question

It is true. Although it's not so much the Watts that are limited, but the battery Amps. You'll be limited to 35A and the charge controller will not go any higher. The Wattage depends upon the battery Voltage. The higher the Voltage, the more Watts, that's Ohms law.
A 48V battery system will yield about 2KW with a 150/35 MPPT.

The way to kill the controller quickly is to go over the 150V limit, keep a good margin below this to stay safe.

WK's advice is good. There's one other thing to consider too, panel short circuit current, usually on the panel label as Isc. Your 150/35 is rated 40A, so for typical 'household' panels a max of 3x (maybe 4x) of paralleled panel strings.

So it's quite possible to go (say) 3000W of panel into that mppt if the panel specs 'fit', and that applies to 12V > 48V output. Many people head this way for poor weather performance.

But take care, match your panels and do your sums..

there is two ways to kill a charge controller: voltage and current above the specifications.. i have constructed my PWM with a adjustable current limit just because i was unable to find this feature on the market and where i live, a sunny day may happen once a week and half solar panel performance is my average.. so my pwm diy project have constant current and constant voltage like a lab power supply (both adjustables).. that avoid to over current my battery pack when the sun is there.. a trick i was tried years ago is to use a dc-dc buck converter from the solar panels to the battery (more efficient than pwm but not programmable) and that work well..

don’t know why this kind of feature (current limit) is not on the market with controller.. or if exist, hard to find it.. because if the controller can read the current, he can to limit it (with pwm, it’s software by reducing the duty cycle.. with mppt, i would like to see a schematic before to tell)..