New Jazz and winter driving

[Muldoon]

Re the new model does anyone have an idea how it will operate in the UK in winter when it’s minus 5 in the mornings? Would the engine run to generate heat for demising and warming the cabin as in normal vehicles? Just trying to imagine the situation when it’s covered in ice. Possibly an electric heater but then the batteries will take a hammering plus being used for propulsion. 

[sparky Paul]

Re the new model does anyone have an idea how it will operate in the UK in winter when it’s minus 5 in the mornings? Would the engine run to generate heat for demising and warming the cabin as in normal vehicles?

I presume so, that's how the CR-V works. There's no electric heating, apart from the seats, windscreen, mirror, etc..

In any case, the CR-V battery doesn't last long driving electric only anyway, a couple of minutes at most.

[jazzaro]

Toyota hybrids, with an E-CVT "different but similar" to the Honda I-MMD power on the combustion engine to warm the engine, kats and the cabin if asked by the user.  Since the engine operates an Atkinson cycle with the throttle valve widely open ad an electric cooling pump, the coolant temperature takes less time than a standard engine to raise and reach an adequate value, so theoretically an hybrid like Jazz should be better than a standard jazz in cold weather.
Also startup should be easier and the car more dependable: Toyota and Honda hybrids have two batteries: the big one has high voltage and high power and lasts many many months without usage; the small one is  a standard car battery, 12v, and during startup it works only feeding the ECUS of the car so needing very low power, it does not have to operate the starter motor because this job will be done by the high voltage lithium battery. So  hardly the 12v battery won't have enough power to start the car, and since there will be less work for it, the 12v battery will last longer than a battery working on a standard car.
On the other hand, chemical reactions inside a lithium battery can be slower at low temperatures, so you could find a lower state of charge at startup if temperatures are deeply low.
Maybe Car and Driver have talked about it in their long term review about a 2019 Insight, having a very similar powertrain to our MK4 Jazz.
https://www.caranddriver.com/reviews/a26287347/2019-honda-insight-reliability-maintenance/

[dfconnolly]

I have had the 2011 Jazz HYBRID for 8+ years now and can verify too that the main big battery effectively spins the rotor to start the engine from cold and on auto stop/start. The 12 volt battery that powers the ECU's and ancillaryies is still the original one!

Toyota hybrids, with an E-CVT "different but similar" to the Honda I-MMD power on the combustion engine to warm the engine, kats and the cabin if asked by the user.  Since the engine operates an Atkinson cycle with the throttle valve widely open ad an electric cooling pump, the coolant temperature takes less time than a standard engine to raise and reach an adequate value, so theoretically an hybrid like Jazz should be better than a standard jazz in cold weather.
Also startup should be easier and the car more dependable: Toyota and Honda hybrids have two batteries: the big one has high voltage and high power and lasts many many months without usage; the small one is  a standard car battery, 12v, and during startup it works only feeding the ECUS of the car so needing very low power, it does not have to operate the starter motor because this job will be done by the high voltage lithium battery. So  hardly the 12v battery won't have enough power to start the car, and since there will be less work for it, the 12v battery will last longer than a battery working on a standard car.
On the other hand, chemical reactions inside a lithium battery can be slower at low temperatures, so you could find a lower state of charge at startup if temperatures are deeply low.
Maybe Car and Driver have talked about it in their long term review about a 2019 Insight, having a very similar powertrain to our MK4 Jazz.
https://www.caranddriver.com/reviews/a26287347/2019-honda-insight-reliability-maintenance/

[John Ratsey]

Myy list of questions for the dealer includes asking what measures are provided to speed up the warming up of the engine so that the stop-start system works efficiently. I was told that the latest model CR-V includes a thermostatically controlled blind for the radiator. It's a no-brainer to keep the cold out of the engine compartment until the engine is hot.

I'm particular sensitive to this aspect since watching the trip mpg on a cold morning start at around 10mpg and creeping upwards before stabilising after about 10 miles.Significant miles at half or less of the warm weather fuel economy wreaks havoc with the overall fuel economy.

The ideal winter solution, at least for starting from home, would be to use a bit of mains power to pre-warm the car. The 1kWh battery won't provide much heat (think 2kW electric fire for 1/2 hour provided the battery is full).

I have had the 2011 Jazz HYBRID for 8+ years now and can verify too that the main big battery effectively spins the rotor to start the engine from cold and on auto stop/start. The 12 volt battery that powers the ECU's and ancillaryies is still the original one!

As a former hybrid Jazz owner I'm not convinced about this. I was under the impression that the 12V battery did the initial starting of the engine (and this is also the case with the new hybrid). Otherwise, if the big battery is flat then the car is dead with no easy means of getting the engine started. Also see the hybrid Jazz forum. Member @Ozzie had to put a new 12V battery into his hybrid because it wouldn't start https://clubjazz.org/forum/index.php?topic=12007.0 .

[dfconnolly]

Doubtless someone out there will clarify!?

