What you see, is not the actual battery voltage, but the charging voltage. The Charger has to apply a higher Voltage, than the battery itself in order to charge it. The more Voltage-Offset you have, the faster you charge the battery. The needed Voltage offset depends on the internal battery resistance at the current SoC against charging. Its the same, like the voltage drop, when accelerating the car and discharging the battery fast, but the opposite way. It see this in so much videos. No, the actual voltage off the lfp-battery does not drop when charging. But the charging voltage drops, and so the Charging power does.
I want to know the same. What is dangerous about driving below 10% in the MG4 SE SR? I have one, and although I don't do it often I do sometimes. The car's manual is very comprehensive and it says nothing about this. I've been down to 4% (in summer) with no issues, and to 8% in winter, the same. We're told (in the manual) to take the car below 10% and charge all the way to 100% and balance every 3 to 6 months, so obviously you have to drive it there. You can't just throw out lines like "don't do that, it's dangerous" without explaining why it's dangerous and what dangerous consequences are being risked. As an MG4 SE SR owner, I want explanations.
Because the difference in voltage between 0 & 100% isnt that big. It is harder tot determine the real SOC. That was a problem in older LFP, not sure if it's still that bad.
@@zarbonidaunlikely unless your battery is poorly balanced as the bottom of the battery will be basically when one of more of the cells bottom out. However in most cases going to a few % is ok but don’t press beyond zero when possible. Personally I have only gotten as low as 6% in 15k miles of driving. I love the simplicity as the curve is very consistent even from 10% charge vs 6% for example so no major need to good too deep!
Hi Chris, the voltage over the charge curve is very interesting. Our Lexus RZ450e does the same thing. I wonder if they used LFP, but that would surprise me.
voltage in the pack stays about the same, its the amps that are delivered while charging that raises the voltage slightly , as amperage goes down , so does the voltage. The pack voltage starts to rise by the end of the charging cycle. Pack itself stays at the same voltage for almost all of its charging curve. That's why it's hard to estimate capacity of an LFP without a good bms.
For LFP the difference between 20% and 80% is just around 50 mV per cell, so the BMS has a hard time correctly estimating how full the battery is. When 10% is displayed you might be down to 0%. It seems Tesla have figured it out, but they recommend you charge to 100% every now and then because above 80% the voltage rise is steeper and thus the SoC easy to estimate. For NMC the difference between 20 and 80% is more like 500 mV so easy to measure.
not sure about MG, but Tesla only long time ago 20 Q4 - 21 Q1 had issues with LFP calibration, at worst you could say if you haven't charged to 100% for along time be careful don't drive close to 0%. But again I don't follow MG som maybe there are some issues.
There are no issues. If you regularly charge to 100% and let the battery balance there are no surprises. In fact it's quite spookily accurate. Do what the manual tells you to do, and know your car, and you'll be fine.
What you see, is not the actual battery voltage, but the charging voltage. The Charger has to apply a higher Voltage, than the battery itself in order to charge it. The more Voltage-Offset you have, the faster you charge the battery. The needed Voltage offset depends on the internal battery resistance at the current SoC against charging.
Its the same, like the voltage drop, when accelerating the car and discharging the battery fast, but the opposite way.
It see this in so much videos. No, the actual voltage off the lfp-battery does not drop when charging. But the charging voltage drops, and so the Charging power does.
I want to know the same. What is dangerous about driving below 10% in the MG4 SE SR? I have one, and although I don't do it often I do sometimes. The car's manual is very comprehensive and it says nothing about this. I've been down to 4% (in summer) with no issues, and to 8% in winter, the same. We're told (in the manual) to take the car below 10% and charge all the way to 100% and balance every 3 to 6 months, so obviously you have to drive it there.
You can't just throw out lines like "don't do that, it's dangerous" without explaining why it's dangerous and what dangerous consequences are being risked. As an MG4 SE SR owner, I want explanations.
Because the difference in voltage between 0 & 100% isnt that big. It is harder tot determine the real SOC. That was a problem in older LFP, not sure if it's still that bad.
Because with LFP battery no-one (even the BMS) knows if you are really at 10% or 0% or 20%.
So your display shows you 10%, but you are at 0%
@@zarbonidaunlikely unless your battery is poorly balanced as the bottom of the battery will be basically when one of more of the cells bottom out. However in most cases going to a few % is ok but don’t press beyond zero when possible. Personally I have only gotten as low as 6% in 15k miles of driving. I love the simplicity as the curve is very consistent even from 10% charge vs 6% for example so no major need to good too deep!
Hi Chris, the voltage over the charge curve is very interesting. Our Lexus RZ450e does the same thing. I wonder if they used LFP, but that would surprise me.
Never knew that voltage drops on LFP battery when you charge,that is so interesting ,never saw on any other type off battery
voltage in the pack stays about the same, its the amps that are delivered while charging that raises the voltage slightly , as amperage goes down , so does the voltage. The pack voltage starts to rise by the end of the charging cycle. Pack itself stays at the same voltage for almost all of its charging curve. That's why it's hard to estimate capacity of an LFP without a good bms.
@@ramunasgudauskas7582 Yes,i can know how much battery in lion battery just with voltage meter
Driving this down to 5% was no problem at all. I did not get your comment on this. We have an MG4 Okt 22 Std.
Why is driving below a 10% soc dangerous with a LFP battery?
For LFP the difference between 20% and 80% is just around 50 mV per cell, so the BMS has a hard time correctly estimating how full the battery is. When 10% is displayed you might be down to 0%. It seems Tesla have figured it out, but they recommend you charge to 100% every now and then because above 80% the voltage rise is steeper and thus the SoC easy to estimate. For NMC the difference between 20 and 80% is more like 500 mV so easy to measure.
Taking up two parking spaces 😢
not sure about MG, but Tesla only long time ago 20 Q4 - 21 Q1 had issues with LFP calibration, at worst you could say if you haven't charged to 100% for along time be careful don't drive close to 0%. But again I don't follow MG som maybe there are some issues.
There are no issues. If you regularly charge to 100% and let the battery balance there are no surprises. In fact it's quite spookily accurate. Do what the manual tells you to do, and know your car, and you'll be fine.