Cut off voltage, KT, 48v - help

[Smurf2]

Hi.
Today I tested to see if the bike will shut off when pass bellow 40v. But not work like I imagined.

I driven long at 0 bars. And one time just something happened between 38-40v. On display 0 bar start flashing and no power. But display worked. That is cut off?

I turn off the battery and turn the bike ON again. What happening is that display show me FULL Bars (4 bars) now. It seems that bars are reset.

I drive with that to 37v, sometimes show 36v. After like 5 min of drive, the display showed 3 bars.

So why continue without cut off? And why display after first cut off start show full bars?

My settings are:
Controller: KT
Battery 48v.
P5=15 (recommend for 48v)
C12=4 (for 40v cut off)

 

[Chalo]

Hi.
Today I tested to see if the bike will shut off when pass bellow 40v. But not work like I imagined.

I driven long at 0 bars. And one time just something happened between 38-40v. On display 0 bar start flashing and no power. But display worked. That is cut off?

I turn off the battery and turn the bike ON again. What happening is that display show me FULL Bars (4 bars) now. It seems that bars are reset.

I drive with that to 37v, sometimes show 36v. After like 5 min of drive, the display showed 3 bars.

So why continue without cut off? And why display after first cut off start show full bars?

My settings are:
Controller: KT
Battery 48v.
P5=15 (recommend for 48v)
C12=4 (for 40v cut off)

Which display are you using?

When you turned the display off and on again, it interpreted your 48V battery's voltage as a full 36V battery. And then you proceeded to damage your battery by driving it below 3V/cell. Don't do that. It's best for the battery that you never reach low voltage cutoff at all.

 

[Smurf2]

Don't do that. It's best for the battery that you never reach low voltage cutoff at all.

KT-LCD11

https://a.aliexpress.com/_EuznWeH

Uh, sorry
But If I set border to higher, like 41v, can I do that?
How do I know then my maximum range? When 0 bars show or?

I remembering my last controller, never shut off, but bellow 40v speed was like 10-15 km/h, and you can drive long like that

Find some, maybe good answer:

 

[Chalo]

But If I set border to higher, like 41v, can I do that?
How do I know then my maximum range? When 0 bars show or?

"Battery bars" state of charge displays are mostly useless. If you use a single specific display and a single specific battery, and you have experience correlating bars with exact voltages, then maybe that's somewhat helpful. But you can set the display to show system voltage, and that's a much better representation of SOC. It's the only one I pay attention to, because I have to deal with a number of different displays.

Set P5=0, so you can see actual voltage in the moment. Understand that only the voltage you see when you're not applying a load represents state of charge. Knowing how much sag you get under load is good data, too, that you shouldn't hide by setting the P5 value to anything other than zero.

I remembering my last controller, never shut off, but bellow 40v speed was like 10-15 km/h, and you can drive long like that

You can wear out your battery quickly like that, too. My advice is, don't. If you need that much range, get a bigger battery.

 

[Smurf2]

Set P5=0, so you can see actual voltage in the moment. Understand that only the voltage you see when you're not applying a load represents state of charge. Knowing how much sag you get under load is good data, too, that you shouldn't hide by setting the P5 value to anything other than zero.

But of P5=15 I think I see actual voltage? When stop, voltage is bigger and calm.
And the goal is watch voltage in load to not pass min. voltage, right?

But you can set the display to show system voltage

I did that.

 

[E-HP]

"Battery bars" state of charge displays are mostly useless. If you use a single specific display and a single specific battery, and you have experience correlating bars with exact voltages, then maybe that's somewhat helpful. But you can set the display to show system voltage, and that's a much better representation of SOC. It's the only one I pay attention to, because I have to deal with a number of different displays.

Set P5=0, so you can see actual voltage in the moment. Understand that only the voltage you see when you're not applying a load represents state of charge. Knowing how much sag you get under load is good data, too, that you shouldn't hide by setting the P5 value to anything other than zero.



You can wear out your battery quickly like that, too. My advice is, don't. If you need that much range, get a bigger battery.

Bars are for clueless factory ebike riders with no other options, or for checking your phone charge. You need to monitor voltage. LVC or range questions can only be answered by the owner and how comfortable they are with abusing their battery. Your brain and paying attention are the best LVC.

 

[Chalo]

But of P5=15 I think I see actual voltage? When stop, voltage is bigger and calm.

If you use any other value than zero, it does voltage averaging over some time period, so you don't see transient fluctuations with any accuracy.

 

[Smurf2]

If you use any other value than zero, it does voltage averaging over some time period, so you don't see transient fluctuations with any accuracy.

Oh average, that's it I will turn to 0 immediately.

According to my post #3, if I set min. voltage cut off like 42v-43v, and when finally power cut off, that can be safe for battery, if I know that I will return to home over 40v?

 

[Smurf2]

I set the biggest possible limit cut off voltage which is 41.5v, C12=7 (it's not 44v like in post #3!).

I tested on flat stop/go test, at full throttle. Average was 43v on load. Only one time passed 41.5v on load which triggered cut off.

In that time I set P5=0, and show 45v actual voltage.

So, I can use that actual "45v" to set my limit for further testing? I will have many tests in the future, and that's why I need to set a limit.

@Chalo, I don't need a bigger battery.

I know that I can drive maybe 10km or more if switch to pedal assist because PAS not have such a big load voltage drop like full throttle. In that case, I can have a separate limit only for PAS, like 44 a.v.? (but need to test load first).

 

[999zip999]

Get a cheap A.H. volt meter for your handle bars . Of couarse this only works if you don't loan your bike to your little brother.
Nobody going to rememnber what you say ? Problem.

 

[Smurf2]

I have a couple of this volt meters.
Already had one installed on my last display.
Not AH. Just volts/percent.