Nine months with the Ryobi 20″ self propelled battery powered lawn mower
Nine months ago I got a Ryobi 20″ self propelled battery powered lawn mower, figured it’s time for a follow-up review as initially I had questions and I didn’t have a good metric of what the thing was capable of.
How much electric power to mow a lawn?
I have about 5900 square feet to mow and a vertical change of about 16 feet from front to back. Going by Google maps and attempting to figure this out I have a width of 52 feet, a depth of 172 feet minus whatever my house footprint is.
So ~30 passes were they laid next to each other, of which 15 would be uphill, meaning the mower is lifting itself 240 feet up and running itself 5160 feet (or about a mile)… minus the house which I’m going to go big and say 2000 feet used for the footprint, deck, and unusable areas.
So, 3160 sq feet of mowing, 240 foot climb, for me on average it takes about 6-7 amp hours @ 40v worth of juice. The 5000mAh battery isn’t enough if I’m using the propeller.
I picked up another battery (with a different tool,) and carry it in the holder and never have a problem running out of juice.
Of course, your experience will vary based on height change, amount of using the propeller, whether you’re bagging or mulching, whether you’re carrying the spare battery on the mower, but I think it’s safe to say 6.5 amp hours for 3160 square feet or about an an amp hour of juice for every 500 square feet.
Mathing out of my area here, but looks like 40 Watt hours per amp hour (at 40v,) my 6.5 amp hour requirement puts it at 260 Watt hours, or 1/4th a kilowatt to mow my yard. about $0.03 of electricity per mow if I’m doing this correctly.
Assuming I’m not, which this article tends to indicate, you’re saving about a buck an acre. They’re claiming gas is 4.7x the price of electric. Not going to dispute that.
Is it better than a gas mower?
Engaged in a Grassacre? Total warfare against 11 inch high grass? Want to annoy the neighbors at 7am on a Sunday? Then no, it’s not better. You will find that the mower isn’t really ready to cut through the jungle although it’s not underpowered.
That said, if you’re maintaining a yard regularly, want to listen to podcasts without cranking them above normal volume, and do not want to deal with smelling like gas, I can’t recommend this enough.
The self propelled version is $379 at home Depot, the push it yourself version is $299, and a comparable gas mower is about $200 (push it yourself,) $299 (self propelled) – so you’re looking at a $100 additional cost initially plus if you need another battery (there’s a $399 version with two 5AH batteries.)
So, $100 more for the mower, and according to this you’re saving about 80% per mow, but even at 50% you’ll break even on your mower purchase at about 25 acres mowed in gas savings.
Does it matter?
Not really, no. Your use case is your use case. Get what you want. I despise keeping gas in my house or around it.