Battery voltage too low?
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
If the vehicle was originally fitted with a glass-mat (AGM) battery then it need to be replaced with one. W211''s and W230's can get away with fitting a lead acid battery, but the battery control unit has a harder time working out the state of charge and usually shuts down battery consumers earlier than is actually required. This is solely an annoyance.
In all later type that have variable battery voltage then it is crucial to have the correct battery type fitted since a lead acid battery won't last very long when it is being charged with upto 15v. It will litterally "cook" itself and wouldn't likely last more than 12 months if it doesn't cause acid damage before then.
VHLA batteries are very long lasting if cared for correctly.
I have a small 760A version fitted to my W201 diesel that I bought new in 2003 for about $500, it's still working fine today and will probably keep going for a long time yet. When they get fully discharged then they need a bit of care to get them operational again. This is where many think the battery has died.
To recharge one you need to have a good second battery and a very good quality charger like a CTEK can detect battery condition. You need you connect the 2 batteries together with jumper leads and connect the charger. Leave it like this for about 8hrs, then dsconnect the second battery and leave the charger on for another 2days. unless they get this very full and deep charge they won't last very long before they go flat again.
I used to take alot of the "failed" batteries home from dealers and simply recharge them, only about 10% had actually failed. I have one in every one of my vehicles.
In all later type that have variable battery voltage then it is crucial to have the correct battery type fitted since a lead acid battery won't last very long when it is being charged with upto 15v. It will litterally "cook" itself and wouldn't likely last more than 12 months if it doesn't cause acid damage before then.
VHLA batteries are very long lasting if cared for correctly.
I have a small 760A version fitted to my W201 diesel that I bought new in 2003 for about $500, it's still working fine today and will probably keep going for a long time yet. When they get fully discharged then they need a bit of care to get them operational again. This is where many think the battery has died.
To recharge one you need to have a good second battery and a very good quality charger like a CTEK can detect battery condition. You need you connect the 2 batteries together with jumper leads and connect the charger. Leave it like this for about 8hrs, then dsconnect the second battery and leave the charger on for another 2days. unless they get this very full and deep charge they won't last very long before they go flat again.
I used to take alot of the "failed" batteries home from dealers and simply recharge them, only about 10% had actually failed. I have one in every one of my vehicles.
Yes,I have had trouble recharging a flat battery. I knew why it went flat & the only way I could recharge it was the way you mentioned.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
If the vehicle was originally fitted with a glass-mat (AGM) battery then it need to be replaced with one. W211''s and W230's can get away with fitting a lead acid battery, but the battery control unit has a harder time working out the state of charge and usually shuts down battery consumers earlier than is actually required. This is solely an annoyance.
In all later type that have variable battery voltage then it is crucial to have the correct battery type fitted since a lead acid battery won't last very long when it is being charged with upto 15v. It will litterally "cook" itself and wouldn't likely last more than 12 months if it doesn't cause acid damage before then.
VHLA batteries are very long lasting if cared for correctly.
I have a small 760A version fitted to my W201 diesel that I bought new in 2003 for about $500, it's still working fine today and will probably keep going for a long time yet. When they get fully discharged then they need a bit of care to get them operational again. This is where many think the battery has died.
To recharge one you need to have a good second battery and a very good quality charger like a CTEK can detect battery condition. You need you connect the 2 batteries together with jumper leads and connect the charger. Leave it like this for about 8hrs, then dsconnect the second battery and leave the charger on for another 2days. unless they get this very full and deep charge they won't last very long before they go flat again.
I used to take alot of the "failed" batteries home from dealers and simply recharge them, only about 10% had actually failed. I have one in every one of my vehicles.
In all later type that have variable battery voltage then it is crucial to have the correct battery type fitted since a lead acid battery won't last very long when it is being charged with upto 15v. It will litterally "cook" itself and wouldn't likely last more than 12 months if it doesn't cause acid damage before then.
VHLA batteries are very long lasting if cared for correctly.
I have a small 760A version fitted to my W201 diesel that I bought new in 2003 for about $500, it's still working fine today and will probably keep going for a long time yet. When they get fully discharged then they need a bit of care to get them operational again. This is where many think the battery has died.
To recharge one you need to have a good second battery and a very good quality charger like a CTEK can detect battery condition. You need you connect the 2 batteries together with jumper leads and connect the charger. Leave it like this for about 8hrs, then dsconnect the second battery and leave the charger on for another 2days. unless they get this very full and deep charge they won't last very long before they go flat again.
