Hi,
I have this object in my .idf file : ElectricLoadCenter:Storage:LiIonNMCBattery. I was wondering if this object has a self discharge rate. For example, if I have a state-of-charge of 100% at 9AM I expect to have less than 100% at 6 PM without charging or discharging. Is this phenomena implemented ? If not how can I manage to add it ?
Thanks a lot !
Hi Gio_GG,
If you turn on the lifetime model (set it to "kandlersmith", more info on that model is here: https://docs.nrel.gov/docs/fy17osti/6...) you will see the charge gradually go down over time. The lifetime model updates daily, so you won't see the change hour by hour, but if you try to hold charge for multiple days you will see the amount of stored energy drop.
Because the lifetime model is changing the capacity of the battery to account for degradation, make sure you look at the amount of stored energy ("ElectricStorageBatteryChargeState"), not the state of charge ("ElectricBateryStorageChargeFraction"). The SoC will look constant, but the amount of energy stored does in fact go down.
Here's an example where I charge the battery in the first day and let it sit idle for weeks:
Asked: 2025-11-20 08:46:29 -0600
Seen: 43 times
Last updated: yesterday
I'm not answering the question, but isn't it a really small effect? According to https://www.ufinebattery.com/blog/why..., the self-discharge for a lithium battery is 2-5%/month, so only like a 0.1% effect over the course of the entire day.
Yes, I agree. I am trying to have a building model which is as stochastic as possible like in the real world. I just want to know how the little stochasticities can affect the results even though they could be small.