Before everyone yells here we go agin, I know on other forums, the subject of fuel cans has been done to death. However, my query is regarding a small amount of fuel, usually less than 5 litres (probably like a couple of litres) carried in a 10 litre fuel container. We dont use the generator much, rely on solar.
If I carry the container in the car, and left overnight, you can smell the vapour. If I carried it in the front boot of the van, where the batteries are, that would concern me with a possible build up of vapour and a potential spark.
The generator is carried in the rear of the car, but no apparent vapour smell.
Swap to a 5L "Fuel Safe" plastic jerry made by Rheem in Australia.
Don't put it in the back of the vehicle or in the front boot with the batteries. Best on the A frame. Same applies to the generator. An incredibly dangerous thing in the case of an accident.
+ 2 for the Rheem fuel containers. Actually I now use two 5 liter ones. They do not smell of fuel either. You said yours do not leak but probably the cap seal is not 100%.