BigTreeTech Can Bus with Voron Revo

[pfm]

I'm doing the Can Bus mod on my Trident. BigTreeTech has a kit specifically designed for Stealthburner. It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end. The thermistor wires are insulated with a cloth insulation which is far too fat to go into the jacket portion of the tiny JST terminal crimp end. A simple solution it to solder some pre-crimped leads onto the ends of the thermistor wires. BigTreeTech includes a set of pre crimped leads in the kit. They are not marked and the BTT manual does not mention them, but presumable, these are leads that can be soldered to wires ends rather than crimping the JST terminals on. As far as I can tell, theses leads are 26AWG (and they are solid wires). I'm having trouble determining the size of the leads on the Revo thermistor (and E3D does not specify). But, I'm thinking they might be 24 AWG stranded. Here's my question -- does anyone know what ampacity I need for the Revo thermistor? Or maybe a better way to say it is, how much current is flowing through the thermistor wires at my over-temp threshold (300C). If I solder the leads provided by BTT in the kit onto the Revo Thermistor wires, Is 26AWG sufficient to carry the current?

 

[pfm]

I'm doing the Can Bus mod on my Trident. BigTreeTech has a kit specifically designed for Stealthburner. It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end. The thermistor wires are insulated with a cloth insulation which is far too fat to go into the jacket portion of the tiny JST terminal crimp end. A simple solution it to solder some pre-crimped leads onto the ends of the thermistor wires. BigTreeTech includes a set of pre crimped leads in the kit. They are not marked and the BTT manual does not mention them, but presumable, these are leads that can be soldered to wires ends rather than crimping the JST terminals on. As far as I can tell, theses leads are 26AWG (and they are solid wires). I'm having trouble determining the size of the leads on the Revo thermistor (and E3D does not specify). But, I'm thinking they might be 24 AWG stranded. Here's my question -- does anyone know what ampacity I need for the Revo thermistor? Or maybe a better way to say it is, how much current is flowing through the thermistor wires at my over-temp threshold (300C). If I solder the leads provided by BTT in the kit onto the Revo Thermistor wires, Is 26AWG sufficient to carry the current?

Here's a bit more info. The Revo uses the Semitec 104NT-4-R025H42G Thermistor. According to Semitec, the resistance at 300C is 8.28 Ohms. So at 24V, that's 2.9 Amps. The max current for 26AWG wire is 2.2 Amps continuous. So it's no go. At 280C the resistance is 11 Ohms drawing 2.18 Amps. So, I could limit my hotend to 275-280C. 24AWG is rated for 3.5Amps --that's a much more comfortable number. Having said all of this -- I'm still a bit unsure what size these jumpers are. Note to BTT -- LABEL YOUR PARTS. Its super frustrating to get mystery parts in a bag. I'll try sending BTT an email and see if they respond.

 

[Sanity Agathion]

Hi, thermistor wires you can either try to do this like on image below https://docs.vorondesign.com/build/electrical/#microfit-pins or just solder JST-GH pigtail provided by BTT. It will work for this distance, additional solder joint and thinner wire on those few cm should not cause very different readings to not be usable. I do not think we are feeding full >2A through thermistor wire.

And yes, BTT had been screamed at for using these shitty connectors rated for AWG 26 wire

 

[drpeej]

Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter

 

[pfm]

Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter

I can't comment on the Mellow, but the BTT SB2240 definitely supports the Revo thermistor. It's a different connector from the PT100 connector.

 

[Sanity Agathion]

Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter

Hi, you probably mean E3D Revo hotend, not extruder? This one https://e3d-online.com/products/revo-voron ? What toolhead do you use? Standard Stealthburner?
Revo hotend has thermistor built into the ceramic heater. You cannot change it for PT1000 or any other. Standard thermistor with Revo is 104NT-4-R025H42G so if you have it defined in printer.cfg as Beta3950 that's wrong and you should correct it.

You will have to take a look whether the board you buy has MAX31865 chip if you want to use PT100. PT1000, 104NT and NTC100k will work without it. Word of advice: if you do not enjoy crimping super-super tiny JST-GH terminals, do not buy those boards from BTT.

 

[ZeroBrain]

Any Revo problems if using the EBB36?

 

[Sanity Agathion]

Any Revo problems if using the EBB36?

No, not really.

 

[Sandman50]

It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end.

Not your question, but these are the connectors. Pre-terminated for 100% simpler assembly:

Amazon.com

JST PicoBlade 1.25mm

BTT also has a new version with PH2.0 connectors.