Discussion Starter · #1 ·
Agree. Looking forward to hearing more after this data can get properly decoded.That'd be great news for degradation, but it doesn't fit with the rest of the available information.
Okay, so SOC-R is an 8 bit SOC number converted to a percentage, and then SOC-U is an artificially created number based on Volt charge ranges?The Volt spreadsheet shows both SOC-U and SOC-R derive from the same PID (015B). They just get scaled differently. The Volt scaling factors won't be the same as the ones for the Bolt.
For the Volt, SOC-U = (015B - 54 ) / 1.34
SOC-R = 015B * 100 / 255
We can only go by SOC reported by the computer. That is the SOC-R number.Seems to me that any app telling you both the Useable SOC % and the Raw SOC % would need user (or programmer) input telling it some specific vehicle data, such as the size of the useable soc window (and where it starts or ends), to determine the Useable %. Which also raises the question... if the Useable SOC is determined by vehicle-specific data, is the Raw SOC also based on specs for my vehicle’s model year, making in possible for battery degradation to manifest itself in changes in the Raw SOC readings? If a battery degraded from 16 kWh to 11 kWh and was then fully charged (87% of 11 kWh), would it display on the app with a 60% Raw SOC reading (60% of the model year’s 16 kWh), or would it continue to read 87%, i.e., 87% of whatever the battery full capacity is?
Yes. The raw data for PID 015B ranges from 0 to 255, where 0 = bricked and 255 = overcharged. The BMS is likely responsible for generating the value, but only GM and LG know how it is calculated (until someone dumps and decompiles the Bolt's BMS. Not holding my breath as we're still waiting on someone to do that for the 1G Volt...)Okay, so SOC-R is an 8 bit SOC number converted to a percentage, and then SOC-U is an artificially created number based on Volt charge ranges?
That may be true if GM supplied SOC-U, but they didn't - that is a volt user calculation tailored to the known capacity of a volt.Let's try this possibility:
SOC-U = the "state of charge% usable" This would be the state of charge % usable for the trip when the "kwh meter" says "0" on the vehicle energy-used display.
SOC-R = "State of charge% remaining" and notes the current state-of-charge of the battery.
The vehicle computer probably has another piece of data (source not yet defined - perhaps another algorithm) that tells it what the battery's available kWh is at 100% SOC-U, then looks at the SOC-R and calculates the kWh used on that trip.
If that is the case, we can derive the battery's usable kWh at 100% charge by subtracting SOC-R% from SOC-U%, then dividing the displayed kwh used by the resulting %.
100-86.7 = 13.3%. 7.3 kwh/.133 = 54.89 kwh usable energy at 100% charge. What is the deepest that anyone has driven a Bolt? What was the kWh used with like 1 mile remaining? I seem to remember in one review where it was really getting low on charge that it was approaching 55 kWh. This would gybe with the total battery capacity of 60 kWh and a 5 kWh buffer.
Even if you reverse-engineered the code, all you'd be left with is the raw voltage information from the battery - unloaded and loaded voltages (at a particular power level) from which the values are calculated. That just begs the question of understanding how those relate to the maximum and minimum permissible charges. Remember that those are not absolute - they're set by the engineers based on their own criteria for battery longevity, performance, and target range.Yes. The raw data for PID 015B ranges from 0 to 255, where 0 = bricked and 255 = overcharged. The BMS is likely responsible for generating the value, but only GM and LG know how it is calculated (until someone dumps and decompiles the Bolt's BMS.