Why use a lead acid 12V battery?

[zwede]

Got my battery tender and can confirm that there is no range loss overnight when the 12V is on the tender.

 

[K-MTG]

I just used an air compressor to top-off the tires on my X. I hope I didn't damage the battery, I also have an always on dashcam.

 

[ig_epower]

Got my battery tender and can confirm that there is no range loss overnight when the 12V is on the tender.

I was thinking of wiring in a charging cable to the jump posts of the 12V battery behind the nose cone. Does anyone know the size of the nut I have to get at the local hardware store. It looks like it is threaded. The purpose is to put in a cable and run it through to the frunk to add on another battery in parallel OR run it below and add on the battery tender on occasion. I want to avoid pulling off the nose cone to frequently.

 

[zwede]

I was thinking of wiring in a charging cable to the jump posts of the 12V battery behind the nose cone. Does anyone know the size of the nut I have to get at the local hardware store. It looks like it is threaded. The purpose is to put in a cable and run it through to the frunk to add on another battery in parallel OR run it below and add on the battery tender on occasion. I want to avoid pulling off the nose cone to frequently.

You're in luck as I just did this. The negative stud behind the nose cone is M8-1.25. The positive already has a nut that you can reuse. Strangely enough the positive stud is SAE.

I cut a hole on the bottom of the nose cone and stuck part of the CTEK quick connector through it. Epoxy on the inside to hold it in place. The CTEK is bolted to my work bench next to the car, so when I park the car it's only a couple seconds to plug in the tender.

 

[FlatSix911]

I'm going a different way and will use a battery tender whenever the car is parked at the house. This will reduce the discharge cycles and should let the battery live much longer.

I've had a CTEK 7002 tender for my classic car for years and it has done a great job, so I just ordered a second one for the Tesla. It's beefy for a tender at 7A so it will keep the 12V battery charged even with the vampire drain. I'm thinking having the tender hooked up I won't lose any range over night either which is a bonus.

I was thinking of wiring in a charging cable to the jump posts of the 12V battery behind the nose cone. Does anyone know the size of the nut I have to get at the local hardware store. It looks like it is threaded. The purpose is to put in a cable and run it through to the frunk to add on another battery in parallel OR run it below and add on the battery tender on occasion. I want to avoid pulling off the nose cone to frequently.

You're in luck as I just did this. The negative stud behind the nose cone is M8-1.25. The positive already has a nut that you can reuse. Strangely enough the positive stud is SAE.

I cut a hole on the bottom of the nose cone and stuck part of the CTEK quick connector through it. Epoxy on the inside to hold it in place. The CTEK is bolted to my work bench next to the car, so when I park the car it's only a couple seconds to plug in the tender.

No need to remove the nose cone...there is a easy mod to keep the 12V accessory plug live when parked for convenient charging

Ingineer said: ↑

BTW, it's a simple matter to keep the 12v outlet in the console live all the time if desired.
It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owner’s manual).

Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals. Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay.

 

[S4WRXTTCS]

Probably because typically you can mistreat a lead-acid battery as much as you want, and it don't care. But, just not as badly as Tesla is treating it. I don't have any answers as to why Tesla is so cruel to it.

Of course the irony is that a lead-acid battery is dying in a car that has a massive lithium-ion battery.

 

[zwede]

After I drive my classic car and hook it to the tender it takes 15-20 minutes until the tender goes to float (full charge). When I hook up the Tesla it often sits 3 hours or more before going to float. Tesla really cycles that poor battery.

 

[Shaggy]

Ford Energis (both models) initially had 12 vt issues and people were modding the original battery compartment with a larger battery before Ford 'fixed' the issue. Ford went through a few dead cars with charged HVB but the 12 vt was dead. I forget the exact reason the car was killing the LVB, but I think they blamed bad batteries.

Rumored you could jump start the car with a lantern battery as all you had to do was throw the main breaker so the HVB could take over. I only had it once but knew how to fix it so I didn't bother with a larger battery. Jump her, car was happily on its way. Ford showed no issue with the battery by the time I got to the dealer... go figure. This was 2 years ago and no issues since.

 

[int32_t]

A friend of mine is a Porsche mechanic. I talked to him about standby current for Porsches, which are themselves loaded with tech, and they're in the 20-40 mA range (ignition off, wait a few minutes) if my memory serves me correctly. That's nothing -- Tesla's 33 Ah battery would last 17 days to 50% SOC at that discharge rate. Tesla might have a giant HV battery, but that doesn't excuse poor stewardship of electrons at the expense of the smaller battery and, ultimately, range lost to vampire drain as a result. There is some serious low-power optimisation in Tesla's future, I think.

 

[jdbob]

Ford Energis (both models) initially had 12 vt issues and people were modding the original battery compartment with a larger battery before Ford 'fixed' the issue. Ford went through a few dead cars with charged HVB but the 12 vt was dead. I forget the exact reason the car was killing the LVB, but I think they blamed bad batteries.

There were a couple of problems. One (that mine suffered from) was that the cell phone modem would get stuck on rather than going to sleep, this could drain the 12V battery over a period of a couple of days if the car wasn't driven in that time. There were also some problems with cables getting chafed and touching the chassis. I eventually just removed my modem since we didn't have AT&T 2G, but did get the new 3G modem late last year when it became available.