DIY/Homebrewed "Bolt-on 75W+ Variable Voltage BEC/FAN DRIVER" - Need a few testers

[autolex]

Hello Arrma family!

Who here in the US is willing to do some testing for me, has room for this and runs BIG fans/escs? (this will be free to you, i'll just ship you some parts with instructions)

I need five or six testers that run between 4S and 8S and BIG power fans/esc's (each of these BEC's should handle 8-12V@5A/60W, thinking those Amazon server fans etc).

I'll pick a few of you based on what I think is a good fit (use case wise) and PM directly for shipping info.

The BEC will end up being about 2" x 1" x 1" and will probably live velcroed/double side taped to the floor of some monster speed run cars/bashers.
(Initial rollout isnt waterproof)

I ordered a dozen chinese buck circuits for testing
(will have a solder version and an EC5 version most likely, these run off the main battery leads, not the balance leads)

Basically: run an ESC Y splitter (or solder directly to an ESC input line) and take up to 8S input voltage and give a regulated 5A adjustable supply voltage output).

Since each channel (1"x1"x2" - keep the size in mind!) is set to a specific voltage it may make sense to target cars that need one both for gigantic servo currents (can be had with a ripple pack) and one for big fan currents (can be had with a pot so fan speeds are adjustable).

Special use case BEC may be in the works (looking at k-bash haha) for those who need less than 4S drive voltages (3s? 2s buck/boost?) to drive big fans?

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Everyone not local to saint louis, mo: Please post an answer

What's your biggest fan/esc load in one car? how many of each?(The specific fan link or a part number is the best. A picture/ebay listing/info about current draw is also good, "11V/0.6A" kind of thing.)​

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Would an EC5 connector (so you could use a Y harness) or raw solder leads make more sense for you?​

​

What Pack Voltages are you normally running? (4S? 5S? 6S? 7S? 8S?)​

Please keep in mind i'm doing this for free as Research and Development, so no warranty (above the ebay seller warranty that supplies them) applies.
If you just want a cheap BEC, there are tons on amazon (>$20), not too many that will do the things this will do when it's done

Continental 48 get priority, purely for shipping ease..

 

[Cereal_killer]

Hello Arrma family!

I ordered some chinese buck circuits for something i'd like to test product development for: a permanent/semi permanent Fan Driver circuit (will have a solder version and an EC5 version most likely, these run off the main battery leads, not the balance leads)

I need two or three testers that run between 4S and 8S and BIG power fans (each of these BEC's should handle 12V@5A/60W, thinking those Amazon server fans etc).

the BEC will end up being about 2" x 1" x 1" and will probably live velcroed/double side taped to the floor of some monster speed run cars.
View attachment 242194

Who here in the US is willing to do some testing for me, has room for this and runs BIG fans? (this will be free to you, i'll just ship you some parts with instructions)

If this works out okay a 3S version could be assembled based on this architecture.

Continental 48 get priority, purely for shipping ease..

Pm me. I'm local. And I use 40mm server fans on one of my Lim

 

[K-BASH]

I'd be glad to test um...I crash alot thou so

 

[autolex]

@K-BASH and @real_name_hidden you guys will get one regardless to test when I give k-bash his 3S cap pack after the parts show up.

 

[RCbuzz]

1. 3-Fans (1x ESC, 2x Motor Cooling)
2. 2x 28,000RPM High speed fans on Motor and stock ESC Fan. Plans to upgrade ESC fans are dependent on if I ever get the 3D printer running to make adaptors for the ESC's .
3. For 3S Rigs an EC5 adaptor would be nice to avoid soldering. For 8S this may not be practical due to added resistance on connectors and the use of two battery packs. I was thinking of tapping on to the ESC side of the wiring to obtain total cell voltage for a BEC.
3. 2S, 3S, 6S, 8S

I have a couple of these (https://www.aliexpress.com/item/3256803026290848.html) I would like to fit onto the 8S ESC.
And the other fans are similar to these (https://www.aliexpress.com/item/3256804245753184.html).

 

[autolex]

1. 3-Fans (1x ESC, 2x Motor Cooling)
2. 2x 28,000RPM High speed fans on Motor and stock ESC Fan. Plans to upgrade ESC fans are dependent on if I ever get the 3D printer running to make adaptors for the ESC's .
3. For 3S Rigs an EC5 adaptor would be nice to avoid soldering. For 8S this may not be practical due to added resistance on connectors and the use of two battery packs. I was thinking of tapping on to the ESC side of the wiring to obtain total cell voltage for a BEC.
3. 2S, 3S, 6S, 8S

the specific fan (even a link or a part number) is the best. a picture/ebay listing/info about current draw is best. looking specifically for a voltage and amperage rating like "11V/0.6A" kind of thing. I've edited my question to be more clear.

