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Repair guides and support for weed whackers, also known as string trimmers, weed eaters, edge trimmers or line trimmers.

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Why does my 18 volt brushless trimmer shut down after 10 min run time

ryobi p2009 trimmer 18v shuts down after 10 minutes with full charge..Is there a heat switch that goes bad or what ?

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Same problem, observed on first use after purchase. With speed set to low, stalling begins after about 10 to 15 minutes. The 4Ah battery still has three bars. The string head metal housing is warm to the touch. Letting it cool for at 30 seconds allows the trimmer to restart, but then it stalls repeatedly


Mine does the same I kept charging my batteries but batteries are good cause I use them on my drills saws radio and they all work just fine so I know it's not batteries mine only works for about 2-3 min and stops I take the battery off and right away put it back in and seems to work for a little bit a few seconds if I let go of the trigger before it stops it seems to work a little longer but not much n then have to wait a couple of minutes to use it again it sucks I strongly suggest not to buy one don't have issues with my other tools except this one it blows


why is this happening because that is exactly what mine does I have new batteries and it cannot be overheated because it only runs for about 2-3 minutes I will run forever when not cutting grass but when I hit the grass is when it stops ??????


I have a Makita grass trimmer, does the same, except mine cuts off after 30/40 seconds, drives me nuts. Surely one could bypass the this overheat cutoff, does anyone know how. ???


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Mine does the same thing it’s the motor overheating there is a temperature sensor that you will need to by pass to avoid this issue

Update (09/02/2019)

Here's the fix guys :

The motor driver power supply inside is overheating and will shut down until it cools to a lower temperature. I installed a small computer fan inside (1.5" square) and directed the air flow over the motor driver heat-sink and eliminated the shutting down problem. Now I can run continuous, I can swap batteries all day and it does not stop.

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This is exactly what I was thinking about doing. It's a good unit and I was hoping to avoid moving to another platform... But, warranty would be void as well. Do you have pictures or further information on your fix before I decide whether or not to crack it open mate?


I have the same problem, can you send me pics, how you wired and mounted the fan


I have the same problem, can you please send me pics, how you wired and mounted the fan. Thanks


I have the same issue anymore ideas

Does adding the fan work? If so how to attach it?


I am having the same problem. I just opened mine and the motor driver sits above the motor with about 1/2" open space between them. The motor has a single sided plastic radial fan similar to this attached to it. The fan is oriented to cool the motor, with the backplate between the motor and the driver heatsink . If could mount a double sided fan, looks like it would cool both the motor and the driver without having to add an electric fan. Don't know why Ryobi didn't do this.


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After reading this post - I decided to add two 24volt DC fans.

My goal was to do limited alterations to device, so I may return this after the mowing season for repair. Its brand new and overheated within one hour of use! The unit has a ton of power comparable to my gas Husqvarna.

Here are some pics of my solution.

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I cant really give you a detailed parts list as I used items I had in my shop.

  • Grey plastic tray out of a “Husky” tool box from Home Depot
  • Micro Rocker (SPST) switch
  • 24 Volt Fans (used 24volt vs. 12 so they could handle the 18 volts w/out adding resistors)
  • Misc screws
  • Wire ties
  • Foam rubber door gasket material (placed on inside edge of plastic container to make more airtight)

I soldered the wires to the (- +) tabs (internally) that come in contact with the 18 volt battery. Then ran the wires out of a vent slot. Used two wire ties to go through vents to secure to the tool with out need to screw into tool. Tool has not overheated since . An alternative to using the rocker switch is to add a Micro Limit Switch Long Hinge inside to start fan when the safety lever is depressed on Ryobi (there is room for a small switch)

BTW I see they have discontinued the unit Homedepot String trimmer

Good luck!

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Having had the same problem with my RYOBI P2009 from new I found like others that it was the 'Electronic Controller' part number 311291005 at fault. It has small heat-sink fins either side for cooling. This is mounted directly behind the motor and the design of the plastic handle in this area seems to not allow sufficient airflow for cooling.

To overcome this lack of airflow I just opened up some of the plastic cooling slots that are adjacent to the heat-sink fins. On one side I just left the 1/8 drill holes and on the other side I removed most of the material between the holes. This allows more ambient airflow as you are using the unit to dissipate the heat better. I did this with battery drill and 1/8" drill bit. You need to dismantle the handle, so you do not damage any wiring/components whilst drilling/opening up the cooling slots.

Of course, this would void your warranty as you are modifying the unit. I don't know why RYOBI didn't build it like this in the first place or at least put a second fan on motor to cool the Electronic Controller.

Hope this helps.

See photos below.

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Maybe is the battery out of life....

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john Cox will be eternally grateful.
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