Charging issue - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

ITZ2BIG · 06-30-2025, 08:09 AM

I'm having a charging issue that has me stumped. My battery never goes dead but if I go on a longer journey ( 2 hours) it goes into battery saver mode. Generally I drive short in city runs. Here's the jist...It's a 2015 Caro 2SS 6.2L std. with only 30,000kms. The original battery lasted 8 years, I replaced it with the proper battery (during the off season) then drove it locally that summer, didn't notice anything. The next summer made a long road trip 4.5 hours (after 2 hours) battery service light popped up. Shut it off for a few minutes, restarted it, light went off...didn't pay much more attention to it til I got home. I've been monitoring the voltage gage constantly on the dash ever since. At start up it pretty good at 13.5-14.5v, the after about 2-5 minutes it goes down as low as 12.3v. I pulled the alternator had it tested which was good but still bought a new one and put it in...same thing.Had the battery tested to be sure, it was good. If I shut the car off & restart it the voltage shoots back up but usually goes down shortly after. I cleaned every possible ground connector plus battery. I even put in a new Interstate Gel mat battery & same up/down with the voltage? Has anyone every had to replace the battery current sensor? I'm thinking it's not giving proper readings? Also I'm working with an electrical shop that says maybe I have to go into the ECM & tell the car a new battery was installed, which I read up on & articles state that isn't nessessary?

gtstorey · 06-30-2025, 08:38 AM

That's the way alternators work on these cars. It charges based upon several different factors.

https://www.camaro5.com/forums/showp...28&postcount=7

CamaroCracka · 07-01-2025, 10:25 AM

I've replaced a few batteries on these and never had to update the computer.

Since I'm pretty old school, I hate the variable charging feature of the Gen5. Makes me very nervous on trips. The 2010 doesn't seem to change, but the 2011 will drop to about 12.5 volts and since it's a 416 with headers, it has the harder time starting. Voltage dropping on long trips would be normal, but I would not think it would throw a message.

Mr_Draco · 07-01-2025, 11:24 AM

Battery Saver mode is for when there is more draw on the battery than the system can keep up with. Either there is an issue with the battery, the alternator, or aftermarket accessories (sound system, lights, etc) is drawing too much amps.

Found a couple other posts of people that had the same problem of it coming on with a good battery and good alternator. Come to find out, Battery Saver mode will also come on if the ECU loses communication with the alternator control which meant part of the ECU was going bad and had to be replaced. After replacing the ECU, their problem went away.

ITZ2BIG · 07-16-2025, 06:59 PM

Update...the alternator shop couldn't find the issue but eliminated the battery, alternator, ground issue & after I changed the CCM current control module on the ground side of the battery which didn't solve it. The suggested I would have to take it GM as their computer system could go more in depth. Still haven't brought it in as I wanted to check it out again myself. The only accessories I added were some running board lights but they've been installed for 6 years & I just started having this issue last summer...I tied into the accessory board under the dash as per the instructions...I'm going to disconnect them and see if it makes a difference? Can't see it but worth a try....That ECU sounds like it could be it as the shop I had it to said there was a communication error with the CCM?

Mr_Draco · 07-17-2025, 01:26 AM

Quote:

Originally Posted by ITZ2BIG

That ECU sounds like it could be it as the shop I had it to said there was a communication error with the CCM?

If they had a comm error, then yea the ECU is the issue and needs replacing.

ITZ2BIG · 07-19-2025, 09:28 AM

If you can come across those other posts that you referred to others that had the similar issue, can you link them to me...thanks

Mr_Draco · 07-19-2025, 11:10 AM

Quote:

Originally Posted by ITZ2BIG

If you can come across those other posts that you referred to others that had the similar issue, can you link them to me...thanks

There's one of them.. https://www.camaro5.com/forums//show...php?p=11310607

ITZ2BIG · 07-29-2025, 09:32 AM

Another update, I had the car to the GM dealership & put on the computer. The ECM had the same date as the current version so it doesn't allow you to reinstall the same on top. The BCM had some updates, so I had them put on. Of course this reset the system & typically the car charges properly for the next 24 to 36h but then drops down to about 12.3 at its lowest. GM garage manager told me there is nothing else they can do.He didn't believe it's a computer issue or a bad ECM or BCM module?
You would think they would be able to tell if it's good or bad? He said he has a good electrical guy that can go over the whole car to try to find a bad wire or pin connector at $120/ hour but that's like writing a blank cheque. I even asked if GM has a R& D dept or technical specialist that you could send them me system info & see what they suspect? He said he'd let me know but it's been a week & no call back?
Any other suggestions out there?

gtstorey · 07-29-2025, 10:13 AM

Are you still getting a warning message or just worrying about the voltage drop you see?

