JBD BMS Wi-Fi Module

C

curiouscarbon

Solar Addict
i connected a victron blue solar UART to a SAMD21 microcontroller that uses 3.3 system and logic voltage. the MPPT UART output is 5.0 logic voltage so i made a two resistor voltage divider to convert the 5V logic signals to 3V logic signals which work safely with the microcontroller UART input pin. it reads the data properly

here is an extremely low quality diagram to illustrate the circuit
1614027478242.jpeg
perhaps this type of voltage divider could be helpful to some attempting connection to BMS UART

edit: photo of circuit
1614027722958.jpeg
it only does RX, but that’s only because i don’t need TX wire in this situation
 
rolandow

rolandow

New Member
I had all the components in your post at home, so I soldered it together for a friend. Then I thought created a small PCB for this would be so much easier. I have never done so though. EasyEDA seems easy enough though, so I have it a try. I never ever created a PCB before, so I'm not sure I got all the parameters right. Of course this is almost too easy to design; just put three components in there and it's done.

Anyways, I was hoping people with more knowledge about this are willing to check my design out: https://oshwlab.com/rolandow/bms-maarten

I tried using as less PCB as possible, so that's why the ESP is sticking out from the side.
 
M

melkier

Solar Enthusiast
rolandow said:
I had all the components in your post at home, so I soldered it together for a friend. Then I thought created a small PCB for this would be so much easier. I have never done so though. EasyEDA seems easy enough though, so I have it a try. I never ever created a PCB before, so I'm not sure I got all the parameters right. Of course this is almost too easy to design; just put three components in there and it's done.

Anyways, I was hoping people with more knowledge about this are willing to check my design out: https://oshwlab.com/rolandow/bms-maarten

I tried using as less PCB as possible, so that's why the ESP is sticking out from the side.
Click to expand...

Did it work? the module?

Very cool on the design ... I also thought the same thing (creating a PCB). If we can get a simple design together, having the board made by JLPCB will cost around $2/each (without the ESP module). Once my project is complete, I was going to pursue it.

Something like this:

You're off to a great start! I'm excited to see the outcome.
 
J

Just John

Solar Addict
melkier said:
Did it work? the module?

Very cool on the design ... I also thought the same thing (creating a PCB). If we can get a simple design together, having the board made by JLPCB will cost around $2/each (without the ESP module). Once my project is complete, I was going to pursue it.

Something like this:

You're off to a great start! I'm excited to see the outcome.
Click to expand...
One thing I might recommend is breadboarding a simple 3.3v regulator and associated capacitor rather than using the module where it supplies multiple voltages and you must cut a line on the PCB. Example schematics abound, and a regulator is about 80 cents in quantity one, I think it also needs two capacitors. Simpler and likely cheaper, as long as you are getting a PCB made.
 
M

melkier

Solar Enthusiast
Just John said:
One thing I might recommend is breadboarding a simple 3.3v regulator and associated capacitor rather than using the module where it supplies multiple voltages and you must cut a line on the PCB. Example schematics abound, and a regulator is about 80 cents in quantity one, I think it also needs two capacitors. Simpler and likely cheaper, as long as you are getting a PCB made.
Click to expand...
Agree 100%
 
rolandow

rolandow

New Member
Well, I must admit that my level of knowledge about electronics is even worse. I got excited by the Arduino world and am trying to follow along, but designing my own circuit is pretty new as well. So would an AM1117 be the right component for this?

@Just John where should the capacitors go (and if it's easy enough to explain, please tell me why) :)
 
D

DJSmiley

Solar Enthusiast
I'd suggest starting with the reference designs as stated in the datasheets


1614159497610.png

If you don't want to fiddle with SMD, you also can get a prebuild module like https://nl.aliexpress.com/item/33013114089.html
(I don't see a schematic, but it looks like this is a copy of the reference design prebuild)
You have to check, but I assume it's using a standard 2.54mm pitch, making it easier to solder compared to tiny SMD.
Off course you don't have to use SMD, but that would increase its size, and for the price of such a module you basicly can't even consider SMD soldering yourself.
 
rolandow

rolandow

New Member
I followed this example:

I added it to my PCB design, using the AM1117-3.3 and the two capacitors. I think it's big enough to solder.
 
