Diesel generator winter start

[natfinsness]

2019 Isata 3 FW. I just noticed when I start my diesel generator, it draws the voltage from 13.7 V down to 12.1 V and takes a little while before it allows me to start the generator. I did not notice this in summer… Seems like I could start it right up.
Is there some kind of heater that is drawing power in colder temperatures?

[Highwayguy]

Originally Posted by natfinsness

2019 Isata 3 FW. I just noticed when I start my diesel generator, it draws the voltage from 13.7 V down to 12.1 V and takes a little while before it allows me to start the generator. I did not notice this in summer… Seems like I could start it right up.
Is there some kind of heater that is drawing power in colder temperatures?

It probably has glow plugs that heat the intake and it won't start until the intake reaches a predetermined temp.
I believe you are experiencing a perfectly normal condition.

[GTinsman]

The coils in a diesel engine pre heat to allow starting,this is most likely the draw you are seeing.

[dward51]

How old is the battery? Batteries are less efficient in cold weather. Hence the term CCA or cold cranking amps is important. If the battery is older, this may be an early indication it is not far off of failing.

[Highwayguy]

Originally Posted by dward51

How old is the battery? Batteries are less efficient in cold weather. Hence the term CCA or cold cranking amps is important. If the battery is older, this may be an early indication it is not far off of failing.

You are reading far too much into this!
He does not have a problem so why create doubt?

[TheWolfPaq82]

Originally Posted by GTinsman

The coils in a diesel engine pre heat to allow starting,this is most likely the draw you are seeing.

X2 saw the same thing on my 2014 GMC diesel. Glow plugs...or whatever like to refer to them as. Big quick draw.

[Bill Davis]

Glow plugs. Normal.

[G Hollingsworth]

It's quite normal for the diesel generator to be hard starting in cold weather and take lots of power to do it. It will be a big difference from summer. Diesel engines ignite the fuel by the heat of the compressed air in the cylinders. They have no spark plugs like a gasoline engine. As such they are very sensitive to air temperature. To help them start, there will be glow plugs or something similar that heat up before the engine will crank. This helps warm the cold air to get it to a temperature that will allow the air fuel moisture to ignite under compression. It may even take a time or two trying before the engine stays running. In addition in really cool weather, it may run rough until all cylinders are firing evenly. Unfortunely you can't "plug them in" like you can your vehicle engine. If you could starting would be much easier, but of ofcourse you would need a power supply for that.

[awellis3]

May I add that if a diesel's cylinders are warm enough to ignite, they will and right away. Don't continue to crank a diesel after it has reached max starter RPM without firing. The unburned fuel will cool the combustion chambers and make the cold start worse.

[RV Randy]

Originally Posted by awellis3

May I add that if a diesel's cylinders are warm enough to ignite, they will and right away. Don't continue to crank a diesel after it has reached max starter RPM without firing. The unburned fuel will cool the combustion chambers and make the cold start worse.

That only applies to newer diesels that have glow plugs or intake heater grids. If they don't light off after 2-3 seconds of cranking, then you recycle the ignition and go through another glow plugs/grid heat cycle.

Older diesels without glow plugs or intake heaters usually require a lot of cranking, puff grey smoke, then finally light off. The air being compressed by the Piston is what creates the heat that finally ignites the fuel. Or you give them a shot of starting fluid to fire quicker. And of course you never use starting fluid on modern diesels that have glow plugs or grid heaters.