Half a plan....what battery and how fast can I go?

Hi folks
Daily cyclist here but I fancy getting on the 'electric highway' as I'm getting on a bit :lol:
So I think I'm going to use a Decathlon Riverside as a donor with a Tongsheng TSDZ2 750w mid motor and I'll stick the open source software on it as I'm an open source fan!
I'm a lightweight at less than 65kg - that's about 140lbs in 'old money' :wink:
So I have 2 requirements:
1) when I go shopping for a quick 20km blast to get a baguette I want to go as fast as possible and p!ss off a few cars and trucks during a 10 minute uphill segment and when I'm 'cruising' along a totally flat valley section
2) 100km+ touring range at a 'leisurely pace' but having to deal with plenty of hills in the French countryside
I recently saw a youtube vid of a guy with a homemade 'spot welder' making a battery pack and I'm happy to give this a go with an old car battery, some weird solenoid and a 'danger button'
In fact I'll go for 2 different battery packs if this gives me flexibility....
Thanks for your thoughts and experiences!
Safe riding!
Allez les bleus!

PS balls I've stuck this in the wrong section
Mods can you move it to e-bike general please?

The key to range, is not just battery capacity, but also how fast you want to go, and how much pedal input are you prepared to contribute ?
have you read the TSDZ2 thread ?... much of the info you need is in there..
Seasons greetings.

The thread with 168 pages or the one with 252 pages?? <where's the 'got a sweat on' smilie?>
I'm prepared to pedal like Forest Gump to break the speed limit, which is generally 50kmh or 80kmh over here :lol:
As I understand it the motor has a built in controller?
I'm not particularly bothered about the LCD display but can I use bluetooth and an android phone to get some info like battery life?
Seasons greetings to you too squire and all other squires out there
PS I hatehills too but alpe d'huez must be conquered one day :wink: :lol:

that homemade spot welder with a danger button youtube video, I think he was using a starter solenoid off a lawn tractor or something, that setup he changed because he was burning holes in the battery when spot welding. he fixed it and tells you how he fixed it so make sure you see that video so you make the right spot welder

A good spotwelder has a "controlled current", "controlled welding time" and "controlled electrode pressure"
I am not saying you can't assemble a battery with a diy spotwelder, but it complicates things.
For a range of 100+ km, you will need a large and heavy battery. How large is difficult to calculate as it depends upon the amount of pedaling you do yourself. If you turn off the motor you can go around the world with 1 battery charge.
To pass cars when going uphill, I doubt the TDSZ2 is the right motor for you. If you load it 2 much, it will overheat, and if you don't have a temp sensor to measure motor temperature and reduce power when needed, it will melt.
TDSZ2 is a good motor to build a street legal bike without the limits of the "closed system" motors like bosch, yamaha and shimano.