I’m not sure how you plan to use PHP for this application.
Speed is the only difference I can see, we run at 8Mhz so no need for the faster unit - the I actually used the “V” variant of the chip which can be run at a lower voltage (although no longer a requirement as we have the regulator).
Moving my powerwall into the garage and setting the BMS up more permanently. Adam Welch very kindly provided a copy of his bracket which I’ve modified to work with the packs i’m using as they are 6 cells high instead of his 5. I’ve also swapped the thermistor so it goes out the bottom of the BMS module and will go in the battery pack to get a better idea of the temperature.
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i can’t wait for my last few parts to show up. my packs are 4x20 so a little taller 
but will still work
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Hi there!
I have just soldered my first board with my heat gun, which went surprisingly well, and with a bit of help from Adam Welch’s video I managed to align the ICs correctly.
Now I’m still at the phase of testing cells at the moment, so I’m not sure how big and how many I will be needing, but a few questions arise in regards to this module.
Am I right in assuming that the larger packs I create, the smaller impact the BMS’s resistor will have, unless you swap it out with a larger value resistor? (are the any limits to this, or guide lines?)
Also the battery wires are quite small, and I guess combined with increasing the resistor, you may run into issues here? (please correct me if I’m wrong)
160 cells per pack might be the one I will be going for, just because it seems like a manageable size, but might also be 200.
Also my I suggest a small change to the next version of the board: How about adding two holes for the “wings” of resistor R1? I can see the space have been left blank, maybe because of this?
Smaller value resistor will increase the current - maximum current you should pull through the board is about 2Amps. The battery wires and sockets are capable of handling 2Amps as per design.
Good idea!
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So this project looks fun and interesting! Looks like I can learn a lot here.
I am planning on building a powerwall 14s100p. Would I be able to use this BMS for it?
Yes this bms would work
Agree with Jman that it should be fine. I’m running 7s96p and it’s working well with packs that size. As a side note is anyone having issues with the packs all dropping off from the ESP so to speak. After moving everthing to the garage i’m finding that the packs will work great for a while but then disappear all at once and looking at the packs the green led’s are flashing so they are in a state where they think the ESP is not present.
Hey guys;
I am still waiting on parts from china.
But, my initial interest in this project was/is about cell/pack balancing.
Is this going on yet?
If not, is it ‘OK’ to start talking through the logic of how it will work? I must admit that I have not looked down into the code yet to see what is going on. Just been waiting to solder the boards.
Bob
The current balance code works by averaging the voltages and turning on the load resistors for the packs over the average for 10 seconds. Collin i have not had any issues with the esp8266 disconnecting. Also @stewart do you know why R3 has been changed from 20k to 68k in the latest version of the github repo?
Its a typo - I merged in the documentation parts list from somebody else - the circuit diagram is still 20K
Wooo all my parts are in. Been working on boards for a couple days. Tried to reflow one… didn’t work so i did one by hand tonight. Got it flashed. Hooked to my pack. used the test code, was able to see it, query it. It stopped being able to query after my computer went to sleep. didn’t know if that was related. i then flashed Colin’s code to my nodemcu to set it up, but after a minute or two while i was trying to configure the nodemcuIi saw the magic smoke puff. I saw a little spark and smoke where the reg710 is. Not sure why it burned up. the voltage of that pack was 4.21.
any thoughts?
thanks!
You may have acidently short circuited. Did you have any metal objects nearby or under the boards?
I trashed one of mine when i blindly connected the power not realising that the leads i had bought had the + and - the otherway around to the pcb connector, that is how i burnt the track up and ultimately a reg710 also 
Yeah i blew 5 of my 7 boards track when i accidently shorted two of the connector cables. I just soldered a piece of wire across the broken track and it works good again. One adum1250z did die though.
no metal that i can see. I didn’t burn up the track (checked that to confirm this morning)
It was weird, it was ok for awhile. the test sketch was able to find it, and report voltage temp ect.
Oh well. i guess ill start swapping parts now and see what still works lol
Ok, i have my board working at the moment. seems to have been running for a bit now. My voltage is off so i need to do the calibration. Could Stuart or Colin maybe chime in on which of the calibration boxes to use and how the values are calculated? No worries if not, im gonna dig through the code in a bit regardless
Im just happy it seems to be stable at the moment
Sigh. Another 710 burned up after just sitting there for over an hour. I wasn’t even messing with it. I was working on a graph thing for my HA system.
Any thoughts? It’s not burning traces. Just keeps frying the 710 after like an hour