Random EV thoughts.....

Water John

This art indicates that the production price diff with ICE will be eliminated by 2024.
https://www.theguardian.com/environment/2020/oct/21/electric-cars-as-cheap-to-manufacture-as-regular-models-by-2024

ELM327

We've heard that a few times.
To be honest, I believe we're already at price parity if the OEMs wanted it

the_amazing_raisin

ELM327 wrote: »

We've heard that a few times.
To be honest, I believe we're already at price parity if the OEMs wanted it

Maybe, maybe not. Part of the price difference if probably because legacy auto makers have been building their own engines for years so any cost associated with buying new machinery have probably been paid by now, they just need to pay the running costs of the plant.


Battery cell manufacturers on the other hand have been building up lots of factory capacity in the past few years and those costs have yet to be paid off, so with time the cells will become cheaper.


In some cases, I would say they're at price parity already. If you take the ID.4 1st and compare it to the new Tiguan with the 2.0l Diesel, the Tiguan comes out more expensive even before you've added things like alloy wheels and metallic paint

innrain

Water John wrote: »

This art indicates that the production price diff with ICE will be eliminated by 2024.
https://www.theguardian.com/environment/2020/oct/21/electric-cars-as-cheap-to-manufacture-as-regular-models-by-2024

Just reading the q3 earnings report from Tesla and came across this

"We reduced the price of Model 3 to 249,900 RMB after incentives, making it the lowest-price premium mid-sized sedan in China"

Silent Running

What do you think lads and lassies, would this be enough to start an EV with a dodgy 12V battery?

I've had it for ages but never needed it.

graememk

Should do. I've heard stories that people have done it with a 9v!

It's basically what some of the li ion battery boosters do.

Silent Running

Silent Running wrote: »

What do you think lads and lassies, would this be enough to start an EV with a dodgy 12V battery?

I've had it for ages but never needed it.

what is the amperage? I've had plenty of batteries with the voltage but not the amperage.

I don't know how many watts the car electronics needs to start functioning, but once they do, I assume the 12v battery will start to receive a charge, then all will start to operate OK.
maybe 10 amps to give an initial boost of 120 watts for the boot up sequence.

Silent Running

Deleted User wrote: »

what is the amperage? I've had plenty of batteries with the voltage but not the amperage.

The cells are healthy. I think they're around 3200mAh each.

I wonder what draw the battery would face in an effort to kick the car into life. If it's just throwing a couple of relays to make the HV battery take over, it wouldn't need much. It's just waking the car up. I'm not going to run my 12V down enough to find out though.

I've read the stories of PP9 batteries doing the job, but haven't seen any evidence of this. If it is true, my battery is overkill.

the_amazing_raisin

Silent Running wrote: »

The cells are healthy. I think they're around 3200mAh each.

I wonder what draw the battery would face in an effort to kick the car into life. If it's just throwing a couple of relays to make the HV battery take over, it wouldn't need much. It's just waking the car up. I'm not going to run my 12V down enough to find out though.

I've read the stories of PP9 batteries doing the job, but haven't seen any evidence of this. If it is true, my battery is overkill.

You'll need to check the allowed discharge rate as well, I think some cells can have an allowed discharge of as low as 0.5C before the cells get damaged.


So if the capacity it 3200mAh then you can supply 1.6A of current @ 12V, giving you an output power of 19.2W.


I know an EV doesn't take much to start, but 20W seems a bit on the low side.


Now if the discharge rate is something like 10C or 20C, then you'll be able to supply over 750W, which seems more like the amount of people needed for an EV to boot up.


Of course, if you only want the battery to be a 'one-shot' and don't care about damage then you can discharge up until they catch fire

Silent Running

cruisey1987 wrote: »

You'll need to check the allowed discharge rate as well, I think some cells can have an allowed discharge of as low as 0.5C before the cells get damaged.


So if the capacity it 3200mAh then you can supply 1.6A of current @ 12V, giving you an output power of 19.2W.


I know an EV doesn't take much to start, but 20W seems a bit on the low side.


Now if the discharge rate is something like 10C or 20C, then you'll be able to supply over 750W, which seems more like the amount of people needed for an EV to boot up.


Of course, if you only want the battery to be a 'one-shot' and don't care about damage then you can discharge up until they catch fire

Do we have any information about what is needed to get the car to wake up?

The HV battery will look after the 12V once the car wakes, so the hit needed would probably be measured in fractions of a second, or at worst a couple of seconds. Even a low C rated battery can provide a burst for a very short time without major damage. It would all depend on the demand the car would put on any jump start battery.

the_amazing_raisin

Silent Running wrote: »

Do we have any information about what is needed to get the car to wake up?

The HV battery will look after the 12V once the car wakes, so the hit needed would probably be measured in fractions of a second, or at worst a couple of seconds. Even a low C rated battery can provide a burst for a very short time without major damage. It would all depend on the demand the car would put on any jump start battery.

I haven't heard of anyone actually quantifying it. We know that jump starters work, and they're optimised to supply a lot of current in a short space of time so likely have a high discharge rate. Looking them up on amazon, they seem to be able to supply 300-1000 amps.


Taking 300 Amps as an example, that gives us a power output of 3.6kW, which is a lot.


When you think about what the 12V battery on an EV is supplying, it's basically the lights, fans, possibly a heater/aircon, some sort of computer (or several computers) and a load of relays and power electronics.


