On Jan 18, 5:16*pm, Terry wrote:
I have a Black and Decker 450 amp jump starter.

The car battery was dead because the lights were left on. *I wanted to
use the car in the morning. *I took the battery charger and put it on
the battery, the night before, intending to trickle charge it.

The next morning the car would not start and there was no juice in the
charger.

I am guessing that the jump starters are not intended to trickle
charge, although I don't see why.

As many have already replied, these devices will not charge a battery.

In addition (in my experience) they will jump a weak battery, but may
have trouble with a cold, completely dead battery. I've used my HF
JumpStart numorous times to jump various vehicle where we at least got
a click or 2 out of the starter solenoid, but when my son left the
lights on overnight on a very cold night, the JumpStart device did not
work. One shot with jumper cables and another vehicle and the dead car
turned right over.