buickanddeere
Super Member
Higher voltage is important. It reduces the current to obtain the same amount of power . Wire/cable/conductor sizes are reduced .
Tractor News Viable Electric Tractor?
- Thread starter Annihilator26
- Start date
chim
Elite Member
I'm not into battery-powered stuff except my DeWalt 20V tools, so bear with me. With the info given on the Greenworks site (and a brief stay at a Holiday Inn Express) it would appear to me that the 82V battery would need an output of around 55A just to run the blades at full load for the 4 hours run time. That's 4.5 kWh each of the 4 hours (based on the three two-horse motors for the blades). I didn't see anything regarding locomotion, so maybe you need to pull it with a diesel tractor. Without more info, my guess is the battery would need to be an 82V, 18 kWh, aka 82V, 220AH to provide power for the blades alone.
The whole thing looks kinda hokey. The deck is described as both 52" and 60", depending upon where you look. Of course it does state that it is an electric start
The whole thing looks kinda hokey. The deck is described as both 52" and 60", depending upon where you look. Of course it does state that it is an electric start
RalphVa
Super Member
- Joined
- Dec 19, 2003
- Messages
- 7,873
- Location
- Charlottesville, VA, USA
- Tractor
- JD 2025R, previously Gravely 5650 & JD 4010 & JD 1025R
I'd like to have one. Started a thread like this about a year ago. Didn't have any info on any available at that time.
Think the overall efficiency, even in a fossil fuel one, is slightly higher than what a diesel tractor runs: fossil fuel with poor heat recovery is 33%. Put in a gas turbine and generate electricity both off the shaft and from heat recovery in the exhaust, and it doubles. Add in nuclear and water power, and you bright the efficiencies up and costs down even more. Now, there's solar and wind power from outside. Solar power wouldn't work well for your own location because you'd need the tractor during sunshine periods, and there's no solar at night. Typically, wind dies down at night, too.
Can't beat the reduced noise and elimination of diesel particulates without a DPF. The 3 to 6 hours running time is great, and recharging overnight is good.
Got to look at the overall energy cycle of making the tractor and the battery and its efficiency vs. overall cost of making a diesel tractor and its efficiency.
It's the future.
Ralph
Think the overall efficiency, even in a fossil fuel one, is slightly higher than what a diesel tractor runs: fossil fuel with poor heat recovery is 33%. Put in a gas turbine and generate electricity both off the shaft and from heat recovery in the exhaust, and it doubles. Add in nuclear and water power, and you bright the efficiencies up and costs down even more. Now, there's solar and wind power from outside. Solar power wouldn't work well for your own location because you'd need the tractor during sunshine periods, and there's no solar at night. Typically, wind dies down at night, too.
Can't beat the reduced noise and elimination of diesel particulates without a DPF. The 3 to 6 hours running time is great, and recharging overnight is good.
Got to look at the overall energy cycle of making the tractor and the battery and its efficiency vs. overall cost of making a diesel tractor and its efficiency.
It's the future.
Ralph
Grumpycat
Elite Member
I'm not into battery-powered stuff except my DeWalt 20V tools, so bear with me. With the info given on the Greenworks site (and a brief stay at a Holiday Inn Express) it would appear to me that the 82V battery would need an output of around 55A just to run the blades at full load for the 4 hours run time. That's 4.5 kWh each of the 4 hours (based on the three two-horse motors for the blades). I didn't see anything regarding locomotion, so maybe you need to pull it with a diesel tractor. Without more info, my guess is the battery would need to be an 82V, 18 kWh, aka 82V, 220AH to provide power for the blades alone.
The whole thing looks kinda hokey. The deck is described as both 52" and 60", depending upon where you look. Of course it does state that it is an electric start
If memory serves correctly Greenworks stated 20 kWh-ish battery at the show.
Your power estimate for the blades assumes worst case full power tallest grass all the time.
Mowers come with different sized decks. I don't fully understand why one would prefer a 52" deck to a 60" but am told many believe they get a better quality of cut from 52" and cite something about how far apart the drive wheels and overlap when cutting.
chim
Elite Member
I used that scenario because it seemed most fitting for their claims of speed. That's a lot of grass being cut and pumped out. If the grass is trimmed frequently, less power could be used. But then mowing twice as often would likely use more power overall.