ITZ2BIG · 07-29-2025, 11:43 AM

Quote:

Originally Posted by gtstorey

Are you still getting a warning message or just worrying about the voltage drop you see?

I'm mainly concerned about the voltage drop as what I've read, it should drop below 12.8v. I am only driving around town but the present situation limits my range as last year when I drove past the 2 hour point, at only charging 12.3/12.4 v the battery saver light comes on. Nothing is more embarrassing then having to call a tow truck for your nice car due to a dead battery. So the answer is no, recent message as I'm not driving far enough to drain it to that point.Let me know what you think out there?

gtstorey · 07-29-2025, 12:34 PM

Are you putting a battery charger on it when parked?

Looks like it can drop as low as 12.5 volts in fuel economy mode. Does the voltage go up when the headlights are turned on? it should.

If it was me, I would start with rigging a good handheld voltmeter attached to the battery as a second check on the voltage reading while driving.

ITZ2BIG · 07-29-2025, 01:22 PM

As I don't drive it often, I do ofter have it on a charger. No, the voltage will drop if I put the lights on. If I remove the battery connections for 15 minutes to reset the ECM, then reconnect the connections, the voltageage works properly for 24 to 36 hours. It will nornally start in the low 14's volts & go up to high 14's volts then after about 10 minutes back to low 14's volts. If i put the air on it will increase into the high 14's volts again to compisate.
After the 36 hour point it starts at about 13.8v, then when I start driving it goes to 12.3v, put the air on, down to 12.1 volts, turn a/c off the it recovers to 12.3v?
Can't figure that shit out?
2 different alternators, 2 different batteries, voltage control module ( ground side of battery) & updated BCM? WTF ?

ITZ2BIG · 07-29-2025, 01:26 PM

Regarding checking the voltage on a handheld unit...when I had it to the first auto electric specialist, they put their $12,000 computer on it while I drove & it corresponded exactly with what my electronic & manual volt meter on the car said....According to it the cars computer was telling it it had enough volts & didn't require it?

06-30-2025, 08:09 AM	#1
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	Charging issue I'm having a charging issue that has me stumped. My battery never goes dead but if I go on a longer journey ( 2 hours) it goes into battery saver mode. Generally I drive short in city runs. Here's the jist...It's a 2015 Caro 2SS 6.2L std. with only 30,000kms. The original battery lasted 8 years, I replaced it with the proper battery (during the off season) then drove it locally that summer, didn't notice anything. The next summer made a long road trip 4.5 hours (after 2 hours) battery service light popped up. Shut it off for a few minutes, restarted it, light went off...didn't pay much more attention to it til I got home. I've been monitoring the voltage gage constantly on the dash ever since. At start up it pretty good at 13.5-14.5v, the after about 2-5 minutes it goes down as low as 12.3v. I pulled the alternator had it tested which was good but still bought a new one and put it in...same thing.Had the battery tested to be sure, it was good. If I shut the car off & restart it the voltage shoots back up but usually goes down shortly after. I cleaned every possible ground connector plus battery. I even put in a new Interstate Gel mat battery & same up/down with the voltage? Has anyone every had to replace the battery current sensor? I'm thinking it's not giving proper readings? Also I'm working with an electrical shop that says maybe I have to go into the ECM & tell the car a new battery was installed, which I read up on & articles state that isn't nessessary?

07-01-2025, 10:25 AM	#3
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 3,041	I've replaced a few batteries on these and never had to update the computer. Since I'm pretty old school, I hate the variable charging feature of the Gen5. Makes me very nervous on trips. The 2010 doesn't seem to change, but the 2011 will drop to about 12.5 volts and since it's a 416 with headers, it has the harder time starting. Voltage dropping on long trips would be normal, but I would not think it would throw a message. __________________ 2010 SS - Kind of an On3 kit, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1 brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. Gen6 ZL1 brakes.