I used to take alot of the "failed" batteries home from dealers and simply recharge them, only about 10% had actually failed. I have one in every one of my vehicles.
I did have a flat battery & knew why & the only way I could recharge it was the way you described. Nice to know I was on the right track.
My battery is also a 70A/hr 760 AEN .Hope they have decreased in price by the time I need one. !
Another label says :- VRCA Battery - Do not open,.
Thanks again.
Carsy
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Hello Jim,
You should be able to read the label on the top of the battery.
Mine is a Varta , Made in Germany 12 V 70 Amp/Hr, 760 AEN , VRCA Battery -Do not open.
Measured Height= 95 mm, length, 275 mm & 175 mm deep.
You should be able to read the label on the top of the battery.
Mine is a Varta , Made in Germany 12 V 70 Amp/Hr, 760 AEN , VRCA Battery -Do not open.
Measured Height= 95 mm, length, 275 mm & 175 mm deep.
MBWorld Fanatic!
Joined: Sep 2007
Posts: 1,481
Likes: 2
From: Southeast
2008 C300 Sport, RWD, US
In general, how long do the current batteries last?
Also, I've noticed that the radiator fan does not continue to spin once I turn the engine off. Probably hasn't done so for a while now. The outside temp has ranged between highs of 93 to 102 degrees F for the last few weeks. Is this an indication that my battery may be below the needed level to continue cooling the engine off after shutdown????
Also noticed that when I get in the car and crank it up(this after driving a few miles and running into a store for a quick pickup)the A/C /c wants to run on high (which would be correct) but before I get going good (say backing out of a parking spot) the fan blower for the A/C will slow down until I get moving at a little faster speed....like 3 or 4 mphs.
Also, I've noticed that the radiator fan does not continue to spin once I turn the engine off. Probably hasn't done so for a while now. The outside temp has ranged between highs of 93 to 102 degrees F for the last few weeks. Is this an indication that my battery may be below the needed level to continue cooling the engine off after shutdown????
Also noticed that when I get in the car and crank it up(this after driving a few miles and running into a store for a quick pickup)the A/C /c wants to run on high (which would be correct) but before I get going good (say backing out of a parking spot) the fan blower for the A/C will slow down until I get moving at a little faster speed....like 3 or 4 mphs.
Thread Starter
Super Member
Joined: Mar 2011
Posts: 803
Likes: 37
From: Bay Area, CA
2011 C300 Sport, P1, MM, Wood, Heated FS, DIY rearview camera.
My battery top says VARTA, 12V 84 Ah 700A (EN). That's why I still don't understand why 14A standby current is normal. It only takes 6 hours to reach 84 Ah capacity. Either I have totally missed something here, or 14A is an index to be interpreted.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
In general, how long do the current batteries last?
Also, I've noticed that the radiator fan does not continue to spin once I turn the engine off. Probably hasn't done so for a while now. The outside temp has ranged between highs of 93 to 102 degrees F for the last few weeks. Is this an indication that my battery may be below the needed level to continue cooling the engine off after shutdown????
Also noticed that when I get in the car and crank it up(this after driving a few miles and running into a store for a quick pickup)the A/C /c wants to run on high (which would be correct) but before I get going good (say backing out of a parking spot) the fan blower for the A/C will slow down until I get moving at a little faster speed....like 3 or 4 mphs.
Also, I've noticed that the radiator fan does not continue to spin once I turn the engine off. Probably hasn't done so for a while now. The outside temp has ranged between highs of 93 to 102 degrees F for the last few weeks. Is this an indication that my battery may be below the needed level to continue cooling the engine off after shutdown????
Also noticed that when I get in the car and crank it up(this after driving a few miles and running into a store for a quick pickup)the A/C /c wants to run on high (which would be correct) but before I get going good (say backing out of a parking spot) the fan blower for the A/C will slow down until I get moving at a little faster speed....like 3 or 4 mphs.
I think the time may vary according to the conditions & type of use the battery experiences. eg whether it is located in the heat under the bonnet or more protected in the boot, extreme weather conditions & the number of starts . Rough roads & low profile tyres may also be a factor.
