now your sounding like less of equipment junky
LoL! Its all a means to an end but fun.
So....did a ride this morning. Its a normal circuit i do with a few undulations in the first half into a headwind, with the second half flat (until the last 2.5km hill) with a tailwind.
26.3km on PAS 2/3 used 99.3 wH for 3.78 wH/km
Then hung the bike up and let it run for an hour. Sucks, boring, and would take ages.
So, did basically the same ride as this morning with a couple of detours but on PAS 8/9 and liberal use of throttle.
29.9km on PAS 8/9 used 262.5 wH for 8.78 wH/km.
Battery effectively drained about 1 km from home. It was low enough so that it was cutting in and out depending on if i was pedaling or not.
Then about 50m from home, BMS cut the power from the battery completely. This reset the meter of course.
So, total usage extracted from my battery (EM3ev, 48v, 11ah, Samsung 29E cells, frame pack) for the whole day from fully charged was:
440.9wH / 11.031 AH as measured on my meter.
One thing i was interested in was how do wH used relate to the battery level on the Bafang display?
I stopped and took notes at various stages. Pen / Paper = poor mans data logger.
This isn't definitive as its only data from 1 ride, but i thought it may be worth sharing.
Fully charged this morning with 4 bars @ 54.34V
Started this arvo's battery draining ride with the display on 4 bars at rest and a voltage of 49.86V, wh used @ 178.4wH.
Went from 4 bars on the display to a consistent 3 bars on the display at rest @ 47.65V, wh used @ 244.0wH.
Went from 3 bars on the display to a consistent 2 bars on the display at rest @ 45.81V, wh used @ 336.6wH.
Went from 2 bars on the display to a consistent 1 bars on the display at rest @ 44.03V, wh used @ 400.6wH.
Motor starting to cut in and out as voltage sags under load, with a flashing battery outline when running, and 1 bar at rest @ 42.67V, wh used @ 440.9wH.
BMS cut the power off completely soon after the voltage sagged under load far enough. Turned the power on and off again to reset and after a couple of minutes to stabilize the meter was reading 42.41V.
Low voltage cut-off programmed in the motor controller is 41V, and i think the BMS is programmed for a 40V LVC.
I think riding at high assist levels until i hit the LVC is the best way i have to test actual battery capacity. Going to have to try this again, but not too often.
High assist is addictive.
And i dont want to do full cycles on the battery too often.
Question for people out there. I thought that wH from a battery could be calculated by Voltage x Amp Hours??
Using Paul's advertised figures that's 46.8V x 11AH = 514.8 wH. I get 440.9 wH measured.
However, i also measured 11.031 AH, which is bang on the advertised capacity of 11AH.
I'm not upset about this as the way i ride i reckon i should get a reliable 75-85km out of that battery. But it may mean i am not understanding something here about battery capacity??