I wrote:
"Uppercase is only used for units named after people; eg, Watt, Ohm, Ampere, Volta."

J Guy noted:
"ohms isn't capitalized, neither is mhos."

Dennis Welbourn:
"and thanks to you I learned something!"

Actually, so did I!
I learnt that, when writing the name of the SI unit in full, I should not use a capital initial; thus the SI units are, as J Guy noted, correctly written watt, ohm, ampere, volt, etc

However, being in an awkward mood, I deliberately left it open to doubt as to whether I was quoting the names of the SI units, or the eponymous people! ;-)
(I think "Volta" should be the giveaway there...)

Of course, the mho never was an SI unit.