How to find range?

[jsisidore]

36V x 10ah = 360W/h what the hell is watt per hour anyway?

So how do you calculate mileage from this figure? I read that in theory it will give me 20 miles BUT how?

 

[sjpt]

There are a huge number of things that effect range. The best way to get an estimate of mileage I know is the Bosch calculator:
https://www.bosch-ebike.com/en/service/range-assistant/

That allows for lots of different factors. It is obviously aimed at Bosch motors and batteries, but that does not make a big difference; general battery and motor efficiency is not that variable. If you have a fairly 'ordinary' legal motor not aimed at superfast riding, select the Active Line motor and 400 battery, and then take off 10% for your 360 battery. Make sure you fill in the details under all three tabs (rider/bike/environment).

By the way, it is not watt per hour, it is watt hour, eg running at 1 watt power for an hour. A kettle uses nearly 3000 watts (but you don't leave it on for an hour), 1 bar of an electric fire around 1000 watts, and old 100w light bulb 100 watts. A typical legal motor will be rated to be able to keep up a steady 250 watts; which would give you just under 1 1/2 hours on your battery. But in practice the motor will probably be giving quite a bit less most of the time, and can peak at a lot more (500watts or even 750 watts) on hills

 

[Andy-Mat]

36V x 10ah = 360W/h what the hell is watt per hour anyway?

So how do you calculate mileage from this figure? I read that in theory it will give me 20 miles BUT how?

The variables are at least the following, I may have forgotten some:-
1) your weight
2) your fitness
3) your PAS level
4) how inflated your Tyres are
5) Tyre type and size
6) weight of bike
7) Type of road/paths you ride on
8) Bike complete setup and state of the bearings
9) setup of the brakes and your usage of said brakes
10) quality of battery
11) Quality of motor and motor controller
12) Style of your riding
13) The amount of wind resistance you and your bike produce
14) number of hills climbed and speed up the hills
15) does your controller "harvest" energy on downhill sections
You must simply go out and see what happens, a fit person uses a lower PAS and a lot more leg power for example., and might live where only good roads and no hills are = Longer battery life!!
regards
Andy

 

[Danidl]

The variables are at least the following, I may have forgotten some:-
1) your weight
2) your fitness
3) your PAS level
4) how inflated your Tyres are
5) Tyre type and size
6) weight of bike
7) Type of road/paths you ride on
8) Bike complete setup and state of the bearings
9) setup of the brakes and your usage of said brakes
10) quality of battery
11) Quality of motor and motor controller
12) Style of your riding
13) The amount of wind resistance you and your bike produce
14) number of hills climbed and speed up the hills
15) does your controller "harvest" energy on downhill sections
You must simply go out and see what happens, a fit person uses a lower PAS and a lot more leg power for example., and might live where only good roads and no hills are = Longer battery life!!
regards
Andy

Probably item 13 is the most significant. Power spent fighting against wind is always power lost. Even small increases in speed against wind results in major power loss. .. what ever your speed , Doubling it means an eight fold increase in wind power loss!. . Worse in winter with anoraks etc...

 

[Benjahmin]

All that said and done (no arguement with any of it) I take the simple approach of assuming a consumption of 10-20watthours per mile. If you're fit you'll be nearer the bottom end. If you're out of sorts and it's windy, you're gonna be near the top end. AK, who cycles the alps, claims around 7Wh per mile (he's disgustingly fit I think !).
So using this simple assumption your battery should give you between 18 and 36 miles, dependant on all of the above.

 

[jsisidore]

Anyone knows of any good 36v 10ah batteries? Around £150 mark
I was looking at this https://www.aliexpress.com/item/New-360Wh-36V-10Ah-High-Power-E-Bike-Lithium-Ion-Battery-Pedelec-Battery-Set-Electric-Bike/32902196199.html?spm=2114.search0204.3.156.652a51bcnD2txU&ws_ab_test=searchweb0_0,searchweb201602_1_10065_10068_10130_10547_319_317_10548_10696_10192_10190_10924_453_10084_454_10083_10618_10920_10921_10922_10307_10820_10301_10821_10303_537_536_10882_10059_10884_10887_100031_321_322_10103,searchweb201603_51,ppcSwitch_0_ppcChannel&algo_expid=e129ccc9-ccea-498a-b665-a98567d4d3c5-23&algo_pvid=e129ccc9-ccea-498a-b665-a98567d4d3c5

p.s. I'm fit but not by choice lol

 

[flecc]

36V x 10ah = 360W/h what the hell is watt per hour anyway?

So how do you calculate mileage from this figure? I read that in theory it will give me 20 miles BUT how?

Questioning on range over the years in this forum has resulted in an average of 12 Wh per mile, so your 360 Wh gives an average of 30 miles for a high proportion of riders on average e-bikes.

Weaker riders use more, typically in the 15 to 20 Wh area, while just a very few riders who are either strong or masochistic use as little as 5 Wh per mile.

The motor systems on a few e-bikes have been greedy, one that was popular a few years ago ate 24 Wh per mile from its 360 Wh battery, thus giving only 15 miles range for the majority of owners.
.

