Hello longtime member and search this subject.. ok got a 2007 hhr 2.4 motor and had a problem yesterday car would not start it was right around zero degrees.. I went and jump it started up and went to test the volts and it was at 15 to 15.20 .. I thinking it’s a little high but I read don brew post it was normal .. so I shut it off it was at 12.8 then after two hours 11.8 .. no check charging light and while I put on headlights, radio , heater , ac it drop to 14.7 .. so I went to check battery it’s 4 years old and remove the caps and seem low on water on some cells so I put water up to bottom of the.caps .. just wondering if the is battery on the way out ? Also have 161000 miles on the car .. I had another 2007 hhr and alternator went out about 210.000 miles .. just here to pick some Brains to figure this out .. if I buy a new battery just wondering if the alternator charging at that rate will it destroy it or go back down to normal charging.. sorry for the long post

 

The battery lost it's charge AFTER you shut the engine down. It's not a charging system issue. Probably a dead cell in the battery.

 

X2^^^^^^

 

ok so 15 15.2 is not bad while car was running .. also I notice a yellow x on of the battery first time checking it so I know the first owner got from a junk yard so they might of put a sticker on side from different battery .. this battery has twist off caps like you use a screw driver on it and mind might be telling me it original out off another hhr ..

 

What ever it is , it’s a dead battery. Get a new one, the correct size 90 /T5 and 650 cold cranking amps.

 

When the engine is running you are measuring the alternator output not the battery. The alternator puts out what is demanded, if the battery needs charging it gets charged.

 

I'll only add after adding water (Distilled only) it is best to charge it to activate the new water.

If that battery has no external vent tube, it is not correct for HHR..

 

well I did add water to it and been starting the car but it’s 4 years old and I’m just going to bite the bullet and by a new one from Walmart everstar which I heard is a great battery at 149.00 $

 

my OE 1st battery lasted well over 10 years, still was ok, but I wasn't wanting to chance it thru another winter..

 

Dead cell in the battery is shorting ( draining the power ) get the proper battery with the vent and make sure it is vented to the outside with the vent tube.