Retaining Heated Seats - MBWorld.org Forums

Jan 21, 2024 | 11:32 AM

DJBenzGLS

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Newbie

Joined: Dec 2023

Posts: 13

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GLS 580

Retaining Heated Seats

Wondering if the 48V battery or accessory system can maintain some heated seat function while car engine not running? Don’t want to drain starter battery but would be nice to keep some seats warm while sitting in car.

Jan 21, 2024 | 03:52 PM

mikapen

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Joined: Oct 2009

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From: Colorado

'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan

Quote:

Originally Posted by DJBenzGLS

I'm pretty sure the seats (massage, heat etc.) are all legacy 12 volt.
As is the heater blower fan, but coolant is circulated through the system via a 48 volt water pump to keep the cockpit warm and windows defrosted. The AC (48v) will also kick in for defrosting.

The starter battery is actually 48 volt as well (ISG) but the car will restart if the batteries get too low.

Jan 21, 2024 | 04:01 PM

rockpool

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Joined: Jan 2024

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2024 GLS580

The 48v system replaces everything that used to be powered by a belt - the AC compressor, supercharger, water pump, power steering pump - If you take a look there's no belt-drive accessories on your engine. Plus it powers the starter motor.

Nothing else - everything else in the car is 12v still, including the heated seats.

48v simply allows the car to use smaller gauge wire and electrical motors.

Jan 22, 2024 | 01:25 AM

wyatt88

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Joined: Feb 2018

Posts: 115

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GLS 450

Another poster mentioned that the A/C button if activated (it says 'rest' on the switch by the way), when the car is turned off, will allow the heating system to blow the residual heat from the engine. I have used this feature many times while dropping off and waiting for my kids during his practice sessions. The car is off but the heat keeps blowing. Works really well.

Jan 22, 2024 | 08:37 AM

jkaetz

Super Member

Joined: Apr 2011

Posts: 542

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2021 GLS580 | 2011 ML350 BlueTec | 2009 Pontiac G8 GXP

Quote:

Originally Posted by DJBenzGLS

The 48v battery powers the ISG and the ISG starts the engine. The 48v battery is the "starter" battery. That said, the 12v battery still runs a lot of things that weren't transitioned over to 48v. There are also a number of systems in place to prevent the scenario you are describing. Keep yourself warm, the car will let you know if there is a problem.

Quote:

Originally Posted by rockpool

While some of what you say is correct, the engine does not have a supercharger, and it does have a belt. The belt connects the ISG, crank, and AC compressor. Yes, the push to 48v is driven by the desire to reduce the amount of wires and wire gauge needed to power all the technology in cars. The last time this was done from 6v to 12v but that was in the 1950's. It is likely that everything will eventually transition to 48v or at least be able to have a 48v input but that will take a while.

Last edited by jkaetz; Jan 22, 2024 at 10:26 AM.