Running voltage
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Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
DISABLING STOCK CHAOS
Any running voltage within these limits [12.6v to 14.9v] is normal by design.
Below 12.3V is a serious issue: "drained by driving" with 90Amps battery currents (aka "yoyo") - That's 1300 Watt of power roasting main AGM + ALT + PreFuse !
You can set your display to show battery sensor data while driving.
As it turns out even "normal voltage swing" disrupt CAN module networking. No voltage swing runs the GDI M276/8 engines better.
> Things you may look into....
- "battery float" (CTEK or better)
- "chassis reboot"
- "experimental ALT-LIN"
Last edited by CaliBenzDriver; May 8, 2025 at 01:09 PM.
Out Of Control!!
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W212 MY'14 M276-3.5NA @75kMi
READ VOLTAGE/CURRENT
Voltage is only half of the equation.
Need to see charging vs. discharging.
You can set your IC display to read both:
VOLTAGE + CURRENT: positive or negative ?
Battery current with or without A/C should hardly change: more or less couple Amps unchanged. ALT supplies 100% power, not battery.
Last edited by CaliBenzDriver; May 8, 2025 at 02:22 PM.
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2010 E550, 273 Engine: 2012 S550, 278 Engine
To make it short and clear, you have no problem.
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
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Out Of Control!!
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W212 MY'14 M276-3.5NA @75kMi
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W213 All-terrain
That's depends of the generation of the car. Some do like that on braking or coasting as the AGM battery can integrate short voltages spikes.
Although, the 14,4V constant voltage has nothing to do with stable CAN network ( there is no other type of CAN network - just stable, if unstable, there is no CAN transmission/) or with fuel pressure . The Voltage is PWM and everything is about the Freq of the pulses, the x.xxV are only a math Integer . Besides Voltages, there is a unique concept like "Energy". Nobody care about Voltage here.
Although, the 14,4V constant voltage has nothing to do with stable CAN network ( there is no other type of CAN network - just stable, if unstable, there is no CAN transmission/) or with fuel pressure . The Voltage is PWM and everything is about the Freq of the pulses, the x.xxV are only a math Integer . Besides Voltages, there is a unique concept like "Energy". Nobody care about Voltage here.
Thread Starter
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e350
Arrie, Thanks. My e350 does the same. Nice to know not an issue. Recently replaced alternator and new H8 battery and was concerned that I have some type of a charging issue even though had no warning lights or messages. This is wife"s car and I just wanted to make sure car was good to go. She loves this car.
Again Thanks. Tom
Again Thanks. Tom
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From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Surprised Cali didn't send you over to his thread:
https://mbworld.org/forums/mercedes-...s-voltage.html
https://mbworld.org/forums/mercedes-...s-voltage.html
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Surprised Cali didn't send you over to his thread:
https://mbworld.org/forums/mercedes-...s-voltage.html
https://mbworld.org/forums/mercedes-...s-voltage.html
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
BATTERY CONDITIONING
Surprised Cali didn't send you over to his thread:
https://mbworld.org/forums/mercedes-...s-voltage.html
https://mbworld.org/forums/mercedes-...s-voltage.html
I recognize there's value in owning a dealer maintained car. Stock is all right for most consumers.
> VOLTAGE DOES MATTER !!
-- The ALT-LIN experimentation is an advanced procedure away from standard MB stock.
-- ALT-LIN has evidenced that multiple chassis run noticeably better with stable voltage.
-- Bosch ECU is non-compliant with Bosch voltage swings.
-- ECU tolerates unstable voltage by derating engine control. Bad from factory is sub-standard.
Stable VOLTAGE = stable PERFORMANCE.
> STARTER BATTERY:
-- Charge status of MB Battery involves more than charging the battery.
It involves battery drain.
+ battery charge
-- battery drain
= charge status
> BEST PRACTICE...
The shortcut is use a good float charger to maintain main battery else battery will get drained by chassis CAN-B.
Don't rely on engine alternator to "charge" a drained battery with it's unlimited 200A current.
Use an overnight charger, not a jump-pack!
Less problems for smart owners.
Last edited by CaliBenzDriver; May 9, 2025 at 05:48 PM.
