McLaren Life banner
1 - 17 of 17 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter · #1 ·
Hi All,
I am a relatively new owner of a 720s. Having owned an Aston Martin and Ferrari, I am familiar with random fault codes mysteriously appearing and my 2019 720s with 4K miles has thrown a few already in the 5 weeks or so I have owned the car.

I drive the car every week and keep it on a trickle charger when parked. However, when I took possession of the car and went to connect the charger for the first time, I noticed the twist ties perfectly in place around the charger’s cables which make me suspect the prior owner never used the charger. The car is three old.

I went for a drive today and noted the battery tender showing a full charge when I disconnected it. I drove for about 45 minutes continuously and when I returned home and reinstalled my charger, it showed the battery only being 75% charged

Since I started topped off, and I assume the alternator would be charging while I was driving, I’m just curious if this drain on battery is typical.

the car dash says 45 days (I think full charge), but the trickle charger suggests the battery is not at fully charged.

Just curious if anyone has noted something similar
 

·
Owner
Joined
·
955 Posts
I always use the charger when not in use and I think I have a similar response. If the car says full charge, it probably is.
 

·
Registered
Joined
·
6,440 Posts
Hi All,
I am a relatively new owner of a 720s. Having owned an Aston Martin and Ferrari, I am familiar with random fault codes mysteriously appearing and my 2019 720s with 4K miles has thrown a few already in the 5 weeks or so I have owned the car.

I drive the car every week and keep it on a trickle charger when parked. However, when I took possession of the car and went to connect the charger for the first time, I noticed the twist ties perfectly in place around the charger’s cables which make me suspect the prior owner never used the charger. The car is three old.

I went for a drive today and noted the battery tender showing a full charge when I disconnected it. I drove for about 45 minutes continuously and when I returned home and reinstalled my charger, it showed the battery only being 75% charged

Since I started topped off, and I assume the alternator would be charging while I was driving, I’m just curious if this drain on battery is typical.

the car dash says 45 days (I think full charge), but the trickle charger suggests the battery is not at fully charged.

Just curious if anyone has noted something similar
Like you I keep the trickle charger connected at home. Not sure what you mean with your statement above “when I returned home and reinstalled my charger, it showed the battery only being 75% charged” The trickle charger does not really show the state of charge of the battery - the orange LED just show that charge is being sent to the battery - when the LED reaches the green level the charger holds at a maintenance current level.

If you want to see the state of battery charge you can navigate the menu on the folding dispay.
Font Gadget Automotive tire Screenshot Electronic device
 

·
Registered
Joined
·
1,352 Posts
On my mclaren charger. Even if the battery level is at 70+ %. The charger light always starts at low. Then quickly will change to 3/4 after a while and eventually to full.
 

·
Registered
Joined
·
294 Posts
As FirstKill just said, when you return home and plug in your mclaren charger, it will not just go to green on the charger, it will take a while to cycle up from 1/2 or 3/4 to full. Doesn't mean the battery is not full, just the charger is going through it's cycles before showing full.

Mine, even after a long drive, will take some time when plugged in for the charger to show the top green dot lit up. Perfectly normal.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #6 ·
Like you I keep the trickle charger connected at home. Not sure what you mean with your statement above “when I returned home and reinstalled my charger, it showed the battery only being 75% charged” The trickle charger does not really show the state of charge of the battery - the orange LED just show that charge is being sent to the battery - when the LED reaches the green level the charger holds at a maintenance current level.

If you want to see the state of battery charge you can navigate the menu on the folding dispay.
View attachment 214757
Yeah, I think you are correct that I am misinterpreting what the trickle charge led light position is indicating. That makes sense that the charger is simply reflecting the level of charge it is supplying to the battery vs the state of the battery’s charge. Yes I am aware of where I can see what the car is reflecting which was why I was questioning the difference between the two. Thanks for the input!
 

·
Registered
Joined
·
690 Posts
question, if your car is driven weekly (assuming lets say 2-3 days) why does it need the trickle?


My 600LT that i had was driven 2 days a week max, and i never had it on trickle. never any battery issues.
 

·
Registered
Joined
·
6,440 Posts
question, if your car is driven weekly (assuming lets say 2-3 days) why does it need the trickle?


My 600LT that i had was driven 2 days a week max, and i never had it on trickle. never any battery issues.
Yes based on your experience I think you have answered the question. No need for trickle charger if car is used frequently.

I started keeping my early 720S on the trickle charger because it would set off alarms at odd hours, windows would lower etc. All this was fixed after a software update.
The trickle charger does no harm to the battery because the trickle charge current lowers to a maintenance level at green LED.
 

·
Registered
Joined
·
123 Posts
I drive my car frequently (2019 720s), but still stick it on the charger in the off chance I might be away and forget about it.

Regarding mystery fault codes: I think that the majority of these are fixed with full software updates. I was having some battery issues where it was saying my fully charged battery was at 2%. The dealer did a bunch of software updates, and the car has been flawless ever since. Maybe some wire got wiggled back into place or something unrelated, or maybe I have not given it enough time, but it really seems that all the software updates they did have cleared out a lot of the voodoo.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #10 ·
question, if your car is driven weekly (assuming lets say 2-3 days) why does it need the trickle?


