Redback 40V Lithium Ion Cordless String Trimmer Featured String Trimmers

Redback 40V Lithium Ion Cordless String Trimmer/Edger (106065): Product Review

GPR Recommendation

Ease of Use
Final Thoughts

A great all-round trimmer and edger

Overall Score 5

So you’ve decided that it’s time to buy a new string trimmer.  You’ve looked at all the pros and cons of gasoline vs. electric vs. cordless and decided that for you, cordless is the way to go.  But there’s a quandary.  What brand, model, voltage and features do you want?

Well, if it will make your buying decision making process any easier, you should know about a string trimmer that I just tested by Redback, their 40V (Volt) Lithium Ion (Li-Ion) unit.

If you’re unfamiliar with the Redback brand, that’s because it’s a relative newcomer to the US string trimmer market. Redback is now being offered in the US by an American company (Frictionless World) and its joint venture partner NGP (an overseas manufacturer). Redback tools have seen great success in both the Australian and European markets.  Currently Frictionless World is the exclusive distributor of Redback 40V branded products in North America and warehouses, ships and supports the products out of their headquarters in Westminster, CO.

>> See our article on Best Cordless String Trimmers

Redback 40V Lithium Ion Cordless String Trimmer Opening Shot
String Trimmer Features

  • Cutting diameter: 12”
  • Weight: 6.9 lbs.
  • Bump spool fed
  • Twin cutting lines
  • Adjustable head angle and handle height
  • Line edger
  • Shoulder belt
  • Run time: varies based on which 40V Ah battery is used

Various 40V Options

Redback 40V Lithium Ion Cordless String Trimmer Batteries and Charger

The batteries and charger can be used with other 40V Redback tools.

Redback offers both “kits” (which include the recommended battery and charger) and chargers and batteries that can be purchased separately (when a trimmer is sold as a stand-alone product).

In the “kit” version of this trimmer/edger, an EC20 (2A) charger is included, along with a 2.0Ah (Amp hour) battery.

I tested the string trimmer using the 2.0 Ah battery, as well as with a 4.0Ah battery and EC50 (5A) charger.

Interchangeable Batteries

Redback has a plethora of 40V tools, such as lawn mowers, chainsaws, leaf blowers, hedge trimmers, pole saws and string trimmers, all of which use the same battery platform.

Redback currently offers 3 different Ah batteries (2.0, 4.0 and 6.0) and while the batteries will fit in all tools in their product line, you’ll want to be sure you’re using the proper Ah for the equipment you’re running (higher Ah for tools that need more power).

I really appreciated this flexibility when I wanted an extra battery for the string trimmer and was able to choose a higher Ah (4.0Ah) to extend run time.

>> See our FAQs About Li-Ion Batteries

Redback 40V Lithium Ion Cordless String Trimmer Batteries

The Redback batteries come in a variety of Ah options.

As a String Trimmer

This Redback trimmer had a lot of nice features.

Bump Feed Twin Line

Redback 40V Lithium Ion Cordless String Trimmer Cutting Head

The cutting head uses a dual line with a bump feed.

The cutting head has a twin spool.  Basically this means that it has two cutting lines coming from one spool, with the two lines opposite each other.

When lines break (which inevitably happens from hitting rocks and sharp stuff), it’s simple to get more line; just bump the line spool on the ground.  This advances the cutting line out to a cutting blade that’s mounted at the edge of the guard (the guard protects you from flying debris).  The cutting blade then cuts each line to the same length for optimum cutting efficiency.

Redback 40V Lithium Ion Cordless String Trimmer Head Disassembled

The head can be easily disassembled to replace the line – just push in the tabs on either side and it’ll pop out.

Simple Line Replacement

First, remove the spool head from the cutting head assembly.  The instruction manual shows detailed diagrams of how to do this.

The spool can either be reloaded (the most common practice for string trimmers) or a new spool can be purchased from the manufacturer that is preloaded with trimmer string.  Reloading the spool yourself is less expensive and only takes a few minutes. Personally, I wouldn’t waste my money buying a preloaded spool, unless the spool broke.

It’s important to load the spool with a maximum of 26.24 feet of line with a string diameter of 0.0629 inches.

