I have a 1997 toyota avalon and I am having problems with electrical power loss. I have replaced battery and sometimes when i go to start the car insert key and nothing happens at all I can keep trying it and eventually it will work just fine.

Check your am fuses. That and the alternator fuse. Had to replace those on a camry and then everything powered on. Should be like an 80 or 100 amp fuse. May look ok, but could be split so that power isn't flowing.

Hi this is a electrical problem .Please check if battery terminals are properly secured with no corrosion built up then check ignition for electrical short circuit

Is the 'check engine light' on? A good starting point is to have the car scanned for trouble codes..Trouble codes will identify what component or part of the car's operating system is faulty.

have battery checked first at autozone

Have you locked and unlocked the driver door with the key ?

Battery is the best bet because the dimming of the lights and clicking of the solenoid which does not have the battery current to engage the starter. Try to find a neighbor with jumper cables or go to an auto parts store to have them test your battery and to buy a battery if it is bad. If your battery light stays on after the jump or replace your battery it is your alternator or the serpentine belt is not turning the alternator.

Sounds like a weak batt cell. You can get your batt tested at your local parts store.

Some dealers put the radio's antitheft code in the owners manual. If it's not there call your local dealer and they can reset the code for a fee.

It won't crank? Does the alarm system works? Like locking and unlocking the doors? If that work, check cranking voltage to starter solenoid with a test light. But before, check all fuses under dash and hood. Make sure battery connections are clean and tight. There is more but try this for now. Let me know of the solenoid test and please ask any questions.

I doubt this is a smart key problem, the key uses a chip and its own battery. Something in the car is causing a drain, a light is staying on possibly. Trunk light, glove box light, under hood light... maybe you have a portable GPS unit plugging into the auxilary port? Just a thought. This is not a common problem that has been reported by Avalon owners as of yet.