So finally, the missing package was delivered, and I have the Seplos Mason 280 battery now operating properly.
Here is my overall summary of how the ordering, delivery and commissioning of this Seplos product worked out for me.
The Good
Overall, the product itself is great. I like it.
It's a well-designed and solidly-built enclosure which does a nice job of housing the 16x280Ah cells and the Seplos 200A BMS with it's screen. The communication buses (CANBus and dual RS-485) work just fine for monitoring with PC and the CAN bus interface to the Victron CerboGX works, although the depth of information provided across CAN is a bit limited.
The "sales engineer" that I dealt with was consistently available on email to deal with issues as they arose. While the communication was consistent, it was often not accurate... see "The Bad" below.
The shipping process was generally good, except for the local courier who screwed up, but that wasn't the fault of Seplos.
The Bad
The system comes as standard with an internal ANMH fuse, specified to operate up to only 2000A. I asked for a Class T fuse (which operates to 20,000A) and was told that I would get one. I didn't get one, and what is more concerning is that the Seplos engineer tried to convince me that the ANMH fuse WAS a Class T fuse. (He didn't succeed!) Don't bother asking for a Class T fuse because Seplos engineers don't know what that is. I have added an external Class T fuse for my own peace of mind.
I was told by Seplos that the V16 BMS I was getting had Bluetooth functionality. It did not. I learned that the BT function is physically provided in the display module of the BMS, so while a V16 BMS might have Bluetooth "functionality" (whatever that means), there actually is no Bluetooth transceiver unless you specifically ask for a Bluetooth Display.
There was a missing busbar in my delivery, which Seplos have promised to send me. I fabricated a temporary replacement to make the system work.
The Ugly
There is an error in the 200A BMS Manual which has incorrectly labelled the CAN-L and CAN-H pinouts on the CANBus connector. The signals are in fact reversed. The manual for the 100A BMS is correct. According to the Sales Engineer, Seplos don't consider this an "error", just a different interpretation.. go figure. Its one of those crappy manual mistakes that never get fixed because once you know about the error its an easy fix and you move on, so no-one bothers to fix the documentation. It remains a trap for new players.
The BMS is rubbish at balancing. My cells were pretty close, but I ended up manually balancing a couple of outliers with a bunch of resistors on alligator clips. I will be keeping a close eye on cell balancing for a while. Note to self - buy a 16S balancer
Ok so that's a very brief summary. I'm happy enough with Seplos and the product that I'm ordering a second unit and have specifically
not asked for a Class T, but
have specifically asked for a Bluetooth display (Extra $10).
Happy to respond to any specific queries.