The simple answer is yes, I can, but I don't usually bother to figure it out. If you want the less simple answer keep reading.

1st of all Why Bother? Watt hours is the magic equalizer when it comes to comparing ebike motors of different wattages, voltages, and designs (hub/mid-drive). I prefer using Amp-hours over Watt-hours to track my power consumption because I don't have the necessary gadgetry to track watts without having to break out the dreaded math. Yeah, I got a good calculator and know how to use it, even know both Ohms and Watts law. But I don't really compare my bike, or my performance doing what I do, with what others are doing. It's ALL about distance with me, not speed. But, when you are good you can ride up on a group of ebikes, all with different motors and voltages, and talk **** about your power consumption vs theirs and zip off again. I prefer to ride up, pull out an inflatable chair, wash my face, cook a pot of coffee for everyone and talk **** about the amount of mass moved per amp hour

The best way I know to be absolutely sure of power usage is to use a Grin Techknowledges Cycle Analyst. There are other devices out there but the CA is the best in my opinion. You can ride for any period of time and it will tell you exactly how much power it took regardless of inclines, weight, weather, road surface, tire pressure, wind, or even hooky bobbing skateboarders. It can also tell you exactly what you are using as you ride, real time. I have looked into getting a Cycle Analyst but it would mean rewiring my entire bike so it is going to wait. But I do think that a CA would be the best way to learn how to best use the electricity stored in that heavy expensive battery.

Here's what I do... I have two batteries (24.4/30.3ah), both are listed as 48v but are closer to 54v. I never charge past 80% full, and don't discharge or deplete past 20%. So I can use 60% of the batteries capacity to ride, or (14.64/18.18ah). I use a Grin Techknowleges Satiator (smart charger) to charge the batteries. It allows me to determine how fast and how much power I allow into the battery. Slow charging and not filling the battery completely will extend the life (number of recharge cycles) of the batteries significantly. When the Satiator is finished it displays how many Amp Hours of electricity was put in the battery. I already know how many miles I have ridden and simply divide the miles ridden by the Amp Hours used, and I get Miles Per Amp Hour (MPAH). If I can get 3 mpah (miles per amp hour) when I am riding fully loaded, I am happy, very happy because it's probably been level or downhill. I almost always ride with front panniers and a bar-bag, blue tooth speaker, K-bar, umbrella, etc., about 115 lbs. of gear and my big ass. In this configuration, I have ridden over 70 miles on a level surface on a single 60% charge. Fully loaded it's more like 50+ miles on a single 60% charge on a level surface. Now comes the variables....... trust me when I say that a hooky bobbing skateboarder kills the MPAH average. The rolling resistance is just horrible.

Someone that rides the same route all the time would be able to give exact numbers, to include altitude gains and losses. Two bikes with different motor types and voltages would be able to get a fair comparison between the two using Watt Hours. I was really good at collecting and documenting the data for the 1st couple years, then I found myself slipping, forgetting to write a number down and then having to guess. Why bother if the data isn't exact, right? Now I use the data to determine the battery performance or degradation. Seriously, it's nice to know but a pain in the ass to determine and chronical day after day. Get a Cycle Analyst and it does it all.

If you stuck with me this long I hope this answers your question.

Yeah, great answer. Thanks. So if you went 70 miles and use 3 miles/AH, that's about 23 AH, and if it was at 48 volts, that's 1,120 watt-hours, very roughly. I guess what I'm getting at is that you'll need to plug in every night or two.

Very interesting indeed. Never saw that chart before. It would have helped me way back when.

Until I can solar recharge I feel like a gypsy on dialysis. Needing to recharge one or both batteries every day. On level terrain you could get two, maybe three rides out of two batteries, Big batteries. If you are a hotel hopper this is perfect. There is plenty of time to recharge everything, shower, eat, and all without worrying about what that sound was. HTC makes a 300w folding solar panel that would cut the cord. Multiple day rides, fully self-supported. A great water filter... or two, fishing pole, slingshot, a bag of small cheeseburgers. Last for days and never have to feel outlet anxiety. They are expensive and I can't find Any real reviews. Also, my batteries are closer to 54v than 48v.

Those panels are fantastic. Are you picturing yourself carrying one? You're not picturing them mounted and soaking sun while you're riding, are you? If not, you'll have to stop and rest to use it, and of course it has to be during daylight hours.

I do envision folding the 300w in half and having it mounted from behind my seat to the rear trailer fender mounting. It would depend on the wind once I had a proper mounting system. Maybe I can employ the carbon fiber spars from the kite I carry to help stabilize it somehow. It's not just daylight hours either, its full hard sunshine. I would buy one today if I could find anybody that has actually used one. $2500.00 is a lot of money to me, not to mention that 17 lbs. is going to dig into my gear list badly.

My Masi commuter weighs in at 26 pounds, My Specialized Aerotec Road bike is 14 pounds and my full suspension Specialized mountain bike is 24 pounds.

I started getting into cycling on a old brown Schwinn Varsity I bought for ten dollars at a garage sale about 10 years ago and did my first two centuries on a yellow Schwinn Varsity. I think those weighed in at around 40 lbs, they were pretty hefty.

Oh how far I have come....

I was riding a Schwinn Varsity in 1966, Big Red. Way too large a frame for me at the time. I busted my balls on that bike many times.

And you have come exactly as far as you should have.

For me, commuting is about economics, convenience, and safety. So, I have never even wondered about my commuter bike's weight. But if I had to guess, I'd say 27 lbs.

you're 55yo, I'm 41 now. I hope I'm still riding when I get to your current age