Hi there!


You don't mention if you have a voltmeter or not.
Since you cannot see electricity, except while sparking, so you need one very badly.

You could have a drain or your alternator is not putting out enough or into the battery to make it through a cold night.

You can check for any drains with the amp meter portion of the voltmeter.
You need to put the amp meter in "series" with the negative cable of the battery and the ground on the car. You will disconnect the cable and hook the meters leads in between.

Start with the ten ampere selection on the dial in case there is a big, big drain.

If you are under one ampere then switch the dial down to the MA or milliamperes side.
All this might require you moving leads into different post on the meter.

The reading will change or get divided into thousandths of one ampere. You want to see about 0.02 on the meter or less. A 0.5 is a drain that can kill a battery in a few days even if you drive it only once a week.

The voltmeter has two function of use. You use the leads in "parallel" to the battery terminals or across the top of the battery. This is the most common way to use a voltmeter by the way.

You want to see 12.65 on a fully charged battery that has rested after any charging.
If you see 12.35 you are well on the way to a dead battery that will not start the car.
If the battery sits disconnected and travels down to the lower number all on its own "quickly" then it has a bad cell.

There can be "long time or term" reasons for this to happen but you are not doing that!
You might want to browse the site for more information on how that works.

I don't use any of their products but the information is good for some mild reading.
http://www.progressivedyn.com/battery_basics.html

Ok, when you have your car running you check the battery voltage and you want to see at least 1.0 to 1.5 volts above the battery rested voltage. So fully charged in can be 13.2 to 14.2 if just started and some loading of lights or the cabin fan idling or revving at a cruise sped.

The other "uncommon or less known" use for the voltmeter is looking for voltage drops due to bad grounds while a circuit is in use. During this test you put the voltmeter lead in "parallel" with each side on the of the cars circuit.
I Like checking fuses this way to see if they are good or blown without pulling them out. Works out nice when I'm into hot panel with multi voltage circuits of a machines controller.

Good is zero volts and bad is supply voltage on each end. It Has To Be a live power available circuit! You learn a lot working with ground points. AC or DC.

The voltmeter meters leads connect at each end of the one side.
Like negative post on the battery to the engine or alternator housing.

The reading should be read 0.000. Like the ammeter reading you want 0.020 or far less less.
If the number showing anything upwards towards a supply voltage, it means there is not a good solid connection.
If you have some then it leads on to locate what is causing the resistance which causes a voltage difference other than zero.
We start with the biggest most important grounds and work towards the smaller ones or the piece of equipment malfunctioning.


I use this method mostly to check the alternators housing grounding, engine block grounding and the body's grounding but it can be used most any place to other known good grounds.

Happy hunting to you!

Phil