I don't find the 12v battery in the Clarity to be any different than any other 12v battery in any car I've owned. Sometimes they do give you a bit of warning with slow cranking, but since the 12v battery in the Clarity doesn't need to engage a starter motor, you might not get any warning. I put a 12v lithium jump pack in the trunk for road trips in case I need it. So far, 2 years on the OEM battery with no issues... although I will put it on a Battery Tender if it will be idle for more than a week. I only have 10K miles on my 2018 Clarity and it does sit in the garage for extended periods.
Off topic: Just ordered this one from Amazon for $50 before tax. Use the 20% coupon + LKSHADL3 code for extra 18% off https://www.amazon.com/gp/product/B07H58NP77