Which EV's charge the batteries as you brake?

Andy From Sligo

which (if any) EV's out there charge the batteries when you brake like the Toyota hybrid cars do ?

And also, do any EV's have any kind of dynamo/alternator or inverter system to charge the batteries as the car is moving ... even if its putting a trickle charge into the batteries?

galvo_clare

Pretty much all of them have regenerative braking I’d say.
The idea of trickle charging the batteries as you’re driving wouldn’t work as it would rob the drivetrain of energy, defeating the whole purpose.

Andy From Sligo wrote: »

which (if any) EV's out there charge the batteries when you brake like the Toyota hybrid cars do ?

And also, do any EV's have any kind of dynamo/alternator or inverter system to charge the batteries as the car is moving ... even if its putting a trickle charge into the batteries?

ELM327

I don't think there is an EV on the market that doesn't have Regen Braking
It varies for each EV wrt the amount of Regen available. AFAIR the Zoe has very little regen whereas the leaf40 and Ioniq have variable regen where the user can select how much (or no) regen they want

KCross

Andy From Sligo wrote: »

And also, do any EV's have any kind of dynamo/alternator or inverter system to charge the batteries as the car is moving ... even if its putting a trickle charge into the batteries?

There are Plugin-Hybrids (aka PHEV) which have a normal petrol engine which charges the battery while driving and it also can power the wheels.... parallel hybrid.

There is also the likes of the BMW i3 which has, basically, a generator in the car which is not connected to the wheels whose sole function is to charge the battery when it gets low.... series hybrid

cros13

When you hear "self-charging hybrid" from toyota it's a deceptive statement. They present it as if it's a point in favor of the car when it's really a point against.

If the car doesn't have a plug, all your energy to move the car is ultimately coming from a petrol pump at six to twelve times the cost of electricity from your sockets at home.

Yes, the hybrid is recovering energy that would otherwise be lost as heat in the brake discs... but you are also carrying 150-250kg more weight everywhere.
For the capacity of the battery they have in those cars (25 to 200 times lower capacity than a full EV) you're also paying quite a lot of money.
That tiny battery can't supply enough power to run a powerful electric motor so you lose out on many of the performance advantages of a real EV as well.

Baller23

Really looking forward to the Kona EV and Niro EV getting here too, although I could definitely hold out for a Tucson EV if they ever get around to producing it

n97 mini

All EVs have re-gen. The traction motor becomes a generator when the wheels are turning the motor (i.e. when decelerating) as opposed to the motor driving the wheels.

zilog_jones

cros13 wrote: »

Yes, the hybrid is recovering energy that would otherwise be lost as heat in the brake discs... but you are also carrying 150-250kg more weight everywhere.

Do you know what also weighs a lot? Diesel engines. The 1.6 diesel manual Auris weighs 10 kg more than the 1.8 petrol hybrid. Toyota's hybrid transaxles are also very efficient in terms of mass, just taking the weight of the batteries and assuming that's some extra burden on the car is a bit silly really.

You're paying extra for the two motor-generators, inverter, and all the other gubbins under the bonnet that a normal ICE car doesn't have. Stuff which rarely breaks, unlike modern diesels, i.e. maintenance costs will be lower.

biko

On the Outlander there are 5 regen settings.
It may seem like too much but I actually use them all.
I notice that I brake much less now, saving on brake pads too lol

https://www.youtube.com/watch?v=ASsq-y2t5-s

unkel

biko wrote: »

I notice that I brake much less now, saving on brake pads too lol

It's a common misconception that only if you use regen, the car doesn't apply the conventional brake system (pads and discs)

Depends on the EV (PHEV) but a lot of them use a lot of regen for a fair bit of use of the brake pedal itself too. I've never payed that close attention myself, but regular poster here liamog saw -100kW on the energy consumption meter, so extremely high regen, going back into his battery when he had to brake hard :eek:

Andy From Sligo

so - does regen kick in automatically .. or do you have to turn the knob manually to the level or regen you need?

PixelTrawler

biko wrote: »

On the Outlander there are 5 regen settings.
It may seem like too much but I actually use them all.
I notice that I brake much less now, saving on brake pads too lol

https://www.youtube.com/watch?v=ASsq-y2t5-s

Kinda wish at the higher settings it activated the brake light. E.g. using B5 coming into a roundabout.

