Simulating battery charge & discharge component

Hey there,

I want to create some kind of component which helps me a bit with my Niu NQi Sport Battery (eScooter).
The eScooter can be charged directly by plugging a cable into it. Thats not the way I am charging it, as I dont have a electricity in the garage and thus, I have to unplug the battery from the scooter and charge it somewhere else.

When the battery is unplugged, I have a sensor where the last known percentage of it is exposed until the battery is re-plugged.

So I have the “last known state” available. I want to have some kind of sensor, which I can use to simulate the natural discharge of an unused lithium battery.
I think this can be done with Node-Red or an automation where I subtract a specific amount of “percent” every X Minutes/Hours.

So this might help me to determine when I have to charge the battery so it does not drop down to 0% which causes harm to a lithium battery.

So, the next step would be: when I plug the charger into the Battery, I want to trigger an automation or flow in Node-Red which handles the charging. I need to know how long it takes to charge 1% of the Battery when it is not being used (when charging it within the scooter, this might take a bit longer as it consumes power for the ECU - control unit which provides GPS and stuff).

As far as I know, lithium batteries are being charged quite quickly when they’re charged less than 80%? So I probably need some kind of logarithmic logic to raise the percentage…

As you can see, its not that simple to have a simulating component for charge and discharge of a lithium battery.
Did anyone else already had similar ideas regarding this topic?
Does anyone have other ideas?

Heading forward to your feedback!

The concept that comes to my mind is to have a helper with the power charge value and a timer that gets started when you unplug the battery and each iteration of the timer would cause the helper value to change. Fairly low-brow but it seems like it would do the trick.

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Yah, something like this came to my mind aswell.
I wonder if there is some kind of specification which says how much kWh are “lost” when the battery is not in use tho. But I could also do some samples like:

  • plug battery in
  • grab current battery percentage
  • unplug battery
  • wait a few hours
  • plug battery in
  • grab current battery percentage

But I dont think that this might be a good way to determine the power consumption…
I’ve found this this article but I am unsure if thats really the case. It says that a lithium battery is discharging 5% in 24h and then 1-2% per month. I am unsure if that is really the case but I could verify this probably with some samples tho.

I think I will give this a try and then gather the informations I have and create some node-red flows.

I think you can get some decent baselines from information online, but the rest is going to be trial and error.

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