PAS level and battery range: is it normal?

Hi there,

I'm pretty new to e-bikes and batteries. I've recently built a steel frame road bike commuter conversion (rear hub). It's working nicely, but my battery seemed to run down alarmingly quickly today and I'm trying to work out if it's normal or not.

These are the specs:

• A 48V 15Ah / 720Wh 30A battery: https://caprouge.com.au/collections/ebike-batteries/products/48v-15ah-720wh-30a-tiger-shark-battery-bak-cells-cpwhbk48-15

• 48V 1000W rear hub motor direct drive, no regen

• Controller, 48v, maximum current rate: 30±1A

I had run a rough estimation on the Bosch calculator tool (obviously not entirely accurate as I don't have a Bosch bike) and it returned 140km. That seems way too high though. I also used the 'divide your Wh by 12 to get km range' method, which returns 60km, and seems much more realistic.

My usage this time was: full charge yesterday, then two rides combining to 25km last night and today which pretty much ran the battery close to empty. It was pretty windy, I live in an area with decent hills, and I tend to ride with PAS level 5 and lots of throttle. So I realise those all decrease range.

My question is, do you think it's reasonable that they would halve the range, if 60km is a reasonable estimate? 30km isn't ideal for my purposes.

The battery is more or less brand new.

Here's a picture of the bike for reference: https://photos.app.goo.gl/jMiYxgWuc5VfEfYr7

Thank you!

https://ebikes.ca/tools/simulator.html

https://ebikes.ca/tools/trip-simulator.html

https://ebikes.ca/learn/batteries.html
Motor Type Rough energy usage
Minimal Assist (using motor only on hills, slower ~30kph setup) 6-8 Wh/km
Typical Assist (~40 kph with pedaling, motor on all the time) 9-12 Wh/km
Power Hungry (either no pedaling, or hauling a load, or going really fast) 14-20 Wh/km

for those whose browser can't render lists

MaximilianMM said:

These are the specs:

A 48V 15Ah / 720Wh 30A battery: https://caprouge.com.au/collections/ebike-batteries/products/48v-15ah-720wh-30a-tiger-shark-battery-bak-cells-cpwhbk48-15

48V 1000W rear hub motor direct drive, no regen

Click to expand...

So let's say 15Ah is actually 12Ah these days - and no, no longer new. Are you able to do a CC load cap test?

And in theory capable of using 20A

Are you getting over an hour?

Is there an LVC?

You aren't letting the pack drop below 42V are you?

Isolated at rest an hour, recovering to 46-47V would be better.

Do you know exactly what model cells are in there?

markz said:

https://ebikes.ca/tools/simulator.html

https://ebikes.ca/tools/trip-simulator.html

https://ebikes.ca/learn/batteries.html
Motor Type Rough energy usage
Minimal Assist (using motor only on hills, slower ~30kph setup) 6-8 Wh/km
Typical Assist (~40 kph with pedaling, motor on all the time) 9-12 Wh/km
Power Hungry (either no pedaling, or hauling a load, or going really fast) 14-20 Wh/km

Click to expand...

Thanks very much, that's really useful.

I did the simulator: https://ibb.co/jv7V6YK

I had to use a motor which is roughly similar to mine. It came out at 40km, which is a bit disappointing.

I splashed out, relatively speaking, on a more expensive battery with higher Wh so I could get more range. 40km just seems low.

I wonder which part of my set up is reducing it, because everything you read says you should be getting more than that, not discounting all the many variables, with 750Wh.

Any ideas?

john61ct said:

for those whose browser can't render lists

MaximilianMM said:

These are the specs:

A 48V 15Ah / 720Wh 30A battery: https://caprouge.com.au/collections/ebike-batteries/products/48v-15ah-720wh-30a-tiger-shark-battery-bak-cells-cpwhbk48-15

48V 1000W rear hub motor direct drive, no regen

Click to expand...

So let's say 15Ah is actually 12Ah these days - and no, no longer new. Are you able to do a CC load cap test?

And in theory capable of using 20A

Are you getting over an hour?

Is there an LVC?

You aren't letting the pack drop below 42V are you?

Isolated at rest an hour, recovering to 46-47V would be better.

Do you know exactly what model cells are in there?

Click to expand...

I'm really sorry, I appreciate the reply but this is all over my head. I don't have any of that information, and I can't run any tests that require specialist equipment.

I won't ask you to explain it all but if you're able to simplify what you mean by this, it would be helpful: You aren't letting the pack drop below 42V are you?

Google terms you don't know, ask specific questions...

Just spending more money does not guarantee good cells were used.

The whole industry is rife with scammers, at least 95%.