J

Just John

Solar Addict
rolandow said:
Well, I must admit that my level of knowledge about electronics is even worse. I got excited by the Arduino world and am trying to follow along, but designing my own circuit is pretty new as well. So would an AM1117 be the right component for this?

@Just John where should the capacitors go (and if it's easy enough to explain, please tell me why) :)
Click to expand...
Really depends on what you want to power, in other words what would be the circuit draw expected. I'm biased since I have lots of experience with the 7805, 7812, 7905, and 7912 lines in TO-220 packages. If you need lower current, everything is also available in TO-92 packages for lower current draws.

This has an example circuit that looks good to me. I've used TO-220 packages in the past simply because they are so easy to find and use heatsinks for, thus up to 1.5 amps. This is for a 7833 (positive denoted by the 78, 3.3 volts denoted by the 33, although 7803 is seemingly an almost identical part).
 
D

DJSmiley

Solar Enthusiast
The 78xx series are also an option, but might be overkill. The TO92 ones are small and work up to 100mA (78L series to be exactly)

I think the AMS1117 are a better option, those can handle up to 1A. Main advantage is it can use the PCB as (small) cooling pad. If size doesn't matter you can use the 7833, but for the pretended purposes I don't see why you would (Considering the price / dimensions of the AMS1117)

The 78L's can't be used, since they are 100mA max, and I see some references to 215mA max power usage in certain circumstances for the ESP01S. ( 802.11b, CCK 1Mbps, POUT=+19.5dBm 215mA), so a 1A regulator would be preferred (You might be able to use a big capacitor to compensate for the >100mA bursts, but I think that's still risky unless you're sure you can calculate the amount of bursts). The regular TO220 ones are big, so I highly would prefer the AMS1117
 
J

Just John

Solar Addict
DJSmiley said:
The 78xx series are also an option, but might be overkill. The TO92 ones are small and work up to 100mA (78L series to be exactly)

I think the AMS1117 are a better option, those can handle up to 1A. Main advantage is it can use the PCB as (small) cooling pad. If size doesn't matter you can use the 7833, but for the pretended purposes I don't see why you would (Considering the price / dimensions of the AMS1117)

The 78L's can't be used, since they are 100mA max, and I see some references to 215mA max power usage in certain circumstances for the ESP01S. ( 802.11b, CCK 1Mbps, POUT=+19.5dBm 215mA), so a 1A regulator would be preferred (You might be able to use a big capacitor to compensate for the >100mA bursts, but I think that's still risky unless you're sure you can calculate the amount of bursts). The regular TO220 ones are big, so I highly would prefer the AMS1117
Click to expand...
Yes, just used the fixed parts rather than the adjustable to avoid extra parts. You must also consider input voltage range, some parts can go up to 40 volts, and others only 12 volts, etc. Like I said, my experience is relegated to the mid to late 1980s, thus my knowledge of more recent parts is limited. Some of the first Taiwan clones on the market left out -5 volts, because nothing used it (except for some edge case cards by IBM). When 2400 baud modems were introduced, it was quickly discovered that the chips used required -5 volts, fortunately the clone makers had left an empty spot to solder in a 7905. I was working for the military and NASA at the time (Redstone and Marshall), and of course they had purchase LOTS of these clones! Anyway, I'm sure there are people with more recent and relevant experience that can suggest parts, I just wouldn't use an adjustable part due to parts count. :)

And yes, TO-220 form factor would not be a good fit.
 
C

corporate.joe

New Member
I'm very much interested in this. I have been planning to use 3 Overkill Solar BMSs for my 3p 8s battery bank once they arrive. Would this same ESP setup work with Overkill? From my understanding they are re-branded JBDs, I may be wrong. They use the same android app.

