Inject dc into output side of laptop power supply?

[Kibayamaker]

I have a HP omen laptop that operates on a 200w 19.5v power supply. I am currently lucky enough to live a nomadic life in a solar powered travel trailer and try to run all my devices on DC rather than use my inverter.

I have been unable to find a commercially made DC-DC power supply for the laptop so I have therefore tried to create my own. It was not difficult to set up a separate DC-DC power supply to output 19.5v at the required amperage, but because the laptop uses a third communication wire to identify the psu, it will not charge.

Please correct me if I am wrong, but it appears it would be difficult to trick the sensing wire into thinking my homemade power supply was a good fit for the laptop.

I am therefore thinking of wiring my diy 19.5v power supply in parallel to the output of the original power supply with the sensing wire still connected. In this configuration, I would NOT plug in the AC side off the original psu.

I am hoping that, if the DC side of the original power supply receives power injected from the output, it will power up the sensing wire tricking my laptop to using my DC-DC power supply.

Could this experiment end up ruining my original AC adapter?

Is there a chance it could work?

Anyone have any better solutions?

It is frustrating because the laptop clearly does not need 200w to charge but yet won’t charge unless it has the oversized PSU which is only necessary when the GPU works hard. I would be satisfied if I could just charge it via DC-DC then need to resort to AC and my inverter off I need full power.

Thanks in advance for any thoughts.

 

[kellys_eye]

Unless you can determine what the actual 'id' signal is then we can't make a proper determination.

That said, using the OEM charger shouldn't pose an issue as it's a very efficient device in its own right - potentially as good as, if not better than, the DC-DC converter you're trying to replace it with. The OEM charger will only 'use' whatever wattage the load desires so isn't going to use 200W 'all the time'.

 

[Bluejets]

because the laptop uses a third communication wire to identify the psu, it will not charge.

Looked up power adaptors for the type you quote and they all came back with standard run-of-the-mill dc plug.
Maybe you need to post more detail, perhaps a photo or two.

 

[Delta Prime]

Or three or four photos. I believe you have way too many solar powered bugs in your system!