2013 T4 Stuck in Battery Refresh/Overcharging

pettaw · Nov 7th, 2018, 09:17

As thread title. My car is 5 years old and has done 80,000 miles.

I had noticed for quite some time that everytime I plugged in my scan tool and looked at live data in the CEM the battery mode was "battery refresh," with the charging voltage being super high, well over 15V. When I looked into it further, even if I did a really long journey and got the SOC up to 100%, when the car sat overnight the SOC would drop into the high 80s or low 90s. I have a CTEK battery tester which is basically a very low function Midtronics machine which tested the CCA at 525 rather than the rated 760, so I reckoned the battery was probably past it and replaced the battery.

Using my scantool I reset the BMS to 0 days and fitted the new battery and performance returned to normal, with the alternator only charging the battery up to the required level and then switching to floating voltage etc. After the battery was approximately 60 days, I happened to plug in my scantool to diagnose something else and I noticed the system had gone to "Battery Refresh" again. So I kept an eye on it for a few days and it continued to be stuck in this mode, even though the battery was completely fully charged, and maintaining it overnight. (When I started the car after sitting for 2 days it would still be at 99% SOC)

I thought, maybe the BMS is playing up, so I replaced the BMS and again, as per procedure, reset the BMS with the scantool. Again, performance returns to what I would expect according to the literature.

However, once again, after approx 3 months, I noted that the "Battery Refresh" mode was activated once again, even though, as I said the battery was already fully charged. Now, I monitored the battery using my scan tool on every commute to work and every drive home. I did note that it did kick out of "Refresh" mode, but once the car was turned off and sat, the refresh cycle kicked in again the next time the car was started. I know that AGM batterys are very sensitive to the charging requirements, one of the reasons all this smart charging was invented, so I'm worried that its overcharging my battery and will boil it into submission soon.

Does anybody know whether there is a software glitch in the car or CEM? I believe that the CEM controls the charging voltage requirements, using the BMS as a guide to the health of the battery. I can't think that there's any hardware failure, I'm much more inclined to think that the software is glitchy.

I will say, for completeness of information, that my journey to work is over an hour each way, of mixed traffic and dual carriageway driving, with plenty of runs so that the engine is running to charge things and not that much start-stop, where the engine is off all the time, so I can't believe that its short journeys.

Help please!

VOLVOBOY · Nov 7th, 2018, 14:28

Hi.
Have you replaced the wrong battery?
There are two.

pettaw · Nov 7th, 2018, 14:53

The BMS only monitors the Primary Battery, it doesn't monitor the secondary battery health and the Battery Refresh function only serves to charge the main battery up to 100%, I think the secondary battery always gets charged up to full.

Long way of saying yes I believe so.

VOLVOBOY · Nov 7th, 2018, 20:32

Hi.
OK. I accept that. Now I`m curious as to how you would know that the secondary battery had failed.

pettaw · Nov 8th, 2018, 08:16

According to the information I have been able to find, it monitors the voltage constantly, certainly it has a voltage parameter of its own in the Data on the scan tool.
If it drops below a certain voltage when autostart is initiated I believe it will block the next autostop from working.

andyg · Nov 8th, 2018, 10:16

Have you fitted any aftermarket kit, like a DAB radio or dashcam for example? If they are connected to a 12v permanent live feed then even the smallest thing can drain enough to confuse the battery sensor and the stop/start charging status. That happened to me with an aftermarket DAB adapter until I changed it to a 12v supply that was switched on/off with the ignition. It sounds like you are very tech savvy and will already have thought of this, but I mention my own small mistake just in case it helps.

tomweston · Nov 9th, 2018, 12:52

Where is the 2nd battery, my old S40 (with stop start) had one behind the front bumper, I was not aware the new V40 had a 2nd one as well?

