Using Four 1.2 Ohm 5W Resistors in Parallel for 0.3 Ohm: Power & Temperature Issues in Circuit

Hello!
I have a rather unusual problem with resistors. I used four 1.2ohm 5W resistors in parallel to obtain the 0.3ohm resistance needed to limit the charging current of the batteries. The problem is only in the power that is exerted on them. 4.5A current flows through the entire set and a 1.35V voltage is deposited on them. Mathematically, they have a power of ~ 6W, which should not be a problem for four 5W resistors. In practice, however, after less than two minutes, the resistors reach over 70 ° C and "feel them on your nose".
The circuit is a transformer with a rectifier bridge and a capacitor, and a set of batteries is connected to this via a W / W resistor.
Why in this system the power across the resistors does not correspond to the relationship V * A = W? (Or recently the math has changed. )
Regards, Michał.

The heat should be constantly dissipated by, for example: [Radiator], in this case there is no outlet and it accumulates powerfully.

Resistors hang loosely on the wires at a distance of 2 cm from each other and 5 cm from the wall under the board where they are connected. They are quite in the "fresh air".

Attach them to a heat sink or a piece of aluminum.

Hello,

Przjaciel wrote:

Why in this system the power across the resistors does not correspond to the relationship V * A = W? (Or the math has changed recently.)

everything is fine, but you are making a certain error of reasoning.
In the documentation, throw a 5 W resistor on the graph titled "power derating curve", you can estimate from it that the thermal resistance of such a resistor is in the order of 40 C / W, in your case there is about 1.5 W per resistor, which gives the temperature difference on the order of 60 C, plus the ambient temperature - the resistor can actually heat up to about 70 - 80 degrees.

best regards

Przjaciel wrote:

after less than two minutes the resistors reach over 70 ° C and "feel them on your nose"

And who said it shouldn't be like this? The temperature depends on the rate of heat dissipation. If it is enough, the resistors will be safe, and the temperature will stabilize, each of them gives off just over 1W. By the way

Przjaciel wrote:

The circuit is a transformer with a rectifier bridge and a capacitor

If you charge car batteries with this charger, this capacitor is not needed for anything, just throw it out and the resistors will be colder.

Yes, it works like a rectifier connected to an emergency power supply (when the gel battery pack is exhausted, it charges them while maintaining the continuity of the system's operation). Such an addition to a solar installation.
When it comes to the resistors themselves, I always thought that they were large enough to easily cut 3-4W, so such a high temperature at low power surprised me.
He'll mount them on a piece of aluminum sheet or an old heat sink, and it should be fine.
Thanks to everyone for your help.