Electronic experts - BLUETOOTH

[Burgerman]

Hate android...

I do find that I am only bothering to use the BT converted charger right now. Its just easier. And simple to do, all self contained so no wires and self powered. My windows laptop is a super thin and light thing like the size of a sheet of A4 paper. Actually less.

[snaker]

A demo of my android app. I was using it to remotely charge a cell. It sounds good


youtu.be/Ba5w2ZtkmtY

[shirley_hkg]

It's cool

[Scooterman]

A demo of my android app. I was using it to remotely charge a cell. It sounds good

It's cool

It is cool, clever

[snaker]

I tried to charge and discharge the 24V pack through the app. It works fairly good.

I found something interesting. I attach underneath the images of cell voltages that monitored by my app and by PL8 software. You can see in my app, they are not equal but in PL8 software they are perfectly equal. I had a look in the PL8 software's source code to check if I did anything wrong. I found that they modify the original cell voltages (through the method BAverage) to make them look "equal". By other words, the unequal cell voltages that are showed in my app are real. The equal cell voltages in PL8 software are fake to look nice.

[Burgerman]

Not quite.
They are rounded from the original 4 decimal place versions to the closest full digit. There is a point where you have to remove a last digit... So is 1.5556 displayed as 1.556, or 1.555 etc??

To see it with no last digit averaging, go to the field shown, and select 4 decimals. All the rounding to the next full digit is gone, and graphs will look less tidy and show accuraccy to 1mV. As will the figures in the PL8.

But generally you dont want this in everyday use.

Note tick box below!

[snaker]

I saw the Show4Decimals option in the source code. And yes, if it is checked they do not modify the cell voltages original values.

But if Show4Decimals is off (by default), the cell voltages are modified through the method BAverage. This method does not simply round numbers like 1.5556 => 1.556. It modifies cell voltages to close their avg value, therefore they look equal. As you see in my images above, the modified ones are very different from the original.

[Burgerman]

Yes, if close enough to nominal values to never worry about it calls them balanced. For reasons of simplifying the display so anything within a few decimal places on the last digit is shown as balanced.

You can select 4 digit/no averaging. But its actually less useful day to day flying planes. So most prefer the 3 digit display. You then only see a cell thats out of balance by a margin thats significant enough to concern yourself with. And 3 full decimals is already beyond measurement accuracy (calibration) of 5mV but not beyond resolution.

If you dont want that, select the 4 decimal option. You will soon get fed up with it. Why? Because its sensitive enough to show up differences in cables, and different resistances as you charge, calibration error and temp and changing resistances in connnectors etc. Shake the balance cables and see a different bunch of digits! And even 3 decimals, is beyond the actual plus or minus 5mV overall voltage measurement accuracy. In other words a votmeter may be calibrated 2V out, and may be repeatable to 5mV as here, but it can still display a 10 digit decimal place!

You dig more will also find that there are 3 different ways to measure voltage too.
The charger charges in pulses, it can measure voltage while the pulse is off. (so cable / cell resistance voltage change not included) and while charging at x Amps. And averaged voltage as you would see on a multimeter eiter at the charger, or at the cells (unloaded voltage) All are different. Sometimes a lot different. And all are correct.

[Fedor]

Hello.
As a result. Now what is the easiest way to make bluetooth for PL8, in your experience, which is more stable? which module? Sorry if I missed it.

[snaker]

The BT module is HC-06. It is popular and very cheap about $3.5 here. It is very old too, there are newer and more modern modules like HM-10. As we only use classic BT serial, so HC-06 is enough.

You can make it internal (professional) or external (amateur ). But both work stably and are EXTREMELY useful. BM's one is internal, mine is external and powered by a powerbank.

[Fedor]

Thanks for the answer. And what is the wiring diagram? I found the pinout on the module. Do I need additional resistors or something like that?

[snaker]

If you want to make it external, it would be super easy. All you need are a HC-06 and a scotky diode.

