Hi radviss‌,

Open Power Options and make sure it is on high performance.

Alienware 15 R2 on game not charging HELP! - YouTube 

I recorded how my problem looks like

Hey! Yes i had that all the time, but it still doesnt fix it..

Hi guys,

I had the same problem, when running my 15 R2 powered by unsupported 90W HP adapter (which I have plenty of as a former HP user). Although this worked fine - same voltage and connector (except boot up warning message about unknown adapter power) all the time when not gaming, some in-game (not all games) was causing this issue - constant cycling between battery and AC power. I believe, that in such case, notebook is drawing more than 90W and so adapter shuts itself down to protect itself and when unloaded, turns up again, but immediately overloaded, so it shuts down... Funny thing is, that adapter ran cooler powering this hungry beast that original HP laptop doing nothing

While using DELL 130W adapter, warning message states, that it was successfully recognized as 130W, but as 180W is minimum, laptop will adjust performance and charge slower. No cycling issue yet, but not charging at all, even when off. And performance is lower.

So for my experience, please check, whether you are using original Dell adapter rated at minimum 180W (mine shipped with 240W, lol, one could almost power a welder by this brick) and cable nor connector is damaged. Or connector not being dirty (both laptop and adapter) as this could cause voltage sag... we have some serious current here.

Do you receive any warning during start up? It may be disabled in BIOS, may be useful to check this too, if you are unsure about your adapter.

Heyy! I have checked that the adapter is from Flextronics and it outputs 240W, i got it originally in the package  On BIOS i also checked under the main tab that its 240W  

I also cleaned it and it also not worked. This is really weird, for me it is also not in every game. Even when im just minimizing my game it still cycles around AC and Battery.

Hi Radviss, yes, yesterday, after I replayed to you, I saw video description, adapter seems to be the same as mine. Unfortunately, today I ran across another thread Alienware 15R2 Charging issues about the same issue. User there was advised to replace AC adapter, he did, bu that made no difference according to his post. So it may be worse than that. Last thing I can think of is to check, if the adapter's barrel plug is hot or warmer, than it should be when issue occurs. If so, it would be pointing towards DC port, if not, it may also be a mobo. Not that you can do much about it, if you're not into disassembling, but port is still easy and cheap to fix. Anyway, I hope it is still under warranty and I would probably not wait any longer before contacting support.

Send me a private message with the service tag so I can assist you further.

Hey! I checked my barrel plug and it was cold, but recently i tried to actually play a game when my battery was fully charged and it worked, no cycling from battery to ac. Yea but it still does not solve the issue, unless i want to keep gaming with this laptop only when laptop is fully charged..

I only get this problem if I try to charge the laptop while gaming when the battery reaches a low state. I figured out why it doesn't charge because the battery is already too hot from gaming and wont charge until the battery cools down for safety reasons. Most laptops are configured this way including other brands. Laptop batteries will get extremely hot if you let the battery drain too low while gaming so to avoid this problem start charging the laptop at 50 percent while gaming. It will charge just fine every single time. You should make this a habit cause letting the laptop die or get too low before charging is very bad for the battery. if this ever happens, shut off the computer for 5 mins to cool the battery down then turn it back on and plug in the ac but again try to avoid overheating the battery by not letting it drain below 30-40 percent especially when your gaming. 

I have the same problem. 

In dota 2 my normal fps is 80-115 but suddenly drops to 30. I have updated my BIOS, video card everything, run stress tests on my video card and processor and all other hardware, but fps still drops. That's when I noticed every time i go check the desktop when my fps drops, the charger pack constantly turns on and of f shown by the blue charging light on the cable and the dimming of my screen.. How do we fix this?

BIOS: 1.3.10
Processor: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60 GHz (8CPUs), ~2.6GHz
Memory: 16384MB RAM
Graphics card: NVIDIA GeForce GTX 970M
Intel(R) HD Graphics 530