 

[NorwegianBasher]

I made a BEC just like this in January 2021 for my E-revo 2.0. Took several pics when making it.
Adjusted it to 8,39v.

Potting stage 1. Used Fujik thermal silicone adhesive.

Another layer. Fully coated.

Added heatshrink

Finished it off with some "black silicone multi purpose glue" on both sides. In theory it should be bash and waterproof. Here is a fresh pic beside some Kraton 6S shocks for size comparison.

The reason I made it. Wanted to run a strong single servo at 8,4v without upgrading the Traxxas electronics. I paired it with an Agfrc A80 40kg servo rated at 4,6A stall current@8,4v. Worked fine for some time, but then my ESC died. (Traxxas electronics sucks). Upgraded radio/receiver and ESC to support higher voltage and did not bother with it after that. Might use it for some fans in one of my rigs in the future, but for now its just laying there. Was a cool project. Super cheap (!), especially compared to buying a BEC locally. Might be a bit risky using an unmodified DC DC converter/BEC like this for a high end servo, but for 12v fans and such it seems like a great idea compared to running a separate battery. A much better and cheaper solution IMO. Best wishes with your project.

 

[RCbuzz]

I made a BEC just like this in January 2021 for my E-revo 2.0. Took several pics when making it.
Adjusted it to 8,39v.
View attachment 242317

Potting stage 1. Used Fujik thermal silicone adhesive.
View attachment 242318
View attachment 242319

Another layer. Fully coated.
View attachment 242320

Added heatshrink
View attachment 242321
Finished it off with some "black silicone multi purpose glue" on both sides. In theory it should be bash and waterproof. Here is a fresh pic beside some Kraton 6S shocks for size comparison.
View attachment 242322

The reason I made it. Wanted to run a strong single servo at 8,4v without upgrading the Traxxas electronics. I paired it with an Agfrc A80 40kg servo rated at 4,6A stall current@8,4v. Worked fine for some time, but then my ESC died. (Traxxas electronics sucks). Upgraded radio/receiver and ESC to support higher voltage and did not bother with it after that. Might use it for some fans in one of my rigs in the future, but for now its just laying there. Was a cool project. Super cheap (!), especially compared to buying a BEC locally. Might be a bit risky using an unmodified DC DC converter/BEC like this for a high end servo, but for 12v fans and such it seems like a great idea compared to running a separate battery. A much better and cheaper solution IMO. Best wishes with your project.

Nice Work!

 

[jkflow]

For fans go to mouser or digikey, search for DC fan 12V 40x40x28, not sure if the link below works.
Delta or Sanyo Denki are the top choices.
Filter by CFM and current draw. CFM is what matters, pick the lowest current rating, though. Consider metal framed fans.
Last but not least you have a couple of part numbers, and you can search eBay, AliExpress etc to see if you can get a better price.

I run smaller version BEC (2A) in front of my fans. I have mine soldered to the ESC plug, and it's a solid setup.
You will find that fans will short out due to abuse and blow your BEC or bring down the entire setup for the run.

None of these will hold up to bashing, jumping etc. I went back to 30 and 35mm fans on my bashers. The fan blades or motor will come loose.

https://www.digikey.com/en/products...YGhZqUtIMy8rnGLdpBcvIIiouIgAEzKACaIAAToAoyiQA

 

[Diem Turner]

For fans go to mouser or digikey, search for DC fan 12V 40x40x28, not sure if the link below works.
Delta or Sanyo Denki are the top choices.
Filter by CFM and current draw. CFM is what matters, pick the lowest current rating, though. Consider metal framed fans.
Last but not least you have a couple of part numbers, and you can search eBay, AliExpress etc to see if you can get a better price.

I run smaller version BEC (2A) in front of my fans. I have mine soldered to the ESC plug, and it's a solid setup.
You will find that fans will short out due to abuse and blow your BEC or bring down the entire setup for the run.

None of these will hold up to bashing, jumping etc. I went back to 30 and 35mm fans on my bashers. The fan blades or motor will come loose.

https://www.digikey.com/en/products...YGhZqUtIMy8rnGLdpBcvIIiouIgAEzKACaIAAToAoyiQA

+1
Digikey is the place. That's where I buy my fans as well.

 

[K-BASH]

@K-BASH and @real_name_hidden you guys will get one regardless to test when I give k-bash his 3S cap pack after the parts show up.

I use these,usely on 4s

 

[autolex]

Might be a bit risky using an unmodified DC DC converter/BEC like this for a high end servo, but for 12v fans and such it seems like a great idea compared to running a separate battery. A much better and cheaper solution IMO. Best wishes with your project.

Thank you! I do like that I can order a potted version (i'll be formally waterproofing with Epoxy barges or 3D printed Epoxy filled boats)
I don't know if i want to mass produce them, but for a specific use case of mine the R&D is already required, so yeah, why not see if I can help others?