Question Laptop reboots every couple of seconds when battery is connected...


Hi all,

Picked up a cheap used 'ultrabook' yesterday: Samsung Series 9 NP900X4C.
It's older, sure, but for all I want it to do, it's more than enough. i7-3517U, 2x4GB and about to add an mSATA SSD to it.

So... When I picked it up, seller wasn't sure if it was charged. Turned on no problem, saw the BIOS reflected the specs I expected to see, all good.

Fast forward to getting it home, flashes the Samsung splash screen & a brief peak at a boot select menu... Then it reboots.
Charged up the battery for a couple hours, no change.

Took the thing apart to give it a clean, new thermal paste etc.
Out of curiosity, I disconnected the battery & cleared the CMOS (has a removable CMOS battery), connected the power adapter up, no battery, and the system works just fine.

Left if charging overnight to see if any change, but exactly the same thing this morning.

  • Am I looking at a dead/defective battery? If so, any thoughts as to why it worked without issue when I picked it up?
  • Is there a potential for a bad connection from the motherboard to the battery? Something causing a short when the battery is connected?
I have no issues picking up a new battery for the thing if it's likely to fix the issue, but best I can find is ~$110 CAD for a new battery.....
That's pretty much what I paid for the laptop, so if it's (potentially) something else, I'd rather avoid doubling down the expense!

Appreciate any assistance.


Mar 6, 2017
IMO, the battery may be worn out, but that shudn't cause a reboot unless the system detects overvoltages or unnecessary loads on the battery which may cause it to damage the system, but then that wud be a system shutdown rather than a reboot... So yeah, something points out to the battery being bad; Do check the battery and see if there is any kind of swelling... Also do try swapping the ram with any spare sticks if u got, just to investigate the occurence...
As to the first instance , maybe the laptop wasnt turned on for a while and when u turned the system on the system booted fine but as soon as the system was used for a while, the worn out battery gave in, just my opinion...


Strange events....
SSD showed up today, so I opened it back up. With the battery disconnected, no issues in booting to the BIOS.

Reconnected the battery & all seems to be working as intended (Well, except the keyboard, but that's another story).