2021 LFP SR+ On a gentle motorway run yesterday from Chester to Liverpool I averaged 200wh/m so with a usable 53kwh battery the cars capable of up to 265miles. Given the weather wasn’t ideal yesterday (14 degrees and windy), the LFP appears capable of marching its WLTP claim (278) in better weather (190wh/m). But my bladder wouldn’t!
The rest of us are still trying to get our heads around this change in battery charging regime! We take care to “baby” the battery pack by only charging to 80 or 90% unless really necessary in the hope of maximising its lifespan. It’s clearly a flexibility bonus to routinely have that extra 20% available on a daily basis. I would keep monitoring the forum and any other legitimate sources for the latest feedback just in case the recommended approach to LFP charging should be modified in the future.
The consumption rate of the car shouldn’t really be affected by the battery chemistry. The fact that your car is efficient may be down to other improvements… in fact I have the impression that my own 2019 car has improved its Wh/mile performance in recent times. I don’t have Teslafi data so that may not really be the case… has anyone seen this?
Given our usage "every charge" is once a week most weeks but occasionally a few charges a week which is pretty much in line with the guidance in the manual. 99% of charging is at home as well so that's a bit gentler on the battery. Will keep an eye out for any change in advice though
No. LFP doesn't have the energy density to allow for a LR LFP battery - it wouldn't fit.
90% most certainly can effect regen. But typically not that much.
I don't understand the concern about regenerative braking after charging to 100%. Unless you charge up at the top of a high, steep hill, you will discharge the battery accelerating much more than you will recharge it subsequently braking.
You would think so ... but in colder weather a reduced regen warning is often on-screen even on the flat for quite a while. Even in not particularly cold weather you can see the warning come on if descending a long hill with the battery at 80%. So long as you are aware what's going on, and don't panic about it, it's no big deal. The query about whether regen remains "normal" at 100% with LFP battery is more from curiosity than anything else ... simply because it would be a different behaviour from the other battery types. Any time regen can replace an otherwise necessary application of brakes there's a small benefit to range (or quite a useful benefit if you live on the top of a very steep hill that you're going to descend soon after charging). However, given the corrosion build up on lightly used EV brakes it may be a worthwhile trade off to give them something to do!
Thing about LFP is that they have a flat voltage curve and usually maxes out at around 3.4V-ish so at 30% or 100% they can be 3.4V. High voltages over time is a reason for concern, on NCA and NMC 4.2V is typically max,, especially in high temps and can cause degradation on most types of li-ion batteries, but the LFP is an odd exception since the voltage curve is flat. A problem with a flat voltage curve is that it`s harder for the BMS to read actual SOC, hence the recommendation to charge to 100% to "help" BMS understand the actual SOC %. If you partially charge a LFP over time it can cause a memory effect and the BMS can report incorrect SOC, a bit like the old Nim-batteries.
I've been charging my SR+ LFP to 100% once or twice per week, and other days I've dropped the max charge to 80-90%. I was thinking this would be the best way to allow the BMS a chance to calibrate, but also avoid any damage to the battery by maxing it out every night. Based on what you're saying, am I wasting my time? Do you think I'd be better off going to 100% every day?
Point of charging a LFP to 100% regularely is to balance the battery as the BMS can struggle with estimating true range since voltage curve is flat. It`s much easier on NMC\NCA where for instance 4.2V is 100%, 4.0V is 80% etc. On LFP 30 and 100% both can be 3.4V so unless you charge it to 100% regularely you can risk that the car says battery is at 80% while in reality it is at 40% which can be very unfortunate on a longer trip where range would suddenly drop from for instance 50% to 15% in a few km as even LFP get a volt drop when the SOC is very low. Don`t remember exactly when it happends, but somewhere between 10 and 30% the voltage starts to drop and then you are close to zero.
I would charge it to 100% atleast once a month, but except for that charge it to the level you need. The longevity of a LFP is about the same sitting at 100% as it is at 50%. A NCA\NMC degrades significantly if left at 100% for long periods, but thrives at 20-60%.
Hi Taraquin, I haven't heard of any SR+ LFP running out of electricity and there is about 40,000 of them on the roads in the UK...
It's not a common problem, but if you partially charge them for long periods of time, the BMS has more trouble reading actual SOC due to same voltage at low and high SOC. Chineese owners has reported this isdue, but Tesla may have found ways to read SOC in other ways than rely on voltage to fix this.
Only 7 weeks in but charge LFP to 100% and car still has regen breaking when we pull out in the morning.
