Where do I plug in the cord to start charging the jump starter (Black & amp; Sage ) 900 peak ,350

The flashing "FL" indicates that the internal battery of the Peak Performance Jump Starter # PKC0AZ is fully charged and is ready to be used.

Taking a complete guess - it probably means it is charging.

Lots of battery powered appliances and tech use an led array that cycles during charging, usually as the battery charge level rises a single led will remain lit at first and then another and another until the battery is completely charged, when either all will be lit or all will go out.

open it and replace battery

Refer to the instructions that came with charger. If you threw them away you have a problem You can go on line and download instructions.
Low Charge Alert (LCA)
On the front of the unit there is a Low Charge Alert port. There is a red plug in this port. With the plug
removed, when the battery level drops to LO, an alarm will sound to remind the user to recharge the
Jump-Starter.
The alarm can be turned off one of three ways:
•
Placing the pin back into the Low Charge Alert port
•
Recharging the battery immediately to bring it to the capacity of 10% or more
•
Pressing the battery indicator display button. If the alarm is turned off by pressing the battery
display button, the alarm will sound automatically again in approximately 1 hour.
The alarm will only be turned off permanently if the battery is in a fully charged state, or the pin is
inserted in the Low Charge Alert port. There is a storage port on the back of the Jump-Starter for the
LCA plug. When the plug is removed from the LCA port, it should be installed in the storage port on the
back of the Jump-Starter.
Charging Jump-Starter Battery
All rechargeable batteries gradually discharge when left idle, and you need to recharge them
periodically to maintain maximum battery capacity. The AC charger plug within the Jump-Starter is
designed to charge using a 110/120-volt outlet.
•
Fully charge unit to the recommended maximum and initial charge time of 24 hours. Thereafter, an
AC typical charge time is 8 to 12 hours.
•
Recharge the unit fully after each use. This will prolong the life of the battery because frequent
discharges between recharges will reduce battery life.
•
Make sure all functions of the Jump-Starter are turned off during recharging

Maybe the rechargeable battery needs replacing. Go to a battery store and buy a replacement.

There should be an ac plug in the back of the unit. plug it up with an extension cord and the display will give you the percentage of the charge remaining. FL is full.

you can buy one at any good car sale shop and make sure you
read all the instructions before useing it as jump starting is always fit red [POS] cable to both cars or batterys first and then fit the black cable lead last,when finished remove the Earth lead [black]First with car doing the charging turned off.
When charging car to car let engine run for approx 4 minutes at 800 rpm then let it idle for 2 minutes before starting the second car

the less amps you can use and the more time you have the better. If you can charge it on 4 amps all day, thats better than say 20amps for a few hours

Have a look at one like yours in store & see what specs are on plug in to charge. It will say Output voltage ..., then how many amps, or milli-amps, for example: ( output voltage 13.5 VDC @ 800ma.) Now find a charger/adapter, with same specs, and plug. Perhaps one your using is very minimal output, or lower voltage. Be sure polarity symbol is same on both too.

Once the battery is totally shot it acts like a resister Try jumping it with another car. If you left your lights on and drained the battery then of course recharge. If the battrey is no good anymore. you got to replace it. Make sure all terminals are clean and tight. Good luck