[BoneCollector]

Originally Posted by RavyaLe

1. During idle conditions/ traffic signals this system is not working. What may be an issue?

In all probability, your battery has gone weak. Once you get it replaced, it'll start working again.

2. Can we bypass this Hybrid tech, by disconnecting that extra battery and drive the car.

I guess it's very much possible. All you need is a battery with lesser capacity than the one used. DDiS SHVS uses Exide Conservo 70DIN battery. The system may not work with lesser DIN batteries.

3. For the diesel model, I think this SHVS is not useful, on the other hand, if any problem arises we have to pay hefty money to replace the extra batteries.

Diesel SHVS are equipped with only 1 battery unlike the petrol ones which have a Lithium battery in passenger compartment. Each Exide Conservo costs around 8.5K. The lithium battery is over 50K I guess.
It's very much useful as it improves the average by quite a bit.

[RavyaLe]

Originally Posted by BoneCollector

In all probability, your battery has gone weak. Once you get it replaced, it'll start working again.

Thank you BoneCollector, appreciate your inputs and I am convinced.

I am surprised why the same SHVS Hybrid tech is not being used for both Diesel and Petrol cars. As you informed, the battery cost of Diesel cars is ~ 9K, whereas in the case of Petrol cars, it will be ~50K.

Today I visited Varun Motors ECIL - Hyderabad Service center for SHVS mode not working in my 1.3 DDIS VDI Ertiga car. The service engineer diagnosed the problem and informed me that the battery has to be changed. At present, I can run the car without any issues, but SHVS mode will not work.

Next month I have 3rd year / 30,000 KM service schedule. During that time I will inform them to replace the battery.

He also scanned the car electronics, ABS function was not working. Surprisingly I am not getting any warning on my speedometer console. Currently, the car is in the service center, I will update the details once I get the car servicing over.

[RavyaLe]

Originally Posted by RavyaLe

I will update the details once I get the car after servicing.

Update after the SHVS Checkup of my 1.3 DDiS VDI Ertiga (Dec.2018 Model).

- Maruti & ECIL Varun Motors Hyderabad team acted swiftly for my online complaint raised on 18th Nov.
- Service person promptly attended to my issues, they also rectified the ABS problem. He suggested even ABS mall functioning may be one of the reasons for SHVS not working.
- After this checkup, my car braking is better.
- He demonstrated my car's SHVS system by swapping another car battery, we did a trial run of about 2 km, SHVS was working in traffic signals / idle conditions, also SHVS symbol (Green SHVS Light) was blinking in the speedometer console.
- Hence he suggested the battery replacement during the next servicing.
- Varum Motors / Maruti have not charged for this SHVS problem complaint.
- To my surprise after this checkup now my car SHVS system functioning normally.
- I think battery replacement is not required at present, maybe the ABS mall function was the reason.

My online complaint registration worked swiftly, Maruti & Varun Motors ECIL Hyderabad team took this on priority and they rectified the problem.

[Leoshashi]

Originally Posted by RavyaLe

I am surprised why the same SHVS Hybrid tech is not being used for both Diesel and Petrol cars. As you informed, the battery cost of Diesel cars is ~ 9K, whereas in the case of Petrol cars, it will be ~50K.

Diesel SHVS cars use single Lead Acid battery in engine bay, costs 8-9k. Petrol SHVS cars use dual batteries, one Lead Acid battery in engine bay which costs 6k while the 2nd Lithium Ion battery is inside passenger cabin, and it currently costs north of 55k as of now.

Hope this clears the doubt.

Regards,
Shashi

[Leoshashi]

Was curious about ISG/MGU specs of Diesel and Petrol SHVS cars. Here's what I found:

Petrol ISG:

Diesel ISG:

[jigar1791@gmail]

Originally Posted by Leoshashi

As promised, here I am with a detailed description of the Smart Hybrid system. There is a lot of nonsense and misinformation circulated in the media. Have a look at this video:

https://www.Youtube.com/watch?v=uPhJ7MPSmYI

The Presenter talks about something being mounted on Flywheel and what not!

When ISG operates as starter motor or in the engine power assist mode, the power circuit transistors are turned ON, and direct current from the battery (lead-acid battery) or auxiliary power module (lithium-ion battery) is converted into three-phase (six-phase) alternating current passing through each transistor side of the power circuit. Three-phase (six-phase) alternating current passes through the three phase (six-phase) winding of the stator to generate torque in the rotor and causing rotation as a motor.

