Forums

Join The Community
RegisterLogin

Battery life concerns

As I reach for the charge cord more frequently for my cell phone every passing day I worry about the implications for my future Model S. I know the battery capacity will diminish every year. Even TESLA puts a NEW battery (<1y/o & <25k miles)as one of their prerequisites for getting the stated mileage. We have had enough TESLA battery powered cars out for a sufficient amount of time to see some data start to come in. At least we should be able to see if the degradation is linear or curved over time.

My cell phone battery's life span is about a year. At that point its down about 2/3 of what it was. I would think the same would be said for a car battery. If 260 miles was what you bought your car for and all of a sudden you could only drive 156 miles, you would probably have major problems doing the things you bought the car for. Or at a the very least, a major reworking of how you get them done. So if my Model S's battery drops below 2/3 of the stated range I would be looking for a new battery. When is that 2/3's number going to be hit?
I understand that supercharging has an effect. Lets assume 2 super charges a month to full capacity. The rest of the charges would be thru twin charging 240volt 100 amp circuits. Driving on average 15k miles a year in south Florida.

Any ideas on battery life degradation projections?

Cell phone and laptop batteries would last longer with sophisticated thermoregulation and charge management software. Nothing lasts forever--which is to restate the 2nd law of thermodynamics--but I think in 8 years' time it will be a rare circumstance for an MS owner to invoke the battery warranty. In the meantime, consider the alternative costs of maintaining, say, the transmission on the ICE vehicle you'd have otherwise incurred.

Is max charge for a 60kw car more than what the car is rated for? Some kinda of Over-Charge type process? I would imagine someone going to a supercharger would be charging until the car says full. Most people try to fill their cars up with gas as few times as possible (if financially able) to limit the time spent at filling stations.

Standard charge is about 90% of full Max. It's what is recommended, and what you get unless you specifically specify Max! That last 10% stresses the battery, especially if left "unused" (not driven) for long.

Ahhh, OK. Well a 10% loss if range isn't too bad if it allows supercharging repeatedly without battery degradation over regular charging. You gotta do what you gotta do.

@Tim, I think Tesla had originally speculated (perhaps even stated?) that Superchargers would be rough on the battery, but they have been supercharging a test vehicle many, many times with no significant degredation (beyond normal expected degredation from the number of charge/discharge cycles) and have since changed the message from "Supercharge when you must" to "Max charge when you must." The party line is now that because the Superchargers deliberately slow down as the battery's charge levels increase, there's no reasonable amount of Supercharging to normal levels that will impact your battery life. So go ahead...Supercharge (just not to a max charge if avoidable!).

A very experienced owner on TMC, with his 10 Rules of Road Tripping, points out that leaving a car Max Charged for months is a problem; hours is not. He recommends always Range (Max) charging: http://www.teslamotorsclub.com/entry.php/96-The-Rules-of-Model-S-Road-Tr...

It's also important to ignore articles that deal with 'cycles'. Most owners operate in the range of 50 - 90% charge capacity, and rarely go from 100% to zero.

Simply charging the batteries doesn't count as a cycle. Otherwise, every time you slow down, you are charging.

I mean going through a cycle. Wish we could edit.

Does anyone know how really cold climate will affect the battery? Where I live we may have temperatures of -20°C and sometimes even -30°C (-4 and -22 Fahrenheit) for weeks on end every winter, and I park my car outside for most of the time...

Svante;
The battery:
1. Will not charge when cold, must be prewarmed, either with a plug or using its own power.
2. Will not drive (well) when cold, must be prewarmed, by plug or use.
3. Will probably cost you 20% efficiency/range at those temperatures.

Ignoring range, it would be very helpful to have the car plugged in to even low amperage "shore power" when parked in the cold. This will keep the battery safe, and will probably enable you to access full power etc. when starting every day.

Thanks Brian!

Off on a tangent here, but I seem to recall a remark made by Elon recently (else I wouldn't recall at all:) that unless you used your battery for target practice or somesuch, the warranty is valid. Maybe in a conference call? The idea was to reassure worried customers-to-be, I infer.

Yes, Elon made it clear that the warranty is unconditional (basically). Doesn't matter if it is your fault or Tesla's the warranty will kick in and Tesla will replace your battery for free.

@Brian

How can you leave a car Max charged for months? Unless you mean Max charge it every day for months. Given vampire load, the car won't stay fully charged for even a day.

Hard to do, but if left plugged in, and set on Max, I assume it would keep topping off to that level. To quote Doug_G,

A few hours at 100% charge has NO measurable impact on battery pack lifetime, and may actually improve battery pack balance.

On the other hand, running your pack down to 0% is really not good for it. Drawing power at very low voltage means much higher current draw. This is more stressful on the cells. Sitting at a very low charge is not good for battery lifetime.
.
Suppose you skipped using Range mode, and now you’re falling short. The battery pack is approaching zero range. It’s not good for the battery. You could get stranded on the side of the road. Suddenly you’re feeling pretty foolish for not using Range mode!
.
So remember: 100% is nowhere near as bad for the battery as 0%. If you’re paranoid then do the Range mode charge just before you leave, to minimize the time spent at 100% charge. This isn’t actually necessary, but it may make you feel better.
.
Never, ever hesitate to use Range Mode. Ever.

Blew the tags; all the last paras are part of the quote:

Yes, there is a warning on the touchscreen about battery lifetime, but IMHO that warning is overstated. Tesla doesn’t want you leaving the car in Range mode for months at a time, because that will slightly increase the rate of degradation of the battery pack. We’re talking months here, not hours!
.
A few hours at 100% charge has NO measurable impact on battery pack lifetime, and may actually improve battery pack balance.
.
On the other hand, running your pack down to 0% is really not good for it. Drawing power at very low voltage means much higher current draw. This is more stressful on the cells. Sitting at a very low charge is not good for battery lifetime.
.
Suppose you skipped using Range mode, and now you’re falling short. The battery pack is approaching zero range. It’s not good for the battery. You could get stranded on the side of the road. Suddenly you’re feeling pretty foolish for not using Range mode!
.
So remember: 100% is nowhere near as bad for the battery as 0%. If you’re paranoid then do the Range mode charge just before you leave, to minimize the time spent at 100% charge. This isn’t actually necessary, but it may make you feel better.
.
Never, ever hesitate to use Range Mode. Ever.

Hm. It would appear the site's tag rules have changed.

Testing:

italics
.
bold
.
both

Nope, the problem was mine. Here's the corrected post:

Yes, there is a warning on the touchscreen about battery lifetime, but IMHO that warning is overstated. Tesla doesn’t want you leaving the car in Range mode for months at a time, because that will slightly increase the rate of degradation of the battery pack. We’re talking months here, not hours!
.
A few hours at 100% charge has NO measurable impact on battery pack lifetime, and may actually improve battery pack balance.
.
On the other hand, running your pack down to 0% is really not good for it. Drawing power at very low voltage means much higher current draw. This is more stressful on the cells. Sitting at a very low charge is not good for battery lifetime.
.
Suppose you skipped using Range mode, and now you’re falling short. The battery pack is approaching zero range. It’s not good for the battery. You could get stranded on the side of the road. Suddenly you’re feeling pretty foolish for not using Range mode!
.
So remember: 100% is nowhere near as bad for the battery as 0%. If you’re paranoid then do the Range mode charge just before you leave, to minimize the time spent at 100% charge. This isn’t actually necessary, but it may make you feel better.
.
Never, ever hesitate to use Range Mode. Ever.


X Deutschland Site Besuchen