Laptop blown component help HP new battery reverse polarity issue - Page 1
Forum section: electronics / repair

author: GeorgeJr
author_rank: Newbie
timestamp: December 06, 2023, 12:12:34 pm
content: 17-BW0011NR HP Envy laptopPD4302 part popped when I accidentally connected a new battery in reverse. Left pin is positive and right pin is negative.Laptop works on AC power fine. Once turned on I can run it with the new battery only fine for a bit.Can’t boot it with battery only.11.55v batteryAnyone know how to ID the right component to replace it? Was able to remove the old one but was too far gone to read anything off of it.Thanks for any help. I’ve painted red on the positive side of the connector to avoid this in the future. Why don’t they have a plug that only goes on one way or at min have screw down unique on one side so it doesn’t line up.

author: GeorgeJr
author_rank: Newbie
timestamp: December 06, 2023, 12:15:19 pm
content: Also when plugged in goes from amber color to flashing white as I suspect it isn’t charging. Computer shows 100% battery charge but acts like it is lower as it shuts down like low voltage after a few mins.

author: macboy
author_rank: Super Contributor
timestamp: December 06, 2023, 04:02:48 pm
content: I see some PRnnnn which are clearly resistors, and PCnnnn which are clearly capacitors, so a logical guess is that a PDnnnn is a diode. Given that it blew up, it may have been a reverse polarity protection diode, connected across the battery in reverse. So when you connected the battery backward, it conducted a lot of current. Usually this is used together with a fuse, polyfuse, or circuit breaker, so that the high fault current trips that protection device. Check if the pads of the diode are connected to the battery power terminals. It also could be a diode used to allow current to feed from charge circuit to battery but not the other way. Connect battery backwards, and this diode, together with flywheel diodes from (for example) charge circuit buck converter, can create a near short. In that case, replacing the diode may restore the charger to working condition.You may need to hunt down a blown fuse. This might even be inside the battery pack, either part of the protection/BMS board, or as a discrete device in series between two of the cells. You will often find a polyfuse and a thermal fuse connected between two cells, to passively protect against heat and short circuits. As a SMD component, fuses are often white, and polyfuses often white or green.I recommend safety glasses as a bare minimum when working with batteries capable of high energy discharge. A short circuit can send molten metal and other shrapnel flying in any and all directions.

author: fzabkar
author_rank: Super Contributor
timestamp: December 06, 2023, 05:47:41 pm
content: Not the same circuits, but the diode is an SMF18AT1G-GP.https://laptopblue.vn/download3.php?id=1812(page 43)https://www.dclabs.lt/dainiaus/wp-content/uploads/2021/02/brix-laptop-cedar_intel_mb.pdf(page 42)That said, ISTM that the laptop should work without the protection diode.

author: GeorgeJr
author_rank: Newbie
timestamp: December 06, 2023, 06:50:33 pm
content: Awesome, thanks I’ll get one soldered in and verified. I suspect because the battery is too low it won’t power on.