UX250h hybrid battery voltage question….

floggit · September 19, 2021

Hello!!!! Used to own an LS400, then a CT200h then left the fold and went vw. Enough said.
Possibly returning as im looking to get back into a hybrid. Been researching the UX250h as it would fit my needs and came across the EV driving thread here.

Little concerned people dont think their getting ev mode enough. The Ct used to go a couple of miles gently before kicking the ice in. Im sure the Ct Battery was something like 500+volts up to 600v or so in sport mode. If im reading the UX specs correctly the Battery is 216v which is considerably less.

Has the hybrid been dumbed down too much? this would explain less EV mode driving.

Im currently looking across all manufacturers with hybrids, some are as low as 48v which seems to be fitting the minimum to class it as one.

Are owners generally happy with the drivetrain or maybe underwhelmed?

hope this doesent sound to negative, i just research cars before purchase to avoid mistakes lol.

steve.

September 19, 2021

My regular driving is probably unique to me as it is almost 100% frequent short urban trips that revolve round my wife's care. On these trips I find it hard to stay in EV mode for more than about 500-600 metres and I've long ago given up the urge to press the EV mode button because the mode not available message always came up.

Having said that, just yesterday I had to do a run along a decent country road and I noticed I was on Battery power for quite a while at some 50mph.

I suppose that means that a different driving environment to my norm would result in more EV gentle cruising.

Herbie · September 19, 2021

33 minutes ago, floggit said:

Little concerned people dont think their getting ev mode enough. The Ct used to go a couple of miles gently before kicking the ice in. Im sure the Ct battery was something like 500+volts up to 600v or so in sport mode. If im reading the UX specs correctly the battery is 216v which is considerably less.

I've never had a CT or a UX so I can only speak from the perspective of an RX, but I think you've misunderstood the way these cars work.

The traction Battery in the RX is, if I remember correctly, 288V but the requirements of the car are varied.

For instance:

MG1 and MG2 are 650V 3-phase AC motors (the Battery is DC)
The aircon compressor is driven by a 500V 3-phase AC variable frequency motor
The power steering is driven by a 48V motor
The 12V system (lights, radio etc) and the 12V Battery are powered/charged by a 14.5V system (the hybrid equivalent of an alternator).

All these things are driven by the 288V DC traction Battery in conjunction with various DC converter/inverter units and other boxes of electronic wizardry.

These cars are amazing feats of engineering and incredibly complex, but one thing they are not, is electric cars. As you already know, if you were to drive on Battery alone then you'd only manage a couple of miles at most, maybe not even that.

Richard1200 · September 19, 2021

I am on my second UX and I do not understand any of of above and neither do I need to understand it. It’s a car that with my type of low mileage driving gives me 52mpg in the summer and 49 ish in the winter. It goes onto electric when it can, that’s all you need to know. I leave the rest up to the clever people in Japan.

Thackeray · September 19, 2021

33 minutes ago, Herbie said:

These cars are amazing feats of engineering and incredibly complex, but one thing they are not, is electric cars.

As usual a very helpful explanation from Herbie on the voltages. And he's absolutely right in pointing out that they are not intended to be electric cars.

All the power the car uses, at all times, has been generated by the petrol engine. While the car is cruising or accelerating, most of the engine's power is used to move the car. The problem is that when a conventional car brakes, the energy that the engine has generated is thrown away as heat.

This is the problem that the hybrid tries to deal with. Instead of throwing away the energy, a generator turns it into electricity. Next problem - what to do with this electricity if it isn't needed at that moment. Answer - store it in a Battery. (Incidentally, this is why the system keeps the Battery about half full in general; it needs to have enough space to store the captured energy.) But you don't need a very big Battery to store the energy you get from braking.

So then after storing this regenerated electricity, the system has to use it or the Battery would fill to capacity. So the Battery is used to help acceleration. Or to cruise at lowish speeds for short distances. But the system's goal is not to be an electric car. Instead it aims to avoid having the Battery too full or it wouldn't have space for saving energy which would otherwise be wasted.

