• 2012 Dodge Grand Caravan w/ ~150K miles
  
• Symptoms (started around 2 years ago):
  • Intermittent battery warning light with "ding" alarm.
    
  • About half the time the the battery warning lights up, car accessories (e.g. radio head unit) will reset and other dash warning lights will temporarily appear.
    
  • Less frequently, climate control will stop for ~30 seconds while everything resets.
    
• No loss of power for driving. Accessories generally work fine.
  
• I replaced the battery around 9 months ago, which didn't resolve the issue.
  
• Year ago, I installed a cheap Android head unit off Amazon to replace the faulty OEM radio, so I suspected that this head unit had gone bad and was drawing too much power, causing the warnings. But when I tested this by disconnecting the head unit, I still experienced the intermittent battery warning.
  

Normally if a battery issue continued after a battery replacement, I would suspect a faulty alternator. But if the alternator were bad, wouldn't the battery have died by now? And wouldn't I experience other power/accessory loss? This makes me suspect something weird like a bad relay or even computer chip somewhere.

I'm selling the vehicle soon, so just wondering if it's worth it to fix this, or just sell it as is. These Caravans are super roomy with the stow-n-go seats folding into the floor, making them great beater work vans for tradesmen, who might not care about the intermittent dash warnings...