Pretty sure I have a dying battery (which is crap given that it's only ~4.5 years old and less than 35k ), but I'm curious what others are seeing.

On my 13 diesel (warm or cold) when I turn the key without cranking the voltmeter in the MFD reads in the low to mid 11s. After cranking I've seen it drop as low as 11.2 before it then raises up to the typical 13.8 - 14.8 range that I'm used to seeing.

What is everyone else (especially diesels) seeing for their volt readings just before and after cranking?



I started paying attention the other week after I got in and got a warning about it having been in battery protection mode even though it only sat for about 36 hours. Since then the interior lights have not been working as expected (turning off too quick after unlocking the car and not manually turning on until after the car has been started) and I had one case where the PCM didn't come on after a warm start.

Given the low reading and how we know these things get wonky with bad batteries I suspect the battery needs replacement even though it still cranks fine.

 

When I got my CTT - the battery did about what you have observed. Had no obvious symptoms like you did with the lights or PCM - but I decided a new battery was in order.

So I put one in - new AGM. It no longer drops below 12V before startup. Usually is sitting around 12.4V or so with the KESSY key on before I start the engine.

I suspect a new battery might make a difference for you.

 

My 2011 CS has been marginal (reading anywhere from 11.8 to 12.4) since I got it 2 years ago. The real clue, although I leave it turned off normally anyway, is that the stop start mode basically doesn't work. I put it on a CTEK charger from time to time and let it fully charge/cycle the battery so if you don't have something similar already it may be a reasonable investment. Anyway, my battery has stayed virtually the same by my doing that any time I'm not going to be driving the car for a somewhat extended period. Although I do plan on replacing the battery some time this year.

 

Yeah that is the only thing that keeps me from saying it's 100% the battery. It mostly gets used for short drives with the longest typical being 12 miles each way 3 times a week, so I suspect that it might just not be getting recharged fully.

Unfortunately I live in a town house with no garage so a charger is out of the question

 

Is it possibly the voltage drop on your CD is because the glow plugs are running? When it's below about 50, the glow plugs on mine will run as it evidenced when the symbol is on at startup...usually this only lasts a few moments...but if they are running, that may account for the voltage drop.

 

Interesting hypothesis. I don't know what kind of drain the glow plug would cause on the battery.

I've actually only seen my glow plug light once in 4+ years and that was when my Gen 1 BlueSpark failed causing a no-start situation until I removed it. I do, however, typically get the "engine starts" MFD message for about 5 seconds or so, but ambient temp doesn't seem to impact the delay between turning the key and it actually starting.

 

A solar windshield charger might help - Not recommending any of these particularly. Our situation is a bit different, when we are off-road we use a 90w solar panel to keep the car and house battery charged.

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http://www.carbatterychargerscentral...ttery-tenders/