Minimum charge

[White Knight]

What i is the safe minimum charge (mileage/percentage) to use Model 3 before charging to the max (90%) without damaging or shorten the life of battery?

 

[JulienW]

There are no absolute numbers that are best or worst for lit-ion but.....the less time spent at a lower or higher state of charge the better. A general good rule of thumb is the 20%-80% rule. If charging higher than 80% or discharging lower than 20% spend less time at those states.

 

[SSedan]

If you think the battery needs to be cycled you are wrong.
The 90% suggested charge is about making sure BMS (battery management system)estimates of charge level are accurate. From a pure battery health perspective it is completely unnecessary.

Far as discharge level plug it in daily and charge to 70-90% whatever the discharge level is is fine so long as you aren't spending a lot of time below 10%. If using 5% a day you can replenish that daily or if you use from 90 down to 10% a day that is fine too, and on trips don't hesitate to tap into the top and bottom 10% just don't let the battery spend a lot of time there.

When I mentioned the BMS estimates the deal there is battery voltage is very stable in a range from something like 10-90%, if the pack is charged to 70% daily the BMS can only estimate charge level based on measurements of input and output. Reason Tesla suggests 90% is because that gets to a point where cell voltage begins to rise giving BMS a measure of real time charge level rather than just an estimate. If limiting peak charge below that you can see range estimates creep down, this is not loss of actual capacity just BMS calibration error which can be reset by letting charge go below 10% and then charging to over 90% so the system can measure voltages at those extremes and find its place again.
Tesla recommends keeping the car plugged in at home because then it can draw from the outlet as needed rather than discharging the battery some thereby reducing discharge cycles on the battery.

 

[gecko10x]

Far as discharge level plug it in daily and charge to 70-90% whatever the discharge level is is fine so long as you aren't spending a lot of time below 10%. If using 5% a day you can replenish that daily or if you use from 90 down to 10% a day that is fine too, and on trips don't hesitate to tap into the top and bottom 10% just don't let the battery spend a lot of time there.

I disagree with the part about constantly staying in a high SOC being OK. Based on the information about general lithium battery chemistry, if you are only using a small portion of the total capacity of the battery, ideally you want to keep the average SOC near 50%. So charge to 60% if you're only going to use 20% before you charge again.

Now, I agree that the above doesn't account for BMS calibration. So, IMO, if you're going to do what I just suggested, you'd want to charge up to 90% at least once every couple of weeks to keep the BMS happy.

 

[SSedan]

I understand the high state of charge being bad argument, since Tesla says set it to90% and keep it plugged in I really don't think it is that bad.

I will admit I keep my S at 70% in fair weather and at times go a few days between plugging in but come winter it is 90% nightly. Winter here near Green Bay is real and dramatically increases energy use.

 

[Darmie]

Good info here. Thanks all.

 

[ucmndd]

What i is the safe minimum charge (mileage/percentage) to use Model 3 before charging to the max (90%) without damaging or shorten the life of battery?

No such thing.

 

[Joe43]

So charging to to 70% during the weekdays and to 85% on the weedend is ok? During the weekdays I typically use about 12% of the battery for my commute and on the weekdays I drive a log more. I typically don't drop below 30%.

 

[JulienW]

So charging to to 70% during the weekdays and to 85% on the weedend is ok? During the weekdays I typically use about 12% of the battery for my commute and on the weekdays I drive a log more. I typically don't drop below 30%.

Sure.

 

[poolmeds]

I understand the high state of charge being bad argument, since Tesla says set it to90% and keep it plugged in I really don't think it is that bad.

I will admit I keep my S at 70% in fair weather and at times go a few days between plugging in but come winter it is 90% nightly. Winter here near Green Bay is real and dramatically increases energy use.

Hi
i am in the UK so weather in winter nothing like you but out of curiosity as i am new to EV - you say battery consumption far higher in winter - is that due to using heaters moe etc or is consumption higher due to car working harder etc?
just trying to learn all the quirks of EV's
thanks

 

[JulienW]

Hi
i am in the UK so weather in winter nothing like you but out of curiosity as i am new to EV - you say battery consumption far higher in winter - is that due to using heaters moe etc or is consumption higher due to car working harder etc?
just trying to learn all the quirks of EV's
thanks

Mainly the heater working. Also the battery has to be heated some too. Use the seat heaters and keep the cabin temp a little lower and this will lower consumption.

 

[duanra]

Also air density, less regen. More rain.

 

[SSedan]

Hi
i am in the UK so weather in winter nothing like you but out of curiosity as i am new to EV - you say battery consumption far higher in winter - is that due to using heaters moe etc or is consumption higher due to car working harder etc?
just trying to learn all the quirks of EV's
thanks

Heating, cabin, seats and the pack, my car has seen -30c.
My commute is short at 6.5miles each way, which means either I need to preheat well in advance which uses power from the outlet or the heater is running hard the whole drive. If good and cold energy use can triple for the first few miles, as the cabin warms consumption falls back nearer normal. The effects of cold are less prominent if you are going on longer trips because you are warming the cabin just once.

The instant heat is amazing, I start because no waiting for an engine to warm up.

You don't see it in use but the pack must be warmed to charge so that raises the electric bill some as well.

 

[Longrangeboost]

We have 2 Teslas model 3, one long range and one performance. We only charge to 100% just before a trip. Daily charging is at 90% as needed and I like to keep the battery at 50% or more. My wife gets busy sometimes and it drops to 30% rarely, in cold weather a warning comes up that the car won’t perform as well. In warm weather that warning doesn’t happen at 30%. Thankfully she doesn’t let it go below 30%. I keep my performance model at 60% to 90% daily. I have noticed a power reduction below 40%, not much just a small difference. This is why I keep mine charged at 60-90%, you never know when a hell cat pulls next to you that hasn’t run against a tesla yet and needs education .