2013 Plug-in 12V Battery Dead when not driven everyday

I have checked the DC-DC Converter and it is outputting 14.3V when the Ready light is on. If the car isn't driven for a few days the battery is drawn down to about 5V. The battery is brand new about 3 weeks ago and I have recharged it with an AGM charger when this happens. According to my DC Clamp meter on the negative cable, the car is completely off, there is about a 2amp draw on the battery. I have pulled the cable from the fuse box for the DC-DC converter and it drops to about 0.4amps. Plugg it back in and it goes right back up. This is with a fully charged battery. Both by an external battery charger and the DC-DC converter with the engine running and monitoring the current draw of about 0.6amps. I need to fix this as the car is driven to work during the week. Is the DC-DC converter a part of the inverter? Can it be replaced by it's self?

TIA for all comments and help.

 

No trouble lights. It is normal in all regards except something is drawing about 1.5amps via the DC-DC converter. If you unplug the converter line in the fuse box, it stops of course. I don't know if it is actually a problem with the converter or something else that is connected to the converter, which I guess could be anything that runs on 12v.
I also checked for any ODBII codes and there are none.
A little more information for the forum members. I do not know if this is a normal condition, but there is a 1.5amp draw on the 12V battery sitting still in the garage. Since this is a plug-in, I plug it into my charger and checked the battery voltage and amperage draw. Unplugged it was 12.66V and 1.5amps. Plugged init was 13.4V and 4.8amps. So the 12V battery does in fact get charged when the traction battery is being charged. However, once the traction battery is charged I will have to see if it still keeps the 12V battery charged and offsets the 1.5V draw. I will update this post with that information.

 

Thanks and that will be my next step once I determine what happens to the 12V battery after the Traction battery is fully charged.

When the traction battery is fully charged and the current flow stops from the wall-mounted external charger, so does the current flow to the 12V battery.

So next task is to monitor the current flow from the 12V battery (1.5amps) and pull fuses from the box under the hood. We will see if that has any effect.

 

Thank you for your input. That is a very good point about the "sleep" states. I went and checked this morning without the FOB in my pocket and the reading was the same, 1.5amps. The battery was still at 12.67V, so it didn't discharge too much overnight.

 

You may very well be correct. I don't have a meter ,at the moment, that will check DC amperage. Hence the use of my Fluke clamp on. It has been very consistent with the measurements I have taken, but I may need to look at finding a good DC amperage meter.

Thank you.