Downhill battery full charge causes engine noise

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niroinca
Posts: 1
Joined: Sat Jun 23, 2018 10:20 pm

Post by niroinca »

I drive the 2018 Niro hybrid. When coming downhill over a large distance where I'm only using the brakes, as soon as the battery goes to full charge either the ICE or the electric motor comes on full speed. I can tell from the very loud noise it makes. I don't understand why it does that. My first guess was that it is running the electric motor at full speed to burn off the excess charge. It is quite loud so it could be the ICE, but it makes zero sense to burn fuel in this scenario. My other guess is overcharging takes it over the acceptable voltage and trips some circuits. Why won't they simply disengage the charging circuits instead of letting it charge to 100%? Has anyone else experienced this?
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2018 Kia Niro LX + tech package

smileymiley
Posts: 13
Joined: Sat Apr 08, 2017 7:25 am

Post by smileymiley »

Don't think the battery should be charging that much. Consesus on here is for the battery to peak around 75%. I'd get it checked out by Kia.
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djbobbins
Posts: 132
Joined: Fri Mar 03, 2017 7:57 pm

Post by djbobbins »

I took my Niro to the Alps last summer and experienced the same thing - the drive from the mountain resort down into the valley was about 15km of downhill, mainly switchback roads.

The battery gets to fully changed and then the internal combustion engine kicks in; my assumption is that this is to provide engine braking of some sort. I did the same trip on multiple occasions and didn't notice any ill effects.
Topicalcat
Posts: 49
Joined: Sat Dec 02, 2017 12:43 pm

Post by Topicalcat »

That comment about engine breaking makes sense. If the battery will accept charge then the action of using the motor to charge the battery will act to retard the car. However once the battery is charged you no longer have that braking effect and for safety sake need the engine.

I would guess that with the throttle closed the engine when it comes on is using little or no fuel, one of the advantages of fuel injection and a closed throttle. I would be interested to hear further comments on this. When I get my Niro and go to France I will have a 30 mile downhill section coming down from the plateau on the Massiff Central on the A75 autoroute after the Milleau bridge down to the coastal plain. I used to come down in a lower gear in my diesel with no throttle and used to record 99.9 mpg which was as much as the display could cope with. In reality it must have been much better than that.
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h2onorth
Posts: 179
Joined: Thu Nov 24, 2016 6:19 pm

Post by h2onorth »

Hi all interesting topic which has been raised before by a few. Some contributors also mentioned a "hot smell" from battery area which is not mentioned by current topic. During this downhill scenario has anyone tried sport mode and manually put car in 2nd or 3rd (speed permitting).
If so what data from car was obtained and was engine speed raised or lowered?.
I read recently that the PHEw car displays the revs in certain modes of driving, in which case this would be useful in this scenario.
h2onorth
JOL54
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Joined: Mon Feb 19, 2018 4:37 pm

Post by JOL54 »

Nowhere is there a rev counter on my PHEV.
jerrytaff
Posts: 120
Joined: Wed Oct 03, 2018 8:28 pm

Post by jerrytaff »

Owners Manual Pages 4-53, 4-54 and and 4-57 show that for the PHEV, if fitted with instrument cluster type B, then the central LCD window displays a rev counter when in sports mode. So, my question is.... which models are fitted with type B? I've only seen type A.

Does the PHEV even exhibit the same behaviour? The HEV tries to maintain the battery charge within a narrow window, so I can understand it using the ICE to apply non-regenerative engine braking when the battery is at the high end of the window. By contrast,the PHEV window is much wider ( 15% to 100%), so I guess that all you need to do is to ensure that the charge isn't too full (say 50%) before entering the long down-hill section, and you will avoid the inefficiency of having to burn off energy to avoid overcharging .
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niroal
Posts: 183
Joined: Thu Jun 29, 2017 11:22 am
Location: North Kent

Post by niroal »

jerrytaff wrote: Fri Oct 26, 2018 6:27 pm Owners Manual Pages 4-53, 4-54 and and 4-57 show that for the PHEV, if fitted with instrument cluster type B, then the central LCD window displays a rev counter when in sports mode. So, my question is.... which models are fitted with type B? I've only seen type A.

Does the PHEV even exhibit the same behaviour? The HEV tries to maintain the battery charge within a narrow window, so I can understand it using the ICE to apply non-regenerative engine braking when the battery is at the high end of the window. By contrast,the PHEV window is much wider ( 15% to 100%), so I guess that all you need to do is to ensure that the charge isn't too full (say 50%) before entering the long down-hill section, and you will avoid the inefficiency of having to burn off energy to avoid overcharging .
Europe PHEV models have the other display (and LED headlights too). If you live at the top of a hill (thinking more of Switzerland than UK) & have home charging then wasteful regen could be an issue in a PHEV. As the HEV doesn't fully charge the battery in normal driving it actually has more capacity for long regen than a fully charged PHEV.

The bit I find annoying with the type A display on a PHEV is if the car is in HEV mode sport mode is manual only, whereas a HEV can have auto sportmode in (obviously) HEV mode.
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RonanTetsu
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Joined: Sun Jul 28, 2024 12:09 am

Post by RonanTetsu »

I'm surprised people know absolutely nothing about engine braking. Engine braking NEVER EVER CONSUMES FUEL. No car ever consumes fuel when engine braking as the engine is only pumping air to decelerate the vehicle. The only thing that happens is that the engine is technically being used so obviously it'll put wear on the engine, but the wear is expected and of no consequence.

Engine braking is literally stated in the Eco hybrid app for the kia entertainment system. Only the charging state (not braking) and engine only mode consumes fuel.
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