The first thing I notice is that it has a thumb throttle which along with the CT101 4-connector controller indicates that it a Razor E300 version 1 with CT101 controller.
The Razor E300 version 1 uses a battery pack with 3-prong connector that looks like this.
I do not have a wiring diagram for the Razor E300 version 1 with CT101 controller however it is exactly the same as the version 1 with CT201 controller except that the throttle and brake switch both go to the same connector. I can not tell from the angle of that connector in your photo exactly how the version 1 with CT101 controller is wired but you should be able to determine this by looking at the throttle/brake connector on the CT101 controller and see which wires go to the throttle and brake lever switch. Here is a link to the E300 version 1 with CT201 controller wiring diagram: http://www.electricscooterparts.com/wiringdiagrams/razor-e300-wiring-diagram-v1-4.jpg
If you use a plug-and-play battery pack, such as the one in the photo above, then it will plug directly into the CT101 controller and you will not need an adapter.
The E300 stem bolt and wedge are not available from Razor and I do not know which size it uses. They are identical to those used on bicycles though so you may be able to find a bicycle bolt and wedge that will work for it. If you wind up finding a bicycle bolt and wedge that works for the E300 please let us know what size it is and where to buy it.
From looking at your photos the only parts I can see which are needed are a battery pack and reset switch. Please let me know if you have any further questions.
I just bought a E300S over the weekend from a family and supposedly just needed a battery. But when I opened her up and compared it to another E300 it did have a different module (CT101) and was missing the wires for the batteries. Also the connector for the batteries on the module had 3 wires (2 thick red/black and 1 thin red) vs just the 2 red/black wires. The breaker looks like its been getto rigged so I plan to put a new one.
Not sure what version this E300S since it has no serial numbers anywhere, but does have LED finger throttle. Also the module has a date of 2004-03-07.
Is the connector on the Battery harness 3 prong connector or a 4 prong?
Does anyone have the wiring diagram for this version with the CT101C or is the wiring the same as the CT201?
Do I need the adapter between the battery and module?
Also does anyone have the bolt & wedge for the steering shaft? My blue one is missing it.
Is there anything else I need?