Solar Powered Weed Wacker

[Astro_Guy]

I believe that I can say with high confidence that I now have the first solar powered weed wacker on the block. It's of the EGO brand featuring a 56 volt 2.5 amp-hour battery. As of last weekend it is being charged using a 90 watt solar panel that charges a 1 KWH LiFePO4 battery via a pure sinewave inverter. The charger is supposed to consume 210 watts. I noted a peak draw of 18 amps off the battery or 240 watts when charging after cleaning up the lawn.

Just to be clear, this outcome was never the intent of the solar installation. My Stihl weed wacker gave up the ghost and I thought of trying a battery powered option. The garden shed where all of my OPE is stored has this off-grid solar setup with excess capacity. I doubt that I've used more than 1/2 gallon of gas in the weed wacker per year in the past, but it will be zero gallons going forward.

 

[AandPDan]

Great idea! What are you using for a solar panel?

 

[skyactiv]

I go back and forth on making my whole home solar with battery backup. I can afford it, but the initial expense coupled with managing the system makes it a no for now. It's easier to pay the bill monthly.

 

[spasm3]

View attachment 172902

I believe that I can say with high confidence that I now have the first solar powered weed wacker on the block. It's of the EGO brand featuring a 56 volt 2.5 amp-hour battery. As of last weekend it is being charged using a 90 watt solar panel that charges a 1 KWH LiFePO4 battery via a pure sinewave inverter. The charger is supposed to consume 210 watts. I noted a peak draw of 18 amps off the battery or 240 watts when charging after cleaning up the lawn.

Just to be clear, this outcome was never the intent of the solar installation. My Stihl weed wacker gave up the ghost and I thought of trying a battery powered option. The garden shed where all of my OPE is stored has this off-grid solar setup with excess capacity. I doubt that I've used more than 1/2 gallon of gas in the weed wacker per year in the past, but it will be zero gallons going forward.View attachment 172918

Very cool! I'm starting a solar project to keep my deep cycle camper battery charged.

I'm trying to figure out your schematic, of how you connected the inverter, the battery and the charge controller.

What post and how did you mount your panel to the post ?

 

[walterjay]

I use a solar trickle charger for my tractor in the winter. That is as far as I am going with solar.

 

[Rand]

I go back and forth on making my whole home solar with battery backup. I can afford it, but the initial expense coupled with managing the system makes it a no for now. It's easier to pay the bill monthly.

With ohio climate and without a sweetheart pawn your electric bill on your neighbor NEM contract.. doesnt make sense.. likely wont for sometime/ever.

 

[Astro_Guy]

Very cool! I'm starting a solar project to keep my deep cycle camper battery charged.

What post and how did you mount your panel to the post ?

The panel is a 90 watt polycrystaline, being not the most efficient. I believe it is this: https://www.solar-electric.com/solarland-slp090-24c1d2-90-watt-24-volt-solar-panel.html

I believe that the panel mount is https://www.solar-electric.com/uni-sp-01a.html . It's mounted atop a 4-inch Schedule 40 PVC pipe with a big poured concrete anchor. 10/2 UG-B wire to the charge contoller, burried in 3/4 inch PVC conduit,

These little off-grid projects are easy for anyone with a modicum of skills.

 

[Astro_Guy]

With ohio climate and without a sweetheart pawn your electric bill on your neighbor NEM contract.. doesnt make sense.. likely wont for sometime/ever.

Apparently you are not factoring in the cost of getting AC power to my shed that is pushing 200 feet of home run from my breaker panel. Trust me, I've more than breaken even already on this.

 

[spasm3]

The panel is a 90 watt polycrystaline, being not the most efficient. I believe it is this: https://www.solar-electric.com/solarland-slp090-24c1d2-90-watt-24-volt-solar-panel.html

I believe that the panel mount is https://www.solar-electric.com/uni-sp-01a.html . It's mounted atop a 4-inch Schedule 40 PVC pipe with a big poured concrete anchor. 10/2 UG-B wire to the charge contoller, burried in 3/4 inch PVC conduit,

These little off-grid projects are easy for anyone with a modicum of skills.

I have a 100watt monocrystalline panel, so similar to yours.

Did you split the solar input to the inverter, before the charge controller?

I'm trying to sort out what wires i see in your pic.

 

[Astro_Guy]

I use a solar trickle charger for my tractor in the winter. That is as far as I am going with solar.

My folks did this for years with a 20 watt panel.

 

[Torrid]

Ok that's cool!

 

[Astro_Guy]

I go back and forth on making my whole home solar with battery backup. I can afford it, but the initial expense coupled with managing the system makes it a no for now. It's easier to pay the bill monthly.

