knightmb
Well-known member
Hx is the conductance of the battery pack as a whole (all the cells) usually measured in Siemens but Nissan is using some other metric name I suppose?What does the Hx number (91.27%) signify?
This percentage is relative to nominal or 100%. The lower the conductance, the less power the battery can take (charging) or deliver (driving). The drop in conductance is *usually* driven by high temperatures and high state of charge. So letting the Leaf roast out in the Sun at 100% SOC is not a great idea.
It can also change based on age and battery temperature in general. Hx is one of those values like SOH that if you obsess over too much it can drive you crazy. Sure you don't want bad values, but they are changing all the time and you can't make predictions from them. For example if your SOH is decreasing by 0.01% every day, you can't take that and predict that your battery with be dead with 1% SOH in xyz amount of days. It might go a whole month(s) without changing. Same thing with Hx, don't try to predict a future battery failure based on a recent history of readings you record. Sure, you want to make note if you start to see a rapid drop in values, so making a history of the values with larger spaces of time leads to more sanity.
A side effect of a low Hx is that you get limited motor power more often. It will happen more often with a cold and depleted battery. It can also slow down fast charging, etc.