DIY Repair: McLaren MP4-12C new Lithium Ion Battery

Even with the best car batteries, I suppose it is inevitable. That day you come out and nothing works and the car won't start. With a McLaren MP4-12C, you can avoid that by keeping the car on a trickle charger, as I have for years when it's not in use.  But even then, eventually the battery kicks off. In my case, it was when the battery hit 13 years old, at around 60,000 miles of use.

Before I was good about trickle-charging, I had had the battery get low a couple times and the car became non-responsive. The problem with that in a 12C is that you can't open the door. And if you can't open the door, you can't open the front trunk latch. There are two ways to solve this dilemma. One is to use the manual key in the hidden keyhole under the door "handle" area (There is no actual handle, but the door hides a keyhole under a panel for emergencies).  The second method, one I have used a couple times, it to take off the front left wheel arch cover (a few small screws) enough to expose the cable that runs from the cockpit to the front latch (that cable sits at about the 2 o'clock position on the wheel arch). You can then pull on the cable rearward with some needle-nose pliers and the front trunk lid will pop free. 

However, in this instance, I didn't need to do either of those, because when I am trickle-charging the car, the front trunk lid/hood stays open a crack. One small win right there. 

Because the car was on the trickle charger, I wondered if I just didn't have it plugged in properly, so after trying a few more time and resetting the charger, its, it was clear the battery was kaput. That sent me to the online forums and to Google search and to all the AI bots to find out what is the best replacement battery for the 12C. Well, it turns out there are lots of options on that one. I won't argue the merits of any particular choice of AGM vs Lithium Ion. I'll just tell you what I chose to do.

I decided to buy and install Antigravity H7/Group-94R Lithium which is a direct replacement for the OEM Battery. I bought mine from Supercar Garage ATL, home of the McMedics. And as I learned form the vendor and from helpful forum posts, you also need to install an "emulator" module between the battery and the old harness in order for the battery to talk to the ECU. And yes, there are cheaper options you may find, but make sure you calculate shipping before you decide in my case, I passed on another good option out of the UK because the shipping charges outweighed the cost savings.

So here's my order and some links: 

https://supercargarageatl.com/products/antigravity-h7-group-94r-lithium-car-battery-1

https://supercargarageatl.com/products/mclaren-battery-module-coming-soon

Not cheap, but a bit better than what the dealership would charge to replace the OEM battery.

OK, enough of that, here's the basic process shown below. You can also find a few Youtube videos on the subject that might be helpful. 

First thing to do its to remove all the lining panels from the front trunk. There is a plastic border/seal that runs around the top perimeter, held on by velcro. After you pull that up, you can see the plastic hold downs and plastic screws. I have no idea why mine seems to include an illogical mash-up of Phillips-head, pup-up push rivets, and Torx-head screws. In any case, I took a photo after I pulled up the trim so I knew which ones to put back in which spot. 

Once you open it up, it looks like this (I once again tried my trickle charger on it). I also confirmed that my battery was original, dated 20 October 2011. From the now-defunct A123 Batteries, Inc.

First step: Pull the small red harness lock to the left and unplug the wiring harness from the left side of the battery, then remove the negative battery terminal from the post. 10MM wrench.

Loosen the strap in the middle using the buckle. This whole thing will be removed from the bottom bolt, so don't worry about whether it's super loose or not.

Now the hard part: Taking off the right side circuit panel from the positive terminal. Hard because you need to move the whole thing out of the way to get to all the hold-down bolts. And the wire harness leading to it is very stiff. Start by popping up the right side of the panel cover, and removing the cover (hinged on left). Then use a 10MM wrench to remove the terminal from the positive post.

The wiring harness is held down by this bolt and clamp in a somewhat tight area. 13MM socket on a short extension worked. Then you can pull the whole contraption off to the right side.

The battery bracket is held down by two 13MM bolts on the left and right, and three 10MM bolts on the front, plus two Torx-head screws.

Once all the brackets are free, it looks like this, time to take it out.

About this time I must have made myself a grilled cheese, because these were the next photos in my series... I made this with my home made cast--iron olive loaf and 4 kinds of cheese plus harissa butter.  Damn, that was good.  Maybe you didn't know that Dave Car Guy is also Dave Grilled Cheese Guy.

OK, back to the buttery.  Ooops, I mean battery (sandwich still on my mind). 

Installation is just the reverse. At first, I thought I had the wrong battery replacement, because it is a few inches less wide. But I confirmed I had the right one, as the vendor explained that the brackets are wide enough to still hold down the narrower battery. They were right.

Look at the pic below and you'll see that I installed the emulator leads on the positive and negative terminals and then plugged the yellow-lead harness into the red/black harness that came off the left of the original battery. That is so the battery can be read by the ECU.

And the confirmation that it is working is that the battery status on the screen interface shows that the battery as received was at 83%. After running for a bit, it was fully charged to 100%.

