[1AS]

I love my car, and do make a habit of plugging in the charger if I'm not expecting to use it for a week or so. It's been fine for 8 months, and 2600 miles. Last Friday night, I drove the car. The next morning cleaned the inside of the front windshield (didn't start the engine, turned nothing on), and 36 hours later, the battery was completely flat. Key wouldn't open or lock the door, etc.
After a trip to the shop (very accommodating- lake Forest Sports Cars), it responded to a recharge, and nothing wrong could be identified. Left alone, it loses about 4% of its charge in 24 hours, which seems okay to them and to me.
I heard no fans running, and don't think I unintentionally left a parking light on.
My questions are, "has anyone else had this happen?", and "any thoughts on what occurred?"
What I've learned is that the lithium ion battery can be completely recharged after going dead, unlike the typical automotive battery we are accustomed to. I'm told that a light touch of the start/stop button can stop the engine, but leave it in one of 3 "start" modes, similar to an ignition key turned to "on" but not "start". I'll have to pay attention to that.
I'm getting it back today, and will let you know if there are any further developments (or not).
All insight appreciated. Thanks

 

[texas mongrel]

I've left mine for up to four weeks whilst travelling and never had an issue. I never use a charger or battery tender, mostly because one of my other cars (Ford GT) is notorious for frying its gauges, and one theory about the failure relates to trickle charging. My car is left unlocked while I'm gone, so I don't know if this influences battery drain? Will be interesting to hear what you're told....

 

[jkheit]

I've left mine for up to four weeks whilst travelling and never had an issue. I never use a charger or battery tender, mostly because one of my other cars (Ford GT) is notorious for frying its gauges, and one theory about the failure relates to trickle charging. My car is left unlocked while I'm gone, so I don't know if this influences battery drain? Will be interesting to hear what you're told....

The worst thing you can do to a lithium ion batter is trickle charge, and top up, or complete depletion. Meaning a lithium ion batter likes to be somewhere between 10% and 90% charge most of the time, with an occasional top up/full depletion to "reset" its memory.

The trickle charge top-up will put the absolute most wear and tear on the battery.

 

[LimeyBloke]

The worst thing you can do to a lithium ion batter is trickle charge, and top up, or complete depletion. Meaning a lithium ion batter likes to be somewhere between 10% and 90% charge most of the time, with an occasional top up/full depletion to "reset" its memory.

The trickle charge top-up will put the absolute most wear and tear on the battery.

So, why does the company supply the car with the trickle charger. This makes no sense. I always leave the trickle charger connected when not in use.
This is a direct quote from the owner manual:
NOTE: To maintain your lithium ion battery in optimum condition, always leave the battery charger connected to the battery and switched on during periods when your vehicle is not in regular use.

 

[Fastlane]

So, why does the company supply the car with the trickle charger. This makes no sense. I always leave the trickle charger connected when not in use.
This is a direct quote from the owner manual:
NOTE: To maintain your lithium ion battery in optimum condition, always leave the battery charger connected to the battery and switched on during periods when your vehicle is not in regular use.

There are special chargers for lithium Ion battery's they work different then trickle chargers. I assume McLaren knows that and the one supplied is the correct type.

 

[jkheit]

So, why does the company supply the car with the trickle charger. This makes no sense. I always leave the trickle charger connected when not in use.
This is a direct quote from the owner manual:
NOTE: To maintain your lithium ion battery in optimum condition, always leave the battery charger connected to the battery and switched on during periods when your vehicle is not in regular use.

That's a good question. Perhaps they are weighing convenience of not having a dead car over longevity of the battery. So if you know you won't be driving the car for 2 months, and there is a decent chance it will be dead, they value the startup over the prolonged battery life.

