Why won't tablet charge directly from 12v supply via fuse block?

[QPiepelr65]

Well that leaves over voltage detection on the device as the no1 culprit.
So looks like the solution is a step down as @Dellmassive suggested or an inverter or a new device.

This was it!! I used the device linked in the last post and now working like a charm! Thanks for the hint.

Now, the other dc device I want to charge from battery is my phone. The wall plug says 4.75w and 0.55a. The converter has 5a and didn't see a lower amperage one available. After doing a little research the higher amps don't matter is that right? From what I read the appliance will only draw what is required so higher adapter amperage is not an issue due to ohms law. Just want to double check that is right in which case I will buy another of these converters and wire it up in the same way as I did for the tablet with the voltage set to that of the phone's wall charger.