Nickel Strip VS Steel Strip
Re: the nickel welds in your first set of photos
it looks like too long a pulse time and not enough amps. those heat marks indicate heat has built up to dangerous levels to get the weld done, even then you say its a poor weld. the nickel is fracturing around the weld site- another indicator of poor weld parameters. you need a much shorter and hotter weld site
I would try lowering the total circuit resistance +/- paralleling another battery to your existing one, then lower pulse time. this will result in a hotter weld and lower heat soaking into the battery and surrounding strip. any time you get those bridging heat marks, something is wrong IMO.
you can also slot your nickel for much easier welds but this is time consuming.
steel is a really crappy conductor so unless you are planning a VERY low power battery (~2 amps/cell), do yourself a favour and at least use pure nickel.
The Verdict
Brushed Nickel:
- Antique or handcrafted look
- Tones from golden to nearly white
- Complements warm colors, earth tones, stone and tile
- Hides water spots and grime well
Faucets: $100 - $300
Hardware: $4 - $12
Brushed nickel is best for:
- Rooms with a warm color scheme
- Traditional, Tuscan or French Country-style homes
- Kitchens with stone, granite or slate counters
- Remodels with a mid-range budget
Chrome:
- Modern or industrial look
- Shiny, sometimes blueish, tone
- Complements cool colors
- Resists rust and corrosion
Faucets: $50 - $200
Hardware: $5 - $15
Chrome is best for:
- Rooms with a cool color scheme
- Modern, Industrial or Farmhouse-style homes
- All-white bathrooms or kitchens
- Remodels on a tighter budget
Stainless Steel:
- Sophisticated look
- Shiny with a faintly blue tone
- Fits seamlessly with most modern appliances
- Extremely rust- and corrosion-resistant
Faucets: $150 - $400
Hardware: $8 - $16
Stainless steel is best for:
- Kitchens with updated appliances
- Rooms with sleek lines and no texture on walls or counters
- Homeowners who want the shape of fixtures to take center stage
- Remodels with a high-end budget