My 600LT that i had was driven 2 days a week max, and i never had it on trickle. never any battery issues.
The trickle charger extends the life of the battery from my understanding. McClarens, Ferraris, and to a lesser extent Astons are known to have battery drain while parked. The trickle charge mitigates that impact.

The reason for my particular question was whether this parasitic drain could be the culprit from random fault indicators that flash, and then resolve themselves either while I driving, or when I restart the vehicle. I have received three or four parking system faults, a suspension system fault, and one other I can’t recall at the moment.

I just had the car serviced and nothing came out of that inspection so I was curious if battery drain might be causing some wonky electronic issues, particularly since it appears the trickle charger was never used, my car only had 2k miles driven over the three years prior to my purchase.
 

·
Registered
Joined
·
714 Posts
Lithium ion batteries have a limited number of power cycles in them. For maximum life, the best way is probably to only charge when necessary to prevent the charge falling below about 50%.
 

·
Registered
Joined
·
6,440 Posts
The trickle charger extends the life of the battery from my understanding. McClarens, Ferraris, and to a lesser extent Astons are known to have battery drain while parked. The trickle charge mitigates that impact.

The reason for my particular question was whether this parasitic drain could be the culprit from random fault indicators that flash, and then resolve themselves either while I driving, or when I restart the vehicle. I have received three or four parking system faults, a suspension system fault, and one other I can’t recall at the moment.

I just had the car serviced and nothing came out of that inspection so I was curious if battery drain might be causing some wonky electronic issues, particularly since it appears the trickle charger was never used, my car only had 2k miles driven over the three years prior to my purchase.
Perhaps better to call the McLaren (CTEK) charger a battery maintenance charger as the low “trickle charge” stops when the battery has reached near full level.
If your car is exhibiting “wonky” issues best to have the dealer service make a check. Mine were resolved with software updates and replacement of the accumulators.
 

·
Registered
Joined
·
225 Posts
On my mclaren charger. Even if the battery level is at 70+ %. The charger light always starts at low. Then quickly will change to 3/4 after a while and eventually to full.
EXACTLY as mine shows as it did on the 12C I had before the 720S. I always thought that you are close to 100% when your done driving. Mine quickly goes to 2 greens in a few hours or so.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #14 ·
Perhaps better to call the McLaren (CTEK) charger a battery maintenance charger as the low “trickle charge” stops when the battery has reached near full level.
If your car is exhibiting “wonky” issues best to have the dealer service make a check. Mine were resolved with software updates and replacement of the accumulators.
Yeah, my car is 3 years old and only 4K miles so I am hoping the random fault codes are from the need for a software update. That runs $200 vs $3-4k for the McLaren A123 battery. I parked the car last night and the left side running lights wouldn’t turn off. The random gremlins are becoming annoying quickly. Fault codes have included parking system failure, key fob not detected, and suspension system failure. The latter temporarily stopped the control on my front lift. Turning the car off and restarting seems to clear the issues but I seem to be getting one or more messages a week. Thanks for the heads up on the software update!
 

·
Registered
Joined
·
123 Posts
Fault codes have included parking system failure, key fob not detected, .... Thanks for the heads up on the software update!
I posted earlier about the software update fixing all the gremlins on my 2019 720s, and I omitted one detail of my experience to correct here:

One thing the software updates did NOT fix is "key fob not detected". That one I suspect has to be related to a weak signal between the fob and the car, or possibly interference from cell phones or similar, and the software updates did not fix anything related to that. The easy fix I have found is I just keep two fobs on me at all times, one in each pocket. I have never had any issue when I remembered to do that. The other fix I have found is that if that occurs, on the days I only have my single fob, I press the giant McLaren logo button to "unlock" the car, even though I am sitting right in the car, and that seems to do the trick. (Others have mentioned placing the fob in special places in the car such as the kangaroo pouch at the front of the seat, or the cupholder area, but that never seems to work for me.) One other thing to make sure of is that I am pressing super hard on the brake when I press the "Start" button, and I have learned not to "double click" the start button by mistake, as that seems to cause random voodoo, I think.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #16 ·
I posted earlier about the software update fixing all the gremlins on my 2019 720s, and I omitted one detail of my experience to correct here:

One thing the software updates did NOT fix is "key fob not detected". That one I suspect has to be related to a weak signal between the fob and the car, or possibly interference from cell phones or similar, and the software updates did not fix anything related to that. The easy fix I have found is I just keep two fobs on me at all times, one in each pocket. I have never had any issue when I remembered to do that. The other fix I have found is that if that occurs, on the days I only have my single fob, I press the giant McLaren logo button to "unlock" the car, even though I am sitting right in the car, and that seems to do the trick. (Others have mentioned placing the fob in special places in the car such as the kangaroo pouch at the front of the seat, or the cupholder area, but that never seems to work for me.) One other thing to make sure of is that I am pressing super hard on the brake when I press the "Start" button, and I have learned not to "double click" the start button by mistake, as that seems to cause random voodoo, I think.
Thanks for the update/clarification! I’m shooting for end of the week for the software upgrade so this helps manage my expectation. Personally I have experienced that simply taking the fob out of the key holder near the key holder and just waiving it near the dash seems to resolve the “key fob not found” fault. I may just change the battery to make sure the fob is providing the proper signal strength … or I may just duct tape it to my forehead while driving:)
 
1 - 17 of 17 Posts
Top