It will not have 1800 lumens, have a look here:
You’d need a solid 6amp draw to make 1800 lumens at the emitter and out the front you’d lose 200-400 lumens most likely.
And I suspect you don’t have a battery really capable of delivering this. The light would also need a very specific driver or direct drive to attain this. Both are highly unlikely in such a light as this.
And at this performance level heat is a major issue. If it isn’t heating up massively within 30 sec, then you are no where near high outputs and amp draws.
And if it is a clone LED and not an XP-L, then performance will generally be lower.
My guess is, your torch is more likely making 600-800 lumens out the front. Which can still seem very impressive. And still be very usable.
You can make and educated guess at this if you have a Digital Multi Meter (they are dirt cheap to buy on ebay etc, £/$5 sort of range). —- You SHOULD already have one if you are using Li-ion as a matter of common sense.
Take a tail cap amp reading. If you are not seeing anything close to 6amps+ then no, it’s all lies I’m afraid.
This doesn’t mean it’ can’t be bright or even a reasonable performing light, but it won’t be what it is advertised as. Which is very common in the flashlight world….
Also you can’t really compare it side by side with a house light bulb. Your torch is using a reflector to focus the light into a beam, the house bulb is not and is lighting up a vast area. If you want to see the difference, at night turn off the house light and point your torch to the ceiling and compare how bright or dull the room looks (not the ceiling, the entire room). It will typically be much duller.
As for batteries. Well it’s always worth having good batteries —— and a good charger.
Personally I quite like these at the moment:
They offer a good blend of high performance and high capacity at a sensible price.
However it is well worth reading up on the differences between protected and non protected batteries and be comfortable with it.