EdgeCase

In a Toyota hybrid you basically put the car into D and drive.
If you brake, the regenerative system does the first part of the braking - slowing down the car and the mechanical brakes do the rest. It's totally seamless and you just press the brake pedal like you would on any car

There's less wear on brake pads, especially in traffic.

If anything the braking is smoother than you'd experience on a normal car.

They also have a "B" mode on the "gear lever" (they don't have gears really). If you select that it engages the regenerative system and it will operate like a drag. It's a similar feeling to changing down gears on a manual car to slow down.

It's handy if you're going down a hill or if you're just gently slowing down and as you become more familiar with the car you tend to use it more.

Other than that - you just turn on car, drive car, turn off car and everything happens entirely seemlessly and automatically.

Hybrids also tend to be very very easy to drive in traffic. There's no "biting points" - stalling is just technically impossible and you have no need to rev. The system is just totally smooth. You can just nudge along at any speed from 0.25km/h to full motorway speed.

What I've really noticed as a big difference, even compared to traditional automatic cars is the smoothness of the power at low speeds. You can smoothly adjust your position in a tight space with a degree of calm and accuracy that can only be delivered by an electric motor. You've huge torque at low speed which an engine can't really deliver.

You really don't have any reason to interact with the nuances of the hybrid system that you would interact with the engine management system on a traditional ICE car. It just works.

ELM327

Andy From Sligo wrote: »

so - does regen kick in automatically .. or do you have to turn the knob manually to the level or regen you need?

In my Ioniq there's a setting you can set from 0 to 3
If you just set it to 2 constantly there will always be regen. But i use the paddles to set it to 0 when I want to coast (and boy does it coast) and 3 when i want to stop.
The new leaf has a similar system.

EdgeCase

OP : I'd suggest you just test drive one. The controls vary a bit. The likes of the Prius has a lot of unique approaches to doing things whereas the cars like the C-HR use control that look more like a traditional automatic, even through they're using the same drive system as the Prius under the hood.

Toyota / Lexus, Honda and Hyundai also do things slightly differently so again, just test drive.

denismc

So can someone explain the actual mechanical parts in these systems?
So you have normal disks and pads but is there a separate set of pads driving a little generator for the regen?
I am just wondering is there an extra failure point there that can go wrong or do they last the lifetime of the car?

biko

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

and https://www.youtube.com/watch?v=BhOEoXfxHMc

Andy From Sligo

so with this high torque and the regen 'braking' am i right in saying these EV's have got to be better on icy/snowy roads are they? whereas in an ICE car they always do say use the engine as a brake in snow and ice rather than your brake pedal.

unkel

My Ioniq was very good in the heavy snow earlier this year. Which in a way surprised me as the car is heavy and has skinnier than average tyres. The throttle control is pretty good though and you would have high torque at very low speeds, which makes it easy to control the traction quite precisely, particularly compared to a manual gearbox ICE car

That said, don't take my word for it, most of my previous cars have been rear wheel drive, which is not great in snow / ice. Let's see what other EV owners have to say.

Andy From Sligo

on another point how do EV cars batteries cope in the cold/icy temperatures. normally with a load of types of batteries ranging from mobile phones to camcorders to even ICE 12v batteries can be very affected by discharging in cold weather , so i am wondering how EV batteries cope? - do they suffer? ... plus of course you have the added drain of having the heater on/ lights on/ heated seat on etc ...

EdgeCase

denismc wrote: »

So can someone explain the actual mechanical parts in these systems?
So you have normal disks and pads but is there a separate set of pads driving a little generator for the regen?
I am just wondering is there an extra failure point there that can go wrong or do they last the lifetime of the car?

They have disc brakes just like any other car.
Regenerative braking works by basically running the drive motor(s) as a generator. The car’s control system applies an electrical load to the motor/generator. That effectively makes it resist against the turning motion of the wheels as that energy is being used to generate electricity which is fed back into the battery.

So when you press the brake pedal you’re sending a command to the management system to start generating electricity from the motion of the wheels. This is used in conjunction with normal mechanical brakes which do the final stop and would also do an emergency brake just like any normal car if you put your brake pedal to the floor.

