I need help to build something that can reduce my battery pack voltage by 1v without overheating.

The battery pack is 4s which is 16.6v but my inverter can only work with 10.4-15.2v.

I've used 2 silicone diods connected in series to reduce the 1v but the diods usually heat up too much that it'll burns up anything I attach them to so, I need a solution.

I consider doing 3s packs as a poor option bcoz then one has only 2 voltage range (10.4-12.3)

Thanks for your inputs.
Pls note: try to be as non technical as possible so I can understand as I have no prior experience with electronics and engineering terms/diagrams.

 

I've used 2 silicone diods connected in series to reduce the 1v but the diods usually heat up too much that it'll burns up anything I attach them to so, I need a solution.

Any method that reduces the voltage (diodes, resistor, linear regulator, etc.) will generate V(drop) * I(load) heat.

An ultra-low-dropout linear regulator may work for that.
It would regulate the voltage at 15V, but then would closely follow the battery voltage as it drops below 15V to minimize power dissipation.

How much is the current draw?

 

Hav you measured your battery pack voltage at the full load?? It probably drops a bit, almost all battery pack voltages drop under the load.
I am saying to measure the battery pack voltage at the battery pack terminals. OR have you already done that??