I hear you there! Attended a cul-de-sac party last night where we were the only ones not having a Generac 22 KV natural gas fired genetator. None of them had a clue what it would cost to run for an extended outage, but they all enjoed bragging about how they had power again in tewnty seconds. Line power came back in 90 seconds on the last interruption. Their generators completed a minimum runtime seesion before I coul pull out my portable generator. I didn't have time to start my portable.

 

[supton]

I hear you there! Attended a cul-de-sac party last night where we were the only ones not having a Generac 22 KV natural gas fired genetator. None of them had a clue what it would cost to run for an extended outage, but they all enjoed bragging about how they had power again in tewnty seconds. Line power came back in 90 seconds on the last interruption. Their generators completed a minimum runtime seesion before I coul pull out my portable generator. I didn't have time to start my portable.

This past winter I did ok with just a 2500W invertor. Couldn't run the well pump but it was just barely enough to run the furnace. Bit of an impulse buy, after one outage that lasted a day--but paid for itself when I had an outage last 3 or so days.

I didn't realize how internet addicted I had gotten, that first power outage had me all but crying for my ability to surf BITOG after the first hour of no internet... finding the invertor on sale was a godsend.

 

[wrcsixeight]

Thats a neat system.
Well done.

I like to avoid using an inverter, when possible.

My 18v Ridgid charger came with an '18v, 60 watt' wall wart.

In reality, open circuit, it is 21.41vDC, and maxes out at 2.02 amps.

So about 43 watts.

I have dc to dc adjustable voltage converters, and use my 150 watt voltage booster to feed the ridgid charge cradle as high as 21.39v, from my 12v dc battery systems in which solar is one of several charging options.

The ridgid cradle has a 10 amp fuse on circuit board.
Now it is blown, and bypassed with a atc fuse holder.

My '150 watt booster' connected in between 12vdc lead acid batteries and ridgid charge cradle, briefly hit 270 watts into depleted 4.0 ridgid battery before that internal fuse blew.

This specific booster i used has no current limiting, only voltage, and setting voltage to 20.5 and hooking it up to depleted baTtery, too many amps flew.

So now i generaLly start it ,75 to 1 volt above battery voltage and dial up voltage in stages to keep about 2 to 3 amps flowing as it charges, but i can charge much faster if needed/desired. And do have a CC/ CV booster i need to wire up so I wont have to babysit voltage.

The Ridgid cradle might even accept juice directly from my sunpower 100 watt portable flex panel whose OCV is somewhere in the 21vdc range.

I've not tried it though.

My lawn tools are makita, but i have ridgid to makita battery adapters.
Should the SHTF, and grid collapses, I could still mow the lawn.

 

[Astro_Guy]

Did you split the solar input to the inverter, before the charge controller?

No. The PV array feeds the MPPT controller which is connected to the battery. The inverter is also connected to the battery. See https://www.mobile-solarpower.com/the-classic-400-watt-rvs-vans-buses.html for the design inspiration.

 

[spasm3]

No. The PV array feeds the MPPT controller which is connected to the battery. The inverter is also connected to the battery. See https://www.mobile-solarpower.com/the-classic-400-watt-rvs-vans-buses.html for the design inspiration.

Thanks!!

 

[BMWTurboDzl]

I go back and forth on making my whole home solar with battery backup. I can afford it, but the initial expense coupled with managing the system makes it a no for now. It's easier to pay the bill monthly.

It's very difficult in northern latitudes. Wood heat and a large bank of lead acid batteries are a must.

 

[Opelman]

That is really neat. I was expecting a picture of a goat.

 

[Rand]

Apparently you are not factoring in the cost of getting AC power to my shed that is pushing 200 feet of home run from my breaker panel. Trust me, I've more than breaken even already on this.

Not to be snarky but apparently you missed I replied to the other guy who was talking about putting in a whole home system.

I really like your setup. I have a shed 120ft from my back deck I want power to. Might end up with some direct burial wiring and using a couple shovels to split the ground and put it 6" down.

I considered solar panel but I want more than just lights and could use powerline networking for a WAP out there too.

 

[Astro_Guy]

Not to be snarky but apparently you missed I replied to the other guy who was talking about putting in a whole home system.

I really like your setup. I have a shed 120ft from my back deck I want power to. Might end up with some direct burial wiring and using a couple shovels to split the ground and put it 6" down.

I considered solar panel but I want more than just lights and could use powerline networking for a WAP out there too.

A couple of things you should think about...

First, electrical codes call for direct burial at a depth of 24 inches or 18 inches in PVC conduit. This is intended to prevent the next homeowner from electrocuting themselves when digging with a metal handled shovel.

Second, there would be a 10% voltage drop over 120 feet using 14 AWG copper wire. Limiting that drop to 5% would require 10 AWG wire. Further limiting it to 3% as generally recommended would bump that up to 8 AWG wire. It all depends upn what you want to power and what voltage it can tollerate. Copper wire has gotten very expensive.