The DN2820 should run on 12v, but may be detecting less than 12v. Have you measured the output to verify you're getting a full 12v, not more or less? Years ago I tried a NUC in my old Chevy Blazer and it wouldn't work with a direct connection. When I checked the power output and it was something like 11.5v. I ended up connecting the NUC to a power socket power inverter and that worked, but it meant having a couple extra boxes. I don't recall seeing the message you're getting. In my case (different NUC model) it just didn't power up.
Your best bet is to get a DC-DC power converter that will generate a clean 12V or (better) 19V output.
Hope this helps.
Hi Jason, i have a stable 12v dc supply from 3 x 100AH batteries that are charged from either solar, a built in battery charger or from the MH when driving. I have never seen the batteries drop below 12.3v and for the main they are above 12.5v.
I don't know if the connector on the AC power pack is different from the 12v dc lead I purchased (though it fits the socket) and this is what it picks up when I get the message to only use the genuine adaptor.
Thanks for your reply and would appreciate any additional thoughts.
Thanks for the reply. I am supplying better than 12v, usually better than 12.5v. Would have thought 19v would be to high and have considered maybe the 12.5v is also too high and as you suggested need something to regulate it to a stable 12v.
Sorry, I was answering from my car yesterday and didn't have access to my reference database. This is the DC-DC Buck Converter that I was talking about, designed specifically for NUCs: Mini-Box.com: DCDC-NUC, 6-48V automotive power supply for NUC, 12V or 19V output.
Hope this helps,