Normal behavior of charging system in Winter?

[RamFan]

Hello all,
I've noticed that since the temps have dropped my needle has risen. Cause for concern or is this ok? Battery is about 5 weeks old by the way, and yes, the temp combined with short trips is causing longer than typical crank times in the morning.

 

[SwampSurvivor]

In the cold, it's not uncommon for me to see 14, 14.5 volts after a cold start. Drops down to 13.5 or so after a few minutes.

 

[eljefino]

Yes. Dodges have a battery temp sensor, everyone else uses a thing internal to the alternator. It needs the extra 1/2 volt to overcome chemical lethargy within the battery.

Either way this is why more light bulbs seem burnt out in winter-- in addition to everyone using their lights commuting in the dark, bad weather, etc.

 

[4wheeldog]

If your temp gauge does that, it is a time to worry. Higher voltage on short trips in winter, still in the "Normal" range is not a concern.

 

[440Magnum]

Others have nailed it- there's a temp sensor in the battery tray, and the charging system raises the voltage until the battery warms up.

Its not a new feature, either- the very first Chrysler electronic voltage regulators in 1970-71 had thermal voltage compensation, but the sensor was in the regulator case itself. Putting it closer to the battery came in the 1990s.

 

[gathermewool]

Originally Posted By: eljefino
Yes. Dodges have a battery temp sensor, everyone else uses a thing internal to the alternator. It needs the extra 1/2 volt to overcome chemical lethargy within the battery.

Either way this is why more light bulbs seem burnt out in winter-- in addition to everyone using their lights commuting in the dark, bad weather, etc.


Maybe that's why half of everyone I see driving around at night or during a storm does so in stealth mode. Very green of them...

/digression

 

[RamFan]

Thanks for all the speedy replies! Would this increased voltage at start / warm up be the cause of the extra cranking time as well?

 

[eljefino]

Longer crank times could just be older gas with "summer" vapor pressure or you need a tune up/ injector cleaning etc.

Is it cranking strongly? It's not arctic yet where you are, I assume.

 

[RamFan]

Originally Posted By: eljefino
Longer crank times could just be older gas with "summer" vapor pressure or you need a tune up/ injector cleaning etc.

Is it cranking strongly? It's not arctic yet where you are, I assume.


Cranks strongly, it was 11*F this morning when I started her up. A tune up is a possibility, the vehicle was meticulously maintained but I do not have the paperwork that shows when the previous owner completed the last plug change.

 

[440Magnum]

FWIW, my Ram (4.7) cranked just a shade longer during the cold snap last week. Literally like 2-4 more compressions before lighting off, but its usually so predictable that I noticed the difference. Seemed to go away with the next tank of fuel, so I tend to agree its probably more related to "summer" gas in cold weather than anything else. Personally, I'd tolerate the slight extra crank for the better performance (and less vapor stink) of "summer" gas year round. Not to mention that in my area we get the occasional 90-degree day during winter and "winter" gas wreaks complete havoc on carbureted cars (and even causes driveability problems on some EFI vehicles) on those days.