Are there any loss of features when communicating with the BMS using this method? Can values/settings still be adjusted? Should I still order at least one BT adapter with the BMSs for initial setup? Guess I could just use serial connection for initial setup and save by not ordering the BT dongle. I have at least 2 months to decide.

I was originally planning on using Bluetooth and connecting a PI to all three of the batteries but if that is a nightmare I would much rather go a different route that is more dependable. I have a PI Zero W that has BT and WiFi built in.

I'm willing to save the nominal $5 without the BT adapter and build this WiFi solution if it is more robust for remote logging. I've played with Arduinos in the past, so I have some experience with programming them. Built a head tracker with gyro for use playing Elite Dangerous when it came out. Linux is my daily driver nowadays.

Oh yeah, Undead rogue on vanilla(Azgalore) back in the day. N.E. druid during Burning Crusade... And I quit playing end of 2009. I don't want to remember what my /played was. Twenties gone.
 
rolandow

rolandow

New Member
@DJSmiley and @Just John : I really appreciate your feedback, but I must admit I don't understand all of it :) I think the conclusion here is that the AMS1117 is a good choice right?

So did I use it correctly in the PCB design with the two capacitators? Is this design going to work at all?
 
J

Just John

Solar Addict
rolandow said:
@DJSmiley and @Just John : I really appreciate your feedback, but I must admit I don't understand all of it :) I think the conclusion here is that the AMS1117 is a good choice right?

So did I use it correctly in the PCB design with the two capacitators? Is this design going to work at all?
Click to expand...
I suspect that it will work just fine, easiest way to find out is to breadboard it and see. If using the fixed voltage version of the AMS1117, I think it is likely a very good choice. The only stipulation I see is that the capacitors be located physically close to the voltage regulator, hard to be far apart on that size board. I don't have a JBD to try it on, but the thread has given me ideas for other equipment that I own with a USB interface that would be nice to access via Wi-Fi. Certainly would work for other equipment that I have with only a serial port.
 
M

melkier

Solar Enthusiast
DJSmiley said:
I'd suggest starting with the reference designs as stated in the datasheets


View attachment 38381

If you don't want to fiddle with SMD, you also can get a prebuild module like https://nl.aliexpress.com/item/33013114089.html
(I don't see a schematic, but it looks like this is a copy of the reference design prebuild)
You have to check, but I assume it's using a standard 2.54mm pitch, making it easier to solder compared to tiny SMD.
Off course you don't have to use SMD, but that would increase its size, and for the price of such a module you basicly can't even consider SMD soldering yourself.
Click to expand...

I urge caution when using the link you sent in Aliexpress. They look like the ones I got from Amazon:

Amazon.com: Anmbest 10 Pack 3 Pins AMS1117-3.3 DC 4.75V-12V to 3.3V Voltage Regulator Step Down Power Supply Buck Module 800mA: Home Audio & Theater

Amazon.com: Anmbest 10 Pack 3 Pins AMS1117-3.3 DC 4.75V-12V to 3.3V Voltage Regulator Step Down Power Supply Buck Module 800mA: Home Audio & Theater
www.amazon.com

Which more than likely damaged 2 of my BMS. Looking on the board near the UART logic, a resistor overheated and cooked. One of the BMS still works, however, the UART has issues and unless I hit it back-to-back every 30s, the ESP needs reset before I can use it (like the BMS has gone to sleep or something). It only did it on the 2 BMS that I tried these voltage regulators on (I thought "cool! direct to 3.3! no lines to cut, and no pads to solder"). On all the other BMS that I have, they have no problem with the buck converter with the inductor.

Now, it could be that I just had 2 bad BMS and it was coincidence that the only 2 I had issues with were the ones I used the regulator I linked above. The price diff between them doesn't make it worth it for me. I had to order 2 more BMS from Ms. Xiao @ JBD.

YMMV, I just wanted to pass that on.
 
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