Jim Nelson
Platinum Member
I found the paper work from the utility system when it was installed in 2014. It says "This letter is formal notification that the 3.375 KW Solar Electric Generating facility tied to meter XXXXXX" etc has met all the requirements to interconnect and operate in parallel with S.D.G.&E's electric system.
I'm a low tech redneck and did mis-state the KWH in my original post but this is what I have. The $16,000 price was after all rebates and installation.Things must be a lot cheaper where you live. We got several quotes on our system and the one we bought was near the middle of the group.
I'm sorry this doesn't fit in with your argument but it is my experience.
Grumpycat
Elite Member
My observation is that installed price has a 100% markup over component costs. You can see good prices for components at Wholesale Solar - DIY Solar, Panels & Complete Systems or Buy Solar Panels, Solar Power Kits, DIY Solar Panel Kits for Sale.
To grid tie under local utility's rules requires a blessed installer. The few don't care to compete so I had 2 quotes for 10 kW which were suspiciously $34k and $35k for $15k of parts I could buy myself but not allowed to install. This coming year I'm building elsewhere. TVA no longer pays more than 1½¢/kWh for grid tie PV so there is no benefit to kissing their... you know. Battery storage will add another $30k but I'll be very close to totally self-sufficient.
Am amazed that 3.4 kW can cover most of your usage. Air conditioning set at 78°F here often runs 1500 kWh/month.
Jim Nelson
Platinum Member
I learned real early in shopping that it is a racket and unless you can diy you're out of luck. I can't due to health and lack of knowledge. We had over $8000 difference in quotes and when our house was built it was designed with solar in the future so the conduit was in place, the main panel was correct, the grounding system was correct, it was just a matter of installing the panels and running wires. We had one guy try to sell us a new service panel and grounding system for $12000 because ours was out of date.
We are pretty careful about our power usage so we're not average, whatever that is, but our system was sized using our billing records for the previous 5 years. For our general area the weather is moderate so our needs are less than in some nearby areas.
Our net metering is like giving any power not used away, we pay $.36 per kWh and they pay us about $.05 for what we sell back to them. Now they need another rate increase .I hope someone comes up with an affordable battery system soon but I don't think I will live to see it.
We are pretty careful about our power usage so we're not average, whatever that is, but our system was sized using our billing records for the previous 5 years. For our general area the weather is moderate so our needs are less than in some nearby areas.
Our net metering is like giving any power not used away, we pay $.36 per kWh and they pay us about $.05 for what we sell back to them. Now they need another rate increase .I hope someone comes up with an affordable battery system soon but I don't think I will live to see it.
Grumpycat
Elite Member
Wow! $0.36/kwh!
A 13 kwh Tesla Powerwall is about $7200, or $10,000 for the first one, installed. They have to put a Tesla Energy Gateway between meter and distribution panel for the Powerwall to know when to charge and when to discharge. And to brute force take you offline during an outage. Sounds like you are a good prospect. There might be a 26% Federal tax credit on that, but might not apply when expanding existing system.
The neet thing about a Powerwall is that it can fake your grid-tie solar into staying online during an outage.
buickanddeere
Super Member
I'm not into battery-powered stuff except my DeWalt 20V tools, so bear with me. With the info given on the Greenworks site (and a brief stay at a Holiday Inn Express) it would appear to me that the 82V battery would need an output of around 55A just to run the blades at full load for the 4 hours run time. That's 4.5 kWh each of the 4 hours (based on the three two-horse motors for the blades). I didn't see anything regarding locomotion, so maybe you need to pull it with a diesel tractor. Without more info, my guess is the battery would need to be an 82V, 18 kWh, aka 82V, 220AH to provide power for the blades alone.
The whole thing looks kinda hokey. The deck is described as both 52" and 60", depending upon where you look. Of course it does state that it is an electric start
Assuming 100% efficiency in battery charge ,battery discharge , the controllers and the motors . If lead acid batteries, do not dis-charge them below 50%.
Better reduce the run time to under 2.0 hrs . And subtract from that the power used by the traction motors . 1.5 hours of mowing time . That is it .