DIYBMS v4

I just placed an order for the controller board on jlcpcb that I made. It should be totally compatible with the ESPController, but has:

1 TLC2944, which I will have to solder myself (UGH!). I did not find any > 20v charge counter that was through hole. This will be used for the main state of charge. It will be connected to a shunt and can handle 48v systems.

1 INA226A, which is available in through hole. I would have used another TLC2944, but it has a hard coded i2c address and I figured it wasnā€™t worth taking additional wemos pins. The INA226 will monitor the PV current and I will need to make a timer to poll this current in order to sum it over time in the wemos. It is not a very critical number, so there isnā€™t a need for another counter like the 2944. However, this cannot handle more than 36v.

4 opto relays. They are able to handle 400mA of and a bunch of volts. These are 2 in each 8 pin DIP, so easy to solder.

I figure I should be able to modify the software so that it detects the 2 amp chips and takes advantage of them or not. I am a software developer, so that doesnā€™t worry me too much. Iā€™ve never made a circuit before, so this should be interesting.

I have 3 ESPController boards and some spare ā€œdanger hotā€ boards (not sure what the proper name is). These have the attiny soldered in already from jclpcb.

Iā€™m in USA WA. Speak up if youā€™d like some.

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Iā€™m in Oregon. How many spare Circuit boards? Are the ESP controllers complete?

You can use a 12v relay but you will require a seperate 12v supply and will need to remove the jumper.

Definatley easier just to get a 5v relay with the jumper installed

Iā€™ve just put together a new video on the ordering from JLCPCB and building process.

Hope it helps people out.

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A post was merged into an existing topic: DIYBMS v4 Shunt Design and discussion

98 posts were merged into an existing topic: DIYBMS v4 Shunt Design and discussion

Hello Stuart,

First off a big thanks for the latest video, not only for having it setup to get them pre-built but also for how to do that process with them.

Everything did look to work properly but they did come back with a question about polarity and I responded with use the polarity in the picture. Heres another big thanks, the gerber files and csv files generate an excellent picture so I was comfortable with my response.

Does it make any sense to silkscreen polarity ? Just looking at the png files from github Im inclined to say no (there just doesnt look to be room), but thought it was worth asking.

Peace,
Liquiz

Anyone have any thoughts on using one of these to power the controller?

I currently have a 3S15P test pack and I decided to wire one of these direct to the pack to power the controller. I now seem to get a lot of communication errors.

Anyone else tried one of these?

There is probably a lot of noise on the power signals. Try putting a large capacitor across the +/- input to the controller.

Thanks Stuart

Any idea what size i should use?

Start with anything you have! Probably 47uF or similar, just make sure the voltage rating is okay (5V+) and ensure you get the polarity correct if its an electrolytic cap. It may be worth also including a low value cap as well - like 100nF.
[Smoothing and Filter Capacitor Calculator - ElectronicBase]

@John_Taves THANK YOU. Tonight I solder! Already have two small 7s packs ready for testing. And @stuart thank you as well for this incredible project. I look forward to the revisions offering more current and more capability.

Thanks Stuart

I may have found the culprit. Dodgy USB lead (aliexpress). I will continue to monitor.

Hello to all! Those who are experiencing problems in the work of DIY BMS. V3, cross charts and reboot esp. Impact of interference. On the esp, pull up the ā€˜RSTā€™ and ā€˜ENā€™ pins to +3.3V with a 2.2kĪ© resistor. On pins 3.3v and ā€˜ENā€™ , hang ceramic capacitors at 0.1mF relative to gnd. For fast real-time balancing, change the last line in the esp code from 20,000 to 500 - 1000
//Update Influxdb/emoncms every 20 seconds
next_submit = millis() + 500;
}

Hi @stuart, I would like to know if you want to collaborate with me and make an affordable commercial version that i can sell in South Africa. I have a small startup that lets people do DIY and Iā€™m looking to make it more affordable to get a salable system for People. Let me know if you are instereste.

https://jlcpcb.com/parts/componentSearch?searchTxt=ATTINY841

there is ATTINY at jlcpcb again
order quickly, there are only 99 pieces.
with this link you can always see which ones are in stock!

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Winner winner chicken dinner. Thank you. Only ordered 15 circuits. Already have 5 controllers on the way so Iā€™ll have spare controllers in the US.

Now only 84 pieces are available.
Congratulate yourself on your catch. I unfortunately ordered 20 pieces without ATTINY, I couldnā€™t wait any longer :frowning:

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I should have looked at the cost difference for 30 but didnā€™t want to hog them all. Iā€™ll have enough for three 7s banks (10 circuits on hand already) which is all I need to get rolling.