What happens when battery goes below 10%

[DTZ]

When I started my ride home from work yesterday my Levo battery was at approx 16% charged, I know that I use approx 9-12% to get home, so rode as normal (mainly eco, a bit of Trail on a couple of short Turbo bursts around a crazy roundabout and a big hill.

Just over half way home the battery dropped below 10% charge remaining and the bike seemed to start limiting power / assistance significantly, Eco mode became almost no assist and on a long uphill slope that I'd normally breeze up in Eco I had to switch to Turbo just to get the level of assistance I'm used to. I arrived home a little hotter than usual, but still had 7% of battery remaining, I would have been happy to arrive home with 1% but had normal levels of power for the last couple of miles.

I use Blevo on my bike and use the smart power settings. The rider watts meter was showing my increased pedalling effort, and Blevo was actively changing the assistance levels within my ranges, but it was evident both from feel and also from the "Bike Watts" meter that the bike was not giving as much power as it usually would for a specific assistance level / input from myself.

Is there some kind of functionality built into the Levo that limits power as the battery runs low? Has anyone else experienced this?

 

[TrailwattsUK]

Your battery bms is designed to protect the cells within aswell as the motor.
Your assist levels will lower as the bms reaches a preset limit to protect the cells from draining completely which damages their stability and health.

 

[OleBCN]

I experienced the same.

 

[Levolized]

I experience loss of power around 40-50% left, perhaps not as bad as you do but you can clearly notice it and it has been like that since day 1...Is my case normal anyone?? Did even notice power changes in the motor after shifting the power cable. When i notice that I switch it on/off and it seams to work proper again...

 

[TrailwattsUK]

Yes as Trailwatts says it´s normal and is called even Smart Controll...But I experience loss of power around 40-50% left, perhaps not as bad as you do but you can clearly notice it and it has been like that since day 1...Is my case normal anyone?? Did even notice power changes in the motor after shifting the power cable. When i notice that I switch it on/off and it seams to work proper again...

If your battery is suffering at 40% there is a fault with the bms or needs diagnostic check.

 

[Levolized]

If your battery is suffering at 40% there is a fault with the bms or needs diagnostic check.

Ok, thanks! So the bms should start kicking in first around 10 procent than? Btw I ment bms not Smart Control...

 

[TrailwattsUK]

Ok, thanks! So the bms should start kicking in first around 10 procent than? Btw I ment bms not Smart Control...

Your bms will take temperature, load and battery percentage (cell state) to calculate the amount of energy it will allow.
This can be from 20% downwards or higher depending on thermal conditions.

If your battery is starting to restrict at 40% then you are either in an oven or top of Everest.

I suggest diagnostic on your battery and motor

 

[Levolized]

Your bms will take temperature, load and battery percentage (cell state) to calculate the amount of energy it will allow.
This can be from 20% downwards or higher depending on thermal conditions.

If your battery is starting to restrict at 40% then you are either in an oven or top of Everest.

I suggest diagnostic on your battery and motor

Thanks, I am not on Everest nor in an oven... We had like 16-20 celcius here for a while so should be pretty optimal conditions for an e-bike I guess...

 

[Specialized Rider Care]

@DTZ Expected behaviour from the MY2019 Levo battery is below (normal temperatures 0° - 50°C)

• 100%-16% SoC: 100% maximum power
• 15%-11% SoC: 75% maximum power
• 10%-6% SoC: 50% maximum power
• 5%-4% SoC: 25% maximum power
• 3%-1% SoC: No power to drive unit, although entire system will still be powered on and lights (if connected) will also work. (we wanted to get you home safely )
• Worth knowing that below freezing Li-ion delivers reduced power even at 100%SoC.
  • Below -20°C and above 70°C the battery won't turn on, or won't deliver power.
  • -20° to 0°C / 50° to 70°C the battery will deliver approx 25% less than the figures above. (as Li-ion cells typically produce some heat during use the battery may still warm up enough to provide full power below freezing)