The engine is also integrated into the hybrid system. It’s just not just bolted onto the side of a normal petrol engine. The system manages ignition and sparking and all of that to tightly coordinate with the electrical drives. One of the motor generator units also starts the engine, replacing a starter motor. The engine is also run at optimal speed for maximum efficiency.

Toyota’s approach uses a power split device which basically is system of planetary gears that allow the mechanical power from the engine and two motor/generators to be combined seamlessly. It’s a little bit like a differential, but more complex and gives the car continuously variable speed. There are no gear changes.

It’s actually an extremely elegant piece of mechanic engineering.

https://www.youtube.com/watch?v=3xeyqGcfb8M

zilog_jones

Andy From Sligo wrote: »

so - does regen kick in automatically .. or do you have to turn the knob manually to the level or regen you need?

When you use the brake pedal it will be applying some amount of regen blended with friction braking (traditional brake discs) - the ratio of how much is regen and how much is friction braking depends on various factors like speed, brake pedal pressure and velocity, etc.

Generally, light use of the brake pedal at moderate speeds will be mostly or entirely regen, very hard/sudden braking will be mostly friction braking (also during an ABS/VSC event, it'll be 100% friction braking), and slowing to a stop (like 10 to 0 km/h) will be 100% friction braking.

Some hybrids and EVs have further controls for regen, but this is mostly to control how much regen occurs when you're not on the pedals - this is there to replace engine braking in a traditional ICE car. Shifting to "B" mode will also increase regen (combined with ICE engine braking in hybrids).

Andy From Sligo wrote: »

so with this high torque and the regen 'braking' am i right in saying these EV's have got to be better on icy/snowy roads are they? whereas in an ICE car they always do say use the engine as a brake in snow and ice rather than your brake pedal.

I found it very easy to drive my Prius Plug-in in the snow (in EV or hybrid mode) on summer tyres, the "Eco mode" reduces throttle sensitivity and gives finer control of gentle acceleration, using the brake pedal lightly didn't cause any drama, and if I tried to do anything silly the traction control would kick in kill power to the wheels. I was able to climb hills (in Cork city) without hassle if I was going slow enough.

Andy From Sligo

so , am i right in saying that the only way the batteries in the car can be topped up with charge is by means of the regen braking and then at all other times the batteries are discharging? and the motor can only be in a mode of either driving the vehicle or charging the vehicle (as in when braking) ?

So no other topping up of the batteries occur when the car is going forward and driving unless its braking?

Where is the engine on the EV, normally in the front is it? - if so , why could they not have put some kind of generator/dynamo/alternator on the back axle and through some kind of inverter to boost the charge so that as the car is driving forward it can send some kind charge to the battery even if it works out a trickle charge ?

EdgeCase

No. They charge when you’re going down hills and inclines and also when the engine is running at maximum efficiency. For example, it makes more sense for the car to use electrical power at low speeds and capture that power while the engine is working at optimal speeds as ICEs are very inefficient at low revs.

In general it’s smoothing out the energy consumption and capturing energy that’s normally wasted.

Full EVs can do the same, just without the engine management requirements.There’s no need for extra motors on the back axel. The whole thing is done from the drive train (the equipment driving the front wheels.)

The control systems on these vechicles are very sophisticated and it’s small, reliable, robust computing technologies that have made them possible as well as solid state power converters and inverters.

Del2005

Andy From Sligo wrote: »

so , am i right in saying that the only way the batteries in the car can be topped up with charge is by means of the regen braking and then at all other times the batteries are discharging? and the motor can only be in a mode of either driving the vehicle or charging the vehicle (as in when braking) ?

So no other topping up of the batteries occur when the car is going forward and driving unless its braking?

Where is the engine on the EV, normally in the front is it? - if so , why could they not have put some kind of generator/dynamo/alternator on the back axle and through some kind of inverter to boost the charge so that as the car is driving forward it can send some kind charge to the battery even if it works out a trickle charge ?

I've a Lexus hybrid and it'll charge the traction batteries when driving if they are low. If you want to know what it's doing turn the energy display on and it will show where the power is being generated and used, just don't look at it for too long when driving.

bp_me

EdgeCase wrote: »

They also have a "B" mode on the "gear lever" (they don't have gears really). If you select that it engages the regenerative system and it will operate like a drag. It's a similar feeling to changing down gears on a manual car to slow down.

