Smart charging alternators.

[Harry Bloomfield]

My large 2L diesel normally does 50 to 55mpg, but it once managed an astounding 65mpg on a trip over to the coast. I generally drive with a light foot, but like to give it an occasional bit of a leg stretch. Towing, it struggles to do 34mpg.

My 3L Granada petrol auto used to do well towing, for the fact that it was a large petrol engine - at 27mpg. Trouble was, it didn't improve much driving solo

 

[Peter.N.]

My C5 2.0.Hdi estate has averaged 47.9 mpg for the last 6000+ miles, in the summer on the motorway I have had in excess of 70 mpg but the mid 60s are more normal. I do drive with a very light foot, generally about 60 mph and 2000 rpm.

Peter

 

[Bodgedbuild]

Doesn’t sound right to me. Regenerative charging, as far as I can recall, only applies to regenerating energy from say, braking systems on electric/hybrid vehicles. Do you have a link that better explains that?

On some "normal" cars the alternator is deliberately under used or not at all during stop start traffic. The ECU uses regenerative braking to replace the work that the alternator would traditionally have done. In effect there is no parasitic alternator load because the braking system is being used instead. The ECU recognizes when it should or should not use either the regenerative system to charge the battery or if it should use the alternator. Normal circuits that would simply supply a voltage to bulbs etc now supply PWM (Pulse Width Modulation) voltage to control that actual power the bulb receives, this way something like a brake light can use a single filament run at different "power" levels depending whether it is used in brake mode or side light mode. Combined it means that the actual battery voltage is all over the place but AGM or Lthium Ion batteries are made specifically to cope...

 

[Mottie]

On some "normal" cars the alternator is deliberately under used or not at all during stop start traffic. The ECU uses regenerative braking to replace the work that the alternator would traditionally have done. In effect there is no parasitic alternator load because the braking system is being used instead. The ECU recognizes when it should or should not use either the regenerative system to charge the battery or if it should use the alternator. Normal circuits that would simply supply a voltage to bulbs etc now supply PWM (Pulse Width Modulation) voltage to control that actual power the bulb receives, this way something like a brake light can use a single filament run at different "power" levels depending whether it is used in brake mode or side light mode. Combined it means that the actual battery voltage is all over the place but AGM or Lthium Ion batteries are made specifically to cope...

Thanks but I’m too old school to understand all that. Lol.

 

[Bodgedbuild]

Thanks but I’m too old school to understand all that. Lol.

Delete what I said and replace with :- "The gearbox has an alternator fitted to it"

 

[empip]

Yes, but, my vehicle even with a diminished capacity battery still did the same thing - ONLY on over run 15 or so Volts. On the throttle, however lightly, just reading a smidge over battery terminal Volts. Headlights on, dip or main, 14.4'ish Volts with smart sensor or without it, throttle or no throttle.
Smart sensor (at neg' post) lead removed, 14.4 Volts all time - stop/start then not available, battery in good shape.
I don't think the added load/drag from the alternator being 'live' all time is noticeable, I felt no noticeable difference so I guess the regen' thing is a bit of b/s - The old diesel has a pretty big open throat pretty much all time so not much in the way of engine braking available anyway.
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[empip]

Ok, 2 tanks of diesel since smart/dumb charging disconnect - 58 mpg (brim to brim etc) computer said 61 mpg or so - the usual.
Fuel consumption about the same as before the disconnect - except battery remains charged, although dropped to 11.8V after 14 days parked up.

I guess we will move to some kind of Toyota sometime after next November's 4th of 5 services included in price.

Honda has been a let down for me - Like a jam sandwich smeared with fruit and vegetables.
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