How To Tell If The Duracell DU37FR Emergency Jump Starter is Charged

Updated 01/26/2022 | Published 11/01/2018

Question:

How will I know if it is ready to use. charged?

asked by: Joe W

Expert Reply:

There are indicator lights on the front of the unit that will tell you the level of charge. You should check the charge level every three months if it is not in use so it will be charged and ready when you need it.

I have attached a review video that will give you more information.

expert reply by: Jameson C

Ken

2/25/2020

I have a peak 600 amp jump starter. When it is plugged into the 110 outlet to charge the display blinks 99. Any one have an answer?

Chris R.

2/26/2020

The "99" on the battery indicator for your Peak 600 Amp Jump Starter simply means that the unit is 99% charged. The flashing just means that it's currently plugged in and being charged. Once fully charged this number should switch over to "FL".

Chris K.

4/19/2020

I have a Peak Performance starter 900 that I have not charged for a while I went to charge it nothing flashes is just a dash and when I unplug it the display stays on and does not tell me the percentage of the battery what does this mean

Chris R.

4/20/2020

How long did you leave the charger plugged in before you unplugged it? It could just be completely dead, so it might take a day or two to completely charge. I would try leaving it plugged in for a long period of time to see if the display eventually changes. Let me know if you've already done this or the issue persists.

4/19/2020

My Peak jump Box says FL and when I went to jump the car the box acted like it was dead. Wouldn’t jump it. So I plugged it back it, and it says FL again.

Chris R.

4/20/2020

It's possible that the battery is too far gone and not able to be jumped. Also make sure the clamps have a secure, solid connection with the battery terminals. If you're still having trouble please let me know.

Bo M.

4/20/2020

I figured the same thing. I guess I will try to google replacement batteries for the jump box. Mine is a 900 and the lights on the box to light up for the work area on the side of the box, I just figured it probably just has enough charge for those to work.

5/1/2020

Hi, I have a peak 600 Jump Starter. The jumpstarter wouldnt come on when I turned the dial to on, so I decided to charge it using the AC plug in the back. Once I plugged it in, the battery display shows a flashing FL, which i assume means fully charged. However, when I unplug the jumpstarter and pull the LCA pin, the alarm comes on and the display shows _ _ . Does this mean the starter needs to be charged some more?

Chris R.

5/3/2020

The flashing "FL" does indicate a full charge, however it's still recommended to keep the unit charging for the recommended time even after getting this display. With this in mind, it could just be that the unit needs to be charged a bit more like you mentioned. The manual suggests a charge time of 18 to 24 hours after each use (or 30 hours before the initial use out of the box).

David Y.

5/21/2020

I have a 900 peak battery starter it’s reading FL but I haven’t use it n awhile, so I plugged it up for a few hour it’s till reading FL which I kno what that mean so is my battery starter gone bad.

Chris R.

5/23/2020

It might be bad but it also might need some more charging. Since it hasn't been used in a while, I would charge it for at least 24 hours before trying to use it.

Lisa

8/7/2020

How do you get the FL to stop flashing on 700 Duralast Jump Starter?

Jon G.

8/17/2020

If the "FL" is flashing then that's an indication that it still needs to charge. If this is like the Peak Performance jump starters then that "FL" will be solid when it's done charging.

Scott G.

10/1/2021

@etrailer_expert. In one thread you say flashing FL means it’s fully charged and in another you say it means it needs more charging. Very confusing. I have this charger and it’s been plugged in for days, for weeks, and when I tried to jump start a car with it it shows zero charge…totally dead. The flashing FL obviously means it is not fully charged. I must have a bad battery. Oddly enough I have NEVER used the unit to jump start anything and yet the Peak unit/battery is dead/defective. Junk.

Les D.

10/21/2021