I drew the diagram on Fritzing. My dad took only 10 or 15 minutes to complete it. I note that the BT in the pic is HC-05 has 6 pins. But the HC-06 only has 4 pin.

[snaker]

That BAverage method adjusts original cell voltages in the range [- 7mV, +7mV] comparing to their avg value. E.g if a cell voltage in range [avg - 7mV, avg + 7mV] it will be shown as avg.

I tried to apply that 'fake' method in my app. Now the cell voltages get perfectly equal

[Burgerman]

Yes because if close enough it doesent matter. If say 8 or 10mV different from the average it will be displayed. At least you now know that if a cell is different to the rest it is balancing at 1000mA. If you remove a decimal place, it makes more sense. Because now you are seeing the best display, and to the actual level of calibration and measurement accuracy - as a group.

No matter how its displayed, the charger itself balances to around 2mV acuracy subject to its calibration error level and preset settings, per channel, which is to 5mV worst case calibration I seem to remember. I wish I could find a way to calibrate exactly to match my calibrated certified fluke test meter on every channel! But whilst I am a control freak this isnt really required.

Cell balancing: Resolution 78uV (16 bit) for 1s-8s Li or A123 (LiFePO4) balanced charging
Voltage calibration: Cell voltage measurements are factory calibrated to a standard traceable to NIST; calibration is to +/- 6 mV
Current calibration: Charge current is factory calibrated on a 4A standard; calibration is to +/- 1mA
Measurement accuracy:
Voltage resolution: 78uV (16 bit)
Voltage tolerance: +/- 6mV
Charge current: +/- 1%

[Scooterman]

If you want to make it external, it would be super easy. All you need are a HC-06 and a scotky diode.

I'm a total electronic numpty. Is this what we need https://www.ebay.co.uk/itm/HC-06-Arduin ... 388ecf3a65 And what rating of diode?

[expresso]

i would like to see a step by step with pictures if anyone wants to do one - for making it external ?

with parts list - links etc,

[Scooterman]

i would like to see a step by step with pictures if anyone wants to do one - for making it external ?

with parts list - links etc,

Ditto

[Burgerman]

Doing it as an external one is exactly the same as doing an internal one. With just one tiny difference.

Internal, its invisible, and works as soon as you connect a power supply to the PL8. It ust needs you to buy a hobby king/ebay whatever 30V to 5V power supply board used for RC battery eliminator. They are cheap. And to solder its 2 tiny wires to where the power comes in from the power supply inside the PL8.

External needs a seperate pain in the ass power supply to power the little board and its trailing around on a wire plugged into the rear.

[expresso]

step by step with pictures would help - at least for me - i am not rushing to open the PL 8 and risk ruining it - for me its safer outside - BUT - if i can see how its done step by step - sort of Windows for dummies - Bluetooth for dummies - i would feel better - - either option would allow you still use the Cable if it craps out ? just in case

[Burgerman]

Yes.

Its like that lithium addon you made first. You will see that its just as simple to do it properly in the end!

My INTERNAL one still plugs in just the same way the FUIM3 did...

The tiny board is just loose inside the PL8, bit of heatshrink. Its wire comes out of the PL8 (I melted a tiny notch with the soldering iron for its wire) and plugs into the PL8 with a simple servo lead (50 pence!).

See cable exiting, and plugging in here:
download/file.php?id=10058&mode=view

Its powered INTERNALLY via one of these:
https://hobbyking.com/en_us/turnigy-3a- ... ction.html

[Burgerman]

You literally need:
1 diode. Type low drop Schottky 1N5817 : https://www.ebay.co.uk/itm/10-x-1N5817- ... 2749.l2649
1 tiny power supply as above post.
1 BT board from eBay. Set to correct settings.
1 RC type servo lead to connect it as my picture.

Then inside the PL8 you need to solder 2 tiny wires to get power.
And then connect to the board. And that diode to the BT board. Thats it, all in one BT capable. 30 meters range reliably. 10 meters indoors through walls. No power supply needed. All built in. Been super reliable here across many months and batteries of all types. Auto connects. Simple! Better than USB.

