Which indicates distance you can travel
- Thread starter Saracen
- Start date
Wh (which is Ah * V) is indeed the measure of capacity that controls range. Of course there are lots of other variables. Also, if the battery doesn't have very good ability to deliver current then it will suffer voltage sag under load (eg up hills), that might mean even though there is capacity left it will cut out to save killing the battery. That could limit the effective range, especially if there is a big up hill fairly close to your destination; quite likely that the battery gets tired exactly as you need it most when you are tired; uphill at the end of a ride.
They're both the same thing. 36v x 20Ah = 720wh.
If you want the most accurate measurement of range, usage and capacity, you should get a wattmeter, which will not only show you the watt-hours used and remaining, but it'll give you a good understanding of how your bike works and how much battery you use in different circumstances.
One can roughly estimate range by dividing the wh by wh usage and how you ride.
If one rides often above the speed cut off then usage can be in 5 -7wh per mile range, if one rides in low power mode a lot ( ie a current control controller) then one can expect to use 8 - 12 wh per mile . If using a higher assist then anything up to 20wh per mile may be used also applies to riding with a high assist cut off.
If one rides often above the speed cut off then usage can be in 5 -7wh per mile range, if one rides in low power mode a lot ( ie a current control controller) then one can expect to use 8 - 12 wh per mile . If using a higher assist then anything up to 20wh per mile may be used also applies to riding with a high assist cut off.
So potentially that is another advantage of using a controller with power based assist levels rather than speed based assist levels ? They are more efficient, if you are adding quite a bit of pedalling effort ?
Yes .
Most crappy speed controllers give max current more of the time until the speed threshold for the power level is reached , the power based current controllers can be more efficient depending on the power it supplies . The KT's for instance put out approx. 13% of the max power in PAS1, others like woosh set this to 40% in the lishui's. More importantly though is riding above the cut off to increase range just as riding with the battery switched off.
My long rides are 160km on a nice sunny, using a 36v battery and 48v one used independently of each other. 36v PF in the triangle and a homemade 13s 7p PF in a rear bag /rack top pannier, mostly all the journey in PAS 1 except for some PAS4/5 climbing up out of Ovingdean on the way home . I usually still arrive back at home with 30 - 40% of total wh available.
@Saracen - in the longer term if you had some means of measuring how many watt hours you used/consume for your different rides then you will over time get to know how much power you are using for your different riding scenarios.
Once you know this and the capacity of your battery, you'll become quite good at working out your range.
I don't have a watt meter on my bike but back in the bike shed I have a home built rig that;
(a) measures how many watt hours I have to put back into the battery to get back to the fully charged state (having started with a fully charged battery of course) and then log the miles done, type of terrain etc. to obtain the watt hours per mile figure mentioned by Neal in post #6
(b) I can also discharge the battery into a dummy load to measure the capacity in watt hours.
These measurements aren't overly accurate but over time have been enough for me to be confident in what range I'll get for any particular ride - so no range anxiety for me lol.
Once you know this and the capacity of your battery, you'll become quite good at working out your range.
I don't have a watt meter on my bike but back in the bike shed I have a home built rig that;
(a) measures how many watt hours I have to put back into the battery to get back to the fully charged state (having started with a fully charged battery of course) and then log the miles done, type of terrain etc. to obtain the watt hours per mile figure mentioned by Neal in post #6
(b) I can also discharge the battery into a dummy load to measure the capacity in watt hours.
These measurements aren't overly accurate but over time have been enough for me to be confident in what range I'll get for any particular ride - so no range anxiety for me lol.
The watt meter /gauge shows simply how much power (watts) the controller is out putting it won't tell you how many wh is being use or has been used for that one needs an anmeter type watt gauge that uses a shunt on the main power feeds.
d8veh's handy little watt meter mod.
Latest Cheap Wattmeter | Pedelecs - Electric Bike Community
d8veh's handy little watt meter mod.
Latest Cheap Wattmeter | Pedelecs - Electric Bike Community
It's a meter that shows watts rather than a wattmeter. A wattmeter shows present watts, cumulative watt-hours, current, max current, amp-hours and things like that, so you can measure the capacity of your battery for each type of ride you do, then during those rides you can see how much of the battery you've used and calculate or estimate how much further you can go.