Nov 7th, 2018, 09:17	#1
pettaw Forum Support Team Last Online: Jul 23rd, 2023 15:29 Join Date: Jan 1970 Location: Glasgow, London	2013 T4 Stuck in Battery Refresh/Overcharging As thread title. My car is 5 years old and has done 80,000 miles. I had noticed for quite some time that everytime I plugged in my scan tool and looked at live data in the CEM the battery mode was "battery refresh," with the charging voltage being super high, well over 15V. When I looked into it further, even if I did a really long journey and got the SOC up to 100%, when the car sat overnight the SOC would drop into the high 80s or low 90s. I have a CTEK battery tester which is basically a very low function Midtronics machine which tested the CCA at 525 rather than the rated 760, so I reckoned the battery was probably past it and replaced the battery. Using my scantool I reset the BMS to 0 days and fitted the new battery and performance returned to normal, with the alternator only charging the battery up to the required level and then switching to floating voltage etc. After the battery was approximately 60 days, I happened to plug in my scantool to diagnose something else and I noticed the system had gone to "Battery Refresh" again. So I kept an eye on it for a few days and it continued to be stuck in this mode, even though the battery was completely fully charged, and maintaining it overnight. (When I started the car after sitting for 2 days it would still be at 99% SOC) I thought, maybe the BMS is playing up, so I replaced the BMS and again, as per procedure, reset the BMS with the scantool. Again, performance returns to what I would expect according to the literature. However, once again, after approx 3 months, I noted that the "Battery Refresh" mode was activated once again, even though, as I said the battery was already fully charged. Now, I monitored the battery using my scan tool on every commute to work and every drive home. I did note that it did kick out of "Refresh" mode, but once the car was turned off and sat, the refresh cycle kicked in again the next time the car was started. I know that AGM batterys are very sensitive to the charging requirements, one of the reasons all this smart charging was invented, so I'm worried that its overcharging my battery and will boil it into submission soon. Does anybody know whether there is a software glitch in the car or CEM? I believe that the CEM controls the charging voltage requirements, using the BMS as a guide to the health of the battery. I can't think that there's any hardware failure, I'm much more inclined to think that the software is glitchy. I will say, for completeness of information, that my journey to work is over an hour each way, of mixed traffic and dual carriageway driving, with plenty of runs so that the engine is running to charge things and not that much start-stop, where the engine is off all the time, so I can't believe that its short journeys. Help please!

Nov 8th, 2018, 10:16	#6
andyg S80 D3 Geartonic 2013 Last Online: Oct 28th, 2019 17:01 Join Date: Nov 2003 Location: Warminster	Any aftermarket kit fitted? Have you fitted any aftermarket kit, like a DAB radio or dashcam for example? If they are connected to a 12v permanent live feed then even the smallest thing can drain enough to confuse the battery sensor and the stop/start charging status. That happened to me with an aftermarket DAB adapter until I changed it to a 12v supply that was switched on/off with the ignition. It sounds like you are very tech savvy and will already have thought of this, but I mention my own small mistake just in case it helps. __________________ ____________________ 1980s: 1 x 745 petrol. 1990s: 3 x 855 petrol. 2000s: 1 x S60 diesel. 1 x S80 diesel. 2010s: 1 x S80 diesel.

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Nov 7th, 2018, 14:28	#2
VOLVOBOY Lazy Member Last Online: Yesterday 20:01 Join Date: Mar 2007 Location: HORLEY	Hi. Have you replaced the wrong battery? There are two.

Nov 7th, 2018, 14:53	#3
pettaw Forum Support Team Last Online: Jul 23rd, 2023 15:29 Join Date: Jan 1970 Location: Glasgow, London	The BMS only monitors the Primary Battery, it doesn't monitor the secondary battery health and the Battery Refresh function only serves to charge the main battery up to 100%, I think the secondary battery always gets charged up to full. Long way of saying yes I believe so.

Nov 7th, 2018, 20:32	#4
VOLVOBOY Lazy Member Last Online: Yesterday 20:01 Join Date: Mar 2007 Location: HORLEY	Hi. OK. I accept that. Now I`m curious as to how you would know that the secondary battery had failed.

Nov 8th, 2018, 08:16	#5
pettaw Forum Support Team Last Online: Jul 23rd, 2023 15:29 Join Date: Jan 1970 Location: Glasgow, London	According to the information I have been able to find, it monitors the voltage constantly, certainly it has a voltage parameter of its own in the Data on the scan tool. If it drops below a certain voltage when autostart is initiated I believe it will block the next autostop from working.

Nov 9th, 2018, 12:52	#7
tomweston Member Last Online: Aug 26th, 2019 10:17 Join Date: Aug 2014 Location: Knutsford	Where is the 2nd battery, my old S40 (with stop start) had one behind the front bumper, I was not aware the new V40 had a 2nd one as well?

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