Recently added heated bed to my RepRap I2. Generally works well but frequently the bed shuts down prior to reaching the set temperature. If it reaches the set temp it will maintain temperature throughout the print. Noticed today that F2 was quite hot (could not hold finger on surface) just as the bed heater shut down. It seems that F2 is overheating as the bed is heating up. There is good voltage to the heater (12.75vdc) as it is heating. Any suggestions? Thx, Dennis. https://reprap.org/forum/read.php?1,674680,674680#msg-674680 Thu, 08 Oct 2026 22:19:43 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,674680,682383#msg-682383 https://reprap.org/forum/read.php?1,674680,682383#msg-682383 Dennis Mc General Tue, 28 Jun 2016 19:00:39 -0400 https://reprap.org/forum/read.php?1,674680,675464#msg-675464 https://reprap.org/forum/read.php?1,674680,675464#msg-675464
I hooked up an ammeter which indicated that the bed is drawing ~9 amps @ 12.75 vdc. Probably as you suggested, the poly fuse is just tripping early. Think I'll try a small in-line resistance. 0.1 ohm should drop the current by 0.5 amp. Maybe just enough to prevent the fuse from tripping.

Dennis.]]> Dennis Mc General Fri, 17 Jun 2016 11:40:54 -0400 https://reprap.org/forum/read.php?1,674680,674872#msg-674872 https://reprap.org/forum/read.php?1,674680,674872#msg-674872
Its rated at 11amp at 12v, are you drawing more than that? If so you need to replace with an appropriate fuse
NB it is voltage dependent, 16v max on most of them.
If your drawing less than 11amp the fuse is probably damaged and needed replaced]]> Dust General Thu, 16 Jun 2016 00:15:31 -0400 https://reprap.org/forum/read.php?1,674680,674695#msg-674695 https://reprap.org/forum/read.php?1,674680,674695#msg-674695 stephenrc General Wed, 15 Jun 2016 13:04:16 -0400 https://reprap.org/forum/read.php?1,674680,674680#msg-674680 https://reprap.org/forum/read.php?1,674680,674680#msg-674680
Any suggestions?

Thx, Dennis.]]> Dennis Mc General Wed, 15 Jun 2016 12:29:39 -0400