Skipping over the heater, the next biggest consumer is probably the computers. It's hard to know how much they consume, but if they're anything like a laptop then ~100W seems reasonable. Presumably they're using fairly low power electronics to limit the drain on the 12V system



Power electronics and relays don't need much to switch on, so maybe something in the order of 200-300W minimum would be my guess to jump start an EV. That gives a discharge current of max 25 Amps

AndyBoBandy

Saw a video yesterday about a guy who's ID.3 died because the 12v battery went flat.. he used a booster to bring it back to life

https://www.youtube.com/watch?v=ujZhC6T1c9A

the_amazing_raisin

AndyBoBandy wrote: »

Saw a video yesterday about a guy who's ID.3 died because the 12v battery went flat.. he used a booster to bring it back to life

Yeah unfortunately EVs are just as vulnerable as ICE vehicles to the battery going flat.


I got rid of my old booster when I traded the Toyota for the Leaf, then went and got a new one when I saw the Leaf's had some issues with the 12v in winter.


I've never had problems myself, but better to be safe than sorry.

eagerv

AndyBoBandy wrote: »

Saw a video yesterday about a guy who's ID.3 died because the 12v battery went flat.. he used a booster to bring it back to life

I have a Noco Boost GB70 which is small enough to keep in car (About the size of a thickish novel). At 2000A it's a bit of an overkill for an EV, but handy for a boat or tractor..:)

slave1

cruisey1987 wrote: »

Yeah unfortunately EVs are just as vulnerable as ICE vehicles to the battery going flat.

Not all of them, the Tesla will top up the 12v from the HV battery if it needs it

the_amazing_raisin

slave1 wrote: »

Not all of them, the Tesla will top up the 12v from the HV battery if it needs it

The Leaf does it too, albeit in a somewhat dumber sense. It'll just periodically charge the 12V from the HV battery without sensing the voltage first



The 12V battery on a Tesla can die too, it happened to Bjorn Nyland once when his 12V battery was losing capacity and his HV battery got too low to charge it. What was really shocking was that his car died beside a fast charger but without the 12v it wouldn't unlock the charge port



It's one of those things that's thankfully rare, but does happen and for the added expense of €30 or so you can save yourself a lot of angst waiting for a recovery vehicle. I think it's worth it but each to his own

drumm23

cruisey1987 wrote: »

T it happened to Bjorn Nyland once when his 12V battery was losing capacity and his HV battery got too low to charge it. What was really shocking was that his car died beside a fast charger but without the 12v it wouldn't unlock the charge port

:pac::eek: haha! that's mad!

-- charge port should obvs have a manual release

jump leads....

AndyBoBandy

drumm23 wrote: »

:pac::eek: haha! that's mad!

-- charge port should obvs have a manual release

In the Model 3 there is a manual release for the plug lock in the boot, so surely they put a manual release in there for the flap!

the_amazing_raisin

drumm23 wrote: »

:pac::eek: haha! that's mad!

-- charge port should obvs have a manual release

They do, although it can be a pain to find in several cars.

Pretty sure the release doesn't make a difference if the 12v is dead. Even if you can connect the plug, the car needs to communicate with the charger before it'll energise the circuit. Without the 12v there's nothing on the car end to communicate

the_amazing_raisin

[Deleted User] wrote: »

jump leads....

That involves a leap of faith in assuming there'll be someone around willing to help. I personally don't have that level of faith in other people

the_amazing_raisin

AndyBoBandy wrote: »

In the Model 3 there is a manual release for the plug lock in the boot, so surely they put a manual release in there for the flap!

The model S and X have one too, although I seem to remember they're in fairly bizarre locations. Something like under the wheel arch maybe

The problem Bjorn had was even though he could open the port there's a locking pin on the socket which prevented him from putting the plug in.

Even if he could plug in, it might not have worked, I've never seen anyone test it but I'm pretty sure if the 12v is dead the charging won't start

the_amazing_raisin

AndyBoBandy wrote: »

In the Model 3 there is a manual release for the plug lock in the boot, so surely they put a manual release in there for the flap!

Here's the Leaf manual release

https://youtu.be/0J9lPGGp3-A

So you need to open the bonnet, remove 4 plastic plugs and a plastic cover, then stick you hand in around a bunch of high voltage cables and search for a release hook...

Think I'll pack a crowbar instead, seems safer

Kramer

Deleted User wrote: »

jump leads....

Wouldn't want to connect jump leads to the HV side - impromptu arc welding .

the_amazing_raisin

Kramer wrote: »

Wouldn't want to connect jump leads to the HV side - impromptu arc welding .

I'd be more worried about the donor car in that case, it'd be getting 400v into it's 12v system

Kaboom

innrain

AndyBoBandy wrote: »

In the Model 3 there is a manual release for the plug lock in the boot, so surely they put a manual release in there for the flap!

I thought of that. For the Kona I have the mechanical key, open the bonnet, open the flap and connect the cable.

But you still need the electronics to work to request/accept the charge. Otherwise the contactor is open.

Regarding the power consumption Kona has screen called Energy Consumption which details how much each component uses. The minimum I got for the electronics was 200W (AC, lights all OFF) at 14.7V works out about 13.5 A.

the_amazing_raisin

innrain wrote: »

Regarding the power consumption Kona has screen called Energy Consumption which details how much each component uses. The minimum I got for the electronics was 200W (AC, lights all OFF) at 14.7V works out about 13.5 A.

Yeah seems about right, I reckon the only way to get lower would be to power the car off and you'd have no readings then.

The difference between car on and off for an EV is probably just that any infotainment screens are off and the computers are in a lower power mode

Black_Knight

AndyBoBandy wrote: »

ID.3 died because the 12v battery went flat.. he used a booster to bring it back to life

Yeah, but could you take 12 minutes 32 seconds to tell me that?