06-30-2025, 08:38 AM	#2
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	That's the way alternators work on these cars. It charges based upon several different factors. https://www.camaro5.com/forums/showp...28&postcount=7

07-01-2025, 11:24 AM	#4
Mr_Draco Drives: 2SS/RS Join Date: Sep 2008 Location: Western North Carolina Posts: 7,359	Battery Saver mode is for when there is more draw on the battery than the system can keep up with. Either there is an issue with the battery, the alternator, or aftermarket accessories (sound system, lights, etc) is drawing too much amps. Found a couple other posts of people that had the same problem of it coming on with a good battery and good alternator. Come to find out, Battery Saver mode will also come on if the ECU loses communication with the alternator control which meant part of the ECU was going bad and had to be replaced. After replacing the ECU, their problem went away.

07-16-2025, 06:59 PM	#5
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	Update...the alternator shop couldn't find the issue but eliminated the battery, alternator, ground issue & after I changed the CCM current control module on the ground side of the battery which didn't solve it. The suggested I would have to take it GM as their computer system could go more in depth. Still haven't brought it in as I wanted to check it out again myself. The only accessories I added were some running board lights but they've been installed for 6 years & I just started having this issue last summer...I tied into the accessory board under the dash as per the instructions...I'm going to disconnect them and see if it makes a difference? Can't see it but worth a try....That ECU sounds like it could be it as the shop I had it to said there was a communication error with the CCM?

07-19-2025, 09:28 AM	#7
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	If you can come across those other posts that you referred to others that had the similar issue, can you link them to me...thanks

07-29-2025, 09:32 AM	#9
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	Another update, I had the car to the GM dealership & put on the computer. The ECM had the same date as the current version so it doesn't allow you to reinstall the same on top. The BCM had some updates, so I had them put on. Of course this reset the system & typically the car charges properly for the next 24 to 36h but then drops down to about 12.3 at its lowest. GM garage manager told me there is nothing else they can do.He didn't believe it's a computer issue or a bad ECM or BCM module? You would think they would be able to tell if it's good or bad? He said he has a good electrical guy that can go over the whole car to try to find a bad wire or pin connector at $120/ hour but that's like writing a blank cheque. I even asked if GM has a R& D dept or technical specialist that you could send them me system info & see what they suspect? He said he'd let me know but it's been a week & no call back? Any other suggestions out there?

07-29-2025, 10:13 AM	#10
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	Are you still getting a warning message or just worrying about the voltage drop you see?

07-29-2025, 12:34 PM	#12
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	Are you putting a battery charger on it when parked? Looks like it can drop as low as 12.5 volts in fuel economy mode. Does the voltage go up when the headlights are turned on? it should. If it was me, I would start with rigging a good handheld voltmeter attached to the battery as a second check on the voltage reading while driving.

07-29-2025, 01:22 PM	#13
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	As I don't drive it often, I do ofter have it on a charger. No, the voltage will drop if I put the lights on. If I remove the battery connections for 15 minutes to reset the ECM, then reconnect the connections, the voltageage works properly for 24 to 36 hours. It will nornally start in the low 14's volts & go up to high 14's volts then after about 10 minutes back to low 14's volts. If i put the air on it will increase into the high 14's volts again to compisate. After the 36 hour point it starts at about 13.8v, then when I start driving it goes to 12.3v, put the air on, down to 12.1 volts, turn a/c off the it recovers to 12.3v? Can't figure that shit out? 2 different alternators, 2 different batteries, voltage control module ( ground side of battery) & updated BCM? WTF ?

07-29-2025, 01:26 PM	#14
ITZ2BIG Drives: 2015 Green Flash Convertible Camaro Join Date: Apr 2016 Location: Niagara Falls, Ontario, Canada Posts: 32	Regarding checking the voltage on a handheld unit...when I had it to the first auto electric specialist, they put their $12,000 computer on it while I drove & it corresponded exactly with what my electronic & manual volt meter on the car said....According to it the cars computer was telling it it had enough volts & didn't require it?