery (energy capacity). The 20V Worx 4.0 Ah battery (WA3578) can hold twice the amount of energy as previous models (WA3525). This extra capacity provides up to double the run time.

  • Are the 20 Volt Max Lithium batteries interchangeable with the 32 Volt Max Lithium Battery?

    While Power Share allows you to share batteries between tools within the same voltage family, batteries should only be used with tools of a corresponding voltage. Use your 20V Max Lithium battery with any 20V Worx tool – even the power tools – but save your 32V battery for your 32V tools.

  • Are lithium batteries interchangeable with the Ni-Cad?

    Our lithium tools and Ni-Cd tools are separate platforms and are not interchangeable. Lithium batteries offer our customers maintenance-free technology without the hassle of managing the memory effect inherent in Ni-Cad batteries.

  • Which charger is compatible with the 4.0Ah 20V Worx MaxLithium battery (WA3578)?

    The Worx WA3742 20V charger and the Worx WA3868 20V quick charger are compatible, along with WA3835, WA3764, and WA3875. Charging times will vary by style of charger.

  • What’s the difference between this battery (WA3578) and the WA3525 20V battery?

    The difference between our Worx 20V batteries is their amp hour rating. The amp hour rating measures how much energy can be stored in the battery (energy capacity). The 20V Worx 4.0 Ah battery (WA3578) can hold twice the amount of energy as previous models (WA3525). This extra capacity provides double the run time.

  • Are there any precautions I should follow?

    Regardless of the tool or job at hand, we recommend that our customers follow standard safety precautions while using our tools, including wearing safety eyewear, gloves, appropriate shoes and clothing, and keeping hair tied back. Always refer to the owner’s manual for complete safety information before operating any tool.

  • What is the guarantee/warranty?

    If you decide the 4.0Ah 20V MaxLithium Worx battery isn’t the right for you, we offer a 30-day Money Back Guarantee from date of receipt (less shipping and handling). Please call our customer service center at 1-866-354-9679 (WORX) and we’ll be happy to assist. For more information, click here.

    Worx batteries are covered by a 1 Year Limited Consumer Warranty and are not eligible for warranty extension.

    View more information on our warranty here.

  • Where can I get replacement parts?

    Many replacement parts are available online under Accessories.

20V 4.0 AH MaxLithium Battery is rated 4.6 out of 5 by 21.
Rated 5 out of 5 by from Awesome Upgraded Worx Battery. I have had my Worx Trimmer for a few years now. Which I can't go a day without. It's absolutely amazing and gets the job done. My battery recently died on me and I needed a replacement quick. I visited the Worx webpage and notice they had a NEW 20v 4.0ah battery. Which provides 25% more runtime than the originally 20v battery can you say "AMAZING"? 1 battery and extra runtime is just what I needed. "YESSSSS". I purchased and received my battery within a few days. Charged that bad boy up and tested it on my trimmer. Boy ol boy when I tell you I finished the job and still had power left in the battery actually shocked the heck out of me. One of the best accessories I purchased for my trimmer. One Happy Thrilled customer. You Guys At Worx Never Let Me Down.
Date published: 2017-10-24
Rated 5 out of 5 by from Love the Worx I have several items and so I got the new 20, AH-MaxL Batteries that is awesome lets me finish the job in just a short time and easy changeable batteries snap off snap on and just minutes ready to use again! I would never go back to those endless cords draging them around the house down the side walks I just like my Worx great tools and great piece of work! I love the performance it gives! I love dove doing my yard work now and looks so great! Carly
Date published: 2017-10-19
Rated 5 out of 5 by from Big Improvement This battery should have been available it makes me happy when Worx improves there tools. This battery has a longer run time and lets you know how much more time you have its a 5 star item for me.
Date published: 2017-10-18
Rated 5 out of 5 by from Great Run time Lasts twice as long as the 20v 2.0 battery so you don't have to recharge between jobs!
Date published: 2017-10-09
Rated 5 out of 5 by from Universal I like the idea of one battery for a variaty of different tools
Date published: 2017-09-18
Rated 5 out of 5 by from 20V 4.0AH Battery Last all most twice the time as the original battery Can finish weed-eating the whole yard with one battery
Date published: 2017-08-17
Rated 5 out of 5 by from last long time i bought this for extra running power great battery last long time
Date published: 2017-08-06
Rated 5 out of 5 by from Improvement Do you don't have any collum or space where anyone can ask questions about your certain products? Just like Review and Questions & Answers in other merchandise products's website now days. It looks you are too behind in web ads to give full info about your product. Sorry, I could"t remain to say this. Now I want to this 20V 4.0 AH MaxLithium Battery (WA3526) is come with its charger? Is WA3526 is compatible with charger WA3733?
Date published: 2017-08-05
Rated 5 out of 5 by from Fast to charge , lots of power and lasts a long time. really happy with it and the Worx Gt2 .
Date published: 2017-07-31
Rated 5 out of 5 by from Battery Great battery and the price was great also. They last along time. Use them in the hedge trimmer, blower and edger. Very happy with my products..
Date published: 2017-07-15
Rated 4 out of 5 by from 20V 4.0 AH Maxlithium Battery I bought this about two month ago ,I am glad I did. It out perform 3 of my 2.0 regular lithium batteries. I also bought the quick charger, the 25 min. charger it takes a little be longer to charge the 4.0 than the 2.0 but it well worth it.
Date published: 2017-09-04
Rated 4 out of 5 by from Hmmm...uh oh I bought two batteries of 20V for my tools. The blower and weedtrimmer I bought as the first generation. The sprayer I bought with these batteries. The new batteries DO NOT fit on old tools. So I still only have one 32V for my trimmer and blower. Can't get too much work done this way.
Date published: 2017-08-24
Rated 3 out of 5 by from Battery seems to be good quality Like it can be used on several tools
Date published: 2018-01-29
Rated 1 out of 5 by from 20V 4.0 AH MaxLithium Battery I'm disappointed with this battery. It was advertised to run for 30 minutes, but it dies after 15 minutes and then I have to charge it for 8 hours before using it again.
Date published: 2017-11-28
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