Watt/Ampere for heatbed

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robvoi
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Joined: Wed Apr 13, 2016 2:12 pm

Watt/Ampere for heatbed

Post by robvoi » Thu Nov 24, 2016 3:43 pm

Hi,

how many Watt/Ampere can I draw for my heated bed when running the GT2560 with 12V?

Thanks
Robert

russellz
Posts: 20
Joined: Thu Nov 03, 2016 5:06 am
Location: France

Re: Watt/Ampere for heatbed

Post by russellz » Fri Nov 25, 2016 9:26 pm

The heatbed measures 3.7 ohm so at 12 V it will draw 12/3.7 = 3.24 A (less a bit for the voltage dropped by the mosfet). So about 3.2 x 12 = 38 W.

Russell.

robvoi
Posts: 23
Joined: Wed Apr 13, 2016 2:12 pm

Re: Watt/Ampere for heatbed

Post by robvoi » Fri Nov 25, 2016 9:34 pm

Hi Rüssel,

thank you for your reply. I would like to know what the max is which I am allowed to draw from this board/port.

Robert

russellz
Posts: 20
Joined: Thu Nov 03, 2016 5:06 am
Location: France

Re: Watt/Ampere for heatbed

Post by russellz » Sat Nov 26, 2016 4:18 am

Have a look at the user manual here https://www.geeetech.com/Documents/User ... GT2560.pdf. It seems to suggest 12 A is the maximum.
However I wouldn't want to go any higher than the current draw of the standard heatbed without extra heatsinking. The heatsink on the output mosfet gets pretty hot as it is. Higher current will make it run hotter and increase the likelihood of failure. I would also be unsure of the rating of the connectors on the board but then I'm cautious.

Russell.

robvoi
Posts: 23
Joined: Wed Apr 13, 2016 2:12 pm

Re: Watt/Ampere for heatbed

Post by robvoi » Sat Nov 26, 2016 4:48 am

Thank you for the advise.

russellz
Posts: 20
Joined: Thu Nov 03, 2016 5:06 am
Location: France

Re: Watt/Ampere for heatbed

Post by russellz » Wed Nov 30, 2016 5:28 pm

Apologies, 3.7 ohm is for the extruder. The heatbed is 1.2 ohms so 10 A and 120 W. I have placed insulation under the bed and I put an insulated blanket on top while pre-heating to speed things up.

Russell.

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