When reloading it yourself, it’ll take a little finesse to get the string through the two holes on the side of the cutter head.  Redback has made this easier by providing tabs on the reel to hold the line in place while it’s being wound.

As you lower the wound string reel into the cutting head, you have to poke the two string lines through the holes on the side of the cutting head. This can take some dexterity, but I found it was pretty straightforward.  It’s not as complicated as it sounds, particularly if you follow the instruction manual.  After doing it once, it will become second nature to you.

Plant Guard

To protect plants from being cut down and trees and save shrubs from bark damage, the trimmer has a plant guard built into the front of the trimmer.  I like that the guard can be rotated 900 up and out of the way when not in use.

Redback 40V Lithium Ion Cordless String Trimmer Plant Guard

The plant guard is adjustable – if you don’t want to use it, just flip it up out of the way.

Adjustable Cutting Head & Shaft

A button activates the adjustable cutting head angle. The button is easy to push and the head locks securely into 5 different positions (from 00 to 720).

This, accompanied with the adjustable shaft length, makes it easy for virtually any sized person to use the trimmer.  This adjustment feature is also great for extending the shaft to reach under obstructions and still be able to trim.

Redback 40V Lithium Ion Cordless String Trimmer Locking Button

There’s also a button on the other side of the shaft. That one doesn’t say ‘PUSH’ and it doesn’t adjust the cutting head – so be sure you’re pushing the right button!


The trimmer handlebar (what your front hand holds on to) is easily adjusted by lifting an unlocking/locking clip under the handlebar to move the handle up and down the shaft.

I found that this made it very easy to create the right balance between the battery at one end of the unit and the cutting head on the other end.  And for even greater overall length and corresponding balance, I could slide the handlebar all the way back toward the battery and slide the cutting head shaft forward.

Redback 40V Lithium Ion Cordless String Trimmer Adjustable Handle

The handle is easily adjustable using the lever (orange tab in the photo).

Variable Speed

Behind the handlebar is the throttle mechanism.  It consists of an interlock safety switch (pull lever) and an On/Off lever.  Both levers work seamlessly together.  I tried to override the interlock safety by not pulling it; this absolutely incapacitated the On/Off switch.

The On/Off switch also acts as a variable speed throttle.  There’s a nice smooth transition from no power to full power.  Moderate power can be held easily as the On/Off switch has a built-in spring that keeps the perfect tension on the handle at all times.

Redback 40V Lithium Ion Cordless String Trimmer Interlock On Off Switch

Shoulder Belt

Redback 40V Lithium Ion Cordless String Trimmer Shoulder-Belt

The shoulder belt helps carry some of the weight of the string trimmer but can be easily removed if you don’t want to use it.

The Redback string trimmer comes with a very nice, padded, and adjustable shoulder belt that clips into the fastening loop near the On/Off switch.

I found this belt extremely comfortable and it really helped take a lot of the weight off my arms and prevented hand, wrist, arm and shoulder fatigue.  I wore the strap almost all the time, and experienced no shoulder pain as a result of wearing it.


The battery compartment is at the end of the trimmer.  I like the fact that it accepts the wide range of Ah batteries noted above, although battery weight does affect balance of the string trimmer. For example, the 2.0Ah battery weighs approximately 2.0 lbs. and the 4.0Ah weighs a little over 2 ¾ lbs, and the weight difference means that the string trimmer balance is thrown off if you change batteries.

To compensate for this, all I had to do was adjust the handlebar position.  If I really wanted to fine-tune the balance, I could have extended or shortened the shaft length.

Redback 40V Lithium Ion Cordless String Trimmer Battery-Compartment

Edging With the Redback String Trimmer

Rotate the head 90 degrees by depressing the shaft coupling button and voilà, you have an edger.

Redback 40V Lithium Ion Cordless String Trimmer Shaft-Extention-90-Degree Rotation

Push down on the orange locking button and rotate the shaft to whatever angle you want.

Thanks to the running wheels located on the side of the guard, the powerful cutting string can be run down the side of the lawn.

I’ve owned a tool that was gas operated and specifically designed for edging.  It had a sharp steel blade and a set of tracking wheels.  This piece of gear didn’t hold a candle to the Redback 40V Cordless String Trimmer/Edger.  I was amazed at how perfect a line I was able to get.

