Replacing the R40Li / 1200R / Automower Battery (Pictures and Steps)

As regular readers will know, our trusty Gardena R40Li has just entered service in its fifth season!

Also known variously as the Flymo 1200R, or Husqvarna Automower, this model was one of the first automatic robotic lawn mowers on the market, and still stacks up reasonably well against the competition.

However, after 2649 hours (see right), the battery had started to fail. The symptoms were fairly obvious:

• Frequently returning to the base after only a few minutes;
• Stopping cutting on manual, when battery showing half full.

In fact, some of the symptoms started towards the end of last season, but a couple of refreshes seemed to (temporarily) help. For this season, though, I decided to bite the bullet and replace the battery.

Over the intervening years, the poor mower has become a bit encrusted with old grass.

This is my own fault, as detailed in my rubber damper pictures and repairs article: I don't take as much care over cleaning as I should.

Luckily the battery compartment cover is easy to find; it sits between the rear wheel (bottom) and spinning plate that holds the three blades (top).

After a bit of scraping to reveal the screws (right), it becomes obvious why the instructions say to drop the cutting disc as low as possible.

Even though (as can be seen in the photo), the screw heads are accessible through the holes, once released, the cover needs to be lifted and slid out.

This is much easier to do if you first drop the spinning disc to it's lowest position, or minimum height, if you prefer.

The screws are, again T20 Torx, which ought to be familiar to anyone who has tried dismantling the auto mower already.

Once removed, the compartment cover reveals three things.

Firstly, there's the battery itself, complete with velcro tab to pull it out of it's moulded compartment.

Secondly, there's the USB port on the left, which I had not previously been aware of, but which I'm guessing would theoretically allow you to mod the mower.

A quick visit to the Gardena site reveals that for the Sileno and Sileno+ models at least, there is also a software update available. The download page redirects to Husqvarna and prompts to install an application, check the connected mower and update the firmware.

Something for a future post.

Meanwhile, the third thing to note is that it remains, despite external appearances, incredibly clean inside the battery compartment.


This is a testament to the rubber seals. Seals which, unlike the rubber dampers, stand up to the constant abuse.


On the left hand side of the page, there are the two batteries.

The one at the bottom is the new one, purchased on Amazon (see "r40li battery"). There were several to choose from.

Bang in the middle of the range of prices, was the one that I eventually bought, made by VHBW, apparently, and rated more or less at the same power as the original.

At the top end of the scale, costing over £100 is the a replacement made by Husqvarna; having read some reviews of the VBHW, I decided that it was worth the "risk".

At the lower end is a replacement at around £45, which just felt a little too cheap -- but I should point out I have only gut feeling to go on, and no basis of any other informed opinion!

I'd give it a shot, if I hand't been an early adopter of the robot mower revolution, and spent top whack for my trusty R40Li. If anyone has tried the cheaper batteries, or can convince me that they're not going to damage my 'bot, let me know.


The last step is just to drop the battery into place, wonder for a last time what that USB socket could be for, and screw the lid back on.

Care is needed to plug the battery into place, as the connector is a tight fit, but other than that, the replacement itself is an incredibly easy job.

The mower reported that the battery was about half full, but it returned to base quite quickly. Perhaps it should have been charged first.

However, the subsequent mowing period was substantially longer than with the old battery, which is a good sign. Only time will tell if the new battery performs as well as the original - over 2500 hours of mowing in a 5 year period seems like a pretty hard act to follow!

Previous articles on R40Li maintenance:

• Replacing rubber dampers
• Replacing blades, and guide to blades on Amazon
• Replacing R40Li / 1200R / Automower wheels