I tested the Standard Battery on my Rover 5 when it was new, and now again after 5+ years and about 5000 miles on this battery. (I have 8700 miles on the bike, but have two batteries which I occasionally swap.) The battery has not noticeably degraded.
The test consists of my riding the bike throttle only fully open on level roads until it virtually quits. I stop every two miles and measure the battery voltage after 60 seconds. The battery is still performing like new, except for the last few miles.
I ride 12 miles most every day, and charge to 80% after every ride. The bike lives in my garage in Florida, so it is subject to 80+ degrees (often 90+) nearly all year. I have a meter on my charger that shows that the charger adds about 110 Ah on a charge, which is about 1/6th capacity. So I'm doing the equivalent of one full charge every 6 days. That works out to about 335 full charge cycles. Rad advertised 800 cycles on the battery when I bought the bike; the cell manufacturers say 500 cycles.
Regarding charging to 80% vs 100%, here is the best data that I have.
I bought a used second battery some time ago. The power connector had overheated and melted. The owner couldn't repair it; so I bought it as a spare and replaced the bad connector. The owner said she had put about 4000 miles on it, which I estimate to be no more than 150 cycles, maybe less. I just tested that battery today.
In the chart, blue is my original battery new, and green is that battery after over 300 charge cycles to 80%. Red is the second-hand battery that was charged maybe 100 - 150 cycles to 100%. Remember we are talking about complete charge cycles.
Most consider the battery to be discharged at 42V, where power drops off. We can see that at 42V the 100% charged battery has lost about 2 miles in distance capability, or about 10%. Not huge, but measurable. It will likely degrade more with additional charge cycles to 100%. I would guess at 300 cycles the loss might be about 20%.
Remember this test is at full throttle with a maximum distance of 20 miles. If you use PAS and pedal 40 miles on a charge, you would likely lose 4 miles.
It is noteworthy that power is not reduced, only capacity or distance. If you don't take long rides, you would never notice the difference.
That's excellent DickB. Good data.
Thank you.
It's impressive that after 5+ years and 5000 miles, your Rover 5's battery still performs like new! Maintaining a consistent charging routine at 80% is key. Just as you enjoy that smooth ride, you can also experience excitement in Snow Rider 3D (https://snowrider-3d.io/). This game allows for exhilarating snowboarding adventures, making it a great way to unwind after testing batteries or any other activity. Keep riding and gaming!