Posts: 453
Joined: Tue Apr 21, 2015 8:07 am
Location: Southern California

Re: Replace 12V battery in 2017-2018 FFE

Wed Apr 08, 2020 2:00 pm

Understood where the 12V battery is. But if your jump starter is in the trunk, and you can't open the hatch, the only way to get to it is through the passenger compartment. Have you tried to do that? You may not even be able to get to that part of the trunk with the hatch down, particularly if you have your "coffin" in the lower area.

I don't own my FFE any more, and my son has the RS in Alabama, so can't check to see how hard it is to get into the trunk area from the passenger compartment. But I'm guessing it isn't easy.
GONE - 2015 FFE, Magnetic with leather interior, debadged & tinted
38,500 miles (since May 2015), average 246 Wh/mile

REPLACED WITH - 2018 Tesla Model3, LR RWD, Obsidian Black
20,000 miles (since Nov 2018), average 235 Wh/mile

Posts: 141
Joined: Sat Jan 30, 2016 4:22 pm

Re: Replace 12V battery in 2017-2018 FFE

Thu Apr 09, 2020 3:55 am

campfamily, True, if 12v is completely gone, the hatch release is disabled.
Fortunately the rear seats fold down to let somebody reach into the hatchback area. I tried it and its not too difficult. Could be for some though.

Posts: 1
Joined: Thu Apr 08, 2021 10:43 am

Re: Replace 12V battery in 2017-2018 FFE

Thu Apr 08, 2021 10:44 am

I don't understand. Do you need to replace the accumulator? Or do you have problems with it? If you are not an expert, I advise you not to climb over the trunk to replace the battery. You may not be able to properly disconnect it and connect a new one in a narrow space. The main thing is not to break anything there... It's better to contact a specialist, . The problem was that I bought an old car, apparently, the battery was not new at all and quickly stopped working. I wanted to fix it, but nothing came of it and I just replaced it with a new one.

Posts: 1
Joined: Mon May 03, 2021 9:14 pm

Re: Replace 12V battery in 2017-2018 FFE

Tue May 04, 2021 5:58 am

This is the main problem with restyled models of the car. They can put the old catalog in a remade car. I had such a problem with my Volvo. I started to have some problems with the electric system because the battery was already weak. I bought a new one but I couldn't find where it is situated. I searched all the engine space but I couldn't find it. I found out on that some cars can have their batteries in the baggage, and it was right. I couldn't even imagine that there are companies that could place the battery under the spare wheel.

Posts: 2
Joined: Thu Nov 30, 2017 11:56 am

Re: Replace 12V battery in 2017-2018 FFE

Sat Jul 31, 2021 7:04 pm

My battery just failed. I didn't use it for a couple of days and I had to jump it as it was only 9 volts. I drove it for an hour and then when I went to use it 4 hours later, it was really low again. Why does the battery only last just over 3 years in a vehicle that has a large start load? I think it I'd due to the dc to DC converter putting out 14.35 volts. 12 volt FLA batteries want a float around 14.0 volts. Just for an experiment, I had a couple of 10 amp lifepo4 battery packs that I wired in. This has worked fine for a couple of days now, so I ordered 8x 8 amp cells and a balancer. This should give me a 16 ampmhr battery and should be fine. It also weighs about 30 pounds less and takes up half the space in the battery box. This battery is also fine at a 14.35 volt charge having a maximum of 14.6 charge. I am thinking this battery will last me 10 years or so for under $100. I wonder why you don't see more installations like this in electric and hybrid cars that do not need the big starting power. I have seen that Tesla is just now starting to use this type of 12 volt battery in their cars now.

Posts: 159
Joined: Thu Feb 21, 2019 11:46 pm

Re: Replace 12V battery in 2017-2018 FFE

Mon Aug 02, 2021 11:18 am

Actually, that is a 15V battery Tesla is using.

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