apologies for the newbie talk but I have finally purchased a couple of these digital amps after hearing about them a couple years back. Set one up (sure 500w) with my wharfedale titan 18inch speaker and it all works nicely. What has amazed me is the power consumption, or rather how low it is! I assumed 500w amp and speaker I would be generally using more than the max 15w/1amp  that my Watt meter is showing!! And 20w was with it pumped right up! Is this normal? You could build a massive rig which would run for weeks right!? on the 500AH battery I've put in my campervan! I'm amazed.. or is my watt meter broken!?

Ahh that makes sense! are there any cheap watt meters that can keep up?? I use an RC meter that I use on my electric bikes..

The first one I have tested sucessfully but the second one irs2092 I cannot find the manual on the website and I am not sure of the connections.. the board is very different from the other one..

Secondly, what supply voltage are you running the amp from? 38.7v RMS is 54.7 volts peak to peak, meaning the supply would need to be at least 55 volts to get that much power. If you are running at 24 or 36 volts, then your maximum power into 8 ohms will be about 32 or 76 watts respectively. Plus, as people have already pointed out, most power meters average over several seconds so will not register peaks.

So, in conclusion, if you up the voltage and lower the impedance, you'll be drawing much more power, and making much more sound.

By the way, the 500 watt IRS2092 board requires a split-rail supply, not single-rail like the T-AMP board. So that means +60v, ground, and -60V. You can achieve this with a set of several batteries, but it would always need at least 2 to function. You *might* be able to power it from a pair of the Sure 500 watt boost converters and a single battery, but I'm not sure how they would react to being wired in a split-rail configuration.