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Electric cars?

Would you buy an electric car?

  • Already own one

    Votes: 10 5.1%

  • Yes - would definitely buy

    Votes: 43 21.7%

  • Yes - preferred over petrol car if price/power/convenience similar

    Votes: 78 39.4%

  • Maybe - preference for neither, only concerned with costs etc

    Votes: 38 19.2%

  • No - prefer petrol car even if electric car has same price, power and convenience

    Votes: 25 12.6%

  • No - would never buy one

    Votes: 14 7.1%
  • Total voters
    198
Jump to new
EV 's do not have an alternator, and do not need one as they have a DC -DC charger that takes the 48 volt or whatever the EV battery packs nominal voltage is, and transforms it back to 13.4 or so for charging the 12 volt battery.
I am surprised there is no software enabler that allows the EV main battery to use the DC-DC charger to maintain the 12 volt battery when the vehicle is not running.
If an EV has a 55 KW battery that is fully charged, it should be able to maintain a 20 amp hour 12 Volt battery at 90% charge for a long time unless whatever is still turned on in the EV drawing from the 12 volt battery is running at 1 amp or greater.
I am also surprised that all EV's do not already have a lithium 12 volt battery.
They are lighter, can hold charge longer, can be depleted a lot more than a lead acid battery for the same nominal output without severe degradation, but of course are more expensive.
Mick
 

12V lead acid batteries do die from time to time. An EVs main battery will keep the 12V battery topped up, however the management system will not allow the main battery to sacrifice itself over the 12V battery -

"...the 12v battery can fail or run flat, especially if the car is left for a long period of time and the main battery has entered its low energy mode."​

Small 12V Lead acid batteries do have some minor advantages over a 12V lithium battery -

"From 2022, many Teslas come with a Lithium Ion Low Voltage battery pack. This has some benefits but can also be more difficult to deal with if it runs flat. This battery typically has a voltage above 12V and as a result a normal car battery charger may not work. If you get a flat battery with these cars then roadside assistance may be the only option.​
​
Coupled with the above, cars with the LFP main battery pack, which are typically Standard Range models, need to regularly top up the main battery to 100% to ensure the car maintains the correct charge level in the low voltage battery."​

Tesla Flat 12v Battery

Tesla flat 12v battery and what to do when stuck
tesla-info.com
 
Yes, that is kind of what I was alluding to and where a small jump pack comes in handy.
Not only if the 12v gets drained, or fails to charge, but when the 12v decides to die of old age exactly at the worst possible time as is usually the case.
You can guarantee the 12v battery will be the cheapest nastiest piece of crap they can lay their hands on. ?
 
With the ole ICE, if you get a car started, the alternator will supply sufficient power to keep the motor running regardless of the state of the battery, so even with a completely dead battery, a jump pack will start the car and the alternator will keep it running, so all is fine until you turn the engine off again.
The big question is , what is the EV equivalent of "starting the engine" to get the alternator running?
If enough power is supplied to open the contactor to the EV battery pack, the contactor for the DC-DC charger, then the 12 V battery should start charging.
If the battery is dead however, it will not charge, but does the EV motor still keep "running" in standby before you put your foot on the accelerator?
Does the DC-Dvc charger (or more likely the software that controls it), still put out 13.4 volts to supply the non EV electricals, like lights, aircon or more importantly, the contactors that open the EV battery pack?
Will need to do some experiments to work these things out.
Mick
 

A lot of 'ifs' there.

What if the alternator has failed and caused the battery to go flat?
What if the battery is dead and affects the Power Control Module (PCM)?
What if the car is an automatic and there is no booster pack available?
What if the Neutral Safety Switch has failed?
What if the ignition switch has failed?
What if the Main Fuse has failed?

​
There are a couple of reasons. First of all, an electric vehicle has two distinct needs when it comes to dispatching electrons: moving the car and everything else. Propulsion is handled by the big, expensive, latest-and-greatest high-voltage battery, because you need lightning in a bottle if you want to do the quarter-mile in 9.4 seconds. For charging, the more voltage, the better. But powering up the stereo does not require 800 volts. Nor would you want that coursing through every circuit in the car, for a variety of reasons. Safety, for one.​
​
We asked Hyundai's EV engineers why the 12-volt battery persists, and Ryan Miller, manager of electrified powertrain development, responded. "All the ECUs in the vehicle are powered from the low voltage, as well as the power relays that separate power from the high-voltage battery pack and the rest of the high-voltage network in the car," he said. "That separation allows us to safely disconnect the high voltage from the low voltage when the vehicle is not being driven or in the event of a crash." You don't want first responders to contend with door locks powered by Doc Brown's Mr. Fusion.​
​
There's also a legacy situation at play. Everyone—manufacturers and suppliers—knows how to make a 12-volt system work, affordably and reliably. Even if you manage to drain the 12-volt battery, you can break out the ol' jumper cables or Weego and solve the problem in a minute or two. Given all the other financial and technical challenges of building an EV, going with a 12-volt system for the car's computers and accessories makes sense. That's particularly true in the case of plug-in hybrids, which often retain as much commonality as possible with their traditional internal-combustion cousins.​
​
It remains to be seen whether the world adopts some other common voltage—24 volts, or 48—but for now, the 12-volt system reigns. Whether that will always mean a separate battery that would work equally well in a 1968 Chevelle is more of an open question. Hyundai, for instance, considered the absurdity of jump-starting an electric car or hybrid and connected its low-voltage systems to the large traction battery, allowing electrified Hyundais to jump-start themselves when you push the "12V Batt Reset" button on the dash. And while that button conjures an image of your standard AC Delco lead-acid, the low-voltage systems are actually run by a 14-volt lithium-ion battery that sits inside the high-voltage battery pack. You won't find that at the local auto-parts store.​

Why Do Electric Cars Still Use 12-Volt Batteries?

