Blown fuse on ego 21” self propelled mower

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Hi. My mower suddenly stopped working. There is no power. The LED light wont even go on. The battery is fully charged. I opened the top cover and found this fuse that I believe is blown. Does anyone know where i can buy a replacement? Thank you in advance for your help.
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Ngoc Tran

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Posted 5 months ago

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William E Hanson

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Go to RCPW.com for EGO parts.
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Bryan

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When you do replace the fuse, please report back. I'd be curious if the power went out because the fuse was blown or if you had a bigger problem that caused the fuse to blow in the first place. Thanks!
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Ngoc Tran

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Bryan, i temporarily bypass the fuse and was able to start up the mower. Thus, I think the fuse is the culprit.
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Bryan

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I just saw this comment. Thanks for the reply!
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Oregon Mike, Champion

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Hi Ngoc. Wondering if you ever replaced the fuse and if that was indeed the problem.
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Ngoc Tran

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Yes, i replaced the fuse and the mower worked. However ,if the grass is too thick the new fuse would burn. I am not sure if this is because the replacement fuse is a “fast blowing” fuse or there is another underlying issue that i have not found. I hope this helps.
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Oregon Mike, Champion

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I'm thinking the fuse shouldn't blow just due to thick grass. The mower has speed control as well as overload control built in that should take care of the thick grass. If a fuse is blowing I think something in one of those circuits is malfunctioning.
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vince tyler

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how did you bypass the fuse and what gauge wire did you use?
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summetj

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I wouldn't recommend bypassing the fuse, because if it blew to protect the rest of the system from a short circuit, bypassing it will cause something to melt. Either the bypass wire (if it's small enough) or the wire/motor somewhere else in the system, or a cell in the battery (which would be the most.....exciting....thing to go wrong).

You can instead measure the resistance through the fuse with a multimeter. If it's blown, it will show infinite ohms of resistance / no connectivity.
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summetj

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Digikey.com has all kinds of fuses, if you can find the writing on the end cap of the fuse that lists it's specifications.   I suspect it is a DC rated fuse (DC rated to at least 60 volts, probably more) with some amp rating on it you can probably buy a generic one (just make sure it's DC rated, not just AC rated....many AC rated fuses have a much lower DC rating (e.g. some 120 volt AC fuses are rated to only 32 volts DC....))
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Ngoc Tran

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Summetj, thank you for the information. The reading on the fuse is 40A 250v. Do you know what is the function of the little circuit board that the fuse is attached to? Can i just get rid of that and just replace with a fuse? The reason i ask is because i dont think i have the tools or experience to remove and re-solder the fuse to the circuit board. Thanks again.
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summetj

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This brand name (Littelfuse) fuse on Digikey is rated at 150V DC (250 AC) and 40A but costs $4.50:
https://www.digikey.com/product-detail/en/littelfuse-inc/0314040.MXP/F6785-ND/2518690

Note that this is a "fast blow" fuse, which is typically used when protecting electronics. It is possible the fuse in the lawnmower is a "slow blow" fuse (without a specific model number we can't tell for sure) but usually a fast blow fuse is used to protect electronics.  

Replacing a fast blow fuse with a slow blow fuse can reduce or eliminate the protection provided by the fuse. But, replacing a slow blow with a fast blow fuse is safe (although the fuse may blow at transient spikes...)


You might be able to find a cheaper option at a local hardware store. I know you can buy "generic" versions on Ebay for a lot less:

https://www.ebay.com/itm/5-Qty-ABC-40A-Fast-Blow-Ceramic-Fuse-40-Amp-250v-ABC40A-ABC40/131037111264?...


The ceramic casing may be necessary to contain DC arcing if the fuse blows. (A cheaper glass body fuse may work, but also may not quench the DC arc as well as a ceramic fuse....)

From your photo is LOOKS like the circuit board is simply used to mount the fuse and provide strain relief for the fuse, so you should be able to  replace the circuit board with an appropriately sized in-line fuse holder, but you should double check to make sure there are no other components on the back/bottom of the circuit board that I can't see in the photo.



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Michael G

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If that fuse is indeed non-removable you can go to an auto supply store (or Digikey as summetj referenced) and purchase a fuse holder. They usually have a length of wire on them.
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summetj

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Be careful with auto store fuse holders....pay extra for a good quality one with a large enough wire to carry the 40 amps. I've had cheap auto fuse holders melt under high loads....