But there is no doubt about it. If you keep it in trickle for long periods of time, it will kill the battery if there's constant trickle/top up. If you have a laptop that you keep plugged in for months at a time, you'll find that battery has significantly lessened capacity to one that you use regularly. It's because of the trickle. Here's an apple article on it (very different context, but the chemistry of the batteries are the same; so unless Mclaren does something very different on the charge cycle when plugged in, the same deterioration should occur).

http://www.apple.com/batteries/
http://www.apple.com/batteries/notebooks.html

Standard Maintenance
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.
...
Long-Term Storage
If you don’t plan on using your notebook for more than six months, Apple recommends that you store the battery with a 50% charge. If you store a battery when it’s fully discharged, it could fall into a deep discharge state, which renders it incapable of holding any charge. Conversely, if you store it fully charged for an extended period of time, the battery may experience some loss of battery capacity, meaning it will have a shorter life. Be sure to store your notebook and battery at the proper temperature. (See “Notebook Temperate Zone.”)

So ideally, you don't want to use it too much, or too little.

 

[jkheit]

There are special chargers for lithium Ion battery's they work different then trickle chargers. I assume McLaren knows that and the one supplied is the correct type.

Ideally their charger would read capacity of the current battery charge, and keep it between 10-90% charge, and apply a charge maybe once every 4-5 days. However, I suspect when you start the car, you'll find it fully charged. I haven't tried, but if someone could check, and see if the car is charged near 100% after being plugged in for say 2 weeks, then we'll know.

For reference, laptop chargers are not smart enough to regulate charge in an intelligent manner like noted above even when plugged in for a long time. They just juice until 100% is reached. Of course, that's a very different setting.

 

[Bob5]

Ideally their charger would read capacity of the current battery charge, and keep it between 10-90% charge, and apply a charge maybe once every 4-5 days. However, I suspect when you start the car, you'll find it fully charged. I haven't tried, but if someone could check, and see if the car is charged near 100% after being plugged in for say 2 weeks, then we'll know.

For reference, laptop chargers are not smart enough to regulate charge in an intelligent manner like noted above even when plugged in for a long time. They just juice until 100% is reached. Of course, that's a very different setting.

Lenovo does try to limit the charge on some of their laptops by cutting off internally, in some manner, the charger input when the charge reaches a specified level. But back to the car, a significant issue with lithium ion type batteries is you can't determine charge levels very accurately by measuring the voltage of the battery.

A number of techniques have been tried, one of which is to actually measure coulombs in and coulombs out on a real time basis. The 12C battery does have a data port on it connected to the cars electronics and it is used for the battery readout you see on the info panel. The situation can arise where the battery, in a conversation with the car, a conclusion is reached declaring the battery is flat and the info panel will inform you that it is flat and the car will not start. Doors still open though, and if you connect the charger to the car, the charger will indicate the battery has a full charge. So who is being truthful here, the charger or the battery?!

Well guess what happens if you pop the trunk liner out and disconnect the data port? Yep, the car starts right up, so the charger had it right. Seems to be a couple of possibilities here. One, the battery is very smart and does all the calculations on what the battery charge is and transmits the value to the car, or two, the battery is sending more basic data and the car is doing the calculating. I don't know which it is at the moment.

Our good friends at Boeing can tell us at length about how the lithium ion weight savings is not a free lunch.

 

[LimeyBloke]

It does seem that Ctek (the maker of our supplied McLaren charger) is producing a lithium charger (see below) for general sale now; This is most likely similar to the one that we received with our cars (albeit, branded with the McLaren logo). I'd venture Ctek did it correctly so that it won't harm the battery, as jkheit has explained.
McLaren absolutely had to let Ctek know that the charger they would be making was for the 12C's lithium battery. .... otherwise!!
http://blog.ctek.com/?p=492

 

[timborama]

Ya, I wouldn't leave the car idle on the charger for 6 months, but 3-4 weeks isn't an issue. The charger is smart enough to cut off. Apple says that because they don't want a fire issue. MY MacBook is ALWAYS plugged into power for 4 years, no issue with the battery. LiPOs only have X number of charge cycles, leaving it plugged in continuously DOES NOT alter to the cycle count.

