MK2A Heated Bed causes board to crash
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@bearer said in MK2A Heated Bed causes board to crash:
https://reprap.org/wiki/PCB_Heatbed site suggest 1.7 is for 12v beds, but they also say the size of the MK2A is smaller there. anyways it also has pictures showing how the dual voltage beds have different connections for 12 an 24v. might be helpful
I just double checked resistance, it reads 1.6Ohms.
I will review the specs on the page you shared. When I talked to the seller they said that this bed gets wired the same regardless of 12V or 24V. I will also contact them again and let them know the resistance I am getting and see if they feel that I have a defective bed or not.
Here is a picture for their website of the board I have for reference.
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@bdelia at 1.7Ohm it would draw just over 14A of current!
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that is defiantly not a dual voltage bed.
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@bdelia According to reprap wiki - MK2b Dual power is what you expected. MK2a seems to be be a single power heatbed (and probably 12V). And in general dual power heatbed has 3 solder pads.
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however something is still wrong here.
a 600W meanwell power supply should be able to handle that.
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Perhaps the wire is too thin, and passing 14A+ (14A is bed alone) causes significant voltage drop.
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yes. you would need a 2mm^2 wire for that.
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@Veti said in MK2A Heated Bed causes board to crash:
2mm^2
I am using 14Gauge wire from my external Mosfet to the Bed.
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If you set your multimeter to read resistance and then short the two probes together, what reading do you get? You need to subtract that reading from the 1.6 ohms that you measured.
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@dc42 said in MK2A Heated Bed causes board to crash:
If you set your multimeter to read resistance and then short the two probes together, what reading do you get? You need to subtract that reading from the 1.6 ohms that you measured.
When I read resistance by shorting the MultiMeter leads it reads .2 Ohms. So, if I understand you then that would mean my bed resistance, if measured at 1.6 is really 1.4 Ohms?
If the above is accurate then it seems the bed is on the fringe of 24V compatible? Does that sound correct?
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Does your board have 2 solder pads or 3? The photo is a bit blurry.
@bdelia said in MK2A Heated Bed causes board to crash:
If the above is accurate then it seems the bed is on the fringe of 24V compatible? Does that sound correct?
No. 1.4ohms would still indicate 12v. I think you're hoping pretty hard that this is just going to somehow work. I think your seller is clueless and is leading you astray. There's no way I would connect 24v power to that heatbed and leave it unattended in my own house.
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@Phaedrux said in MK2A Heated Bed causes board to crash:
Does your board have 2 solder pads or 3? The photo is a bit blurry.
@bdelia said in MK2A Heated Bed causes board to crash:
If the above is accurate then it seems the bed is on the fringe of 24V compatible? Does that sound correct?
No. 1.4ohms would still indicate 12v. I think you're hoping pretty hard that this is just going to somehow work. I think your seller is clueless and is leading you astray. There's no way I would connect 24v power to that heat bed and leave it unattended in my own house.
Thanks for your thoughts. I have sent an email to my supplier for the bed and am waiting for a response. Worst case I am out about $50 for the bed and will have to source another one.
Does anyone here have a recommendation for a 24V 300x300 heated bed? I would prefer to source in the USA if possible for shipping timeliness.
Thanks
Brett -
https://www.filastruder.com/products/e3d-varipower-heated-bed-pack?_pos=1&_sid=80bc0b874&_ss=r
Not sure if that suits your bed shape though.
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Do you have a link to the item you've purchased?
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e3d makes 300x300 beds
https://e3d-online.com/collections/printer-parts-electrical/products/high-temperature-heated-bedsbut they are ac beds.
their variopower bed 24v is only available in 300x200
https://e3d-online.com/collections/printer-parts-electrical/products/varipower-bedyou could try and source a voron 2 buildplate with a Keenovo heat pad
https://store.digmach.com/collections/voron-parts/products/build-plate-for-voron-2-3d-printer?variant=31774400675885 (us store but sold out, you could ask on the voron discord for other suppliers)
the matching kenoovo heater is avaiable in 24v (though voron guide says go with ac version at nearly twice the power)
https://keenovo.store/collections/standard-keenovo-silicone-heaters/products/keenovo-square-silicone-heater-3d-printer-build-plate-heatbed-heating-pad?variant=8324020895799but to be honest if you are going for a 300x300 bed, you are in the territory of ac beds.
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You could get a nice cast aluminum bed and put a 24v silicone heater on it. 713maker.com has some nice stuff. This is a 300x300 bed https://713maker.com/ft-5/ft-5-heated-bed
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@Phaedrux said in MK2A Heated Bed causes board to crash:
Do you have a link to the item you've purchased?
Here is a link to what I purchased:
http://www.zyltech.com/zyltech-3mm-aluminum-heated-heat-bed-3-sizes-available/If you look at the description I purchased the one labeled as 300 x 300 MK2A Heated Bed.
300 x 300mm MK2A Heated BedOutside dimension: 330x330 mm
Usable size: 300x300mm
Resistance: 1.05-1.3 ohm
Voltage: 12-24 V (recommend 24V for better performance)
Pre-wired with thermistor and power cable -
Thanks. That helps.
In that case your measurement of 1.4 ohms is closer to the 1.3 ohms they specify.
Still not clear how it's capable of 12 or 24 without different wiring, but at least Zyltech is a recognizable brand and not just some ebay seller or something.
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Still not clear how it's capable of 12 or 24 without different wiring, but at least Zyltech is a recognizable brand and not just some ebay seller or something.
From the specs it is effectively a powerful 24V bed, at 24V it is nominal 0.52W/cm^2 which is a little over the recommended 0.4 and at 12v it is at 0.13W/cm^2 which is borderline useless imho - so calling it dual voltage is BS.
At 24W and 1R05 to1R3 it's 550W to 450W and 23-18A, but OP is using a external mosfet so that should be fine, leaving voltage drop due to thin wiring or power supply over current protection kicking in (prematurely).
