Prius V / Alpha Mileage

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SATTV

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#319779 2-Jun-2025 10:46

Hi All,

I have a 2015 Daihatsu Mebius which is a rebadged Prius Alpha

When I first got it I was getting about 650km to a tank, I am now getting about 550km to a tank. approx 17km / l

I friend who has a similar model says he gets about 900km to a tank and a few Uber drivers say the same.

From what I can tell it has a 40l tank, I thought it was a 35l tank until the other day when I put 36l into it.

Does anyone know what size tank these have, it could be the fuel tank sender is not right.

Toyota have cleaned the trottal body and changed the spark plugs but this has made no difference. I suspect the crank angle sensor and oxygen sensor is OK otherwise Toyota would have picket it up on their scan.

I am starting to think that the battery is on its way out.

I do have a ODB2 dongle that I have never used but I dont have any software to read the car info.

Any thoughts / info / advice / recommendations.

John

( I am in Auckland if that makes any difference )

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Mad Scientist
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#3379777 2-Jun-2025 11:19

i think you need a new battery. how much is a new battery?

10 years is an eternity for batteries. my wife's new iphone, its battery degrades 10% in one year. can't tell on my samsung as it doesn't have that data.

gzt

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#3379780 2-Jun-2025 11:50

You took it to Toyota and they could not tell you what is wrong? I'm extremely surprised. Is there more to the story?

BlakJak

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#3379787 2-Jun-2025 12:06

SATTV:

Hi All,

I have a 2015 Daihatsu Mebius which is a rebadged Prius Alpha

When I first got it I was getting about 650km to a tank, I am now getting about 550km to a tank. approx 17km / l

I friend who has a similar model says he gets about 900km to a tank and a few Uber drivers say the same.

From what I can tell it has a 40l tank, I thought it was a 35l tank until the other day when I put 36l into it.

Does anyone know what size tank these have, it could be the fuel tank sender is not right.

Toyota have cleaned the trottal body and changed the spark plugs but this has made no difference. I suspect the crank angle sensor and oxygen sensor is OK otherwise Toyota would have picket it up on their scan.

I am starting to think that the battery is on its way out.

I do have a ODB2 dongle that I have never used but I dont have any software to read the car info.

Any thoughts / info / advice / recommendations.

John

( I am in Auckland if that makes any difference )

You haven't said what mileage you have done. I have a 2015 Prius Alpha that's about to clock 120,000 - I've had it for nearly two years and bought it when it had about 98,000km on it. I'm in Wellington and have to deal with lots of steep hills, in particular the one I live near the top of.

Typical efficiency is about 14.9km/L or about 500-to-550km per tank. Most I've put in is about 38L?, usually fill up just as the low fuel light comes on and usually that's 33-35L I think.

Total KMs will affect the efficiency of your battery. But also driving style will influence range, I probably have a heavier-than-average foot at open road speed but I also enjoy efficiently using the battery when commuting in traffic, almost gaming whether or not I can keep the ICE from starting.

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SATTV

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#3379795 2-Jun-2025 12:56

The mileage is 130 000 km

When I took it to Toyota in Grey Lynn I got the distinct impression they did not know what to do.

I think they only do servicing and not much else.

A new battery is about $2500 I am told, I would consider an aftermarket battery that has a higher capacity but would need to come from a reputable company that specialises in that sort of thing, there are plenty of guys around here that swap batteries around but I am at that stage in life where I do it once and do it right.

John

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lNomNoml

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#3379796 2-Jun-2025 13:00

SATTV:

The mileage is 130 000 km

When I took it to Toyota in Grey Lynn I got the distinct impression they did not know what to do.

I think they only do servicing and not much else.

A new battery is about $2500 I am told, I would consider an aftermarket battery that has a higher capacity but would need to come from a reputable company that specialises in that sort of thing, there are plenty of guys around here that swap batteries around but I am at that stage in life where I do it once and do it right.

John

Yeah sounds like battery needs to be replaced, surprised Toyota didn't tell you this or at least do a battery health check, if you want to do it right the first time I wouldn't go aftermarket.

gzt

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#3379797 2-Jun-2025 13:02

You need an accurate diagnosis before you go deciding to replace anything

gzt

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#3379798 2-Jun-2025 13:15

I have a Prius Alpha 5 seat with 180km. It's currently sitting on 20.2km per litre. Pretty much the spec 5.1 litres per 100km.

When I'm driving I turn on pwr mode nearly every time. My partner does not bother with that and gets slightly better mileage. My partner is the primary driver recently.

By the way, a lot of people seem to think you get best mileage in B mode. That is absolutely incorrect. B mode is not for that purpose at all. B mode is engine brake mode.