[jazzaro]

Myy list of questions for the dealer includes asking what measures are provided to speed up the warming up of the engine so that the stop-start system works efficiently. I was told that the latest model CR-V includes a thermostatically controlled blind for the radiator. It's a no-brainer to keep the cold out of the engine compartment until the engine is hot.

I'm particular sensitive to this aspect since watching the trip mpg on a cold morning start at around 10mpg and creeping upwards before stabilising after about 10 miles.Significant miles at half or less of the warm weather fuel economy wreaks havoc with the overall fuel economy.

The ideal winter solution, at least for starting from home, would be to use a bit of mains power to pre-warm the car. The 1kWh battery won't provide much heat (think 2kW electric fire for 1/2 hour provided the battery is full).

Hybrid Accord and CRV also have an exaust gas heat exchanger like this.
https://www.youtube.com/watch?time_continue=74&v=wHLgnTO9d7I&feature=emb_logo
Probably Jazz and Insight, since they are cheaper and have a smaller engine, doesn't have this device. We will check.
Concerning the electric warmer, L series engines can mount a PTC heater fixed on the rear side of the engine block. In USA the heater is an OEM part (working at 115V), in Europe we can mount a third party heater provided by Defa
https://www.defa.com/electrical-preheating/engine-heaters/find-engine-heater/
Easily this heater will be avaiable also for the mk4, since it will go on the coolant drain plug.

As a former hybrid Jazz owner I'm not convinced about this. I was under the impression that the 12V battery did the initial starting of the engine (and this is also the case with the new hybrid). Otherwise, if the big battery is flat then the car is dead with no easy means of getting the engine started. Also see the hybrid Jazz forum. Member @Ozzie had to put a new 12V battery into his hybrid because it wouldn't start https://clubjazz.org/forum/index.php?topic=12007.0 .

In the IMA and I-DCD hybrids the startup comes by the high voltage battery and the hybrid electric motor. They still have a traditional starter motor but only for backup, driven by the 12v battery so if the high voltage circuit fails, then the car can still be used.
The I-MMD has not a backup starter motor, so the only way to power on the ICE is to feed one of the two motor/generators, that work only with high voltage. Consider that the high voltage battery can keep its charge for years, since it is completely disconnected when the car is off: the 12v last much less because it stays connected with some ecus (such as the door lock), so there is a little but continuos power drain. So it's better to use the 12v to feed ecus and relays, and then leave  the high voltage system to drive the ICE.

[John Ratsey]

I agree that Lithium batteries should hold their charge but perhaps the HV battery isn't completely disconnected when the vehicle is switched off. See page 431 of the UK 2021 Jazz manual (attached) which says that the vehicle should be driven for at least 30 minutes every 3 months to keep the HV battery from dying.

[jazzaro]

That's quite new for me. I've seen a Prius, unused for one full year, that started without problems when the owner put a new 12v battery; the HV one had still about one third of the full charge.
In a italian blog, two crv hybrid have been left parked during the covid lockdown: one had the 12v battery completely off after 28days, but the HV was still at 2/3, no discharge. The second CRV started without problems after 2 months, also for this car the HV was at the same level of two months ago.

[Jocko]

The Honda instruction was to protect the Life of the HV battery. The examples you give may possibly have done the batteries some long time harm.

[jazzaro]

The Honda instruction was to protect the Life of the HV battery. The examples you give may possibly have done the batteries some long time harm.

bho... What spoils a battery is leaving it at low state charge, not leaving it unused. Sometimes leaving it unused brings the battery to lose charge going and staying low SOC and yes, this is bad. But as far as I can see you need more and more than three months to be dangerous for your battery. At this point I have a doubt; would this mean that every jazz, built in Japan and sent to Europe, will have to be switched on and kept running for 30 minutes if it has not been sold in 3 months after its assembly?

[culzean]

Leaving Li-Ion battery above 80% charge can also damage them,  where lead acid batteries need to be kept above 80% for long life.

IIRC they store Li-Ion batteries at about 40 to 45% charge for maximum shelf life.

https://www.plugincars.com/eight-tips-extend-battery-life-your-electric-car-107938.html

https://batteryuniversity.com/learn/article/types_of_lithium_ion

[Jocko]

bho... What spoils a battery is leaving it at low state charge, not leaving it unused. Sometimes leaving it unused brings the battery to lose charge going and staying low SOC and yes, this is bad. But as far as I can see you need more and more than three months to be dangerous for your battery. At this point I have a doubt; would this mean that every jazz, built in Japan and sent to Europe, will have to be switched on and kept running for 30 minutes if it has not been sold in 3 months after its assembly?

Honda's words in the manual, not mine. I assume the batteries are shipped in a state of charge that is best for their long life then charged before delivery. But you appear to be the font of knowledge. You tell me.

[jazzaro]

But you appear to be the font of knowledge. You tell me.

I can leave you to tell the truth.

[guest4871]

@ Jazzaro

I have found your all thoughts very worthwhile.  Thank you for all your comments which all add to the font of human knowledge.