 

[jkheit]

Ya, I wouldn't leave the car idle on the charger for 6 months, but 3-4 weeks isn't an issue. The charger is smart enough to cut off. Apple says that because they don't want a fire issue. MY MacBook is ALWAYS plugged into power for 4 years, no issue with the battery. LiPOs only have X number of charge cycles, leaving it plugged in continuously DOES NOT alter to the cycle count.

Hmm, I've seen laptops like this, in particular, MacBooks and there are major issues. Mainly, that when you take the laptop off the plug, after about 15 minutes, the battery life drips to 20% of it's original capacity. That's why Apple posts that you should NOT keep it plugged in all the time (see quote above in the trail).

If you didn't have an issue, that's great. But it's a well noted issue; just check the apple discussion forums for tons of posts.

Here's one of many threads on the topic:

https://discussions.apple.com/thread/3974536?start=0&tstart=0

 

[timborama]

Hmm, I've seen laptops like this, in particular, MacBooks and there are major issues. Mainly, that when you take the laptop off the plug, after about 15 minutes, the battery life drips to 20% of it's original capacity. That's why Apple posts that you should NOT keep it plugged in all the time (see quote above in the trail).

If you didn't have an issue, that's great. But it's a well noted issue; just check the apple discussion forums for tons of posts.

Here's one of many threads on the topic:

https://discussions.apple.com/thread/3974536?start=0&tstart=0

I think Apple is more worried about things like unattended fires, bursting lipo packs, etc. than degradation.

 

[1AS]

I was told the charger was specific to the car, and the use of any other "normal" charger would damage the battery. AS

 

[jkheit]

Lenovo does try to limit the charge on some of their laptops by cutting off internally, in some manner, the charger input when the charge reaches a specified level. But back to the car, a significant issue with lithium ion type batteries is you can't determine charge levels very accurately by measuring the voltage of the battery.

A number of techniques have been tried, one of which is to actually measure coulombs in and coulombs out on a real time basis. The 12C battery does have a data port on it connected to the cars electronics and it is used for the battery readout you see on the info panel. The situation can arise where the battery, in a conversation with the car, a conclusion is reached declaring the battery is flat and the info panel will inform you that it is flat and the car will not start. Doors still open though, and if you connect the charger to the car, the charger will indicate the battery has a full charge. So who is being truthful here, the charger or the battery?!

Well guess what happens if you pop the trunk liner out and disconnect the data port? Yep, the car starts right up, so the charger had it right. Seems to be a couple of possibilities here. One, the battery is very smart and does all the calculations on what the battery charge is and transmits the value to the car, or two, the battery is sending more basic data and the car is doing the calculating. I don't know which it is at the moment.

Our good friends at Boeing can tell us at length about how the lithium ion weight savings is not a free lunch.

It's interesting, but somehow I doubt most chargers are smart enough to do what we're talking about. Most chargers, just charge until full. So what usually happens is the batter keeps getting topped off. I'm not familiar with Lenovo, so it's cool if they do something more. But to do it right, the charger would have to detect, (a) that it's plugged in for a long time, e.g., say over 1week, and then as long as it stays plugged in (b) let charge drop to say 20% and then fill up to 70% and cycle back and forth as long as it's still plugged in.

However, if the device is plugged in for say less than a couple of days, it should always top-up.

For a laptop, generally, you want to almost always top up because you want to use it unplugged.

Perhaps it's different for the Mac because it's rare you would use the charger to topup; rather you'd use it to do a jump or just keep the batter at a reasonable level for longterm storage. So I take it back. Perhaps it's smarter.

Again, the easy tell is after not driving the car for 2 weeks on the charger, if you start the car and it reports 100% charge, then you know it is NOT behaving in a smart way to maintain the health of the battery. If it's in the 80% or lower range, then it IS maintaining a charge in a smart way.

 

[jkheit]

I think Apple is more worried about things like unattended fires, bursting lipo packs, etc. than degradation.