Your electric car or plug-in hybrid is propelled by a sophisticated lithium-ion battery, but you'll probably also find a lead-acid 12-volt battery in there somewhere. Don't throw away your jumper cables just yet.
www.caranddriver.com
 
Yes the good old days, when all you needed was a bale of hay and a trough of water and the horse kept working and the only drop out could be picked up in a bucket then put on the garden. ?
 
Yeah, but most of the If's were supplied by you.
I did some searching regarding the charging of 12v batteries in an EV.

One of the interesting things I found when reading Electronic design for RV
was that some of the pins on the Pilot controller revert to 12 volts when charging has been completed and the charging connector removed, thus its normal state is a live 12 volts.
Depending on how that 12 volt is managed, it means either a contactor, digital switch, or some othe rdigital component will be drawing some current. So there will always be some current drain from the 12 volt battery, no matter how small.
And just to confuse things, I found two quotes that basically said direct opposite things.
From KBB
Then there is Toms guide
So one guru says tha ta 12 volt battery usually charges at the same time the car is charged,
The other guru says that this "borrowing" of charge does not usually happen when the car is plugged in (I am assuming he means plugged in to a charger).
I saw other discussions that suggest that some vehicles only energise the Dc-Dc charger for the 12 volt battery when the battery is in traction mode, ie running, although this seems to be not part of the charging standards.
When i finally get my toy ev running, I will have to look at the canbus messages on the DC-Dc charging circuitry to find a deffinitve answer for that controller.
Mick
 
I know when I went on a months holiday in October, I put a trickle charger on the 12v battery, me of little faith. Lol
 

Just pointing out that there is no infallible system in the automotive world.

Even an ICE vehicle battery has a constant draw of current. My wife's previous car (now our daughters), a Honda Accord Euro, would kill batteries if we left it standing for too long. We've gone through a higher number of batteries than normal, with the average battery life at 30 months, and the current best is a Century Ultra Hi Performance battery with 3 years and still going.

Each EV manufacturer may use a different 12V system, but they are still the same basic system. and some manufacturers are better than others. I believe that the Tesla system is one of the best, it not only maintains the 12V battery but notifies the driver when it detects an issue and recommends replacement.
 
I think in that rare case I just call road side assistance or a battery guy and get a new battery.

As I said I happy to be a Guinea pig on this one for you guys, my car is 3 years old, and I am not going to change the 12 V until either Tesla tell me too or it fails, let’s see what happens.

I think flat 12V in Ev’s are going to much less of a problem than in ice cars though.
 
With your cash, you will probably just buy a new car, when the 12v battery fails. ?
 
So last night I did some checks on the electrical diagram for the DC-Dc charger in the toy car.
The key switch /ignition/start switch supplies 12v to the DC-DC converter which enables it to start charging.
When the key switch is turned off, the EV battery via the DC-DC-Charger cannot charge the 12 Volt battery.
So in this case, if I am to leave it for extended periods of time, I would need to have a trickle charge on the 12 battery.
According to EV central , the drain on the 12 battery during idle varies from vehicle manufactturer.
The BMS and controller as well as the display are always on on in the toy car, so there will be a small current draw all the time.
And when the wall charger is plugged in, unless the the key is turned on, the 12 battery does not also charge.
So it pays to really understand how your EV charging system works, knowing whether the 12 V battery keeps being charged by the DC-DC converter during hi voltage EV pack charge, whether it charges during long storage, and whether it is switchable to do so.
The toy car allows the key to be on during charge, so that radios, aircon, demisters etc will still work, but the the traction control is interlocked so you cannot drive away with the charger cable attached. I think I will add a switch to the system to enable the DC-DC charger regardless of whether the key is on for longer term storage, rather than add a 12Volt trickle charger as well as the granny charger for traction battery maintenance for long term storage.
Mick
 
What happens when a Tesla is forgotten in a shed for 2 years -

 
This looks interesting -



 
Now this is what I am looking for in EV.

Small but not tiny. Well built. 300k plus range . Enough speed to keep up with the traffic. In production. Current price probably 22-24k for Australia.

Check out the excellent you tube driving review. The company that produces these has more exotic models.

Low-cost electric hatchbacks are finally making a big Leap into the market​

Source: Leapmotor

Aside from Nissan Leaf, EV hatchbacks have been missing from the Australian EV market. But that may be about to change soon.
Last week, Australia’s first low cost EV hatchback was spotted being tested on the streets of Sydney.

Now the news is surfacing of an EV hatchback brand exporting cars to Israel which looks promising for other markets like Australia.
Leapmotors is a Chinese EV brand that focuses on affordable EVs. Its T03 hatchback has just been launched in Israel after the brand opened its three showrooms in the country.
The T03 is an affordable city hatchback. It’s slightly smaller in length than a Toyota Yaris coming in at:
  • 3,620 mm in length
  • 1,652 mm in width
  • 1,577 mm in height

It’s powered by a 55 kW motor that drives the front wheels and offers 155 Nm of torque which is plenty for inner-city driving.

The motor is fed by a 36.5 kWh battery pack which can deliver up to 300 km of WLTP range.

For a car that costs less than $15,000 AUD in its local market, it offers a 10.1” infotainment screen as well as three outside cameras and twelve radars for level 2 autonomous driving.

This is quite remarkable to see the specifications and what’s included for that price. Even after shipping, local delivery and dealership costs, it could be an EV that’s available in the Australian market for under $22,000.

Low-cost electric hatchbacks are finally making a big Leap into the market

Aside from Nissan Leaf, EV hatchbacks have been missing from the Australian EV market. But that may be about to change soon.
thedriven.io

 
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