[expresso]

ok i may do this one day - but i like a parts list with links to each part - i dont know what i am looking for etc,

then i can purchase all the parts and see what i am ready to do it - how hard is it to open the pl8 -

[Burgerman]

5 screws... Pull.

[Scooterman]

Nice one BM, I'll have a go at fitting one internally as well.

He who dares...............

[expresso]

5 screws... Pull.

ok - do you have links to each part thats needed - every item- the Power link didnt work - no longer for sale

BT board - Server wire etc, - i have no idea if i do a search - theres millions =

if you can when you get a chance - each item with link to it

do you have any pictures when you did yours ? so i can follow step by step ?

thanks

[Burgerman]

No just whats on this thread. Bit it shows all you need, and it shows where stuff came from, and the learning proces. As in what didnt work out later on.

Like a simple signal diode, was replaced by the low drop one. And so on.

Seriously if you want to do it, I suggest forst getting a BT board from woodyGB as it needs configuring to correct baud rate etc. (programming) before its used. Save you the bother/learning.

[expresso]

sure thing - if i can get one from Woody already done and ready - i would - along with anything else he may have that needed

i am not in a rush to do this - i am fine with the cable since charger is close - but can be useful -

now what if your running two chargers at once - if they are both BT - would that interfere with each other etc ?

the link you posted for the battery inside - show no longer available -

[swalker]

I have not been able to test mine yet, because my PL8 is back having warranty work done on it.

I purchased a DTD brand HC-05. The difference between the HC-05 and HC-06 is the HC-05 can operate in master or slave mode, whereas the HC-06 only supports slave mode. Slave mode is what we need.

Either one needs to have some parameters changed. For my HC-05, I wired the HC-05 up to an Arduino nano on a breadboard. Doing so should really use a voltage divider to reduce the nominal 5 volts to 3 volts going to the HC-05 RX pin.

Changing the parameters on the HC-05/6 requires configuring it for command mode. Once it is in command mode, you can use AT commands to alter the various parameters.

Putting the DSD brand HC-05/6 into command mode requires holding down a tiny button while power is first supplied. The led will start flashing on and off at about 0.2 Hz to indicate it is in command mode. To take it out of command mode, simply cycle the power without holding down that little button.

There are many programs available online that allow a PC to communicate with an HC-05/6. I modified one and used it to send the appropriate commands to my HC-05. I believe they are the same for the HC-06, but have neither checked the datasheet nor tested myself.

To make sure you are corrected, simply send "AT" (without the quotes).

To find the baud rate, stop bit, and parity, send "AT+UART?" (without the quotes).

To change the baud rate to 1900 with 1 stop bit and no parity, send "AT+UART=19200,0,0" (without the quotes).

If you want to change the PIN, send the "AT+PSWD=987654" (without the quotes), where 987654 is an example of a 6 digit PIN.

I purchased the DSD HC-05 here: https://www.amazon.com/gp/product/B01G9 ... UTF8&psc=1

I purchased the diodes here: https://www.amazon.com/gp/product/B07BT ... UTF8&psc=1 (why buy one when you can buy an assortment of 200:)?)

I purchased an assortment of Arduino nanos here: https://www.amazon.com/gp/product/B0775 ... UTF8&psc=1

I bought a kit with breadboard, power supply, breadboard wires, and lots of components here: https://www.amazon.com/gp/product/B01ER ... UTF8&psc=1

I bought a collection of wires with servo connectors here: https://www.amazon.com/gp/product/B01JK ... UTF8&psc=1

You don't need nearly all that stuff to do this limited project, but having that laying around has been immensely useful for a variety projects I am involved with right now.

I have attached the Arduino project I used to communicate with the HC-05.

Steve

[swalker]

More pictures

[snaker]

now what if your running two chargers at once - if they are both BT - would that interfere with each other etc ?

Each charger will have a different COM port. If using on a phone, each charger will have a different BT name. So they will not be conflic.