Using seat heaters in aux mode

[Jazzik]

@Jazzik,
Re:How/where do you know/see....

On Mk3 - .....

This forum: Honda Jazz Mk4 - 2020

[richardfrost]

You may interested in my experience when parked,  the car had full charge on 12v battery,  when I switched on the heating,  the engine started, when I turned off the heating the engine stopped. I tried this several times,  always the same, still full charge on battery. This must be how the Jazz system is designed, the heating doesn't use the 12v battery if not necessary.

No. What’s happening here is the system is detecting high power drain and the need for heating. Heated air comes from the running engine, heated seats are a high drain on the 12v system, hence the engine kicks in. The heated seats will not be running on the high voltage system.

[CB72]

You may interested in my experience when parked,  the car had full charge on 12v battery

How/where do you know/see that the car has full charge on the 12v battery?

Use a multimeter or scanner with a OBD2 Connection

[Lord Voltermore]

Its quite normal for the engine to start up and not  go into EV mode for quite a long time when you first set off  if you have air conditioning or heated seats  on.   You can demonstrate this by switching the air con etc off. The car will often then immediately go into EV mode, but the engine will restart immediately if you switch  the aircon etc back on again. 

I believe these systems run at 12v  ,using charge  from the small 12v battery . The 12v battery is kept topped up  by the large High Voltage battery which in turn is recharged by the ICE engine starting up.

 The charge bars displayed are the HV battery, not the 12 v.    But when the system detects  (or possibly even anticipates) a high current draw  from aircon or heated seats it immediately restarts the ICE engine to keep the High voltage battery charged, rather than using up some of its battery reserve  .Regardless of how many bars are remaining.

The same thing happens in normal driving. Sometimes the ICE starts in order to   charge the HV battery when you still have quite a few HV  bars remaining. Even when you might expect it to remain in EV mode for longer such as travelling down hill .  Other times it will stay in EV mode right  down to 2-3 bars.   I've given up trying to anticipate when it might go into EV mode . It just works.

[Kremmen]

 The charge bars displayed are the HV battery, not the 12 v.

That's what I thought, but, on numerous occasions, after trickle charging the 12v battery, the charge meter has gone to 10 bars and not corrected itself until after some ICE recharge cycles

[Nicksey]

My Jazz always seems to start with the engine, very rarely (reverse gear) does it start and move off in EV mode. Even when no heater/ICE etc is on, the engine generally is the first start option. Granted, within a few hundred yards the EV will kick in. Start ups are never a truly quiet experience either. The 1.5 Atkinson does tend to be almost diesel like at the start. Having been used to the Renault TCE motor for the last decade, and it's ultra quiet starts, the Jazz is almost agricultural. I even noticed this on two different test drive vehicles prior to purchase, and the Advance I was loaned during first service. Admittedly, when warmed up and running I find it nicely quiet, and the engine/EV/mixed transitions are almost imperceptible.

[5thcivic]

That's the point, when cold the engine revs enough to get the oil round and warm up fast as possible, when hot only needs to rev enough to charge up the HV battery according to load, hence quiet unless you floor it.

[Lord Voltermore]

The typical hybrid situation. In colder weather it needs to use  ICE more often.  Fuel consumption suffers but its still better  than most 'conventional 'cars can manage ,but the advantage may not be huge.  Its in warmer weather where they really show their advantage.  Overall your bank balance and the  environment will benefit.   
 

[Kremmen]

When I used to do my fortnightly 30 mile run from near Heathrow to Reading the scenario was ....

For the first 10 miles or so the mpg was nothing special. The engine hadn't warmed up properly so was inefficient and running quite a lot. After the midway point of about 15 miles when the engine and the car interior was warm the mpg rose mile by mile

What I did notice though was the Jazz heater was able to push out warm air sooner than my 2013 9G Civic. The drive to Reading was over the same initial roads that I used to commute, about 5 miles, so I knew exactly where the Civic heaters started pushing out warm air. The Jazz is about half the distance.

I wonder if the lack of a normal high grill stops the majority of cold air cooling the engine so it warms up quicker.