At "48V nominal" I assume 13S, which means drop dead empty 0% SoC is like 40V

Letting the pack get that low every cycle is going to murder it quickly, maybe only a few dozen cycles.

If you stop earlier, e.g.

> Isolated at rest an hour, recovering to 46-47V

Then you would get a lot longer lifespan.

Same with traveling slower, losing weight, getting a higher capacity pack, not charging all the way to 4.2Vpc (54.6V) so many factors have impact.

But average DoD% is a very big one.

An LVC protects the battery from you, isolating the battery when voltage drops too low so you don't murder it so quickly.

______
Are you getting over an hour?

Is there an LVC?

Do you know exactly what model cells are in there?

john61ct said:

Google terms you don't know, ask specific questions...

Just spending more money does not guarantee good cells were used.

The whole industry is rife with scammers, at least 95%.

At "48V nominal" I assume 13S, which means drop dead empty 0% SoC is like 40V

Letting the pack get that low every cycle is going to murder it quickly, maybe only a few dozen cycles.

If you stop earlier, e.g.

> Isolated at rest an hour, recovering to 46-47V

Then you would get a lot longer lifespan.

Same with traveling slower, losing weight, getting a higher capacity pack, not charging all the way to 4.2Vpc (54.6V) so many factors have impact.

But average DoD% is a very big one.

An LVC protects the battery from you, isolating the battery when voltage drops too low so you don't murder it so quickly.

______
Are you getting over an hour?

Is there an LVC?

Do you know exactly what model cells are in there?

Click to expand...

There's a limit to what you can Google, and the specificity of the questions you can ask if you lack the knowledge to know where to start. Thanks for your patience, I'm learning as I go.

The battery is bought from a very reputable seller, the description says this:

Tiger Shark Battery, known for its durability and water resistance. Backed with high quality BAK 18650 cells.

Built with a 30A continuous discharge, this battery is built for higher powered motors, run at maximum power

All cells used in our batteries are 100% new and tested to International Electrotechnical Commission (IEC) standard 62133-2-2017 or 2012, beware as many Australian suppliers do not mention the brand of cell used

So I'm confident they're good cells.

It's this controller: https://www.ebay.com.au/itm/174122305305

It seems there is LVC as standard; Low voltage protection: DC40±0.5V

I also understand it's not good practice to run it super low, or charge too high.

But all of those things affect lifespan, primarily. None of that should be affecting the current range of a brand new battery/bike, much. Of course over time they will.

So I am still left asking, is it reasonable to be getting only 25km on this set up right now? And if it is, what accounts for the big discrepancy from what I've read about what you can expect from 750Wh?

This can be a complex question with many details needed to answer.
Most of your data is theoretical..IE “720 Wh” pack. Unless you do a capacity test, you do not know precisely what capacity you have available between “fully” charged and “nearly empty”. I guarantee it is not 720 Wh.....likely closer to 600Wh !
“Pretty much Run it nearly empty” ....how are you measuring this ?....Wattmeter or Voltage measurement ?
What voltage range..fully charged ? ..to ..”nearly empty “?
Does your controller have a display to tell Wh or Ah consumed ?
Are you using just throttle control, or cadence or Torque sense control ?
What is your average / max speeds that you ride ?
Depending on the various combination of the above factors, it is not hard to consume 15-20 Wh/km !

Hillhater said:

This can be a complex question with many details needed to answer.
Most of your data is theoretical..IE “720 Wh” pack. Unless you do a capacity test, you do not know precisely what capacity you have available between “fully” charged and “nearly empty”. I guarantee it is not 720 Wh.....likely closer to 600Wh !
“Pretty much Run it nearly empty” ....how are you measuring this ?....Wattmeter or Voltage measurement ?
What voltage range..fully charged ? ..to ..”nearly empty “?
Does your controller have a display to tell Wh or Ah consumed ?
Are you using just throttle control, or cadence or Torque sense control ?
What is your average / max speeds that you ride ?
Depending on the various combination of the above factors, it is not hard to consume 15-20 Wh/km !

Click to expand...

Thanks, and yes, I appreciate it's complex with many variables, so just after a rough feel for whether what I'm getting is in the normal range.

I have a simple battery level display on the controller display, and on the led lights, so I ascertaining battery level on that. From fully charged (light goes green, full bars) to 'nearly empty' (1 red light on battery = 25% or less; 1 bar of 4 on display). So technically I guess it may have had up to 25% in it still.

I'm using pas cadence on level 4/5 mainly, and occasional throttle boost.

I would say my average speed is around 30km/h. Max speed would be 40km/h.

