Member Since: 22 Apr 2012
Location: Rome
Posts: 2326
Voltage drop at crank
Hi guys,
as many of You already know, our cars are hungry of Ampere during crank and a "tired" battery result in the well known "bing... Special programs fault, HDC etc."
This is caused by voltage drop below 10,5 volt over the can bus looped ECUs.
Surfing on the web, many users (from other brands) try to fix this issue adding in parallel to these ECUs a capacitor and a diode (i suppose to avoid reversing current drop) which should be able to maintain the voltage above 10,5 volt during the crank phase.
So my question is: Is there anyone who has experienced this process already?
I have seen many SPL passionates adding big capacitors (1 or more Farad) close to the battery right to avoid voltage drop to the amplifiers, so i was thinking to try something similar between the battery and the CJB
Any suggestion is welcome!- Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
- Full underbody protections
- Tree/Rock sidebars
- Prospeed roofrack & ladder
- Compressor guard
- Raised Air Intake
- Driving lights (2+4)
- 50 mm Waffle boards
- Altox Heater control
- Overland Rooftop Tent
- Rear seats entertainment
- Front & Rear camera
- GVIF
- Removable tow bar
- Cubby box fridge
- BFG KO2 265/65R17
- iidTool BT
14th Dec 2022 3:42 pm
zig
Member Since: 09 Sep 2005
Location: Scotland
Posts: 650
In starting the vehicle I wait until I receive the "bing" indicating that the start-up built-in-test (BIT) has completed before I turn the key further and engage the starter motor.
This is so that the dip in voltage as the engine is cranked, which is worse in cold conditions, does not result in the start-up BIT does not flag up errors and limit functionality.
Your diagram got me thinking that the posts might be angled differently on different batteries... but despite your Bosch being labelled S4 013, it is listed as a 019 battery style.
... and it's the biggest pile of absolute bull and contradictory misinformation I think I've ever found on t'interweb
So will have to get back to Googling!.
Dean
====================================
2011 D4 XS - OBD port protection, RLD spare wheel protector, All LED interiors lights, Timed Climate enabled, iiD tool paired.
2011 D4 Landmark - Stolen from same dealer before I paid for it
2011 D4 GS - Stolen whilst at dealer ... All LED interiors lights, DRLs, Spare Wheel protector.
1996 300Tdi - Eaten by tin worms
2011 D4 XS - OBD port protection, RLD spare wheel protector, All LED interiors lights, Timed Climate enabled, iiD tool paired.
2011 D4 Landmark - Stolen from same dealer before I paid for it
2011 D4 GS - Stolen whilst at dealer ... All LED interiors lights, DRLs, Spare Wheel protector.
1996 300Tdi - Eaten by tin worms
In this situation, it's more a matter of design than post shape:
Click image to enlarge
.
18th Dec 2022 3:17 pm
jenseneverest
Member Since: 12 Jun 2017
Location: somewhere
Posts: 769
well for a few minutes and about 5 quid in parts its worth a try, im having the same voltage drop issue since it got cold, and TBH never been happy with the positive terminal anyways. will try tomorrow weather allowing. Will stick the batt on a proper charge too, Great pic @Frisian Driver
18th Dec 2022 5:07 pm
Sidestick
Member Since: 22 Apr 2012
Location: Rome
Posts: 2326
Frisian Driver wrote:
I modified the extremely bad original clamps. From the outside, the looked very well. Since then the spook is over.
.
Do You have a link for that clamps?- Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
- Full underbody protections
- Tree/Rock sidebars
- Prospeed roofrack & ladder
- Compressor guard
- Raised Air Intake
- Driving lights (2+4)
- 50 mm Waffle boards
- Altox Heater control
- Overland Rooftop Tent
- Rear seats entertainment
- Front & Rear camera
- GVIF
- Removable tow bar
- Cubby box fridge
- BFG KO2 265/65R17
- iidTool BT
well for a few minutes and about 5 quid in parts its worth a try, im having the same voltage drop issue since it got cold, and TBH never been happy with the positive terminal anyways. will try tomorrow weather allowing. Will stick the batt on a proper charge too, Great pic @Frisian Driver
Thank You!
BTW: Any manual movement of the negative pole cable bends the lower part of the clamp into a larger diameter and the contact area decreases. The minus cable is stiff like an iron bar.
(...) Will stick the batt on a proper charge too, (...)
If you have a BMS system (like D4), then you must wait for about 20 minutes before installation. Directly after disconnection from loading the voltage will drop and then slowly recover to its normal value.
If you are interested in I will look for the name of the voltage drop and the voltage diagramm.
18th Dec 2022 10:22 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8243
Side stick: It would be easier just to buy a new battery and keep it fully charged It can when others can't,
It will when others won't,
It goes where others don't.
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and contradictory misinformation I think I've ever found on t'interweb 
... All LED interiors lights, DRLs, Spare Wheel protector.
