40W Cartridge Heater Compatibility with Viotek PSU

[3DR]

I'm going to do the hotend upgrade shown here:- http://www.youtube.com/watch?v=xvXKt3xDt4E as part of my v2 build but I'm concerned if the stock Viotek PSU has enough juice to cope with the current draw? The 2 stock resistors are reading 7.6 ohms a piece so we'll be jumping from a total hotend power draw of 9.4W to 40W, having read some other threads mentioning possible problems with the Viotek being man enough for the job I'm wondering if its worth starting out with a better PSU too. Any recommendations for a better PSU? Thanks!

[Eric]

I'm going to do the hotend upgrade shown here:- http://www.youtube.com/watch?v=xvXKt3xDt4E as part of my v2 build but I'm concerned if the stock Viotek PSU has enough juice to cope with the current draw? The 2 stock resistors are reading 7.6 ohms a piece so we'll be jumping from a total hotend power draw of 9.4W to 40W, having read some other threads mentioning possible problems with the Viotek being man enough for the job I'm wondering if its worth starting out with a better PSU too. Any recommendations for a better PSU? Thanks!

I think you made a math mistake. The stock resistors may be 7.6 Ohms each, but you use two of them wired in parallel, which means you end up with a 3.8 Ohm heater load. At 12V that'll give you a current draw of 3.16 Amps. Or a power draw of about 38 Watts. A 40W cartridge heater isn't going to be a problem. But you do have the option of buying a 30W one instead and it would work...just take a little longer to heat up.

[3DR]

Arh thanks, I didn't realise they were wired in parallel, I'll go with the 40W.

[Eaglezsoar]

A heater cartridge of 40 watt should have a resistance of approximately 3.3 ohms.