You shouldn't use B mode. B mode simulates engine braking by actually providing engine braking and this uses some amount of fuel to first spin up the engine to the rpm necessary.

Either use cruise control and it will use regen braking to maintain speed (newer cars with "full range" adaptive cruise can use the friction brakes too) or use the brake pedal gently yourself and the initial stages will use only additional regen (up to about 12kW worth).

Fun fact on models other than the prius having more conventional controls... the CHR has a kickdown button under the throttle

Video posted above is not a bad intro but very out of date. Gen 3 onwards removed the drive chain and added the speed split device which was the limiting factor in the speed at which you could drive in 'golf cart' mode in favour of gearing. Gen 4 went totally mad from there.

Alkers

Does lifting off the accelerator illuminate the brakes in EVs or is the deceleration only similar to coasting in an ICE?

unkel

Simona1986 wrote: »

Does lifting off the accelerator illuminate the brakes in EVs or is the deceleration only similar to coasting in an ICE?

Good question. It depends on the EV

i.e. in Ioniq you have 4 settings of regen:

0 - no regen
1 - mild regen
2 - strong regen
3 - very strong regen

If you use 2 or 3, as soon as you lift of the accelerator, the brake lights come on

zilog_jones

Andy From Sligo wrote: »

Where is the engine on the EV, normally in the front is it?

When talking about cars, "engine" usually specifically means an internal combustion engine (ICE), so there is no "engine" in an EV, only electric motors. Of course, "motor" on its own can be a bit ambiguous, but when talking about hybrids or EVs it usually refers to the electric motors (not the ICE).

why could they not have put some kind of generator/dynamo/alternator on the back axle and through some kind of inverter to boost the charge so that as the car is driving forward it can send some kind charge to the battery even if it works out a trickle charge ?

It wouldn't make sense to be putting energy back into the battery that you've just taken out - with extra losses. It would lead to the vehicle being less efficient.

If you engage a dynamo on your bicycle it creates additional resistance, and you need to work slightly harder. You don't get anything for free.

A "generator" in an EV would be a petrol engine that is only there to charge the battery, i.e. not connected to the drivetrain. The BMW i3 REx and some others have this.

ELM327

zilog_jones wrote: »

When talking about cars, "engine" usually specifically means an internal combustion engine (ICE), so there is no "engine" in an EV, only electric motors. Of course, "motor" on its own can be a bit ambiguous, but when talking about hybrids or EVs it usually refers to the electric motors (not the ICE).



It wouldn't make sense to be putting energy back into the battery that you've just taken out - with extra losses. It would lead to the vehicle being less efficient.

If you engage a dynamo on your bicycle it creates additional resistance, and you need to work slightly harder. You don't get anything for free.

A "generator" in an EV would be a petrol engine that is only there to charge the battery, i.e. not connected to the drivetrain. The BMW i3 REx and some others have this.

+1


This idea of using a dynamo on an EV for some sort of perpetual motion comes up a lot when people new to EV ask me about it.
I generally explain it by comparing how hard you have to cycle with a dynamo up a hill compared to without one. Then you can see the lightbulb illuminate, energy isn't free.

liamog

Reminds me of the people who suggested a wind tunnel/turbines to capture passing air.

https://alcse.org/the-american-wind-powered-car/

On the one hand, yep captures energy, but the drag is increased so no free power.

Andy From Sligo

ELM327 wrote: »

+1


This idea of using a dynamo on an EV for some sort of perpetual motion comes up a lot when people new to EV ask me about it.
I generally explain it by comparing how hard you have to cycle with a dynamo up a hill compared to without one. Then you can see the lightbulb illuminate, energy isn't free.

on the one hand I can see that on the other hand you are not always driving up hills - so if one was fitted and only engaged on the straights and downhill (along with regen charging) then that resistance isnt going to be than negligible is it - the output driving the motor is going to be way way more powerful than the resistance a dynamo would present - if I were designing a system I think I would try and use the whole offering that are there to put charge back into the battery, using lightweight components as to not add extra weight to the car. So if that be dynamo + inverter + Regen braking + Solar power in the roof + yes indeed wind coming in through the front grille and into some kind of turbine generator that too.

zilog_jones

The car would be more efficient by just applying less power to the wheels, than applying more while trying recover some energy at the same time as consuming it. It's a bit pointless really. Regenerative braking is the only meaningful way of recovering energy - it's applied when you want to lose momentum anyway.

