Kingfish
100 MW
Sangesf, is the single-battery comment directed towards my way? If so I’ll try to answer: I use arrangements of 5S1P to create battery assemblies. They are all the same make & model, I don’t mix chemistries, K.I.S.S. Thus, I can evaluate the “whole” battery assembly as one, having 2C charge, 15C discharge. But then I run with a large capacity and experience a voltage sag of 0.4V at WOT which I think is fine and good for two motors. (I hope that was helpful). And I’m with you on the observation: Pull easy and the batteries will be of less trouble. Mine get physically beat-up over time so I doubt I’ll ever see 1,000 cycles. Not complaining, just observing; we make the bed we sleep in. :lol:
Miuan: The next bike design is targeted at twice the speed and twice the distance. Allow me to shed a bit of light on what I have learned between the two cross-country trips I’ve made:
Now we understand the limits: 8 hours (sleeping), 125 VAC, 50A service commonly available at 40% of the RV parks around the country (which BTW, vary from $11-35/day; much cheaper than motels – and the power is free). 125 * 50 = 6250W/hour MAX (likely theoretical at best), and 8 * 6250 = 50kW. Frankly, I’d be happy with 32 to 40 kWh if for nothing else but to keep the weight and the cost down.
Anyways, this is how I think about batteries and weight. Imagine now given all of this, that weight is not our friend, and that it is a drag (literally) on our system. How can we reduce that weight and improve our performance (aside from going slower)
Am I drifting off-topic? 2WD systems have a lot of potential beyond just bicycles.
~KF
Miuan: The next bike design is targeted at twice the speed and twice the distance. Allow me to shed a bit of light on what I have learned between the two cross-country trips I’ve made:
- P0 eBike was FWD, 9C 2806, 37V 10S9P. I had a crappy charger experience (issues documented and resolved in time for next year). Went 550 miles in 3.5 riding-days, longest was 173 miles with some opportunity charging (twice). Speed was about 24-26 mph (need to double check), and I could cruise at 29 mph on a flat easy enough. Me and the bike weighed 350 lb.s; batteries were 23 lb.s.
- P1 ebike is 2WD, Ebike-Kit (might be 2807-equivalent), 63V 15S26P. Had a better charger that used about 1kW/hour, and took roughly 8-9 hours to recharge my whole assembly. Farthest on a single charge was 165 miles of California Hwy-1 between San Rafael and Fort Bragg (hilly, windy, curvy). Average speed that day was closer to 23 mph (not worthy of bragging rights, but I got there), though I could easily cruise at 32 mph and could climb hills without any issues (other than what has been documented). I took 4.3 times more batteries to go about the same distance as last year, except that I had the pleasure and power of climbing hills without resorting to downshifting in most cases, and I towed a trailer with 50 pounds of additional gear on board (not counting batteries). Me and the bike: 450 lb.s, with 100 lb.s of that in batteries.
- Next bike: Proposed – is a 2WD electric motorcycle (someone coined eMoto and I like that term). Mathematically, the motors are designed to handle 75 mph, though realistically 65 mph is more fitting: Need to be able to travel on the freeway without getting run over. Minimum distance is 300 miles with average weather. Hence, twice the speed & twice the distance means 4X the batteries… optimistically. 5X would be better. Aside from weight, which is now 400-500 pounds, we have to find a way to charge it! The bike can’t come into the motel room like before; I have to go to RV Parks or EV Charging Stations (hey dnmun, you got yer ears on?). I spec’d out the “road trip” and 300 miles is barely making time for where I want to go. 300 miles / 60 mph = 5 hours in the seat. Now let’s flip this around and look at it from the other end of the telescope.
Now we understand the limits: 8 hours (sleeping), 125 VAC, 50A service commonly available at 40% of the RV parks around the country (which BTW, vary from $11-35/day; much cheaper than motels – and the power is free). 125 * 50 = 6250W/hour MAX (likely theoretical at best), and 8 * 6250 = 50kW. Frankly, I’d be happy with 32 to 40 kWh if for nothing else but to keep the weight and the cost down.
Anyways, this is how I think about batteries and weight. Imagine now given all of this, that weight is not our friend, and that it is a drag (literally) on our system. How can we reduce that weight and improve our performance (aside from going slower)
Am I drifting off-topic? 2WD systems have a lot of potential beyond just bicycles.
~KF