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gzt

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#3379800 2-Jun-2025 13:24

When I took it to Toyota in Grey Lynn I got the distinct impression they did not know what to do.

That sounds bad. I'd call or write the management or head office about that. You paid for expert diagnosis and didn't get anything even close imo.

Batman

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#3379902 2-Jun-2025 14:40

SATTV:

The mileage is 130 000 km

When I took it to Toyota in Grey Lynn I got the distinct impression they did not know what to do.

I think they only do servicing and not much else.

A new battery is about $2500 I am told, I would consider an aftermarket battery that has a higher capacity but would need to come from a reputable company that specialises in that sort of thing, there are plenty of guys around here that swap batteries around but I am at that stage in life where I do it once and do it right.

John

does @Ruki change hybrid batteries? he seems to be the hybrid guy around here

gzt

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#3379903 2-Jun-2025 14:50

SATTV: I have a 2015 Daihatsu Mebius which is a rebadged Prius Alpha

Is this a five seat or a seven seat? Different battery. In any case you need some skilled diagnosis before anyone knows it's a battery issue. Battery issues are relatively rare ime, especially at that low mileage.

SATTV

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#3379911 2-Jun-2025 15:20

Batman:

does @Ruki change hybrid batteries? he seems to be the hybrid guy around here

I believe he swaps out bad cells for other used cells.

When I spoke to him in the past he wanted the battery unit on his bench for a few days.

If I recall you need the battery for the car to work so I would be without my car which is very impractical for me.

John

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Scott3

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#3379967 2-Jun-2025 15:28

SATTV:

Hi All,

I have a 2015 Daihatsu Mebius which is a rebadged Prius Alpha

When I first got it I was getting about 650km to a tank, I am now getting about 550km to a tank. approx 17km / l

I friend who has a similar model says he gets about 900km to a tank and a few Uber drivers say the same.

From what I can tell it has a 40l tank, I thought it was a 35l tank until the other day when I put 36l into it.

Does anyone know what size tank these have, it could be the fuel tank sender is not right.

Toyota have cleaned the trottal body and changed the spark plugs but this has made no difference. I suspect the crank angle sensor and oxygen sensor is OK otherwise Toyota would have picket it up on their scan.

I am starting to think that the battery is on its way out.

I do have a ODB2 dongle that I have never used but I dont have any software to read the car info.

Any thoughts / info / advice / recommendations.

John

( I am in Auckland if that makes any difference )

17km/L = 5.88 L/100km. That's not bad at all for pushing around such a large body.

Based on the below, the 2015 Prius v (alpha) is rated at 4.4 L/100km, so you are 33% more than this. Generally fairly hard to match rated fuel consumption, but still this is a little more than I would expect, but not so much that it cannot be explained by driving style etc.
https://www.toyota.co.nz/about-toyota/toyota-news/2015/june/versatile-prius-v-adds-more-for-2015/

Rating for the same car on the us EPA cycle is 5.6L/100km on the combined cycle, so you are in that ballpark.

And a quick google search turns up examples of others getting similar numbers:

https://www.reddit.com/r/NZcarfix/comments/1eckaus/prius_alpha_fuel_economy/

And you are close enough to the center of the bell cuvre on fuelly

https://www.fuelly.com/car/toyota/prius_v

As such I am not seeing anything here that creates alarm bells there there is anything massively wrong with the car.

What do you mean by "similar models" - if you are comparing to the regular Prius, it is a lot smaller car with a similar size fuel tank (42 L for the 3rd gen vs 45L for the Daihatsu Mebius), is one would expect it to go further.

I wouldn't pay too much attention to range - how far you are willing to run the tank low has a really big tank. A quick search turns up that your car has a 45L tank, so there is another 150km of range in your tank when before you do a 36L fill. (of course it is not). Based on my lexus hybrid, it is not unusual for the light to come on when you still have well north of 100km of fuel remaining.

L/100km (normally used in NZ, but km/L is fine if you prefer) is the best metric to track. Ideally using actual fill volumes, not dash reported values which can be inaccurate.

If you are concerned about the car mis-reporting fuel levels, this is fairly easy to check by comparing full volumes with the tanks size, but be aware Toyota's are knowing for having the fuel light come on with a decent percentage of fuel still remaining. This is by design, so not a fault, but can be challenging for those that want to use a larger portion of their vehicles range. Never worth pushing the limits and running out of fuel.

Cars economy does sometimes decline with age, but the 650km -> 550km you state, is 15% and would be more than expected.