 

[wheeliepete]

I was looking at this https://www.aliexpress.com/item/New...lgo_pvid=e129ccc9-ccea-498a-b665-a98567d4d3c5

The spec. looks terrible, 12 amp max. discharge prob. means cheap Chinese cells and will struggle to power any bike. This battery at least has reasonable LG branded cells for not a lot more money. Also shipped from German in 3-4 days. You really do get what you pay for with battery packs.

https://www.yosepower.com/en/product/Original-LG-Cell-36V10.4Ah/36V12.8AH-Lithium-ion-Battery-Electric-Bicycle-Bottle-New-Black-DIY-69.html

 

[jsisidore]

The spec. looks terrible, 12 amp max. discharge prob. means cheap Chinese cells and will struggle to power any bike. This battery at least has reasonable LG branded cells for not a lot more money. Also shipped from German in 3-4 days. You really do get what you pay for with battery packs.

https://www.yosepower.com/en/product/Original-LG-Cell-36V10.4Ah/36V12.8AH-Lithium-ion-Battery-Electric-Bicycle-Bottle-New-Black-DIY-69.html

I bet you're right, I bet they are the cheapest possible batteries. I have no idea what a max discharge current means, I can imagine it means if a motor needs more than 12 the battery will give away no more than 12 amps. But question is would a motor need more than max allowed?

 

[flecc]

But question is would a motor need more than max allowed?

Yes, to reach its full potential power. Also a battery short of what is needed results in the cells discharging at their limit, stressing them and shortening battery life.
.

 

[sjpt]

If it gives 12 amp at 36 v that will give max power of 12*36w = 432watt. Quite likely the volts will drop as it gives max current, so in reality somewhat less that 432 watt, especially as the battery gets nearer empty.

Your motor will probably be rated for 250 watt continuous, but will be able to give bursts (eg for hills) up to 500watt or even 750watt. So the 12 amp max on the battery will reduce that and limit your hill climbing.

Also, using the battery at its max power may add strain to the battery and reduce its life (not sure about that part though).

p.s. What Benjahmin says below is quite correct. I forgot to mention the role of the controller as well as battery and motor. Without the controller limit and with a big battery the motor might take even more ... and burn itself out.

 

[Benjahmin]

Well, it all depends on the maximum current rating of your controller. If it is more than the maximum current rating of your battery, then it is going to suffer. How this will show is the voltage going down very quickly under high load conditions (high assist settings or hill climbing). It could mean that the system cuts out due to the lvc (low voltage cutout), which is there to protect the battery voltage from going irrecoverably low. After a few minutes of no load the voltage would recover sufficiently to be used again - until the next high load demand. This will result in the cells being stressed and battery life being severely shortened.
It depends on what you want to achieve with your bike, but the rule of thumb is to buy the best quality you can afford. Recommendations will be plentiful if you state what you need to do with it.

Crossed with Flecc and SJPT

 

[Nealh]

Ride you bike till battery hits lvc, then you find what wh per mile you afe capable of for the prevailing conditions.

 

[jsisidore]

I need it to get me through the hills sweat free and I'm looking towards TSDZ2 either 250w or 350w

 

[Woosh]

I need it to get me through the hills sweat free and I'm looking towards TSDZ2 either 250w or 350w

the way marketing people say that their TSDZ2 is 250Wor 350W or 500W or even 750W is very confusing. Tongsheng makes the same motor for two voltages: 36V and 48V. The controller is programmable, It is factory set at 16A but can be changed.
36V at 16A = 576W maximum
48V at 16A = 768W maximum
The motor is labelled 250W for road legal kits.
I would suggest you get a road legal 48V TSDZ2.

48V 16A is a good trade off between hill climbing ability, stress on the motor and stress on your battery.

How to find range?

You can use the motor simulator here:
https://www.ebikes.ca/tools/simulator.html

You want to look at the load curve versus speed. You can set your weight and gradient, the math is done for you.

For example, this is a 5% gradient:

https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MBPM&axis=mph&grade=5

The load chart gives (approximately) maximum speed at 18mh with the 48V TSDZ2 (768W battery power) and 15mph with the 36V TSDZ2 (576W battery power).
The battery consumption per mile is battery power / speed.
Climbing a hill at 18mph, battery consumption is 40WH-42WH per mile,

this is a chart for flat road:
https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MBPM&axis=mph&grade=0

the 48V TSDZ2 maximum speed is 28 miles, battery consumption is 27WH per mile.
The 36V TSDZ2 maximum speed is 23mph, battery consumption is 25WH per mile.

The above examples assume the motor is derestricteed.
If the motor is restricted to road legal, the battery consumption at 15mph is the same for both 36V and 48V, 12WH per mile.

Now the range.

The maximum range is battery capacity in WH / battery consumption per mile.
If you have a 48V TSDZ2 kit with 12AH battery, maximum range is about 576WH/12WH/m = 48 miles.
However, it is unpleasant to ride assisted when the remaining battery capacity is below 20%, the practical range is 20% less than the maximum range, about 40 miles.

 

[jsisidore]

I see. Quite confusing to a layman. The motor is limited to 15.5mph but not physically.
And in that sense 48V makes more sense as it will pull more juice from the battery and get me quicker uphill while staying below the limit. That's how I see it.

I had a look and I cannot find 250W 48V motor, I see only 500W and 750W

 

[wheeliepete]

http://wooshbikes.co.uk/?cdkit#tsdz2

 

[jsisidore]

I found a 48v 250W kit but the pound per hour does not agree with me.

I am planing to spend no more than £400-450 because over £600 I can get a new bike and sell mine.

 

[it is i footpump]

I have a tdz 250w fitted to Carrera subway one, I also have the yosepower 36v 10ah which was £160 about 2 years ago. not sure if its lg cells
I have amps set to 16( but have run it at 13 in the past)

I mainly use sport mode and on hot sunny days , no wind and fairly hilly get 25-30 max range, if its cold and windy this drops nearer to 20 miles range.

I also have an enerprof 13ah 36v battery pack which is quite light weight at 5lbs, which I carry in a strong saddle bag, and use both battries connected together this gives a range of 60-65, I use this set up if doing journeys of about 40 mles in total so do not have to worry about running out of power.

 

[jsisidore]

Alright I will wait till spring, maybe rules will change.