Smart BMS 4S 12V Lifepo4 Lithium Battery Management PCB Protection Board with Balance Leads and Wireless Bluetooth - Supports 4 Cells 12.8 Volts DIY Programmable (150A)

This is a very capable BMS. I built it up around 55ah batteries in a 2P4S configuration. Seems to do a good job of balancing during charge, maintaining about a 2-3mV max differential between cell pairs. Discharge is even until the lower end which probably indicates I have a weak cell in there. This thing is robust! I screwed up when initially connecting a switched the battery and load/charge sides. Honestly it worked just fine except indicating discharge on charge and vice versa. Corrected that mistake and everything is working well. Bluetooth connection is very handy for setup and monitoring, it even has a strong signal allowing better than 10m separation between spots on opposite sides of the house and on two different floors. The one down side for me is the three 10 AWG wires, I’d rather see a 6mm screw terminal like Overkill Solar offers, allowing for more flexible hookup options. I’m looking around for terminals to modify at some point, but for now I just crimped on a connector for 4 gauge with my hydraulic crimped. The three 10ga yield an equivalent of about 5ga, so they’re adequate. All in all a good buy.

A little pricier than the other brands but there is a reason for that. It works very well and the Bluetooth connection and app is a great thing to have. Highly recommended.

This thing is solid. I have been using it for a week or so and it has had no issues. Max charged at 60 amps and drew at 25 for several hours. Zero heat up both times. The balance feature starts when .03v is showing. Not sure how effective it is on a massive 12v battery, but its there. The bluetooth feature works well and the thing overall seems great for the price. Problem? The google play store app is some sort of funky truncated version of the app it is supposed to be. You need to go to the mfgs website and download their app and then install it on your device. This is a big no-no for cybersecurity purposes. It is not vetted by the play store thus is a far greater risk. If you have a burner device to put the app on, you are golden. If not, beware. Other than that issue, i like it and may even buy another in the future. EDIT/UPDATE 1/2: the iPad app that costs $6.99 is very nice. I like it better than the android apps for sure. Plus it has to go through the app store. Your judgement on whatever security that may or may not provide, bit it is one additional layer nonetheless. Bms still working well. EDIT UPDATE 2/2: so I just got done with a solid hour and a half or so pumping 3 miles into our car. It got warm but not hot. Charging now. The iPad app is best/safest in my opinion. The longer I have this the happier I am.

Compact form factor, well-built, performs well, and the app provides the essential info, regarding state of charge, char/discharge rate, cell voltage and balancing status.

My biggest complaint is the mobile app needed to actually use the BMS. it works just fine but will not work without location turned on... Why the heck does a bms app need my location turned on to function 😒

So far I’m very happy with this BMS. It paired perfectly with the iPhone app. Config was easy and straightforward. Definitely a good alternative to the Overkill units which have been on back order for quite some time. The only downside is the length and gauge of the connection cables. They’re a little short and only 6 AWG. Definitely would have preferred some of the options offered by Overkill.

This wouldn’t send full voltage through and wouldn’t support my inverter. It works fine as a voltage meter/monitor for each of 4 LiPO4 cells.

Great BMS only one warrning if you plan to change password in app remember to put at least 6 digit if you use 4 didgit app will take it and no access to bms until you reset with special dongle

Habe das BMS erstmal testweise an 6Ah LiFePo4 Zellen gehängt und es funktionierte sofort. Konnte dank der App auch alles einstellen was man einstellen kann. Was n bissel fehlt (oder ich habs übersehen) ist ein Passwort für den Zugang. Aber da kann man sich auch nen Schalter bauen, welcher das BT Modul einfach die Spannung unterbricht....sollte auch gehen hihi... Habe bisher etwas "Interessantes" herausgefunden, und wusste am Anfang nicht, wo eigentlich der Fehler liegt. Unter "Function Setting" gibt es einen Schalter "Switch Function" Wenn man diesen auf Grün macht, kann man das DisCharge auf der Monitoring Seite nicht selber umschalten, (Es steht dann unter "Protection" -> "Locked") das macht die "App" bzw das BMS selber, aber erst wenn geladen wird. Ich habe aber nicht getestet, wenn X Ampere last anliegen, ob das BMS dann trotzdem durchschaltet.... Im März kommen leider erst die 105Ah Zellen, dann kann ich hier nochmal editieren... NACHTRAG: Also. Nun hingt das BMS zuerst an 4x105Ah Eve Grade A Zellen, und ich muss sagen, das BMS liefert immernoch. Die angegebenen Werte der Schutzschaltungen hab ich dann mal auf die jeweiligen Zellen angepasst und auch nachgemessen, mit 0,01V Differenz (Messungenauigkeit) Wird der OVP/UVP Schutz geschalten. Kurzschluss wollte ich nicht testen haha Mittlerweile hängen 4 BYD 125Ah Grade B Zellen dran, und auch da keine Bedenken. Wollte mir zuerst ein DALY BMS bestellen, mittlerweile bin ich damit sehr zufrieden. Die High und Low-Temp Cutoffs habe ich als einziges noch nicht getestet, das steht aber auch noch an...