Dear LeoShashi,
My 2018 Ciaz Petrol MT (facelift) has a peculiar issue - I do not see the SHVS working everytime when I'm stationary in Neutral.

This issue has started to come up somewhere around Sept '21. Initially, I thought the wires may have been eaten over by rats and mice (yes, our society's parking is infested by rats - nothing has worked to stop them, tried from concretizing the parking bays, to keeping cats to deep cleaning the compound to have anti-rat sprays in the engine bay!)
Yes, wires were eaten up (the wire which is connected from Lead-Acid battery to the SHVS motor (most likely, as I wasn't present during the service on account of Covid related restrictions)), got them replaced with new ones and then for a few days, the system worked for about 85% of the times.

However, post Diwali upto now, I see the SHVS behaving sporadically, turning off the engine for about 50% instances.

Our trusted SA (we get all our cars serviced/repaired through him) checks the battery health (conventional battery), and the result says 40%.
Senior technician concludes - problem is the lead-acid battery. Asks us to re-charge it fully, and then see if the issue still persists or otherwise.

Questions -
1. We have completed 3 years/28K kms with the car, conventional OEM battery meter check says battery health is at 40%. This behavior seems fine or is there something wrong with our battery?

2. If so, what should be the ideal conventional battery health to keep the SHVS system running as it was during first 2 years of usage?

3. Is the technician/SA correct in their conclusion - getting the conventional battery charged at 100%, which should solve the issue?

Note -
The car was recalled to inspect possible faults in it's MGU, and that was replaced during the annual service.

Your thoughts, please.

[Leoshashi]

Originally Posted by jigar1791@gmail

Questions -
1. We have completed 3 years/28K kms with the car, conventional OEM battery meter check says battery health is at 40%. This behavior seems fine or is there something wrong with our battery?

2. If so, what should be the ideal conventional battery health to keep the SHVS system running as it was during first 2 years of usage?

3. Is the technician/SA correct in their conclusion - getting the conventional battery charged at 100%, which should solve the issue?

Note -
The car was recalled to inspect possible faults in it's MGU, and that was replaced during the annual service.

Your thoughts, please.

Yes if either of the batteries is weak, the SHVS will not work as expected. Check it's electrolyte level, get the battery charged and it should work(assuming rest of the hardware like wiring etc is in perfect shape).

PS: My XL6s Conservo had electrolyte at its minimum level even before first service. During my regular fiddling session, I noticed this and asked my SA if it's normal. He was shocked and clicked pics to file a FITR(Field Inspection Technical Report) if it happens again. Thankfully it was a one off case, of QC issue from Exide factory and the level hasn't dropped since.

I believe batteries like mine die prematurely. Yours has lived a decent life, nothing great. Still I'd recommend to get it charged once. Will help in extending its usable life.

[ragwhos]

Well, not a physics forum, but thought some might like this and it would help settle the debate about the impact of the "mild-hybrid" system

The relationship between Power and Torque is fairly simple - power is just rate of doing work, i.e. rate at which torque is applied or motor rpm ( multiplied by suitable constant for conversion to the same units )

Torque = Power / 2 * π * rotations per second

or Torque = Power / (0.105 * rpm)

So, I assume the 18,000 rpm figures are just when acting as a generator if the power and torque values are correct. The power produced at 18K rpm and 60NM torque would be around 150hp, much better than the engine! So no

Applying the formula, if the Torque and Power values are right, the motor must be spinning at less than 270 rpm at peak power of 1.7kW

A Ciaz 16 inch wheel is around 1.4m in circumference

So, at anything over 23kmph, the electric motor is in overdrive and I wonder what torque boost it can actually produce, even at lower speeds the gear ratios needed to apply any meaningful torque at the wheels is

I know this isn't a proper hybrid but could this motor even move the car by itself? A thought experiment to prove how useless this really is.

Even ignoring all other static friction, and just using tyre's static friction (approx coefficient of 1), a force of F=ma needs to be applied at the wheels

F= 1100*9.8 = 10780
Applying this across 0.2 radius wheels

Says the torque required to move the car is around 2156Nm --- A 60 Nm at the motor means a gearing ratio of 1:35
Peak power at 270 rpm translates to 7.7 rpm at the wheel or 0.6 kmph

So, no, it can't move it.