EV's don't need grilles, that would just create more drag. Again, wasting energy to generate some - always a net loss.

ELM327

Andy From Sligo wrote: »

on the one hand I can see that on the other hand you are not always driving up hills - so if one was fitted and only engaged on the straights and downhill (along with regen charging) then that resistance isnt going to be than negligible is it - the output driving the motor is going to be way way more powerful than the resistance a dynamo would present - if I were designing a system I think I would try and use the whole offering that are there to put charge back into the battery, using lightweight components as to not add extra weight to the car. So if that be dynamo + inverter + Regen braking + Solar power in the roof + yes indeed wind coming in through the front grille and into some kind of turbine generator that too.

Consider that regen has at least a 30% energy loss. I imagine energy loss from drag by fitting an air turbine etc is worse.


So let's imagine you are at a slight incline which is followed by a slight decline. It is more efficient to slow down going uphill and allow the car to speed up going down hill then to maintain the same speed throughout (this applies to fossil fuel cars too).


If you use a dynamo on the way down then you need more energy to power the dynamo/regen. So you use 100% on the flat , 120% to climb the hill and 80% on the way down. If on the way down you apply the regen then you will reduce speed quicker and need to accelerate tomaintain speed. Turning the 80% to 100%. Energy / motion/ work/force isn't "free" in an energy sense, you need to spend energy to move.

TheBoyConor

Andy From Sligo wrote: »

......
And also, do any EV's have any kind of dynamo/alternator or inverter system to charge the batteries as the car is moving ... even if its putting a trickle charge into the batteries?

That would be equivalent to trying to make a perpetual motion machine. It makes no sense and physically cannot work.

Same goes for anything like fitting wind turbine or similar devices on or about the car. These generate electrical energy, correct, but in doing so they also cause drag which saps the car's kinetic energy.

I hear these types of "why dont they......" proposals from time to time and all they do is demonstrate that the proposer lacks a fundamental understanding of the basic physics of energy and motion.

TheBoyConor

Andy From Sligo wrote: »

so , am i right in saying that the only way the batteries in the car can be topped up with charge is by means of the regen braking and then at all other times the batteries are discharging? and the motor can only be in a mode of either driving the vehicle or charging the vehicle (as in when braking) ?

So no other topping up of the batteries occur when the car is going forward and driving unless its braking?

Where is the engine on the EV, normally in the front is it? - if so , why could they not have put some kind of generator/dynamo/alternator on the back axle and through some kind of inverter to boost the charge so that as the car is driving forward it can send some kind charge to the battery even if it works out a trickle charge ?

You need to understand that putting a generator on the back wheels, or whereever, will absorb energy from the motion of the car which must be compensated for by drawing additional power from the battery.

Trying to do what you suggest and make your battery last longer would simply not work as you would be trying to defy the laws of physics - specifically the prinicple of conservation of energy.

Generators don't just spin freely and pump out power - they take force to turn. Ever plug a kettle into a generator and switch it on? - You'd notice that when you swtich it on the engine will labour heavily. This is because the electrical load the kettle draws makes the generator more difficult to turn and the engine must provide this extra effort.

mr chips

There is a German EV startup whose name escapes me which has put solar panels on a city car, but in reality this isn't very practical or cost-effective, even now after the cost of solar PV has fallen so much from where it was 8-10 years ago. Panels have to be big enough to generate a meaningful amount of power, something that the surface area of an average car just can't provide. They also need to face the sun at the correct angle to achieve maximum efficiency. If you had panels on the bonnet and roof and even the boot lid, then parked for several hours on a steep slope so that the roof is slightly more angled towards the sun, on a bright summer's day you might get 15-20 km worth of juice.

Just for comparison - my solar array at home has the same surface area as maybe six or seven large saloon cars (a unit of measurement whose recognition is long overdue ...), is ideally positioned to capture the maximum amount of sunshine throughout the day and is never shaded apart from one corner for maybe half an hour at dawn in the middle of June. Now at that time of year, if the house consumption was zero, a full day's sunshine would provide enough juice to fully charge a 24kWh Nissan Leaf, maybe even a 28kWh Ioniq, but not a 30kWh Leaf. However on the cloudiest days in the third week of December, it wouldn't provide a quarter of that.