 

[TrailwattsUK]

@DTZ Expected behaviour from the MY2019 Levo battery is below (normal temperatures 0° - 50°C)

• 100%-16% SoC: 100% maximum power
• 15%-11% SoC: 75% maximum power
• 10%-6% SoC: 50% maximum power
• 5%-4% SoC: 25% maximum power
• 3%-1% SoC: No power to drive unit, although entire system will still be powered on and lights (if connected) will also work. (we wanted to get you home safely )
• Worth knowing that below freezing Li-ion delivers reduced power even at 100%SoC.
  • Below -20°C and above 70°C the battery won't turn on, or won't deliver power.
  • -20° to 0°C / 50° to 70°C the battery will deliver approx 25% less than the figures above. (as Li-ion cells typically produce some heat during use the battery may still warm up enough to provide full power below freezing)

Great info to have ?

 

[eTrax]

@DTZ Expected behaviour from the MY2019 Levo battery is below (normal temperatures 0° - 50°C)

• 100%-16% SoC: 100% maximum power
• 15%-11% SoC: 75% maximum power
• 10%-6% SoC: 50% maximum power
• 5%-4% SoC: 25% maximum power
• 3%-1% SoC: No power to drive unit, although entire system will still be powered on and lights (if connected) will also work. (we wanted to get you home safely )
• Worth knowing that below freezing Li-ion delivers reduced power even at 100%SoC.
  • Below -20°C and above 70°C the battery won't turn on, or won't deliver power.
  • -20° to 0°C / 50° to 70°C the battery will deliver approx 25% less than the figures above. (as Li-ion cells typically produce some heat during use the battery may still warm up enough to provide full power below freezing)

Would this be the same for MY2022 ?

Have to say I prefer getting 100% all the way down to ~4% let the user decide their faith or at least give them the option to do so.

 

[Paradan09]

Would this be the same for MY2022 ?

Have to say I prefer getting 100% all the way down to ~4% let the user decide their faith or at least give them the option to do so.

Not much can be done about it. We all want big light batteries, so the manufacturer choses the most energy dense cell that can still deliver the power( energy and power are inverse proportionate). If you check the OCV curve (open circuit voltage) for Li-Ion cells you see that the voltage drops significantly at the end. That means you would have to compensate with a way higher current (DC Power=Voltage x Current). The cell can not deliver that current due to the inner resistance and therefore the voltage drop would be even higher. If you are not careful in that area you are getting the battery to a too low voltage where it would become a fire hazard trying to recharge it. Therefore manufacturers cannot allow it.
There manufacturers could use more power dense cells that don’t taper off that dramatically but then a battery of the equal size and weight would have less usable energy. Or they could limit the accessible lower area - same result, less energy.

 

[eTrax]

Not much can be done about it. We all want big light batteries, so the manufacturer choses the most energy dense cell that can still deliver the power( energy and power are inverse proportionate). If you check the OCV curve (open circuit voltage) for Li-Ion cells you see that the voltage drops significantly at the end. That means you would have to compensate with a way higher current (DC Power=Voltage x Current). The cell can not deliver that current due to the inner resistance and therefore the voltage drop would be even higher. If you are not careful in that area you are getting the battery to a too low voltage where it would become a fire hazard trying to recharge it. Therefore manufacturers cannot allow it.
There manufacturers could use more power dense cells that don’t taper off that dramatically but then a battery of the equal size and weight would have less usable energy. Or they could limit the accessible lower area - same result, less energy.

Makes sense, but I do know my Bosch and Shimano buddies are getting full (relatively speaking) mode usage down to the last few percent just before the system shuts down. I feel robbed with 9% left and a final stiff climb to get me back out of the woods. Gimme that 9%-5% even if its 50% max.

 

[Paradan09]

It just means that those batteries have a smaller usable window. They could be labelled bigger with the compromise of the tapering off.