Orion Tr 12/12/30 (not smart!) blinking green

Hi all,
Until this morning, my booster was working fine. Now, I only get a green rapid blinking light on the Orion. The manual for the non-smart version is very, very short and does not mention any Led at all. Does anyone know what it means?
This morning, I was using the Orion to load the battery having my van in idle for 20 or so minutes (there was a thunderstorm so I could not drive), may it be the main battery has a bit too low of voltage?
Thank you for any pointers, I really need this to work for… work Hehe.

The non-smart Orion is NOT designed as battery charger!

Well, I found out about that after some research, but the guy who built our van thought it would be a good idea… So maybe I will replace it soon, but for now I have to deal with it. The older manuals mention it as suited for battery loading so it somehow should be OK I guess…