The car just clicks and doesn't start.

Your starter is probably intermittent remove starter and get a bench test done for free at autozone

A jump starter needs to be an expensive higher quality unit to start a cold engine with no help from the vehicle battery.

A starter that just clicks could be faulty or equally be short of current...

This a battery jump pack that is used to jump start a car. Some units have an ac adapter built in so you can charge the battery in the jump start pack. My unit has a spot to connect the ac adapter to the jump pack so you can charge the battery in the jump pack. My ac adapter has been lost. I know I have to buy a new ac adapter so I can charge my jump pack, what I do not know is if the input (from the ac adapter) is 120v 60 hz
I understand that the DC output needs to dc12v. I do not understand the milliamps. The battery in the jump box is 12v 10 ah ( what ever that is). I just want a new ac adapter to charge the jump pack with that is not going to damage anything.

Dead battery

Dangerous practice to try & jump a dead battery

The battery cables could be loose at either end or corroded internally

Most likely the battery is worn out, if original to car
since it was new, or the starter solenoid is worn

You do not want to jump any vehicle made after the
year 2000 or your asking for possible problems with
todays electronics.

You need a good battery that has been tested & fully
charged, then only jump with a jump pack,not another car

GET A JUMP START WITH SOME JUMP CABLES FROM ANOTHER CAR OR A JUMP PACK? TAKE WHEN IT HAS STARTED TAKE OF JUMP CABLES FROM BOTH CARS AND REMOVE THEM AWAY THEN UNDO THE NEGATIVE CONNECTION FROM THE BATTIERIE AND TAKE IT OF BAT IF THE CAR DIES THEN YOU'RE ALTINATOR IS DONE FOR YOU WILL NEED A NEW 1 OR RE FURB 1, HOPE THIS HELPS

Clicking noise usually means a bad connection at the battery terminal. It can also be a bad connection at the starter or solenoid.
Re-clean and tighten battery cables,and if that doesn't do it,re-tighten starter connections.Don't overtighten as copper-bronze studs can break easily.If your Ranger is standard shift (4 or 5-speed), don't get under the car or in front of it without the battery cables disconnectede or the shifter in neutral,as any current you inadvertently send thru the starter can engage it and run you over or knock the vehicle off jackstands or blocks. don-ohio

Is it one click or multiple clicks. If it's multiple clicks, it sounds like a dead battery. Voltage isn't always an indicator of a good battery, you need to have enough cranking amps to be able to start an engine also. If you have dash lights and it only clicks once, you could have a bad starter. An easy way to check this is to try and jump start the vehicle. If it starts up with a jump start, you need a new battery. If it still doesn't start up and it just clicks, you probably need a new starter.

Good Luck!
~Brandon

Even a new battery will go dead if the car is running on the battery instead of the alternator.
Check alternator output.
First charge the battery up.
Then check voltage with a meter from Harbor Freight ($3).
Should be 12.5.
The start engine and rev it up.
Should go over 14.
But also clean and grease battery terminals, alternator terminals, and check engine ground strap.

replace starter.

If you have a multimeter, connect it to your battery, and select an appropriate DC voltage range. On my multimeter, I use the 20volt setting.

If your battery shows 12-13.8 volts, then it is not the issue. If your battery voltage is low, then you will probably need a new battery. A flat battery can also indicate that the alternator is not recharging your battery properly, but it could also just mean that your battery is old and needs replacing.

If your engine wont turn over, and if your battery is good, it could be a faulty starter motor.

Those jump start packs need to be charged often, or the battery inside them can stop working. It is possible that your jump starter pack is also broken.

Try jump starting the car from another vehicle, with jumper leads. If you know your battery is dead, you could also just replace it with another one.