01-18-2022, 11:32 PM
(01-18-2022, 05:46 PM)tomh009 Wrote:(01-18-2022, 04:42 PM)danbrotherston Wrote: Yes, like I said, I don't know what wattage the units I looked at were actually using, but there are a wide variety of units available with different battery system:
Here's the 1700 USD Toro unit I was quoting:
https://www.toro.com/en/homeowner/snow-b...-60v-39926
Even if we take the same current draw of 3C (I used 5C which is a typical maximum draw for LiIon batteries) the larger batteries will lead to a wattage of 2700 Watts or 3.6 HP.
Given Toro has another unit for 999 USD that's also at 60 watts, seems like the Ryobi system is significantly less powerful for the price. But obviously the blowers could be drawing less than maximum power.
I'm also not 100% sure how the power draw would be distributed, the motor should draw more power when under load, so it could be that the maximum power is significantly higher than 3C and 20 minutes is only the average runtime leading to an average draw of 3C.
Are those coulombs you are using for current? A coulomb is one ampere for the duration of one second, I think you want just plain old amperes (and then power is measured in watts, and one watt is equal to one amp at one volt).
Anyway, that Toro has two 7.5 Ah batteries. If it has the same 20-minute runtime at heavy load, then it's 22.5A x 60V x 2 = 2700W. That's roughly the same as a 20A household circuit. (Coulombs are generally not useful for calculating power as they include the time element.)
Of course, if the Toro can run only 10 minutes on those batteries, then the draw is much higher.
No, C in this case refers to charge rate. 1C means 1 hour charge and charge, so amps==amp hours. 3C means 20 mins run time.
But again these are continuous numbers. I suspect snow blowers have some peaks and valleys in demand so we are only seeing an average when you look at duration.