I have the same battery in both my old Peugeot & tractor . The car battery lasts for over 6 years but the tractor battery gives up after 3 years because it is mounted in front of the radiator ( heat affected) , gets thrown around more ( no sprung suspension) & sits without use for longer periods. I should charge it up more frequently with a charger.
This link has some interesting info on our AGM ( glass mat) batterys http://www.marine-electronics.net/te...aq/b_faq.htm#4
Thread Starter
Super Member
Joined: Mar 2011
Posts: 803
Likes: 37
From: Bay Area, CA
2011 C300 Sport, P1, MM, Wood, Heated FS, DIY rearview camera.
"true" standby current
I measured my dad's 01 Hyundai XL300L. About one hour after engine turned off, everything was off. a meter in series with battery at negative terminal. reading was 70mA. I measured my 02 QX4 the same way, reading was about 80mA. Will measure my 00 RX300.
I also noticed when I read the C300 current from the instrument meter, some lights turned on due to car parked in the semi-dark garage. I repeated reading on the driveway, current went down from 14A to about 7A, and meter still operates to get the reading. Therefore, it will never be an "actual" standby current. I will measure it the same way as on my other cars.
So, 14A or 7A is a "standby" current, and meanwhile it is not an actual one. If it is actual, my battery will die overnight.
I also noticed when I read the C300 current from the instrument meter, some lights turned on due to car parked in the semi-dark garage. I repeated reading on the driveway, current went down from 14A to about 7A, and meter still operates to get the reading. Therefore, it will never be an "actual" standby current. I will measure it the same way as on my other cars.
So, 14A or 7A is a "standby" current, and meanwhile it is not an actual one. If it is actual, my battery will die overnight.
Last edited by C300CA; Jul 18, 2011 at 11:51 AM. Reason: wrong spelling
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
MBWorld Fanatic!
Joined: Jan 2007
Posts: 1,152
Likes: 29
From: Sydney, Australia
190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
It's not standby as such, you still have the accessories on.
Once the vehicle has "gone to sleep" (this can take upto 10mins after vehicle is locked) then current draw should be below 50mA. what you are seeing on the dash is only available when the ignition is still in the accessories position hence the much higher current than what you are expecting to see.
Once the vehicle has "gone to sleep" (this can take upto 10mins after vehicle is locked) then current draw should be below 50mA. what you are seeing on the dash is only available when the ignition is still in the accessories position hence the much higher current than what you are expecting to see.
Member
Joined: Oct 2009
Posts: 120
Likes: 0
From: Los Angeles
2015 C300 4Matic
I stumbled onto this after a google search to help me in my current predicament and figured I'd post to revive it rather than start a new thread.
Anyway, I've got a 2012 C230 Sedan and I recently installed some aftermarket radio stuff that I'd like to use sometimes when the car is off. I purchased a 2nd battery and a battery isolator so it would use the car battery during normal usage and switch to the secondary battery when the car is off.
Unfortunately this battery isolator (and almost all others from my research)
automatically cut off from the main battery at anything less than 12.6 volts which in theory sounds OK but when I'm idling my car my battery voltage is at 12.2 volts almost no matter what. I realize that this could be because of blue efficient design but having the alternator/battery voltage that low worries me and more importantly makes it so that my isolator will cut off the supply from the main battery basically anytime I'm not in drive or pushing the amperage a lot.
Perhaps this is O K and the 2nd battery will end up basically working as a standalone power supply for my additional radio equipment but I really liked the idea of being on the main car battery just as you normally would but it switching over once the car was turned off.
your thoughts and advice are greatly appreciated.
Anyway, I've got a 2012 C230 Sedan and I recently installed some aftermarket radio stuff that I'd like to use sometimes when the car is off. I purchased a 2nd battery and a battery isolator so it would use the car battery during normal usage and switch to the secondary battery when the car is off.
Unfortunately this battery isolator (and almost all others from my research)
automatically cut off from the main battery at anything less than 12.6 volts which in theory sounds OK but when I'm idling my car my battery voltage is at 12.2 volts almost no matter what. I realize that this could be because of blue efficient design but having the alternator/battery voltage that low worries me and more importantly makes it so that my isolator will cut off the supply from the main battery basically anytime I'm not in drive or pushing the amperage a lot.
Perhaps this is O K and the 2nd battery will end up basically working as a standalone power supply for my additional radio equipment but I really liked the idea of being on the main car battery just as you normally would but it switching over once the car was turned off.
your thoughts and advice are greatly appreciated.