Anyway, it wasn't too bad. Try it yourself and send me any questions.

DIY Repair: Aston Martin Navigation Screen

I've had my 2007 Aston Martin V8 Vantage since November 2006 and have written about my experiences in a couple prior posts (See: Long Term Ownership Costs).

I often tell people that it is the only car I'll never sell. It's not the best in any one thing, but it is very, very good at all things, and still one of the best looking cars (IMO) ever made. 

It has also been extremely dependable, never causing me any big issues and in many cases, fairly easy to work on myself for example: My D-I-Y brake change .  

There is no doubt that a dealership repair cost will always be a more expensive proposition that an D-I-Y repair, and this post is about another one of those instances.

The pop-up navigation screen is very 2007, and was a cool feature back then. But unfortunately it is a point of weakness and these units sometimes stop popping up when engaged. The problem is a small set of gears. In my case, I was fairly sure it was a gear issue since I could hear the small electric motor running when I engaged the screen, but it wouldn't move. I was able to gently move the screen up by hand without much resistance, so another reason to believe the gears have broken. I wanted to fix this before I considered a full upgrade to an Apple Car Play solution for the interface.

I called the Aston dealer and was told they don't fix these units, they just replace the whole navigation system screen and unit.  Cost is something in excess of $2000.  But the gears to fix this are just $17.  So I decided I'd "pay myself a couple grand" to learn how to do this.

There is a great online helpful video by Richard at Repants.lol which takes you through the steps of fixing this issue. That's what I followed to make this all work. First step is to disengage the screen cover from the screen unit. In my car there were two small tabs hugging the sides of the unit, so a little lateral pressure pulled them off and allowed the screen to be free of the cover. (some other cars have two metal bars holding this on, not my model). Watch this other video by Richard at Repants to see more info on removing this panel.

Using small plastic trim tools, I found it easier to start at the top of the "ski slope" center console cover. You have to be very gentle, particularly with the piano black cover, as it can be easily cracked if you flex it too much.  I found the top to be stiffer than the lower section, so I used a tool on each side to pop it up. After that, the center and bottom pressure holders came up more easily as I grabbed and pulled up on the unit gently.  Did I mention gently?

Unplug the wire harness from the starter button as you lift the cover.

Four metal screws hold down the nav screen unit.

After removing the screws, also unplug the two wiring harnesses from the backside of the nav unit.

You can see the tabs at top, bottom, and center which keep the ski slope cover on. Also a good time to re-glue the foam bits around the vents.

To replace the gears, the first step is to remove the small black plastic cover. One screw on the front and a pressure tab inserted at the back. I like to tape the screws to stuff I take off so I don't lose track of where they go later.  The pressure tab at back is shown in the yellow circle below.

Now to remove the left side cover over the gears and motor (see red circles below). You loosen the two screws on top of the main panel and remove the other three screws on the left of the photo. Note one is hidden under the foam piece at back. You can now remove that left side metal shroud. 

There was one more panel I had to remove and I didn't take a pic. It has one small screw next to the motor that has a slide-in tab holding down the cover. Watch the excellent video by Repants to get the idea of how to loosen that screw to remove the last cover which holds the small electric motor.

I could now see the clearly broken pieces of the final gear that have fallen away from the last axle.

With the gear area exposed, you can easily slide off the first two gears. The ones to be replaced by the kit I bought were the half-moon one on the final spring-held axle and the second fat one shown here half way off the axle. The one in my hand gets re-used. The last part to remove is the small c-clip, washer, and spring retainer on that final gear axle (second photo below). The c-clip and washer also come with the 2-gear set I ordered. The pieces of the broken half moon are shown below after everything is apart.

Installing the new gears is easy, I just made sure to put on the half-moon gear in the right direction (it goes onto slots/tabs on the axle, so it is clear how it goes on), then add the washer and c-clip before placing the spring back in place. I used a silicone based grease to lightly lubricate the plastic gears for longer life. Then just re-install the plate that holds the motor. 

Now re-install the cover plate with the three screws, making sure to "tuck" the metal plate back under the larger cover plate on top. Finally, re-install the small black cover with one screw, making sure to tuck the rear tab into its slot.

Plug the two wire harnesses back into the Nav screen and re-install in dash with 4 screws.

Replace the ski-slope center console piece, making sure to plug the wire harness back into the start button

Align the center console cover over the tab insert holes at top and bottom and use gentle pressure to click them back in.  You can then snap back down the Nav screen cover and the two side tabs will re-engage on the screen unit.

The Screen works again! 

Total cost:

$17.00 gear set from Aston Installations (can also buy from Redpants)

$30.00 shipping from the UK

$22.00 Tariff collected by DHL (yes, paid by me, not by the importer or exporter)

$69.00 Total cost and a couple hours of work.  Better than $2000 at the dealer!