So if it's 600Wh and I'm using 20Wh/km that would give me 30km. So about what I'm getting! Thanks, that's helpful.

Maybe I'll have to invest in another battery for longer trips.

I suppose the level of PAS/assist/wind really does make a huge difference.

How come actual Wh is so much lower than advertised can I ask?

How come actual Wh is so much lower than advertised can I ask?....

Click to expand...

Because they lie !....or at least use the most optimistic figure !
Really, for an ebike, the battery range can be infinite,...just depends on the pedal input of the rider
The real consumer of power is speed...or to be precise wind resistance. Closely followed by hills and weight.( especially with a hub motor )
In reality < 5-10 Wh/km is unusually low,..a bit like hypermileing for economy in a car.
10-15 Wh would be typical/ good result , and 15-20 Wh would be a poor but not unusual result.
PS, i have a similar capacity 48v, 16Ah pack with a “bar” type capacity ( voltage) display.
When it runs down to the last bar, and i recharge,..it only takes 6 Ah to fully recharge ( so about 300Wh)
And that incidentally is roughly 1+ hrs, 25 km of off road hilly trails ..but mid drive set up.

There is no objective 750Wh capacity

All depends on the discharge rate what the actual capacity is.

So even the "most honest" vendor will assign a nameplate capacity of 15Ah that will only be true at say a 0.05C discharge rate, well below one amp.

And that assumes top quality cells, which you CANNOT accept vendors' claims, only validated by trusted forum vendors doing objective IRL stress testing.

At a high rate, say 15A (1C) that pack might in reality deliver only 12Ah, and for longevity you will only want to pull say 9Ah,

so now you're down to 430Wh

And that is only true for the first 5-10 cycles

every cycle after that capacity declines

the greater the Ah you want to pull per trip

the higher C-rate discharge performance you push

the faster that decline will be.

And unless you learn how to do objective cap tests yourself, most accurately and easiest with a CC dummy load

you won't be able to anticipate just how fast

and proactively buy a new replacement pack in anticipation.

Some users only get 50 cycles and the pack is at EoL

others might get 500 800 or (with a huge pack, low C-rates usage) maybe even 1000 cycles

Hillhater said:

How come actual Wh is so much lower than advertised can I ask?....

Click to expand...

Because they lie !....or at least use the most optimistic figure !
Really, for an ebike, the battery range can be infinite,...just depends on the pedal input of the rider
The real consumer of power is speed...or to be precise wind resistance. Closely followed by hills and weight.( especially with a hub motor )
In reality < 5-10 Wh/km is unusually low,..a bit like hypermileing for economy in a car.
10-15 Wh would be typical/ good result , and 15-20 Wh would be a poor but not unusual result.
PS, i have a similar capacity 48v, 16Ah pack with a “bar” type capacity ( voltage) display.
When it runs down to the last bar, and i recharge,..it only takes 6 Ah to fully recharge ( so about 300Wh)
And that incidentally is roughly 1+ hrs, 25 km of off road hilly trails ..but mid drive set up.

Click to expand...

Thanks! I notice you're in Sydney too :wink: I'm Eastern suburbs, hence the hills. My 25km was up to Watson's Bay - hills and big headwind. Hopefully around flats and low wind it would be a lot better.

john61ct said:

There is no objective 750Wh capacity

All depends on the discharge rate what the actual capacity is.

So even the "most honest" vendor will assign a nameplate capacity of 15Ah that will only be true at say a 0.05C discharge rate, well below one amp.

And that assumes top quality cells, which you CANNOT accept vendors' claims, only validated by trusted forum vendors doing objective IRL stress testing.

At a high rate, say 15A (1C) that pack might in reality deliver only 12Ah, and for longevity you will only want to pull say 9Ah,

so now you're down to 430Wh

And that is only true for the first 5-10 cycles

every cycle after that capacity declines

the greater the Ah you want to pull per trip

the higher C-rate discharge performance you push

the faster that decline will be.

And unless you learn how to do objective cap tests yourself, most accurately and easiest with a CC dummy load

you won't be able to anticipate just how fast

and proactively buy a new replacement pack in anticipation.

Some users only get 50 cycles and the pack is at EoL

others might get 500 800 or (with a huge pack, low C-rates usage) maybe even 1000 cycles

Click to expand...

Thank you for the info, much appreciated.

MaximilianMM said:

Hopefully around flats and low wind it would be a lot better.

Click to expand...

Big YES to that!

Here, this may help you decode john61ct's posts:
https://endless-sphere.com/forums/viewtopic.php?t=38854

Everyone wants more range, buy a second (the same) and run it parallel that should hold you for a year.

Thanks both.