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Low battery protocol, KS18a 1200W 1360Wh


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Yesterday i drove my batteries to depletion. It is considered unwise, so I do not recommend that you repeat it. 

In the firmware version 1.20, low-battery safety speed limitation was added. A good reason to test how it was implemented. The KS18 responded in three stages to the low battery.

I started with full batteries. I drove a lot uphill and downhill (an estimated total of 400 meters up). Around the 60km mark the first stage kicked in.

Stage 1: Despite the fact that i did not reach the speed-alarm speed, a double beep informed me that I was going too quick for the battery charge left. Slowing down the beeps went away, and I could do 15-20 km/h without problems. On accellerating, the beeps returned immediately. The beeps were not set to a particular speed. I know this, because downhill I could still reach higher speeds. Accelerating slow was no problem, but a quick accellerating resulted in beeps. Gradually the speed I could reach lowered. The battery LED indicator, went between 4 and 2 LEDS. Everything on and below 2 LEDS made it beep.
Conclusion: whenever the voltage dropped because of the power asked, the beeps kicked in. 

Stage 2: I kept the speed mostly so that the beeps would not sound, and slower and slower i went, until all battery LEDS started to flash in unison. This was well over the 65 km mark. Also, continually single beeps (longer than normal beeps) were played in sync with the flashing LEDS. I continued at the terribly low speed of 8-10 km/h feeling completely confident that i would not hurt myself in case I would "fall" off. 

Stage 3: The 8 km/h speed was no longer possible around the 71 km mark. My kingsong started tilt back to 5 km/h and after another 2 km even below that. Riding had become virtually impossible/useless, and decided to call it a day.

I immediately plugged my wheel in to recharge, and assume that I did do no damage to the batteries. I learned the following:

1) The KS has a good protocol for low voltage/low battery
2) After the first stage kicked in, I still could go a reasonable distance: 13 km. If you are not in the middle of nowhere, you can still reach a busstop or a charge-point of some sort. 
3) This is the most important lesson: I will never again ride continually above the 2beep speed alarm, because it is the same as the low-voltage alarm. Two beeps means I have to slow down, whatever the reason for the beeps. So, set you speed-alarm accordingly. 

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@johrhoj Thanx for this Report!

To Point 3: You mean you dont ride any  faster when you hear the 2 beeps from/because of "low voltage" Alarm, or?

You did not mean the second Speed Alarm of the app, or? i do not think it is the same as the low voltage Alarm, because it stays where you have set it



Everything else  you Report i can confirm from my KS14c!!! The KS protocol forl ow voltage is fantastíc....You just have to listen to it/recognize it! and nothing will happen!

I learned what you reported on a very hard uphill....between 40 and 20% (4 or 2 LED) the 2 beeping starts....and it is exaclty like you said...it is driven by the amperage you try To draw from the batteries, because on a hozontal street by normal acceleration everything was still working great...



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