If the UX doesn't seem to allow electric-only cruising as much as earlier hybrid versions, then that must be because the regenerated power is being used to a greater extent to support the engine. But it makes no difference to the overall goal, which is to avoid throwing away energy by braking when it could be saved in the Battery.

floggit · September 19, 2021

Thanks for the replies,the hybrid in the CT for me as a first hybrid had a big impact on the way the vehicle drove and was just concerned by the comments in the ev mode thread, but yeah i get the Battery assists the engine supply power for everything not just the drive. Certainly not going to affect a decision to buy but need to have expectations inline with what your getting. Still plenty of research to do lol.

royoftherovers · September 19, 2021

Aptly put as usual Herbie.

ColinBarber · September 19, 2021

8 hours ago, floggit said:

Little concerned people dont think their getting ev mode enough. The Ct used to go a couple of miles gently before kicking the ice in. Im sure the Ct battery was something like 500+volts up to 600v or so in sport mode. If im reading the UX specs correctly the battery is 216v which is considerably less.

Has the hybrid been dumbed down too much? this would explain less EV mode driving.

CT has a 201.6 V Battery pack, the UX uses a 216 V one.

The electric motor operates at 650 VAC on both the CT and UX, and both can produce 80 bhp.

The biggest difference is the newer hybrid systems assist the petrol engine more that previous generations, rather than just switching to EV mode. The UX does however have the ability to switch into EV at speeds greater than 70 mph, something the CT cannot (max around 50 mph).

The UX is a full hybrid. Those mild hybrid 48 V efforts are not much more than start/stop vehicles. The UX doesn't quite have the economy of the CT, it has a bigger more powerful ICE and it is a less aerodynamic/larger vehicle, but it is much more refined.

MartinH · September 19, 2021

Is this latest UX powerplant identical to that used by Toyota in Corolla and C-HR do you know?

floggit · September 19, 2021

1 hour ago, ColinBarber said:

CT has a 201.6 V battery pack, the UX uses a 216 V one.

The electric motor operates at 650 VAC on both the CT and UX, and both can produce 80 bhp.

The biggest difference is the newer hybrid systems assist the petrol engine more that previous generations, rather than just switching to EV mode. The UX does however have the ability to switch into EV at speeds greater than 70 mph, something the CT cannot (max around 50 mph).

The UX is a full hybrid. Those mild hybrid 48 V efforts are not much more than start/stop vehicles. The UX doesn't quite have the economy of the CT, it has a bigger more powerful ICE and it is a less aerodynamic/larger vehicle, but it is much more refined.

Perfect explanation, thankyou. Spending a few hours looking through the website/ brochures. Its all looking good 👍🏻

paulrnx · September 19, 2021

I’ve had two IS hybrids and I’m on my second NX hybrid. I recently had a UX250H and I found it no different to drive than these other than it was quite a bit more economical.

MartinH · September 19, 2021

UX has 2.0 litre ICE tho, whereas IS has 2.5 l ?

ColinBarber · September 20, 2021

14 hours ago, MartinH said:

Is this latest UX powerplant identical to that used by Toyota in Corolla and C-HR do you know?

Identical to the 2.0 engine option in the Corolla and C-HR.

EvilRacer329 · September 21, 2021

I understood from my Lexus salesperson (and then later confirmed through research) that the NX, IS, CT etc. were all using 3rd-gen Toyota/Lexus hybrid tech, and the UX was the first with their new 4th-gen tech. Hence higher-efficiency motors and generators, higher speeds in electric mode, all that good stuff. I found a few tricks for getting maximum juice into the Battery, at which point I could trundle through 20-30mph town sections in almost exclusively electric mode.

Ironically I find the Battery never gets very full driving in town, probably because I'm not doing enough regenerative braking to refill the Battery. The engine running will top the Battery up only to a relatively low level if there are no other reasons for it to run. Fire it up on the driveway with the climate control set quite high and it'll run just to warm the engine up in an attempt to heat the cabin. Because the engine doesn't need to move the car while this happens, it dumps everything into the Battery, and you can almost get a full charge.

I quite enjoy playing with the hybrid system to get as much distance as possible each trip in EV mode, averaging 25% of my mileage over the last year. On motorway trips, it's low (single digits), but on trips with more town work I can easily beat 50%. The CT I drove as a courtesy car I had to work much harder to get it to drop into and then stay in EV mode, but I daresay it's all about familiarity with that particular system!

Honestly, it's all pretty incredible tech. No power steering pump, no engine-driven air conditioning compressor, no starter motor, no belt-driven alternator...in a lot of ways it's a very elegant design. I'm a big fan.

Nick