AK 20 Lithium-Ion Battery

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A powerful and lightweight 36-volt battery for those who value balanced performance.

Product Description

The power of STIHL, now in a battery. STIHL Lithium-Ion batteries deliver the power-to-weight ratio you’ve been waiting for. The AK 20 is part of the STIHL AK Series, weighs only 2.7 lbs. and is great for applications where more run time is needed. Our batteries are engineered for minimal loss of charge during storage and performance that runs the power tool until the battery is depleted. Indicator lights show the battery level of charge, so you can plan your productivity accordingly. Inside the battery, sensors monitor temperature and automatically shut down if the battery ever becomes hot. Ready to take your battery power to the next level? Then switch to the STIHL battery products.

Run time may vary based charge level and operating style.

View Our Usage Chart


1.2 kg (2.7 lbs.)
108 Wh
36 volt
2.8 Ah
AK Series
*Stored energy. Useable energy will be less.

Important Information

WARNING! Improper use of any power tool may cause serious or fatal injury. Read, understand and follow carefully the operating and safety instructions in your instruction manual before using such products.

STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.


AK 20 Lithium-Ion Battery is rated 3.5 out of 5 by 8.
Rated 1 out of 5 by from Do not buy this battery unless you realistically need 12-15 minutes of run time This battery is advertised as a 20 minute run time battery and after 2 months of use I'm not getting anywhere near 20 minutes. I just reached out to Warranty and was told the realistic run rate is 12-15 minutes. Do yourself a favor and either buy the bigger battery or switch from battery to gas because this is definitely not worth it.
Date published: 2019-09-29
Rated 2 out of 5 by from Battery AK20 does not last as long as we need it to The AK20 battery did not last more than 15-20 minutes for me to use it on our blower for the amount we need it. And this has not changed in the year we've had it.The sales person told us it lasted him 2 hours, which is what we need. I saw him a few months later and told him this and he said to take it back to him to check out. We have not had the time to do that.It works great with the trimmer since we don't need it for more time than that.We should take the battery in to get it checked out but now it is a year later. Not sure what options we have. Is 15-20 minutes of constant use normal?
Date published: 2019-06-17
Rated 4 out of 5 by from Although pretty expensive I prefer it over the AK 10 for my trimmer Provides good power and pretty good run time in a FSA 56 trimmer. By the time it runs down I am ready for a break and in about an hour it is ready to go again as am I. What I do not like about it is once it is the charger it is very difficult to get out, Stihl really needs to address this issue. I have used another battery and charger and they have the same problem.
Date published: 2019-06-13
Rated 4 out of 5 by from Very good battery but consider the projects involved This battery is quick to charge and light weight. However, consider the projects involved in using this battery and tool. The battery life is only about 30 minutes of pretty constant use with my blower. Most of my projects take a bit longer so I'm getting another battery to swap to so I can keep going. Just love the convenience of this product and would certainly recommend this battery and brand.
Date published: 2019-03-14
Rated 4 out of 5 by from easy to use but to short running time i only get about 10 minutes running time out of it.the guy at the nampo show in bredasdorp told me up to 45 minutes and stihl says up to 35 minutes.i am not happy with that.stick to the truth.
Date published: 2018-09-30
Rated 5 out of 5 by from Good battery Running this in my saw provides longer lasting power than expected. Gets most jobs done on a charge. Surprising longevity.
Date published: 2018-03-11
Rated 4 out of 5 by from big improvement over the stock battery This is the battery my Stihl weed eater should have come with. Could only get about 15 minutes out of the stock one. Ran this one for 15 minutes and it hadn't lost a bar. A hundred bucks for this battery, and two hundred for the weed eater. I love it. But being into it for three hundred is a little steep. This battery is heavier. But well worth it. I love Stihl products. But just put the good battery on it to begin with.
Date published: 2017-10-20
Rated 4 out of 5 by from great bang for the buck. What a new and innovative product. its not all about voltage like some of the competition would like you to believe. 36volts and 2.8ah is a great entry level battery that gets the job done for the homeowner at an affordable price !
Date published: 2017-08-25
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