How to plan how much battery I need for a TSDZ2?

skestans · Aug 2, 2019

Because the TSDZ2 is a torque sensitive assist, how much battery you need directly depends on how hard you pedal (or not) if I understand correctly.

I never measured how many watts I can pedal, and I never owned an e-bike. I have a steep (8-9%) hill for about 1500m to go back home, the rest is mostly flat. I weigh 85kg, the bike (without motor or battery) is under 15kg. I also plan on adding bags to the back so I can go on errands.

I'd like a 52V battery, and I'd like to go on longer rides on the weekend (the lake is 20 km away one way, flat)

So how do you plan your battery size and capacity in this case?

Nick2 · Aug 2, 2019

Hi!
I have TSDZ2 48V / 750W.
From your parameters (1500m 8-9% incline), your home is about 120 - 135 m above the city level.
I have similar situation, although somewhat lower (about 60 m above the city level). And I am a bit heavier than you.
I have a LG brand 48V battery in 13s4p configuration, 12.6Ah.
With fully charged battery I can go to the city and back to my home 4 times, totaling about 60 km, without range anxiety

Didn't test the range on the flat terrain only, but I believe it would be about 80 - 100 km if the speed is moderate (no more than 30 km/h).
Based on this I believe that you should be able to go to the city and back at least twice on one charge, also 40 km round trip to the lake shouldn't be a problem at all.
But there is a catch 22 - TSDZ2 is somewhat sensitive to overheating, and I would be careful not to burn the motor or the plastic gear on that long hill. Also i ordered some heat conductive silicon sponge to drain the heat to the outer casing, and the thermometer with the probe, so at least I would be able to monitor what is going on inside.

skestans · Aug 2, 2019

Nick2 said:
Hi!
I have TSDZ2 48V / 750W.
From your parameters (1500m 8-9% incline), your home is about 120 - 135 m above the city level.
I have similar situation, although somewhat lower (about 60 m above the city level). And I am a bit heavier than you.
I have a LG brand 48V battery in 13s4p configuration, 12.6Ah.
With fully charged battery I can go to the city and back to my home 4 times, totaling about 60 km, without range anxiety
Didn't test the range on the flat terrain only, but I believe it would be about 80 - 100 km if the speed is moderate (no more than 30 km/h).
Based on this I believe that you should be able to go to the city and back at least twice on one charge, also 40 km round trip to the lake shouldn't be a problem at all.
But there is a catch 22 - TSDZ2 is somewhat sensitive to overheating, and I would be careful not to burn the motor or the plastic gear on that long hill. Also i ordered some heat conductive silicon sponge to drain the heat to the outer casing, and the thermometer with the probe, so at least I would be able to monitor what is going on inside.

Thanks. I'm not sure the altitude matters but in case it does my house is at about 700m altitude.
I heard about heat dissipation, I plan on installing a temperature sensor and the open source firmware. Have you tried it or are you using the OEM software?

Alex W · Aug 6, 2019

skestans said:
Because the TSDZ2 is a torque sensitive assist, how much battery you need directly depends on how hard you pedal (or not) if I understand correctly.

There are a ton of variables, the most important one for my battery life is the max speed at which I get assistance. If I set this at about 30kmh I will get incredible battery life because on flats I just use human power, but on hills the assist starts to kick in. If I bump it up to 35kmh my range will drop by 30% because now I'm using the motor on the flats too.

This has a much bigger effect on my range than the level of assist that I run.

The type of bike and it's efficiency matters too. I have identical setups (same motor, controller, CAv3 configuration) on two bikes, one is a lightweight hybrid with very low rolling resistance tires and a bit more aerodynamic riding position. The other is a mid-tail cargo bike that is more upright, has very inefficient tires (Benno cargo bike tires are more like motorcycle tires than bike tires), and where my son is normally aboard (kills aerodynamics). I get about twice the range with the same battery on the hybrid as I do on the cargo bike. So on my hybrid I can carry a very small 36v5ah battery (180wh) and get 50km range, on the cargo bike I carry a 36v14ah battery (500wh) and get about 70km range. For both bikes I can parallel in a spare 36v10ah (360wh) battery if I need a boost in range.

If you described the bike a bit and your fitness level I could maybe make a guess. Your distances sound short though, so I'm guessing that a 400-500wh battery would be fine.

parajared · Aug 14, 2019

You would need to know the watt hours of your battery:
ah x volts = wh

for instance
10 amp hours x 44 volts = 440 watt hours

10 watt hours per mile = you are in good cycling condition and have an efficient bike
20wh/mi = pretty typical cyclist condition, pretty typical bike
30wh/mi = not atypical especially when you are dealing with loose soil, winds or heavy loads
40wh/mi = not unusual for a joyride or a very heavy load

allow maybe 15% "fudge factor" for detours or sudden onset wimpiness.

skestans · Sep 17, 2019

Alex W said:
skestans said:

Because the TSDZ2 is a torque sensitive assist, how much battery you need directly depends on how hard you pedal (or not) if I understand correctly.

Click to expand...

There are a ton of variables, the most important one for my battery life is the max speed at which I get assistance. If I set this at about 30kmh I will get incredible battery life because on flats I just use human power, but on hills the assist starts to kick in. If I bump it up to 35kmh my range will drop by 30% because now I'm using the motor on the flats too.

This has a much bigger effect on my range than the level of assist that I run.

The type of bike and it's efficiency matters too. I have identical setups (same motor, controller, CAv3 configuration) on two bikes, one is a lightweight hybrid with very low rolling resistance tires and a bit more aerodynamic riding position. The other is a mid-tail cargo bike that is more upright, has very inefficient tires (Benno cargo bike tires are more like motorcycle tires than bike tires), and where my son is normally aboard (kills aerodynamics). I get about twice the range with the same battery on the hybrid as I do on the cargo bike. So on my hybrid I can carry a very small 36v5ah battery (180wh) and get 50km range, on the cargo bike I carry a 36v14ah battery (500wh) and get about 70km range. For both bikes I can parallel in a spare 36v10ah (360wh) battery if I need a boost in range.

If you described the bike a bit and your fitness level I could maybe make a guess. Your distances sound short though, so I'm guessing that a 400-500wh battery would be fine.

I had missed your answer until now. I'm not athletic but I'm in good shape. I can ride the bike up the steep hill and go 6-7 km/h (although I'd be sweating a bit and breathing heavily like you would when running).

I plan on having two separate sets of use for the bike. Around 5-10km return when going to work, mostly flat except that one 700m uphill portion. And I'd also like to go on longer rides 40-50 kms on weekends. Should I get separate batteries, or should I just get a larger battery and only charge it 50% during the week, and 80% on the weekends when I want to go farther?

How to plan how much battery I need for a TSDZ2?

skestans

100 W

Nick2

10 mW

skestans

100 W

Alex W

10 W

parajared

10 kW

skestans

100 W

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