auraslip
10 MW
- Joined
- Mar 5, 2010
- Messages
- 3,535
As has been discussed a few times recently there is an interest in converting either a pre-made electric lawn mower to lithium or converting a gas powered mower to electric. I'm trying to figure out how much power the electric mowers will have in comparison to gas mower, but trying to wade through all the manufacturers marketing is really making it hard on this newb. My goal is to replace my current Toro mower with a name plate rating of 6.5 hp (but reported to the EPA as only 3.7hp) with an electric with at LEAST as much power.
First is choosing between two options;
craigslisting a used "1200w" black and decker - Less than $100
strapping this motor made for electric lawn mowersto the deck of a freebie "trash" mower. - $160 for the motor + $20 for the lawn mower chassis
The motor is a Tecumseh 90000A
The upside to this motor is that it directly bolts to most lawn mower decks, and accepts standard blades.
The question here is, "Which is more powerful, the pre-made mowers or the Tecumseh motor?" None of the pre-made mowers have any information about the motors other than vague wattage ratings. On the other hand, the pre-made mowers will be less work and cheaper.
Back to the Tecumseh motor though. Can we calculate torque, current draw, and power from the information given? Realisticly, I'd just want to find out how it'd compare to a gas mower, and how much current it pulls.
Finally, battery choice: I need probably two hours of run time. 6s 5ah lipo packs would be perfectly modular, cheap, and easy to work with. But 6 * 3.8v nominal = 22.8v - slightly under 24v. So I'd have less (or the same) amount of power as with saggy lead acid. Plus because LIPO's discharge curve isn't flat, I'd lose power as I went along. 7s would be nice, but would require combing 3s + 4s packs. Not as simple. 8s would probably have the blade spinning way too fast!
Another options would be 8s of lifepo4. Either 8s2p of 10ah headways or 20ah thundersky cells. All three options are near the same price, but the modularity of the lipo would make it easy to upgrade capacity (also I could use it on my bike later on!) Also there is weight, size, and charge rate issues.
I'm really psyched to try out the power logger for the mower. It's gotta the same features as the cell-log such as lvc and hvc alarms, but also can monitor 4 temp sensors (for the motor!), keep track of wattage and power use, and also check the motor RPM. Only problem is that it's for 6s.... As is the battery medic I plan on using to balance...
So any one have a stock electric lawn mower they can install a watt meter on to check actual power consumption?
Some other conversions:
http://jeanegan.com/2007/06/01/lawn-mower-conversion/
http://www.arttec.net/Solar_Mower/index.html
http://visforvoltage.org/blog/jdh2550_1/2076
First is choosing between two options;
craigslisting a used "1200w" black and decker - Less than $100 strapping this motor made for electric lawn mowersto the deck of a freebie "trash" mower. - $160 for the motor + $20 for the lawn mower chassisThe motor is a Tecumseh 90000A
The upside to this motor is that it directly bolts to most lawn mower decks, and accepts standard blades.
The question here is, "Which is more powerful, the pre-made mowers or the Tecumseh motor?" None of the pre-made mowers have any information about the motors other than vague wattage ratings. On the other hand, the pre-made mowers will be less work and cheaper.
Back to the Tecumseh motor though. Can we calculate torque, current draw, and power from the information given? Realisticly, I'd just want to find out how it'd compare to a gas mower, and how much current it pulls.
Finally, battery choice: I need probably two hours of run time. 6s 5ah lipo packs would be perfectly modular, cheap, and easy to work with. But 6 * 3.8v nominal = 22.8v - slightly under 24v. So I'd have less (or the same) amount of power as with saggy lead acid. Plus because LIPO's discharge curve isn't flat, I'd lose power as I went along. 7s would be nice, but would require combing 3s + 4s packs. Not as simple. 8s would probably have the blade spinning way too fast!
Another options would be 8s of lifepo4. Either 8s2p of 10ah headways or 20ah thundersky cells. All three options are near the same price, but the modularity of the lipo would make it easy to upgrade capacity (also I could use it on my bike later on!) Also there is weight, size, and charge rate issues.
I'm really psyched to try out the power logger for the mower. It's gotta the same features as the cell-log such as lvc and hvc alarms, but also can monitor 4 temp sensors (for the motor!), keep track of wattage and power use, and also check the motor RPM. Only problem is that it's for 6s.... As is the battery medic I plan on using to balance...
So any one have a stock electric lawn mower they can install a watt meter on to check actual power consumption?
Some other conversions:
http://jeanegan.com/2007/06/01/lawn-mower-conversion/
http://www.arttec.net/Solar_Mower/index.html
http://visforvoltage.org/blog/jdh2550_1/2076
It actually ran quite well and blew through really tall, thick, grass without hesitation....and then smoke started coming out of holes in the cover. 
