I'm a field service engineer and have been for over 30 years and cannot understand why engineers won't touch battery repairs? I do and so do plenty more I know the onky repairs we don't do us warranty work.
As for brands fitting tgeur own batteries? Yes it happens but most still use a battery company maubky GNB or Ernersys in the UK
With Lithium things are changing most manufacturers suooky with their own batteries in the machines and field service engineers are being trained to repair them particularly the larger brands Linde etc
I can see hydrogen moving up there is a new battery that has promise the solid state quantum batteries may move up when more people start using them
Lithium is a dead horse, it has its place but not in the mainstream.
Lead acid will see most of us out.
The smaller customers won't touch main dealer stealers, but plenty of independent battery service companies without all the BS overheads sucking up a good portion of work.
this is actually not new, when the hydrogen cell batteries first came out they had to have a certified tech on hydrogen cell tech to work on them, nobody else was allowed. Now with these new lithium batteries and possibly sodium they are installing electronics on them which would require training as well. The mfg would require the certified tech and it would be up to the dealer to make sure their tech's were trained.
And to be honest, back in the day we used to do our own battery repairs then if we knew how, otherwise we called the battery company to do it.
Today tech's are very picky about what they want to work on unlike a couple decades ago when most tech's i knew were cross-trained.
and what dexter said is true, the mfg is just paying to put their name on them, they are still built by the main battery mfg's in most cases.
Odds are the big three are the ones supplying the batteries to the fork lift companies. just a sticker that says their brand