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New G-Wagen model discussion

Pete460332

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#2
Thank goodness for the 12V electrical system being standard in the 300! What is "automatic day time driving lights"? The dual 12V/ 24V electrics is going to fool lots of autoelectricians :)

Peter
 

Chris B

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#3
It seems like the G300CDI make use of 3 batteries and the other 2 models only 1. Why will this be?

(sorry my knowledge of auto-electricity is minimal)
 
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#4
...... What is "automatic day time driving lights"?...
Peter
My understanding is....It's a system where a vehicle is fitted with sensors that detect low ambient light (dark cloudy day, driving under a tunnel etc),the sensors then relay this info to the vehicle head lamps which then automatically switch on.
 

munga

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#5
It seems like the G300CDI make use of 3 batteries and the other 2 models only 1. Why will this be? (sorry my knowledge of auto-electricity is minimal)
I guess the 1 battery provides the 12v supply as normal and the other 2 provide the 24v supply i.e. connected in series.

My understanding is....It's a system where a vehicle is fitted with sensors that detect low ambient light (dark cloudy day, driving under a tunnel etc),the sensors then relay this info to the vehicle head lamps which then automatically switch on.
I think in this case the are always on when the engine is on to comply with new legislation coming into effect in Europe. Automatic means they come on when you start the car and they cannot be turned off unless you turn on the real lights.
 
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Pete460332

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#6
My understanding is....It's a system where a vehicle is fitted with sensors that detect low ambient light (dark cloudy day, driving under a tunnel etc),the sensors then relay this info to the vehicle head lamps which then automatically switch on.
Are the day-time driving light any different to the "normal" night time driving lights?
Peter
 

Gelände

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#7
The G300CDI is equipped with a 24V starter motor, like Darcy said 2 of the batteries will be used in series to power that. I assume the 3rd one is the "house battery" for aux devices.

The higher voltage on the starter will also increase torque. Would be interesting to see how they charge them with a 14V alternator.

Another nice thing to note about the 24V aux power point is the fact that you (the manufacturer) can use thinner wiring due to lower losses (lower current) at higher voltages. Most fridges accept 24V in any way.

Peter, I assume the driving light will be similar to the LED crap you see on the new Audis, its main aim is to make you visible to other road users, not so much to light the way.
 

Gerhard van Rooyen

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#8
The G300CDI is equipped with a 24V starter motor, like Darcy said 2 of the batteries will be used in series to power that. I assume the 3rd one is the "house battery" for aux devices.

That is confusing Danie,

Usually duel battery systems have a mechanism/relay that prevents the aux power devices from using the battery that starts and operates the vehicle (especially modern ones with ecu's and the lot) -- so if the G needs 24v to start (and then to run all the other vehicle electronics) then there will be no 24v supply for aux, only 12v? -unless they worked out some electric trickery which i don't understand yet?
 
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Gelände

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#9
Why they went 24V I don't know?, might be due to some Military equipment that requires 24V. I figure they just kept the design "as is".

There are both 12 and 24V aux power points in the G. See http://www.mb4x4.co.za/forum/content.php/36-Video-of-the-W461-G300CDI-coming-to-South-Africa-in-2011

Like I said, in some cases supplying equipment with 24V is beneficial especially if the draw a lot of current. But I suspect the one 12V battery is isolated from the 24 bank.

Lets wait and see...when Michel gets his.
 

munga

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#11
That is confusing Danie,

Usually duel battery systems have a mechanism/relay that prevents the aux power devices from using the battery that starts and operates the vehicle (especially modern ones with ecu's and the lot) -- so if the G needs 24v to start (and then to run all the other vehicle electronics) then there will be no 24v supply for aux, only 12v? -unless they worked out some electric trickery which i don't understand yet?
Good luck getting someone to jump start you when your fridge has been running all night off the 24V! Best to travel with at least 2 G300 Professionals or with 2 extra batteries in the boot! :razz:
 
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munga

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#12
The G300CDI is equipped with a 24V starter motor, like Darcy said 2 of the batteries will be used in series to power that. I assume the 3rd one is the "house battery" for aux devices.

The higher voltage on the starter will also increase torque. Would be interesting to see how they charge them with a 14V alternator.

Another nice thing to note about the 24V aux power point is the fact that you (the manufacturer) can use thinner wiring due to lower losses (lower current) at higher voltages. Most fridges accept 24V in any way.

Peter, I assume the driving light will be similar to the LED crap you see on the new Audis, its main aim is to make you visible to other road users, not so much to light the way.
Danie I reckon they just connect the alternator in parallel to the 2x 12V batteries to charge them "individually". I see the G300 Profesional has the same spec alternator as the G55 probably to cope with the extra load. The G350 is a lower spec alternator. By lower spec I don't mean quality but the requirements from the alternator are less.
 

Gelände

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#13
Danie I reckon they just connect the alternator in parallel to the 2x 12V batteries to charge them "individually".
Then they need some "floating ground", how do you connect the 2nd series battery to the alternator without buggering the 1st battery's live? AFAIK the Land Cruiser 100VX also had a 24V starter system.

BTW Darcy, what DC voltages are used in the subs? Ships? In avionics we use 28V.
 

munga

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#14
Then they need some "floating ground", how do you connect the 2nd series battery to the alternator without buggering the 1st battery's live? AFAIK the Land Cruiser 100VX also had a 24V starter system.

BTW Darcy, what DC voltages are used in the subs? Ships? In avionics we use 28V.
Yes I can only assume the alternator ground and battery/chassis ground are not the same or there is a diode preventing current flowing back to the aleternator ground and the alternator is not exactly 14V (i.e. 14.6V/14.7V) to compensate for the diode drop? Or the diode protection is built into the alternator? Like you said let's hear from you once amazimmy gets his.

Also like Peter said this will confuse a lot of auto electricians! ::razz:
 
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Pete460332

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#15
Re: Who's going to the G launch?

A quick search for G350 Bluetech VIN gives:

WDB4633462X######

G300 professional

WDB4613332X182493

Should provide enough for hours of EPC fun! :razz:
Looked up the 300 Professional:

Yes it has 2 alternators 12 and 24 V one . Also engine has no replaceable sleeves or oversize pistons , so if it gets damaged new block required!
Peter
 

Gelände

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#16
I guess thats the more 'elegant' solution, was afraid they might use a 'monster DC-DC converter'...
 

Gelände

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#17
Does anyone (Alan, Michel ?) know why the G300CDI professional is "equipped" with this bulge on the bonnet, and the G350CDI with the same engine not? Maybe the extra alternator?

 
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#18
Hello

1. Did MB say how many G-wagen have officially been ordered in RSA?
2. Who knows which dealerships will be displaying the G-Professional
in Gauteng?

Thanks