DIY electric cordless grass trimmer

Hi to all !

Am planning to build one RC grass trimmer. I took the part for RC from kids car and redesign it for my purposes.

Unfortunately the biggest problem is that i can not find some 500W or stronger DC motor for a trimmer ( at least 6000 RPM's ).

GOAL:

- to power up the grass cutting motor with 36V battery pack that will be located on some kind of metal carrier.

- to power the gear motor from the same battery pack.

- to power DC / DC converter from the same pack :-)

There is one other way. I can make the version with cord and power the trimmer from some stationary battery pack ( i got cca 1500m2 to lawn ).

Where can i find some used 500W DC high speed trimmer motor ?

GM

Reply to
gm
Loading thread data ...

Black and Decker Li-Ion strimmer (which is a 36V drive)? Not sure of the RPM but it should be fast enough. I have one of these and the motor is pretty powerful (feels like a mains strimmer, at least for the 20-30 mins the battery runs for).

Might seem extreme buying a strimmer for the motor but you will get a battery carrier, battery, charger and motor speed control circuit to cannibalise too.

Reply to
Tim Watts

Take the vacuum hardware out of a Roomba. Add the RC car's wheels. Put the engine from a gas-powered trimmer on top, the business end underneath, and the wand in your junk pile.

Put it on your lawn, start it, and walk away. Retrieve when it runs out of gas or refill as needed.

Call it a Lawnba.

Mark L. Fergerson

Reply to
Alien8752

--------------------------------------- Your idea is nice but to complicated :-)

I found one other solution :-) I can not stop laughing but the idea is great !

Look at this:

formatting link

I can add one 12/220 1KW converter and that would do the trick. This would be really strong and effective.

The only negative part is the power consumption and the fact that i can not turn it on / off all the time. Hmm, am wondering how long would this run if i connect it to some 12/

110Ah car battery and on the other side this ON / OFF situation can harm the motor....

GM

Reply to
gm

Den tirsdag den 7. juli 2015 kl. 16.56.15 UTC+2 skrev gm:

formatting link

formatting link

?

500W sound like a lot, I think the regular robot mowers are ~100W including everything

-Lasse

Reply to
Lasse Langwadt Christensen

no safety features at all, good thing he remembered to wear his Chinese safety shoes ;)

-Lasse

Reply to
Lasse Langwadt Christensen

------------------ i made one test with electric grinder. Damn that was strong. I used 800W - 11000 rpm grinder and i must say, this is a monster :-) This should be used for plowing and not for grass cutting :-)

I connected grass trimmer - grinder to 12V-1,5kw inverter and directly to 12V / 85Ah car battery. I dont know how long ( in reality ) would this accu hold but i guess that with some lower wattage ( let's say 500W grinder) i should be enough for cca 2 hours ? Maybe less because of inverter lost... What do you think ?

Reply to
gm

my electric strimmer (Stihl FE-55) has an 860W motor.

label watts don't determine the power draw of the motor much, mechanical load is a much bigger factor. get out your clamp meter and measure amps on the battery lead.

--
umop apisdn
Reply to
Jasen Betts

In a used electric lawnmower. 500W is over 1/2 horsepower.

Reply to
whit3rd

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.