57s battery charging problem
06-28-2021, 11:46 AM
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Maybach 57S, Range Rover Sport Supercharged, CLS 63 S AMG
57s battery charging problem
Hello fellow Maybach owners,
I am trying to solve my 2006 57S charging puzzle. From time to time I get red dash saying BATTERY CHARGE. Both batteries are new and I check the charging with a voltmeter. After I start the car it charges rear battery for about a minute and then engine rpms fluctuate a bit and charging disappears.I have read a lot about the battery power supply module and after 2 weeks of various tests and checks I have bought and installed the new BNS module from the dealer. To my surprise nothing happened and it still stops charging the batteries. I have removed the alternator previously and took it to test, it showed 14.3V and had no issues with it, so I put it back. The relay next to the BNS also works as I have manually tested it, it clicks and switches the batteries. Sometimes it drives for a day or two without any issues and then it starts again. Does anyone know if the alternator is controlled by the engine's ECU? Its a single wire to the alternator, next thing is to check if it is being controlled properly or the alternator actually died. imho dead alternator would not charge the batteries at all and now it sometimes does. from what I have found there is not much left to check and change in the charging system, as its only one module which is now new, one relay which only switches the front battery charging on after the rear reaches 10,8V or lower and 2-3 fuses which are obviously good. thanks for any help as my local dealer cant help me and don't even know where to start!!!
Vaidas
I am trying to solve my 2006 57S charging puzzle. From time to time I get red dash saying BATTERY CHARGE. Both batteries are new and I check the charging with a voltmeter. After I start the car it charges rear battery for about a minute and then engine rpms fluctuate a bit and charging disappears.I have read a lot about the battery power supply module and after 2 weeks of various tests and checks I have bought and installed the new BNS module from the dealer. To my surprise nothing happened and it still stops charging the batteries. I have removed the alternator previously and took it to test, it showed 14.3V and had no issues with it, so I put it back. The relay next to the BNS also works as I have manually tested it, it clicks and switches the batteries. Sometimes it drives for a day or two without any issues and then it starts again. Does anyone know if the alternator is controlled by the engine's ECU? Its a single wire to the alternator, next thing is to check if it is being controlled properly or the alternator actually died. imho dead alternator would not charge the batteries at all and now it sometimes does. from what I have found there is not much left to check and change in the charging system, as its only one module which is now new, one relay which only switches the front battery charging on after the rear reaches 10,8V or lower and 2-3 fuses which are obviously good. thanks for any help as my local dealer cant help me and don't even know where to start!!!
Vaidas
Last edited by SixtyThreeAMG; 06-28-2021 at 11:52 AM.
06-29-2021, 04:28 AM
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Maybach 57S, Range Rover Sport Supercharged, CLS 63 S AMG
Update:
On cold engine charging is good,when car reaches 186F it suddenly stops. Checked it 5 times and alternator dies exactly at 186F. Rpms jump a bit and voltage drops, feels like some other system kicks in, similar to AC or aux pump. I am starting to think its heat related and alternator overheats or the voltage regulator has a leak or smth...
On cold engine charging is good,when car reaches 186F it suddenly stops. Checked it 5 times and alternator dies exactly at 186F. Rpms jump a bit and voltage drops, feels like some other system kicks in, similar to AC or aux pump. I am starting to think its heat related and alternator overheats or the voltage regulator has a leak or smth...
06-29-2021, 04:46 AM
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Maybach 57S, Range Rover Sport Supercharged, CLS 63 S AMG
Update:
On cold engine charging is good,when car reaches 186F it suddenly stops. Checked it 5 times and alternator dies exactly at 186F. Rpms jump a bit and voltage drops due to load change. I am starting to think its heat related and alternator overheats or the voltage regulator has a leak or smth...
On cold engine charging is good,when car reaches 186F it suddenly stops. Checked it 5 times and alternator dies exactly at 186F. Rpms jump a bit and voltage drops due to load change. I am starting to think its heat related and alternator overheats or the voltage regulator has a leak or smth...
Last edited by SixtyThreeAMG; 06-29-2021 at 07:03 AM.
07-06-2021, 02:55 PM
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Maybach 57S, Range Rover Sport Supercharged, CLS 63 S AMG
Update #2:
Replaced alternator, cleared all ecus from errors and started the car. It ran at 14.2-14.3 on both batteries, warmed up to 186F and ran for about 15 minutes or so till the red BATTERY CHARGE error popped up again. Both batteries charge at 14.3 and 14.2 V after engine starts. No more relation to the temperatures as it evebn got to 200F without errors during the first run. Now for the first time I got P2095 (NO CONNECTION TO COMPONENT G2 (GENERATOR) (P0620). There is a single blue wire going from the voltage regulator on the altertnator to front SAM and connects to the engine's ECU. I have checked the comntinuity and it is good, wire is soft and nice throughout all it's length. After some research we found, that there is some sort of intervention behind the windshield wiper panel. Removed the panel and found that there is a non original wire with a soldered 60A fuse going to the prefuse box. Apparently a 40A burnt inside the prefuse box on one of the red positive terminals and someone made a ghetto fix by using an external wire and soldering a fuse outside. Removed the bo, installed a 40A fuse and restored to OE setup as obviously the soldering or the pretty mucbh loose connection might have gotten warm. Started the car, ran for 30 minutes without any mistakes, took it for a 30 mile trip and got the red dash again going at 60 mph on a highway. Now I found out that my rear ground wire on the battery is warm and battery is warm too. Going to put a much much thicker ground wire tommorow and continue my battle with zero info on the web or anywhere else.
P.S. the P2095 is back too.
Replaced alternator, cleared all ecus from errors and started the car. It ran at 14.2-14.3 on both batteries, warmed up to 186F and ran for about 15 minutes or so till the red BATTERY CHARGE error popped up again. Both batteries charge at 14.3 and 14.2 V after engine starts. No more relation to the temperatures as it evebn got to 200F without errors during the first run. Now for the first time I got P2095 (NO CONNECTION TO COMPONENT G2 (GENERATOR) (P0620). There is a single blue wire going from the voltage regulator on the altertnator to front SAM and connects to the engine's ECU. I have checked the comntinuity and it is good, wire is soft and nice throughout all it's length. After some research we found, that there is some sort of intervention behind the windshield wiper panel. Removed the panel and found that there is a non original wire with a soldered 60A fuse going to the prefuse box. Apparently a 40A burnt inside the prefuse box on one of the red positive terminals and someone made a ghetto fix by using an external wire and soldering a fuse outside. Removed the bo, installed a 40A fuse and restored to OE setup as obviously the soldering or the pretty mucbh loose connection might have gotten warm. Started the car, ran for 30 minutes without any mistakes, took it for a 30 mile trip and got the red dash again going at 60 mph on a highway. Now I found out that my rear ground wire on the battery is warm and battery is warm too. Going to put a much much thicker ground wire tommorow and continue my battle with zero info on the web or anywhere else.
P.S. the P2095 is back too.
