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So, my mechanic had left the car with the ac on full blast, and my car ended up with the high voltage battery completely depleted, and roughly 33% rechargeable. MPG aslo dropped by quite a bit. My model is a 2019 with lithium battery pack, and only has 95k miles on it. They supposed to come with automatic reconditioning, but occasionally this doesn't happen. I researched what this 'reconditioning' procedure is, and some mechanics may have tools to charge and deplete the battery pack several times, and restore it to much of its former glory. I don't have the tools, but I can do the charging and depleting from the car, as the "Empower" window shows the state of charge on my car, as well as the energy output to the electric motor. First I tried fully charging the battery for longer time, but that didn't do anything to recover the cells. Then I used the Empower window, to make sure the battery got completely depleted, by running the car on electric only. In Empower, a fully charged battery reaches about 2.25 bars (equals roughly 22kW or 30HP on electric motor output). I kept the motor output at 2 bars on the Empower indicator, where it struggled to reach even 50MPH (where as before it could easily do 70MPH at 2 bars). Once the battery level lowers to 2 bars, lower the motor output to stay below the state of charge indicator. If the output exceeds the state of charge, the engine will start, and you want to prevent this from happening, as you don't want to charge the battery just yet. At least not until the state of charge is below 0.1 bar (roughly 1-2 hp motor output). You'd have to have a fine foot, to keep the motor output under the state of charge the entire time, and a large safe space, where you won't hit anything, and won't bother cars behind you, as the car will slow down going on all electric. A good place to do this, if you don't own a dyno, is on a long straight road, without any side streets, preferably at night or late in the evening, when there's no traffic. And put lane assist on, as you need to switch your focus between keeping the car on the road, just not to end up in the ditch, and keeping the motor output below the state of charge on the indicator. Once the state of charge reaches nearly zero, the engine will automatically engage. You'll want this to happen with the SoC being as low as possible. When recharging, I find the battery charges fastest between 2.5 and 2.75 bars in eco mode, as less power is transferred to the wheels in eco mode, amd more power is harvested by the generator. You don't really need to fully charge the battery, but at least let it run up to 1 of 2 bars. The bms just needs to trigger the dead cell to charge. Once it charges, it can later figure out how much charge the cell can hold as you're driving normally, during its automated reconditioning procedures. Hence, the phase of emptying the battery cells during a manual reconditioning, is more important than the charging phase. Then repeat the process (completely empty the battery, and recharge) for a few times. Sometimes you can recover a significant amount of battery. Other times, only a little, as cells have lost even more voltage potential over the course of time when the bms bypassed them. Charging from a depleted state, will trigger a 'try to charge the cells'-action in the BMS, for those cells that are considered dead. The BMS will never charge these cells when the pack is charged up, because the charge current would be too high for the 'dead' cell (the dead cell would be charged from the other cells in the pack, and could overheat). Instead the BMS just disables the cell it sees as not functioning, until the rest of the pack has a similar low voltage. Then it'll try to charge the cells, just like the other cells, with a low current (divided over the other cells). The BMS will only try to charge the dead cells, when the rest of the pack is relatively balanced with the dead cell in terms of charge. I've repeated the process of charge discharge, about 5 times, and while I haf lost nearly 2/3rd of the battery charge before manually reconditioning, due to the error of my mechanic, I estimate that roughly 1/4th has been recovered since then, to a SOC between 50% to 66% of new (estimated). I'll probably need to redo the procedure again to about a good 10x charge/discharge cycles to have it working good again. Should take roughly 2 hours time (estimated). The procedure is nowhere explained, which is why I created this thread. If your battery has recently died, it should work without any expensive tools. I recommend to do the manual reconditioning procedure only when you've recently noticed a significant drop in mpg, and electric range. For me, that didn't happen until 95k miles. You apparently also can manually charge individual cells in a pack, when the above procedure was unsuccessful, by opening the pack, using a 1,2V charger, some crocodile clamps on each pouch cell cathode and anode pins, and bringing individual cells back to life through directly charging them (without bms). This procedure is significantly more tedious, but could save you thousands on repairs, if you have the time. That's also how battery repair shops repair a battery pack. They first recondition, and only replace the cells when necessary.

HI, I have just bought my first hybrid. It's a 2017 Fusion Hybrid Titanium and I have had it for about 1 week. I have driven it on the highway, and around town. It seems like no matter what I do, the battery charge indicator only peaks at 50% full. I have driven about 100 miles so far probably 50/50 highway and city. I'm averaging 43 MPG which is great. It seems to charge well when I stop and coast. My Questions: Since I just bought the car (used - it was a rental car before). 1) Should I make sure it will fully charge the battery? How do I fully charge it? 2) Should I expect the gauge to hover around 40%-50% at all times? Thanks for the help. I'm a hybrid newbie! BL