I'm sure that's a worry, but they have tech notes specifically that leaving the charger ;lugged in for a long time kills the battery. Read through the thread. There are plenty of people with that problem. There are a bunch of articles/sources on this:

http://www.gamersnexus.net/guides/899-battery-myths-li-ion-battery-management

A slow trickle-charge to a battery already at maximum capacity can also harm its total lifespan, though, and so leaving a system constantly plugged in is inadvisable; the increased heat produced by the charging unit will damage the battery, as will unnecessary charging. Some laptops will intelligently disable charging once the battery has reached full capacity and will only resume charging once drained to a predefined level.

http://lifehacker.com/5875162/how-often-should-i-charge-my-gadgets-battery-to-prolong-its-lifespan

Don't leave it fully charged. Similarly, lithium-ion batteries don't need to be charged all the way to 100%. In fact, they'd prefer not to be—so the 40%-80% rule you heard is a good guideline. When possible, keep it in that range to prolong its life as long as you can. And, if you do charge it to 100%, don't leave it plugged in. This is something most of us do, but it's another thing that will degrade your battery's health. If you need to charge it overnight, use something like the Belkin Conserve Socket to stop it from charging after it's full.

 

[Bob5]

If you were to actually fully discharge a lithium battery I an pretty sure you destroy it. These batteries have internal circuits that shut if off before full discharge occurs, at least the laptop batteries do this sort of thing.

For a car battery that pumps out 100 or more amps when called on its a little hard to see an internal circuit within the battery that would do this cutoff function when the charge got too low, which has made me suddenly realize that that is why the car itself refuses to let the car be started if it thinks the battery charge is below a certain point and if the charge drops even lower due to a light being left on it will totally disconnect everything to protect the battery from full discharge. Since the charger is directly connected to the battery the car can't protect against overcharging.

Somebody at McLaren fully understands what is going on and it would be good to hear from them. And if they do shed some light here it will be yet another indication that they are a different kind of car company and a cut above the rest.

 

[jkheit]

If you were to actually fully discharge a lithium battery I an pretty sure you destroy it. These batteries have internal circuits that shut if off before full discharge occurs, at least the laptop batteries do this sort of thing.

For a car battery that pumps out 100 or more amps when called on its a little hard to see an internal circuit within the battery that would do this cutoff function when the charge got too low, which has made me suddenly realize that that is why the car itself refuses to let the car be started if it thinks the battery charge is below a certain point and if the charge drops even lower due to a light being left on it will totally disconnect everything to protect the battery from full discharge. Since the charger is directly connected to the battery the car can't protect against overcharging.

Somebody at McLaren fully understands what is going on and it would be good to hear from them. And if they do shed some light here it will be yet another indication that they are a different kind of car company and a cut above the rest.

That makes a lot of sense--kind of a battery self-preservation circuit. It would be great for them to chime in, agreed.

 

[noone1]

Where is the battery charger? Is it under the luggage compartment liner? I'm not there to look, and my brother says he doesn't see a charger anywhere. Does he need to unscrew the liner in the luggage compartment? Is there one under there?

 

[Markjayw]

Where is the battery charger? Is it under the luggage compartment liner? I'm not there to look, and my brother says he doesn't see a charger anywhere. Does he need to unscrew the liner in the luggage compartment? Is there one under there?

The charger port is to the right of the hood latch inside the front boot. It uses the cigarette adapter. Charger should be in driver's side mesh pouch in boot.

McLaren provides the high output CTEK charger with the 12C. It is fully capable of maintaining our batteries. Now the cheap one that Ferrari provides with their cars, well that one would probably cause problems.

 

[noone1]

Yeah, I see the port, but I actually don't have a charger or at least can't find it. I assumed it would have been in the trunk under the liner, but based on what the manual says, I should have a whole bunch of stuff in the trunk when in fact I have nothing. Did you have that first aid stuff and tow hook/etc in the trunk as well, or is that just an EU thing? There are straps in the trunk that would seem to hold that stuff that the manual shows, but there is nothing.

The car was bought used from the dealer, but I did not seem to receive either the battery charger, the car cover, or any of the stuff the manual shows in the trunk. I understand that used cars are sometimes missing tools and stuff, but if it's on the sticker I'm shown, I expect it to be with the car.

Guess I'll have to be contacting the dealer again...