New Grass Trimmer Goes Lithium Ion Power! - RC-Monster Forums

sikeston34m · **New Grass Trimmer Goes Lithium Ion Power! -** 04.22.2010, 11:33 PM

Troy Bilt just came out with a new electric trimmer.

http://www.lowes.com/pd_110523-65481-TB57_4294857347_4294937087?productId=3006629&pl=1&currentURL=/pl_String%2BTrimmers_4294857347_4294937087_?rpp=15 $No=15

Of course, I had to run down and get one.

It's pretty powerful and easy to use. It's not as powerful as a gas trimmer, but starts much easier than one of them.

The charger seems pretty smart with Red and Green leds indicating charging or not. Charge time is a bit slow IMO. At 4.5 hours of charge time, I believe it to be charging at around 1.3 amps.

I haven't taken apart the head unit yet, but it appears to be a really powerful brushed motor. It spins the head at 8000 rpms and does cut through pretty thick stuff with ease.

The trigger is variable speed, but does have an overly stiff return spring.

The Lithium Ion Pack is what interested me the most. Advertised at 20 volts and 6000mah, it does pack some electrons.

Of course, I had to take the pack apart.

As I finally got out the last screw, I was expecting to find a number of 18650 cells inside. Or perhaps some soft Lipo cells.

Much to my surprise, I found neither!

Housed inside the tough plastic casing is 5 of the largest Lithium Ion Prismatic cells I've ever seen.

They are arranged in a 5S pattern with a Battery Management Circuit.

There is also an "in the pack" battery fuel gauge. 4 Led's tell 25%, 50%, 75%, and 100% Charge.

The Management circuit is connected to each cell via what looks like a balancing lead. This leads me to believe it does perform the balance function.

I did run it completely down to check for a LVC. The LVC is present and hard cuts at 3.2 volts per cell.

The charger charges to a conservative level of 20.60 volts.

While I had the pack apart, I couldn't resist the opportunity to solder in a quick charge lead.

This will allow me to quick charge with my Superbrain in about an hour.

What's_nitro? · 04.22.2010, 11:45 PM

Awesome. It's about time we had some decent cordless yard tools! Though, I'm still going to build my own personal lineup. :) Got any pics of the guts?

bruce750i · 04.23.2010, 09:48 AM

Sounds cool thanks for the info.

TexasSP · 04.23.2010, 10:54 AM

There are some others too, worx has had theirs out for a while. Plus you can get it with a rapid 30 minute charger.

http://www.worxyardtools.com/lithium...mer-edger.html

lincpimp · 04.23.2010, 11:24 AM

Pics? You are letting us down James, I want to see those cells! Wonder what c rating they are? Must be pretty good as load on that unit will not be light.

Semi Pro · 04.24.2010, 01:45 AM

Quote:

Originally Posted by lincpimp

Pics? You are letting us down James, I want to see those cells! Wonder what c rating they are? Must be pretty good as load on that unit will not be light.

agreed, i want pic of the pack damn it

bruce750i · 04.23.2010, 11:46 AM

I just checked one out here. I got a salesboy over real quick after squezing off some amps in the store. Hehe (it even had string in it and it sounded impressive)

sikeston34m · 04.24.2010, 03:46 AM

Quote:

Originally Posted by bruce750i

I just checked one out here. I got a salesboy over real quick after squezing off some amps in the store. Hehe (it even had string in it and it sounded impressive)

The very same thing happened to me!

The dude came over and asked me where I had it plugged up!

I told the dumbasss it had a battery pack!

LOL

Bondonutz · 04.24.2010, 01:24 PM

This is interesting to read as I'm in the market for a new weed whacker myself.
A buck and a half is not to bad a price if it's actually powerful, I have a small yard so a charge should get me through easily ?
Let us know what kind of run time it gets !
All that work opening it up and No pics of the cells ?

sikeston34m · 04.24.2010, 09:23 PM

Quote:

Originally Posted by Bondonutz

This is interesting to read as I'm in the market for a new weed whacker myself.
A buck and a half is not to bad a price if it's actually powerful, I have a small yard so a charge should get me through easily ?
Let us know what kind of run time it gets !
All that work opening it up and No pics of the cells ?

I've cycled it twice so far, neither time was completely charged either.

Each time, runtime was over an hour, cutting some fair sized stuff too.

BrianG · 04.24.2010, 02:14 PM

Bondo, like you, I too have a small yard and tried an electric weedeater (this one to be exact) and have been pleased with it so far, and I have it going on two years. It's not Li-Ion, and therefore a bit on the heavy side for some (a little modding could put a 4s lipo in there

), but I have more than enough runtime to do the trimming and edging for my yard and then some. It doesn't cut though really thick weeds like a gas one would (so if you are clearing a field, it won't "cut" it

), but perfect for basic trimming and edging uses.

lincpimp · 04.24.2010, 02:34 PM

I have a 4 stroke weed wacker. Great, would recommend it to anyone. Only things 2 stroke I have left is my husquavarna 575xp chainsaw (6+ hp, yeah!) and a craftsman edger from the 70s. Make no mistake that edger is great, only 2 stroke I have enver seen that starts 1st pull EVERY time. My neighbor threw it away and I asked if I could have it. Replaced the reduction gear drive and put a new blade on it, works like a champ. All I need now is a backpack blower, the old electric unit is a bit cumbersome with the new house...

I still want to make the rc weedeater, just finished redesigning the floating deck in my mind, need to get it on paper and see if I can get a build going...

zeropointbug · 04.24.2010, 02:54 PM

IMO, I wouldn't but that weed wacker, the LiOn battery they use is most likely crap, and will only last a few years. I say modify your own gas one with some Headway LiFe or A123 cells, that would be a skookum unit.

sikeston34m · 04.24.2010, 08:41 PM

Quote:

Originally Posted by zeropointbug

IMO, I wouldn't but that weed wacker, the LiOn battery they use is most likely crap, and will only last a few years. I say modify your own gas one with some Headway LiFe or A123 cells, that would be a skookum unit.

If I get 2 years of service from this pack, I'll be happy with it.

Then I'll modify it to have even more capacity.

The Battery Management circuit interests me because it operates with the Lithium Ion.

A protective circuit this size opens the door for use with other things as well. Without having to worry about discharging the cells too far.

sikeston34m · 04.24.2010, 08:45 PM

Sorry for not taking pictures guys.

The case uses torx screws. I was able to get them out with an allen wrench, but it was a pain.

I'll pick up some torx drivers soon and take pictures.

I also want to do a few other things when I have the pack apart again.

1. Install a 5S Balance lead that goes outside the pack so I can keep an eye on individual cell status.

2. Install a couple of power plugs so I can run a power analyzer on the setup. This will enable me to know the average amp draw, the peak amp draw, etc. Works kinda like an Eagletree. Hmmmm........I could even run an eagle tree on it, then we'll know how the cells carry the load.

Even if these are "only" 10C cells, that's still 1200 watts of power.

Not too shabby IMO.