I'm planning to use a CC/CV buck converter to float charge 12V SLA battery. The issue is that pretty much all buck converters I was able to find on Aliexpress and ebay have the shunt for current sensing between the input and output ground. So technically non-isolated regulators don't share the same exact ground, but through a shunt.
If the load needs to draw something way higher (5-10A) than the buck module is designed for (~500mA max CC for charging the battery) the shunt causes large voltage drop if the external load's current passes through it.
However if I connect everything to the main circuit ground (before the buck, and thus before the shunt) the buck converter doesn't see what current is being drawn and will damage the battery, because there's no current regulation.
I would like to avoid complex battery charging circuits and I'm not able to isolate the battery completely, because I want the load to be able to be powered from Vcc (the same +12V input for the circuit and the buck converter), so the ground will need to be the same for the whole circuit.
What are my options in this case and is this the correct approach?
Buck converters, most of which I've got: