Upgraded BIQU B1 hot end to a BIQU H2 500c and this is making me CRAZY!

Well… I have had a perfectly functioning stock BIQU B1 for the past year and a half and had a great time printing all kinds of things, pre-made designs and designs of my own.

I have only been printing PLA this whole time and recently wanted to get into TPU, PTEG and possibly ABS and such.

Since I was looking at changing to a direct drive extruder, I figured I might as well get something that can handle the hotter temps, so I got the BIQU H2 500c.

Well, the documentation that came with it is mostly useless and it is printed on a post card.

I managed to get the hardware all arranged reusing the original cooling fans and got it all wired the way it needs to be, the one hardware problem is with the X axis endstop which I am still sorting out.

But the bigger, MUCH bigger problem is within the software, MARLIN to be precise. It just seems absolutely insane that a company, such as Bigtreetech, can produce a commercial 3D printer and an upgrade component such as the H2 500c that is supposed to be a direct fit for that printer, and yet provide absolutely no updated firmware. Not only that but they expect you to be able to understand their convoluted half baked directions to edit and compile your own update.

So… I have effectively bought and installed a device that has disabled my printer.

I thought, surely there must be plenty of people that have purchased an H2 500c for their BIQU B1 and that I would be able to get this thing going…

I feel like I am losing my sanity. Spending hours trying to find the correct settings only to find SOME, then, trying to find where in MARLIN to change those settings…

I have downloaded Bigtreetech’s version of MARLIN for the BIQU B1 which is old and is not even compatible with my motherboard without making changes ( I have the 1.4 Non Turbo).

I made the mandatory changes for my board, but I can’t find all of the referenced changes for the new hotend in MARLIN that are in the crappy postcard that came with the hot end…

I sure hope someone here can help. :face_exhaling:

What I am really hoping is that someone here has already gone through this and could just get me a copy MARLIN that works with this setup.



I was able to find some info online that should help you out. I have liked a couple of videos below that show the process of installing it and changing the settings. It seems as though you will not need to change any firmware to use it, you will simply have to set your esteps to 932 and change the motor current to 0.8A (Although I would only try this one if you run into problems)

Hopefully this is helpful!

Yes, I have watched those videos multiple times, I think the issue is that the one I have is the H2 500c and it comes with a MAX31865 V2.0 driver, and to be able to use it at the higher temps I’m sure the default MARLIN will not suffice. I can change the esteps without any problem.
This is the crazy “manual” that was included.

HI @ilistr8er

Your base firmware for the 1.4 non turbo is here

So here are a couple of things I have found within Marlin. If you are using an upgraded thermistor you can modify the default Marlin firmware using this variable

All these options can be found in the Configuration.h.

// If you have a hotend and thermistor capable of over 290C you can set the max temp value below.
// Setting this higher than 290C on a stock or traditional thermistor will damage it. Refer to your thermistor documentation to see what max temp is.

If you are using the factory thermistor and just want to update its max threshold using the following variable

// Above this temperature the heater will be switched off.
// This can protect components from overheating, but NOT from shorts and failures.
// (Use MINTEMP for thermistor short/failure protection.)
#define HEATER_0_MAXTEMP 275
#define HEATER_1_MAXTEMP 275
#define HEATER_2_MAXTEMP 275
#define HEATER_3_MAXTEMP 275
#define HEATER_4_MAXTEMP 275
#define HEATER_5_MAXTEMP 275
#define HEATER_6_MAXTEMP 275
#define HEATER_7_MAXTEMP 275
#define BED_MAXTEMP 120

I know building firmware is a bit daunting just don;t cripple any of the safety features and compile after every change. If you make multiple changes and try to compile and it fails it may be difficult to undo what the error is.

Let me know if this helps.

Did a little more digging, The base Configuration.h and adv.h files are located in the base marlin config under examples.

Within those files, you will have all the pinouts and configs in place already for the factory printer.
replace the files in this examples directory with the basic ones in the marlin folder and that will put you in the right path.

I sure thank you for the help, I will look into this as soon as I get home. What do you make of all of those other changes that the list in their “instructions” for that hotend?

if it was me, Setup VScode and get a build started with the specific config I posted above. Once this is functional (you can home the printer and all of that) then move onto the head-specific items.

You should be ok from that point. The hardest part is making it compile error-free the first time.

Yeah, I understand what you’re saying about just getting it going and then try to adjust from there. I have spent the last few days trying to make those changes in the instructions only to be hit with a ton of errors so I will try what you are suggesting. Thank you so very much for restoring my hope… and sanity :crazy_face:

All is good, TBH, Been there before with certain printers. new day, deep breath and it reduces your willingness to throw it into traffic on a busy highway.

Boy aint that the truth.

I am still soooo frustrated. I think I have had it with this… I just want to print, I don’t want to learn the programing a printing system.

I have never seen VSC before a few days ago, I don’t have the patients to try and learn how to use it so that I can figure out how to edit the files to try and compile something that I then will have to troubleshoot.

When I purchased this BIQU H2 500c extruder, it was because it was advertised as a direct fit for this printer. When in reality what has happened is it cost me $100.00 to disable a perfectly functioning printer.

Like I said in my original post… I was hoping someone could just provide me with the firmware update so I could just go back to printing, this is really removing the joy for me.

In case you can’t tell all of my attempts to follow your suggestions not fruitful. Starting with the fact that I could not find "#define HIGH_TEMP_THERMISTOR_TEMP 285 " anywhere, then those Configuration.h and adv.h files files were no longer supplied within those versions of MARLIN, there instead was a link to download them, which I did.

While trying to import them I kept noticing VSC was saying that Configuration.h has 51 problems and adv.h has 66 problems… so… I deleted all of them and downloaded them all again and VSC still reports the same thing and I still don’t understand what I am supposed to do with all of it.

This is just one frustration, the whole VSC problem thing, that may be normal, I don’t know, but all these little details that I know nothin about makes me hate even wasting my time on it knowing it is not going to work.

I know this is just a long rant and I am sorry. I’m gust so frustrated and I just want to print.

I will probably just have to take a loss on this whole endeavor.

HI @ilistr8er

I know it’s frustrating, Just for curiosity are you Local to us here in Hamilton? we do have a store front in hamilton that we would be able to build it for you and get it functional.

Unfortunately, we cannot provide the firmware without seeing the printer as I have to test all the safety functionality of the printer before I can let it clear my shop for Liability reasons.

Most of the people here on the forum have the same opinion, we will absolutely help you get it up and running but cannot build the firmware for you. More carefully on what we would’ve had to call a pseudo-custom printer at this point.

I say that knowing it’s not custom but the firmware to run it will be 100% custom. If you have not modified the firmware at this point could you put the original print head back on and resume normal functionality? You could always sell just the upgraded head and recoup some cost from it.

Sorry, I hate to see people frustrated with their 3D printers. It is not a hobby that is stress-free but does bring a lot of joy with success.

I do appreciate the help and advice.

I am in S.E Oklahoma.

I understand what you’re saying about the liability thing, it just seems very odd that the company that made the hardware to upgrade the hardware that they also made would not just simply supply the firmware, I’m fairly confident if that was the case I would be printing right now.

As far as reverting back to what I had, that is what I am planning on at this point, it was an Amazon purchase and I believe I am still within the return window so that shouldn’t be a problem. The sad thing for me is, I really wanted to try a direct drive extruder, and now after this I can see the only way that is going to happen is if I just go buy a whole new printer that already has that capability and I can hardly justify that.

Again, thank you Jason for your input. Hopefully in a day or so I will be printing again and I can return here to look at some more interesting and fun things.

Hey @ilistr8er

Glad to hear that, I am glad you have a plan. I agree that if you are providing the Printer and the upgrade the firmware should be readily available. I am 100% on your page for that one.

It is the one thing I will give creality credit for if their printer does not have a BLtouch they do sell the brackets and “kit” to install it along with instructions and firmware. They require a little more maintenance, but my entire print farm is built on them.

they do not “open source” their firmware anymore as they used to keep with the Idea of 3D printing but they are holding their weight with cost/vs supported upgrade model.

We will always be here to help you were we can. Nice to see people on here from the US and other places around the globe.

Just out of curiosity, what is your take on direct drive extruders. I bought some spools of TPU ( not the extremely soft stuff, A95 I think) and I know it CAN be successfully run through a bowden setup but my understanding is that the quality can be an issue (stringing and such).

That was my whole reason for the change in the first place.

let me qualify my answer first, I have been 3D printing for about 15-16 Years and for the first filament I printed with the orange Weed Wacker line. I bought a 25KG spool at our local John Deer Dealer for about $30. So that being said I can print a lot with some pretty brutal equipment.

So… Is it possible to print TPU on a Bowden setup? Short answer, Yes.

There are a lot of variables. Your printer has to be tuned well, have Accurate temps and you have to print painfully slow, 20mm/sec. It generally will print with bond tech-style gears and you need to have a well-restricted (but not overly) filament path. Yes, stringing does tend to be an issue because you cannot retract at all using this method so you have no way to depressurize the hot end on a layer change or non-print move. Think of it this way, You are literally trying to push a rope across the ground, really depends on the immediate situation as to whether you may be able to do it.

Direct drives do make it so much easier, your prints will be cleaner and because you can reduce your retraction distance you can potentially make your prints finish faster no matter what filament you use.

Hope this helps answer your question

It helps very much, thank you.

I guess I’ll be putting a Creality Ender 3 w/Direct drive on my wish list.

So, if I’m understanding what you were saying before about Creality, is it the case that if a person buys a stock entry level Ender 3 with a bowden setup, then later upgrades to a direct drive Creality would supply the firmware update?

yes absolutely, they also have the firmware for BLtouch and combos thereof. Also because of the community support there is also firmware out there for Filament runout sensors and again combos there as well.

I will definitely look to Creality for my next printer setup.

Thank you so much for the help and info. I will stop bugging you now (for a while anyway :wink: )

All good, Anytime