In summary, if the torque and power figures in that sheet are correct, the SVHS mild-hybrid system is nearly completely useless at giving any meaningful torque boost at the wheels because the motor can't really apply torque at over 270rpm

I think the system could still be quite useful for the Engine Stop/ Start functions and to compensate some friction losses at the drive train when running via regenerated (brake) energy, and so overall useful at improving fuel economy. But have a negligible impact on performance or drivability.

P.S. I know rolling friction is much lower once the vehicle is moving, but the point about low rpm and gearing ratios is still valid.

[setuniket]

Is there any indication as to the minimum voltage in the primary Lead Acid battery for the auto start to function?

After the ISG replacement, the Auto Stop light started blinking again, I checked with SA, he indicated that it may due to low voltage in the primary Lead Acid Battery which is now 3+ years/50k kms old.

I will be taking the car to Exide dealer to check battery health. The minimum Voltage values would be a good indicator to get the ISG or the battery replaced.

Originally Posted by Leoshashi

Was curious about ISG/MGU specs of Diesel and Petrol SHVS cars. Here's what I found:

Petrol ISG:

[jigar1791@gmail]

Originally Posted by Leoshashi

Yes if either of the batteries is weak, the SHVS will not work as expected. Check it's electrolyte level, get the battery charged and it should work(assuming rest of the hardware like wiring etc is in perfect shape).

I have attached a GIF showing how the SHVS indicator constantly blinks the moment the car is cranked up in the 1st shelf.

During my recent visit to MASS, the SA confirmed he needs to check the wirings, the alternator and then perform the entire software upgrade procedure to deduce the error. For which, I was quoted about 1,500/- + taxes. Upon politely declining, the SA mentions let's get the battery health test done, and if that's okay, we will further investigate the root cause.

Got the vehicle's battery test done, and the test report shows 4 bars as the current health before the battery life zeroes out. Is this normal? Should I change the battery, or ask the SA to check the wirings and then perform associated activities?

In this month, I will also get my battery recharged (a rather cheaper option to play around with some deductions by ourselves ) and then check is the indicator still flashes or the Mild-Hybrid system works well.

I believe batteries like mine die prematurely. Yours has lived a decent life, nothing great. Still I'd recommend to get it charged once. Will help in extending its usable life.

The car will be completing 4 years in February '23. I expect tire change + battery replacement as the major maintenance milestones at 4 years/35,000 km mark. If the above exercise (battery recharge AND/OR wiring check) solves the problem, I plan to replace battery in next year, upon hitting 48 months of ownership.

[mohan41]

Full hybrid car specs mention both the Petrol engine power/torque and Motor's power/torque numbers and also the combined power of both. For example, for Hyryder the specs mention - "... This petrol engine is coupled with an electric motor that puts out 79 BHP and 141 Nm. The combined power output available at the wheels is 114 BHP"

With the mild hybrid though the ISG power output seems quite small (1.8KW) , torque is not so - 50Nm. Wonder why Maruti does not publish the motor's power/torque and combined power numbers, if the motor really provides assistance to engine in delivering the power to wheels?

[RSMM]

I am curious to know why Maruti's SHVS system need two different type of batteries. Is ISG system work only with Lithium battery or it works in combination with Lead acid battery ? I want to know Why SHVS system can not work only with Lead acid battery ?

[Sankar]

Originally Posted by RSMM

I am curious to know why Maruti's SHVS system need two different type of batteries. Is ISG system work only with Lithium battery or it works in combination with Lead acid battery ? I want to know Why SHVS system can not work only with Lead acid battery ?

Lithium Ion battery has much higher power density than the 12v lead acid battery, it can charge and discharge faster. Although the li-ion battery pack used in the mild hybrid are a lot smaller than whats in a strong hybrid it still can store a lot of energy compared to the 12v lead acid battery. Its used to store regen energy and supplies power to ISG to assist the engine in acceleration and at low engine speeds.

12v lead acid battery has much much lower power density so it can neither store a lot of regen energy nor can it supply a lot to assist the engine. The li ion based mild hybrid is an evolution of the lead acid based mild hybrid systems of the past. In the older system ISG worked with lead acid battery only. In the present Maruti has put the lead acid battery based ISG mild hybrid systems in K12C K12N vehicles with auto start.

Theoretically speaking a li-ion battery based system don't need the lead acid battery for powering the 12v systems. But all hybrids and evs still seem to retain the 12v lead acid batteries along with their large battery packs.

[walchan99]

I have the 2023 Ertiga. Is this excellent post valid for this (newer) model, or would there be any basic changes?

Thank you.