Recommended by Tesla Service Center to Charge Roadster in Range mode to optimise the battery

[nicky _cwt]

Recently, I visited to Tesla Service Center and discussed about battery care. They recommended me to charge in Range mode around once a month to optimise the battery.

Are you guys are doing this? I remember I read some posts that mentioned that charging in Range mode are harmful to the battery. Thus, not sure it is a good recommendation to follow or not.

Please give me your thoughts.

 

[X.l.r.8]

I do, but I have to. I do long trips and it’s just outside the standard range, especially in winter. The balancing is done at the top end at max voltage but minimum amps so it makes sense to balance the pack occasionally, but once a month is possibly overdoing it. The cells don’t like to be stored at max voltage so it’s best to ensure as soon as it’s done to be driving. If you have not range charged before be careful of the initial loss of regen for the first few miles, even though I know it’s gone it still surprises me how fast the car rolls without it.

 

[SSedan]

As said this is about balancing, but then storing at high SOC can be bad so make sure to drive just after completing.

 

[dhrivnak]

Yes I ensure I range charge a few times a year to keep the battery in balance. And yes I try to drive a few hours after a full charge and I do not do it when above 80F

 

[eHorses]

I can see the benefits of range charging to balance the pack for a car that’s driven on a regular bases. But what would you do if the car is in storage or put away for the winter? Charge it to standard and reset it to storage mode after charging?

 

[ML Auto]

You don't need to range charge to balance the battery. That is just bad advice. The only reason to range charge for rebalancing is when the battery is so far out of balance one brick can't maintain the minimum voltage required for balancing. But if that is happening you have a bigger problem anyways. Standard mode is plenty sufficient to keep it balanced. Just keep it plugged in and it will wake up every 24 hours to charge and balance itself. Storage mode does not balance at all-after a long time in storage mode the battery can be so far out of spec it can take weeks to recover.

 

[eHorses]

You don't need to range charge to balance the battery. That is just bad advice. The only reason to range charge for rebalancing is when the battery is so far out of balance one brick can't maintain the minimum voltage required for balancing. But if that is happening you have a bigger problem anyways. Standard mode is plenty sufficient to keep it balanced. Just keep it plugged in and it will wake up every 24 hours to charge and balance itself. Storage mode does not balance at all-after a long time in storage mode the battery can be so far out of spec it can take weeks to recover.

So, is it best to keep it plugged in at the standard charge setting even if you don’t driven it for weeksor in long term storage?

 

[ion_1]

Standard charge, keep it plugged in, you will be fine. With time it will balance even if out of balance somewhat significantly.
Range charge should be minimized, although very minimal degradation, range charging is worse for Li-ion vs standard charge. This is just fundamental to the chemistry in Li-ion. As noted above, if you have to range charge, get state of charge down soon to minimize further degradation (although slight).

Also, it is much, much better to always recharge the car when convenient vs. letting the battery discharge low before recharging (i.e. many shallow dept of discharges vs. fewer deeper depth of discharges.)

 

[hcsharp]

You don't need to range charge to balance the battery. That is just bad advice. The only reason to range charge for rebalancing is when the battery is so far out of balance one brick can't maintain the minimum voltage required for balancing. But if that is happening you have a bigger problem anyways. Standard mode is plenty sufficient to keep it balanced. Just keep it plugged in and it will wake up every 24 hours to charge and balance itself. Storage mode does not balance at all-after a long time in storage mode the battery can be so far out of spec it can take weeks to recover.

This is correct.^^^ All of it. The advice to charge in Range mode once a month is obsolete (by nearly 9 years). Tesla changed the firmware in 2011 to balance after every standard mode charge. For long periods of storage it's safer to leave it plugged in standard mode. Storage mode doesn't leave enough "cushion" of charge if something goes wrong and you're unable to charge it for a while.

Having said all that, it doesn't hurt to charge in Range mode once in a while if you need it for a long trip.

 

[nicky _cwt]

Thanks a lot for all the advice. I think I will stay using standard mode for balancing the battery.

 

[hanknum]

I'm going to re-hash this to see if any opinions have changed over the last few years...

My son is going off to college so a few things are going to change...
- We need to save more to offset the college cost
- Going to mothball the Roadster and drive his BMW Z4.
- Remove the Roadster from insurance... no sense insuring the Roadster, Z4, & my DD, when I ride my bike to work half the time.

The Roadster has 63k miles with a CAC of 111 on the original battery. I assume that it is best to keep it on standard charge (32A), other than 'storage mode". If it makes any difference, the car is stored in my garage, and I have OVMS, so if I do do storage mode and something goes wrong, I would be able to react quickly.

Please lmk your opinions.

Thanks.

 

[eHorses]

I would lower your amp to 12-16, if it’s not hot in your garage, and keep it set at standard mode.
I go bare all the time with cars that are in long term storage.

 

[hanknum]

I would lower your amp to 12-16, if it’s not hot in your garage, and keep it set at standard mode.
I go bare all the time with cars that are in long term storage.

Thanks eHorses... not sure what you mean in your second sentence.

 

[Botbldr45]

yea, Tesla Service Centers have few techs that know Roadsters. Standard mode is my go to unless I'm driving a long trip. Go with hcsharp's recommendation. He is a legand.

 

[hanknum]

With the weather getting better, I've been thinking about driving the Roadster again. But currently still in storage. I've got a couple more questions...

- When in storage, is it better to have it plugged into my 240V or 120V charger?
- I did swap over to the 120V last week just to test and it charged slightly more... added about 6 miles (98% to 100%). Why is that?
- Is it more efficient (cheaper elec bill) for me to charge on 120V or 240V?

Thanks.

 

[gregd]

Hi Hank,

240v is generally better than 120v because in the summer it allows the car to actively cool the battery (run the A/C). The A/C takes too much power to be run with 120v input. 240v is also a bit more efficient. For the same power, the higher current on the 120v side of the charger causes more energy to be lost due to heating of the wires and circuitry (current squared times resistance) than at 240v. On the flip side, it takes longer to charge at a lower input current, so the total heat can be more. I believe the "sweet spot" for efficient charging is 240v at something around 24 amps, more or less (16 to 32 amps, somewhere in there).

My mental model as to why you get a bit more range at 120v is that the charging is sneaking up to the limit, making it easier for the charger to determine where "full" is without going over. Overcharging quickly leads to "bad things", so it's avoided at all costs. Consider running full speed at a brick wall; you definitely want to slow down before you get there. I've found that the nightly "top-up" charging will increase the stated range slightly over a few nights; you get to about the same place eventually at either voltage.

 

[hanknum]

Hi Greg,

Thanks for the info and the analogy (what movie was it from where the character would say "Explain it to me so a 2yo could understand it"? )