Hello landau...
I take it, based on your question, that you don't yet understand how to use Ohm's Law calculation to determine, among other things, the fundamental, linear relationship between resistance and amperage.
For both your safety, and to obtain maximum performance from your equipment... this is just one of many things you'll be best served by learning. Click on my second sig line hyperlink, read the article, and all linked articles within... twice.
Most APVs have a stated lower resistance limit based on amperage (current) and wattage output... and some will have manufacturer set limit a bit higher than what amperage and wattage outputs might otherwise indicate. If you read the specifications for your
devices, they typically list those values.
For example... if you run the numbers for an MVP2
through an on-line
Ohm's Law calculator... the lower resistance limit of 1.3Ω+/- matches nicely with the 11watt/3 amp output. Running a resistance lower than the stated current output potential is of no benefit.
Some makers set resistance limits, strangely... higher than the devices output potential. Perhaps they feel it to be an extra margin of safety... or perhaps they're not keeping up with current trends.
Cheers