Right there is the answer. They would rather sell oddball battery sizes and convoluted specialized cable connections that are all high dollar vs a universal cheaper alternative found easily and where anyone can quickly fab up their own cables with minimal investment in supplies and tools.

They also need to get on board with battery disconnects.

In my previous thread from 2016 I gave price comparison in going from two 6volts in series to a single group 31 12 volt on my 4040 battery conversion.

https://talk.newagtalk.com/forums/thread-view.asp?tid=655904

Here is those costs again from 2016 I'm sure it's much higher now.

Cost breakdown was as follows

HD disconnect $38.00

1000 CCA group 31 battery $100.00

3 new custom cables with ends, shrink tube and loom $54.00

Paint and steel I already had.

Total $192.00

This setup seemed to spin engine over faster than before and had no problem starting tractor. Real test will come later when temperatures drop.

Just price checked JD parts.

Two 6 volt batteries $162.79 ea = $325.58

Cables depending on which ones by serial number $40.36,$17.90,$37.03, $22.46

Still no disconnect switch included either which gives you a range of $406.30-$420.87 just for batteries and cables.