In terms of PV, it's better to have a proper array of panels mounted on the ground or on the roof of your house, out of the shade, and have a battery which can store any surplus energy generated. This way, you'd have the option to continue meeting your domestic electricity requirements after sunset, and/or partially charge your car with "free" energy if your panels have produced more than your house needs. That's my long-term plan, anyway!

Andy From Sligo

TheBoyConor wrote: »

That would be equivalent to trying to make a perpetual motion machine. It makes no sense and physically cannot work.

Same goes for anything like fitting wind turbine or similar devices on or about the car. These generate electrical energy, correct, but in doing so they also cause drag which saps the car's kinetic energy.

I hear these types of "why dont they......" proposals from time to time and all they do is demonstrate that the proposer lacks a fundamental understanding of the basic physics of energy and motion.

well ... you cannot expect us to all be physics, mathematicians and scientists now can ye?

unkel

mr chips wrote: »

There is a German EV startup whose name escapes me which has put solar panels on a city car, but in reality this isn't very practical or cost-effective

The Sono Sion. We have a thread about it here:

Linky


As you can see from that thread, I agree with your sentiments

mr chips

Ah yeah, that's the one. The only real value I can see in the panels is (a) if you had a commute of say 6-8 miles, in which case it could suit someone without access to home or work charging so long as they could park it in direct sunlight from 9-5, meaning they wouldn't constantly have to worry about the availability of public chargers, or (b) if you were heading off on holidays and had to leave it at the airport - you park it even as it went into turtle mode and come back to a fully charged car, so long as you were taking a two-week break ...

Andy From Sligo

mr chips wrote: »

Ah yeah, that's the one. The only real value I can see in the panels is (a) if you had a commute of say 6-8 miles, in which case it could suit someone without access to home or work charging so long as they could park it in direct sunlight from 9-5, meaning they wouldn't constantly have to worry about the availability of public chargers, or (b) if you were heading off on holidays and had to leave it at the airport - you park it even as it went into turtle mode and come back to a fully charged car, so long as you were taking a two-week break ...

do Solar panels still need bright sunshine these days to work? - i thought we had come on a lot since they first were invented and that they work with any kind of daylight?

mr chips

They still work on a dull day, but they work even better on a bright day! In total, my array produces as much power as my house would use throughout the year, including most of our water heating for showers etc, and if I had an affordable way to store all of the surplus I'd probably be able to go off grid entirely. While we generally go through 8-11 units a day depending on the time of year (more in winter, less in summer), the panels will provide as little as 3 or 4 on a really dark December day, so they can generally only supplement our needs for that month. By contrast, the highest output I've seen in summer was 28. Unsurprisingly, most of the year the output is not at either of those extremes so we don't end up sending the majority of it to the grid over the course of the year.

Thankfully I live where I was able to get a feed-in tariff, so from a financial perspective the net effect is that we're better off in the medium and long term. Nevertheless, the amount of energy needed to propel a 1.7 tonne car at 120kph for 300 kilometres is probably double or even triple what my solar array can provide on even the longest, brightest summer's day. And the array has a much greater surface area available to absorb solar energy than any car does.

unkel

mr chips wrote: »

Nevertheless, the amount of energy needed to propel a 1.7 tonne car at 120kph for 300 kilometres is probably double or even triple what my solar array can provide on even the longest, brightest summer's day.

Indeed, but there's another side to it as well. The average Irish car does 17k km per year. My car has a battery of 28kWh and a range of 240km

In other words, my car uses just 5kWh per day based on average mileage

From your production figures I guess your solar array is about 4kwp? If so, it would be able to produce 5kWh on about 250-300 days per year?

liamog

Add about 10% to for charging losses, but the principle is sound. You'd probably also want some local storage at home.

Would a Solar (DC) to Battery (DC) to Car (DC) be more efficient than the converting to AC?

ELM327

liamog wrote: »

Add about 10% to for charging losses, but the principle is sound. You'd probably also want some local storage at home.

Would a Solar (DC) to Battery (DC) to Car (DC) be more efficient than the converting to AC?

Car has an AC motor though so that would be the first (and only) conversion needed.


