Last February 2022 we bought three Dyness B3 battery modules to make up a solar system with two Victron Multiplus working in parallel. We managed to set up the system correctly with the info received from Dyness and it was working OK. After some weeks of use, we realised that the battery bank was too little for the inverting power capability of the multipluses, and we decided to buy two extra B3 battery modules.
The new modules were bought June'22 and tested. There started the problems: when connected together with the original modules it was obvious that something was not working well, we started to receive communication alarms from the batteries. We had the impression the modules were not communicating properly through the CAN bus. We asked Dyness technical staff and for our big surprise they told us, after asking for the S/N of each module, that the three first modules and the two second modules WERE NOT COMPATIBLE!!! They updated the product (new current specs, new BMS...) and did not even change the name of the model. Incredible.
From the outside the modules looked slightly different, we noticed it upon reception. Not big differences, the only obvious is that new model has an RJ "COM" connector in the frontal panel, to the left of the two CAN bus connectors. All the rest is basically the same.
I have been working in the electronics & telecom industry for more than twenty years and I never saw such a compatibility break from any label. Even more having in mind that battery modules are designed to work together.... The Dyness staff did not accept to give us a solution, just told us we had to go back to the dealer. Well, I have done so but our dealer says they can not change my modules by the compatible model without Dyness approval, and Dyness is not responding their messages. So now we ended up with two modules for a value around 2300€ that we can not use... Maybe we will get some solution from our seller but this is still very uncertain. What is crystal clear is that Dyness is not properly responding to the problems they cause to customers because of their poor development policy, to say it in a polite way.
So a word of warning for all seafarers: be very careful buying Dyness B3 modules from different sellers or at different times: it is not said that they will be compatible!!!
Regarding our company, for sure we will avoid putting ourselves again in the hands of this label.
