This winter has been a cooler than normal winter where I live and about a week ago I noticed when starting up the engine (V6) in my 2017 Impala that it didn’t sound quite normal one morning after sitting for a few days. At this time I also noticed that there was a message on the DIC (Driver Information Center) display about identifying me as Driver Number 1 for a few starts afterwards. The temperature has been below freezing here for the last 60 days – normally we get a January thaw for a week or so but that did not happened this year. A few days ago I got the voltmeter out and checked the battery voltage showing at the positive and negative battery posts (not the terminals) after the vehicle had sat overnight at a temperature of about 10°F (-12°C) – got a reading of 11.9 volts (yellow flag). Started the engine (cranked ok) and then checked the battery voltage after a minute (both displayed on the DIC and the voltmeter) and was getting a reading of 15.1 to 15.3 volts. I have noticed that the battery voltage being displayed on the DIC while driving for the last few months always seemed to be about 15.0 – 15.3 once the engine had been started and running for a few minutes and never seemed to drop much but I do a lot of short trips (about 4 miles) so the under hood temperature never gets very warm this winter. I did a few more voltage drop tests between the battery posts and terminals just to verify there was not a connection problem and they checked out ok. The battery that came with the car when I got it had been replaced back in 2022 about 4 months earlier than when it was traded according to the service records I got with the car but the car had only been driven about 40 miles in that time period so it sat for a lot of days. My experience with batteries has been that being left without the engine being started once or twice a week tends to drain down and recharge a battery can make a battery fail prematurely – especially with newer vehicles that have kept alive modules like a 2017 Impala does. I have a battery that I remove and charge periodically from my summer car over the winter months so it got placed in the trunk as a backup plan (along with the booster cables I keep there) and I ordered a new battery for the car which I picked up yesterday. This morning I decided to do a voltage test using my Fluke multimeter which has the ability to record minimum and maximum voltage levels over time and thought I would share the results as it may help others get a better understanding of how battery voltage can change as a battery ages and what seems to be an acceptable voltage level can drop to a point where modules may not work properly when the load of a starter cranking and engine is placed on them.
This morning I popped the hood and connected the meter before starting the engine and got a reading of 12.01 volts - temperature this morning was just above freezing at 35°F (2°C) – slightly higher than thee voltage level I had gotten when the temperature was at 10°F (-12°C). I then placed the meter in the Min/Max record mode and left it connected and I started the engine and let it run for a few minutes. I got a Maximum voltage reading of 14.96 (vehicle running and charging) and a Minimum voltage reading of 9.34 volts (engine cranking).
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This confirmed to me that purchasing and installing a new battery would be a prudent thing to do. Some might argue that since it is the last week of February and I might have gotten another summer and fall out of the old battery and this may be true but here is a few of the reasons I chose to be proactive rather than reactive. The battery is almost 3 years old and the longer it remains in the vehicle the more likely it is that it will fail at some point in the future to start the engine. The alternator is trying to recharge a battery that is close to failing every time that the engine starts and as the condition of the battery gets worse the charging system will have more demand placed on it which can lead to having to replace both the battery and the alternator when the battery gets to the point where it will no longer crank and start the engine – I was taught a long time ago that an alternator in newer vehicle systems is there as a battery maintainer and not a battery charger. Years ago when vehicle charging systems were overbuilt alternators were more forgiving when batteries were no longer performing their job properly and a vehicle would get boosted a few times when the weather got cold for a week or two. In modern vehicles each component of the charging system is not overbuilt due to weight and cost factors and a weak link in the system will quickly cause other components to fail.
After replacing the battery and installing the new battery I used the meter and did a similar test – the new battery had been sitting in the trunk overnight so it was very close to the same temperature as the old battery. I measured the battery voltage of the new battery before connecting it and got a reading of 12.7 volts and once connected I turned the headlights on for a minute and got a reading of 12.3 volts after I turned the lights off and before starting the engine. The Maximum voltage reading I got was 15.3 volts and the Minimum voltage reading I got while cranking was 10.25 volts.
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The Maximum voltage readings (14.96 versus 15.3) is only a difference of 0.34 volts but the Minimum readings (10.25 versus 9.34) is a difference of .91 volts which is significant since the Minimum voltage level is what each module has to operate with during the time the engine is cranking over to supply fuel and spark at the proper time to make the engine start and run. At 9.34 volts on a day where the temperature is just above freezing if the weather turned cold and the vehicle sat for a couple of days the Minimum voltage level could drop to below 9 volts and that is when modules can get confused or simply stop working properly.
Stay tuned and as time permits I will post more information about how to replace the battery and some of the fun I had along the way. I encountered a seniors moment and left the new battery in the trunk with the trunk lid closed (since it was drizzling) until I removed the old battery - keyless trunks - what a joy.
This morning I popped the hood and connected the meter before starting the engine and got a reading of 12.01 volts - temperature this morning was just above freezing at 35°F (2°C) – slightly higher than thee voltage level I had gotten when the temperature was at 10°F (-12°C). I then placed the meter in the Min/Max record mode and left it connected and I started the engine and let it run for a few minutes. I got a Maximum voltage reading of 14.96 (vehicle running and charging) and a Minimum voltage reading of 9.34 volts (engine cranking).
This confirmed to me that purchasing and installing a new battery would be a prudent thing to do. Some might argue that since it is the last week of February and I might have gotten another summer and fall out of the old battery and this may be true but here is a few of the reasons I chose to be proactive rather than reactive. The battery is almost 3 years old and the longer it remains in the vehicle the more likely it is that it will fail at some point in the future to start the engine. The alternator is trying to recharge a battery that is close to failing every time that the engine starts and as the condition of the battery gets worse the charging system will have more demand placed on it which can lead to having to replace both the battery and the alternator when the battery gets to the point where it will no longer crank and start the engine – I was taught a long time ago that an alternator in newer vehicle systems is there as a battery maintainer and not a battery charger. Years ago when vehicle charging systems were overbuilt alternators were more forgiving when batteries were no longer performing their job properly and a vehicle would get boosted a few times when the weather got cold for a week or two. In modern vehicles each component of the charging system is not overbuilt due to weight and cost factors and a weak link in the system will quickly cause other components to fail.
After replacing the battery and installing the new battery I used the meter and did a similar test – the new battery had been sitting in the trunk overnight so it was very close to the same temperature as the old battery. I measured the battery voltage of the new battery before connecting it and got a reading of 12.7 volts and once connected I turned the headlights on for a minute and got a reading of 12.3 volts after I turned the lights off and before starting the engine. The Maximum voltage reading I got was 15.3 volts and the Minimum voltage reading I got while cranking was 10.25 volts.
The Maximum voltage readings (14.96 versus 15.3) is only a difference of 0.34 volts but the Minimum readings (10.25 versus 9.34) is a difference of .91 volts which is significant since the Minimum voltage level is what each module has to operate with during the time the engine is cranking over to supply fuel and spark at the proper time to make the engine start and run. At 9.34 volts on a day where the temperature is just above freezing if the weather turned cold and the vehicle sat for a couple of days the Minimum voltage level could drop to below 9 volts and that is when modules can get confused or simply stop working properly.
Stay tuned and as time permits I will post more information about how to replace the battery and some of the fun I had along the way. I encountered a seniors moment and left the new battery in the trunk with the trunk lid closed (since it was drizzling) until I removed the old battery - keyless trunks - what a joy.