If you charge now at home you take DC from the sun, convert to AC during EVSE/domestic charger to charge the car, then convert to DC (onboard charger)to put into the battery, then convert to AC to drive the AC motor.


Solar direct to battery in DC would be more efficient, this is one of the many benefits of home DC charging. I often post my theory that if we do shift en masse to EVs then home charging will be done in DC

mr chips

unkel wrote: »

Indeed, but there's another side to it as well. The average Irish car does 17k km per year. My car has a battery of 28kWh and a range of 240km

In other words, my car uses just 5kWh per day based on average mileage

From your production figures I guess your solar array is about 4kwp? If so, it would be able to produce 5kWh on about 250-300 days per year?

Yeah, just under - 3.92 kwp. It produces more than 5kWh most days, tbh - even now it's usually still at 7 or 8, and I think I worked out the annual average at over 9 per day. If the output could be spread across 24 hours instead of just during daylight, it would meet or surpass our daily usage for nearly 10 months of the year. So I'm keen for battery prices to come down!

This is a bit of a sidetrack to the thread, but ... when our PV array was installed, the old analogue meter was supposed to be replaced with a digital import/export meter within a few weeks. Instead, it was nearly a year and several emails before they got round to it (I live in NI so the utility responsible is NIE).

In the meantime, the analogue meter went forward at night of course, but generally went backwards during the day - quite slowly when it was cloudy, quickly when it was bright. The only exceptions to that were when the kettle, toaster or microwave were switched on - even on a bright day, the meter would still go forward, but not race like it would when e.g. boiling a kettle after sunset*. Of course, from April to August there were a lot more hours of daylight to just keep driving it backwards, or at least continue meeting our electricity needs in the evening. Plus of course our evening usage would be much reduced at that time of year - little need for lights, spending more time outside instead of in front of the telly etc.
(*getting solar panels installed turns you into your dad!)

Anyway, the net effect of this was that by the time NIE finally installed the import/export meter, the meter reading was actually lower than it had been at the time the panels had gone live, eleven and a half months previously. And not just a bit lower, something like 200 units lower. Which was nice. Since then, we've replaced a lot of spotlights with LEDs, replaced a very old fridge-freezer with much more efficient separates, learned to not have kettle and toaster on at the same time etc so we import a fair bit less from the grid now. Even though the period of surplus really only runs from late March to early October (especially as we now use electricity instead of oil for hot water), we still exported over 800 units last year.

Back on topic - yeah, I get what you're saying about the average power requirements for driving an EV. Very few people do 200-300km every day. If I had the likes of a Powerwall - and an EV to go with it! - I could divert any PV surplus into it and use it to run the house and top up the car at night. So in theory our annual surplus which we export to the grid would meet most or all of an EV's charging needs. But since so much of that surplus is generated in the summer rather than being spread evenly across the year, we'd have to do hella more mileage during that time to actually use it all!

unkel

Nice post, particularly this bit:

mr chips wrote: »

*getting solar panels installed turns you into your dad!

hi5

Regenerative suspension should be coming eventually, would be great on some of the roads around where I live.

nsi423

KCross wrote: »

There are Plugin-Hybrids... parallel hybrid.
...
There is also the likes of the BMW i3... series hybrid

Right, of course, I didn't think of it like that before. Makes sense when you put it that way!

Is any other manufacturer doing series hybrid? It's been argued here before but I think it is a great solution while batteries are less than, say, 60 kWh. Then again I'm biased!

Even BMW are giving up on it with the new bigger battery i3, at least in Europe
https://electrek.co/2018/10/05/bmw-i3-all-electric-gas-range-extender/

zilog_jones

Mazda have been working on something for some time now, using a rotary engine of course: https://www.autoexpress.co.uk/mazda/98958/mazda-confirms-return-of-rotary-engine-as-ev-range-extender

mr chips

Huh ...

Mazda’s EVs form part of its plan for 95 per cent of its sales to be electrified by 2030, with 5 per cent being pure EVs.
Speaking at the 2017 Geneva Motor Show, European R&D boss Matsuhiro Tanaka said: “[A fully electric car] is one of the possibilities we are examining. A small car is best for an EV because bigger vehicles get too heavy with bigger batteries, and that doesn’t make sense for Mazda.”
While Tanaka didn’t go into detail on the new model, it’s expected to be a rival for the Renault ZOE.