Seplos display reading 0

[powerpole]

I have 2 Seplos 48v 50a bms. Both when connected read all zeroes on the LCD display. The cell voltage is completely blank. The temps are all -230C or so. Tried two boards and 2 LCDs, same result. Light blinks in blink3 mode (0.5, 1.5 second pulse) which means warning. Soc lights show 2/4. Please let me know what to check!

 

[tigerwillow1]

Since you have two of every component, that pretty much rules out the first few things I'd say to check. You did try both display cables? It says there is a warning, but you don't know which one, except the SOC lights would seem to rule low SOC out. If it really thinks the temp is -230, it could be a low temp warning. Can you hook it to a PC and run the app to see which warning it is? About the only other thing I can think of is verifying that the individual cell voltage wires are connected properly, including not having mixed up the two bundles plugging into the BMS.

 

[powerpole]

Yup verified volts at every wire except thermocouples of course. I'll try the other display cable. If I can't get it to display I'll likely just have to buy other bmses. Thanks for the reply!

 

[tigerwillow1]

I have 3 100A Seplos BMSs that are working ok, and there are a bunch of other forum members who have them working. If the 50A model is the same thing except for fewer FETs or something like that, it's not a "none of them work" situation. There was an issue a while back with a batch that had some bad diodes. I don't remember what the failure symptoms were. There's a thread about it hiding somewhere in the forum. (I found it by entering site:diysolarforum.com seplos diode into a search engine). The guy who had the diode problem is one of the more knowledgeable Seplos BS users. Perhaps you could try a DM to him to see if he noticed this thread.

 

[powerpole]

Thanks. Seriously considering just buying overkill bmses at this point. I need something I can trust and this readout issue is pretty hokey. I may just pop these Seplos boards for sale here shortly. Thanks!