If you want more fuel economy from the car, I would look at all the normal stuff:

Check the cars service is up to date. Old (or incorrect viscosity) engine oil, or transmission / gearbox fluid can have a material impact on fuel consumption. On my leaf I swapped 100,000km factory filled fluid to a redline brand gearbox oil (same rating as OEM, but known to be slightly thinner), and my efficiency measurably increased.
Windage - If you have anything added to the exterior of the car, it will add aerodynamic drag. take roofracks off when not using them and save 5 - 15% fuel.
Cargo / weight - While hybrids are less impacted than non hybirds due to regenerative breaking, extra weight does have an impact on fuel consumption. Clean out the car of stuff that is not actively needed.
Tire-pressure. Has a big impact of rolling resistance. Maintaining manufacturer recommended pressure is good practice, but fuel can be saved by pushing a little higher (never exceed tire max sidewall rating) Not unusual for people to run a car like yours are 40psi.
Low rolling resistance tires - worth a 3 - 10% fuel saving over regular tires. Something to consider when your tires are due for replacement
Driving style, This is massive Fuel efficient driving can save 10 - 30% compared to aggressive driving. Look up fuel efficient driving style if you are not already aware. Avoid dangerous / illegal hypermiling methods such as drafting.

Consider what you have changed on the car since you got it. If you changed the low rolling resistance tires to regular tires, and added a roof rack, that alone would account for 15% extra fuel usage.

On the battery, while the capacity of your battery will have degraded since new, It is unlikely a 2014 with 130,000km will have any battery issues. The degradation will have some impact on milage, but it will be fairly minor.

the 5 seat versions of the v / alpha have NiMH batteries, which are quite mature in this application. In general for non taxi use, they are expected to last the life of the vehicle.

I have a 2006 Lexus RX400h with 230,000km with the same chemistry batteries. Scanned them last year, and they were still north of 70% health. If you are worried you can buy the Dr Prius app and run a discharge test like I did. (I was diagnosing another issue)

Batman:

i think you need a new battery. how much is a new battery?

10 years is an eternity for batteries. my wife's new iphone, its battery degrades 10% in one year. can't tell on my samsung as it doesn't have that data.

This is unhelpfull. The lifespan of a cell phone battery has nothing to do with the lifespan of a different chemistry, actively cooled automotive battery. Cars simply have longer design life's than phones.

I have a 2006, 230,000km Lexus hybrid, which i tested last year and still had north of 70% health.

Non plug in Hybrid battery pack replacements run at $1k - $3k, so are not something that is done frivolously.

BlakJak

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#3380362 4-Jun-2025 09:28

Scott3:

17km/L = 5.88 L/100km. That's not bad at all for pushing around such a large body.

Based on the below, the 2015 Prius v (alpha) is rated at 4.4 L/100km, so you are 33% more than this. Generally fairly hard to match rated fuel consumption, but still this is a little more than I would expect, but not so much that it cannot be explained by driving style etc.
https://www.toyota.co.nz/about-toyota/toyota-news/2015/june/versatile-prius-v-adds-more-for-2015/

Rating for the same car on the us EPA cycle is 5.6L/100km on the combined cycle, so you are in that ballpark.

And a quick google search turns up examples of others getting similar numbers:

https://www.reddit.com/r/NZcarfix/comments/1eckaus/prius_alpha_fuel_economy/

And you are close enough to the center of the bell cuvre on fuelly

https://www.fuelly.com/car/toyota/prius_v

As such I am not seeing anything here that creates alarm bells there there is anything massively wrong with the car.

I really appreciated you posting this. Thank you - interesting stuff.

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wellygary

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#3380363 4-Jun-2025 09:35

Scott3:

I wouldn't pay too much attention to range - how far you are willing to run the tank low has a really big tank. A quick search turns up that your car has a 45L tank, so there is another 150km of range in your tank when before you do a 36L fill. (of course it is not). Based on my lexus hybrid, it is not unusual for the light to come on when you still have well north of 100km of fuel remaining.

Sounds like Toyota Behaviour, had great fun riffing with our kids on our last road trip...

Road Sign: 180 km to destination... Trip computer 130Km of range,

Fuel light comes on about 20km from destination, keep on driving......
When we filled it, there were still 11 litres in the tank according to the handbook specs

(60 litre tank, but everything is gauged off 50 , leaving a 10 litre margin )

BlakJak

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#3380370 4-Jun-2025 09:57

I don't ever intend to run my car that close to the margin... if nothing else I like to leave something for emergencies.

Several years ago I was towing a trailer with some trademe-aquired furniture in it and wound up basically coasting into a service station due to under-estimating the impact said trailer would have on my fuel efficiency. Lesson learned!

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