The cutter guard provided pretty good protection from flying dirt and grass, but as with all power tools, wearing the proper safety equipment is mandatory, especially safety glasses at all times while using the trimmer/edger (we recommend the John Deere safety glasses from WileyX).

Redback 40V Lithium Ion Cordless String Trimmer Edging

The Redback string trimmer is also a darn good edger.

Charging and Battery Life

The “kit” version of the Redback trimmer/edger includes an EC20 (2A) charger and 2.0Ah battery.  With this configuration, I found the charging time was around 70 minutes and the run time was approximately 25 minutes.

I also tested the EC50 (5A) charger and 4.0 Ah battery.  The charging time was approximately 45 to 60 minutes for the 4.0Ah battery, depending on how much charge was left, and a run time of just over 50 minutes.

The difference in charging time is nice (shorter is more convenient) but the biggest difference in batteries is the run time.  As Ah increases, so does run time. So if you’ll be doing a fair bit of trimming and edging, you may want to consider buying the 4.0 Ah battery instead of the 2.0 Ah that comes with the kit.

One thing I really appreciated was the battery indicator lights. Simply press the button on the end of the battery and the lights will illuminate to show how much charge is left.

Redback 40V Lithium Ion Cordless String Trimmer Battery Indicator Lights

A handy battery life indicator on the end of the battery makes it easy to see how much juice is left.

String Trimmer Warranty

Redback offers a 36 month warranty on all its 40V line of products.  This covers both stand-alone purchases and kit purchases (where the charger and battery are included). The warranty is a pretty standard one that covers against material defects and workmanship. It doesn’t cover consumables, misuse, abuse, loss, theft or unreasonable/outrageous customer requests.

As Redback points out, “Our customer service team tries to bend over backwards to handle reasonable customer issues”.  If a customer has an issue, Redback recommends calling them directly and they will try to remedy (within reason) the problem. They are clearly trying to set themselves apart by providing customer service that goes above and beyond.  As Redback puts it, “we take it personally”.

Battery Warranty

The batteries are warranted for 36 months as well.  But Redback states that Lithium-Ion batteries are considered “consumables” and as such have a limited lifetime warranty. After 500 discharge cycles, expect the batteries to hold only 80% of a full charge. It’s not defective, it’s just wearing out and will need to be replaced eventually.

The batteries are geared toward homeowners and not towards the commercial user, so someone who only has one battery and charges/discharges it every day, multiple times a day might wear out the batteries in just a year.

Redback prides itself on customer service though, so they encourage anyone with concerns to contact the customer service department for help.

To reach Redbacks customer service:
Toll Free: 877-487-8275 (Press “2” at the message to skip straight through to Customer Service)
Real people are available 7AM-5PM Mountain Time Monday – Friday
Email support is also available at [email protected] – that email goes to the entire Customer Service team.


This is one of the best string trimmers I’ve tested.  It has plenty of power, is quiet, is a supreme edger, and has longer battery run times than I expected. It’s well-balanced and the cutting head and adjustable length shaft make it easy to get into tight spots and areas that I couldn’t have reached with a fixed length shaft string trimmer. The shoulder belt makes a big difference it minimizing body fatigue and the universal battery box that accepts all of Redback’s 40 V Ah batteries is another plus.

Where to Buy It

Available on Amazon (Prime) for around $139.99.

Extra batteries are also available from Amazon (Prime).  Prices range from $69.99 for a 2Ah to $109.99 for a 4Ah.

Last update on 2023-03-27 / Affiliate links / Images from Amazon Product Advertising API

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Disclaimer – GPReview would like to thank the manufacturer/distributor for giving us a free sample to review. There was no expectation that it would be a positive review and we received no compensation for writing it. All opinions expressed here are those of the author based on personal experience using the product.

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2 Comments on Redback 40V Lithium Ion Cordless String Trimmer/Edger (106065): Product Review

  1. George Wolfe

    After reading the reviews on I am concerned about parts availability and service. Apparently there is no contact info on the Manufacture/Distributor either.

    • Jack Hemingway

      Hi George,
      We have found that Redback is a very proactive company. I’m sure they can help you out.
      Here’s their customer service number (877) 487-8275. Let us know how you make out.
      Thanks for following the Gardening Products Review.

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