SVOLT Lithium Battery 48V 106AH 5.09KWH - RS232 Comms Working - Pace BMS 16S100A (15S)

Been following this thread with interest because I picked up one of these SVOLT packs about six months ago for my tiny house build and the RS232 comms side of things had me pulling my hair out for weeks.

What finally cracked it for me was realising the Pace BMS needs the baud rate set correctly before you try anything else — sounds obvious in hindsight, doesn't it. Once I had that sorted and was reading proper data through to my Victron Cerbo GX, everything just clicked into place. State of charge, cell voltages, temps — all coming through cleanly now.

The 15S vs 16S thing is worth flagging for anyone new to this pack. Mine's running as 15S in practice and I've got it sitting at a nominal 48V system quite happily. The cell balance has been surprisingly solid over the months, I'll be honest I expected more drama.

A few things I'm still curious about:

• Has anyone managed to get two of these in parallel with the Pace BMS talking properly to a Victron system?
• What are people using for the RS232-to-USB cable — I went through three before finding one that actually worked reliably
• Anyone noticed the temperature sensors drifting at all over winter?

Would love to hear from others running this particular pack long-term, especially in a fixed off-grid setup rather than a van or motorhome where the temperature swings are a bit more predictable. My tiny house site in Wales gets properly cold and that's been my biggest concern going into this winter.

Really interesting thread — I've been lurking on this one for a while because I've got a similar situation on my narrowboat.

Quick question for @Nessa68 or anyone else who's cracked this: once you've got the RS232 comms talking properly, are you able to pull the data through into Victron's ecosystem at all? I've got a Cerbo GX on board and I'd love to get the SVOLT pack showing up on the VRM portal rather than flying blind on state of charge.

Is anyone using a protocol converter of some sort, or did you write a custom driver? I've seen some GitHub projects for Pace BMS integration but not sure which ones are actually working reliably in a real install versus just looking good in a README.

What cable pinout ended up working for yours in the end?

@Nessa68 nothing says "off-grid adventure" quite like losing six months of hair over a serial port that was invented before you were born 😄

Went through something similar getting comms working on my garden office setup — turns out the cable pinout diagrams floating around online are about as reliable as a British summer.

Worth double-checking your null modem vs straight-through cable situation if you haven't already — that caught me out embarrassingly late in the game. Also, if you're running Victron kit, the VE.Can to RS232 route saved my sanity eventually.

@ForestDweller narrowboat installs are a whole different beast with vibration and damp — curious whether your BMS comms stay stable underway or drop out on choppy bits?

@Nessa68 worth clarifying something that catches people out with these SVOLT packs — the Pace BMS RS232 implementation isn't standard UART framing. The protocol uses a specific request/response structure where you must send a correctly formatted poll command before the BMS will transmit anything. A lot of people wire it up correctly and assume it should broadcast, then conclude the comms are dead.

If you're using a USB-RS232 adapter, verify your adapter is actually RS232 voltage levels (±12V swing) and not a 3.3V TTL adapter mislabelled. I made that mistake initially on my boat build — the logic analyser showed data but the BMS wasn't responding because the voltage levels were insufficient.

What baud rate are you configured to? Default on most Pace units is 9600, 8N1, but I've seen batch variations shipped at different rates.

@Nessa68 hang in there — I went through almost exactly the same thing with mine last year! One thing that really helped me was grabbing a proper USB-to-RS232 adapter with genuine FTDI chipset rather than the cheap CH340 clones. The clone chips can introduce timing issues that make the Pace BMS go completely silent even when everything else looks correct. Also worth double-checking your null modem wiring — I'd assumed straight-through initially and wasted a weekend on it. Once I sorted those two things the comms came up almost immediately. @RiverRunner makes a good point about the implementation quirks too, so definitely worth reading that carefully before you go further. What software are you using to poll it? I've had reasonable results with a basic terminal emulator first just to confirm you're getting something back before moving on to anything more complex.

@Nessa68 six months is nothing — I wasted the better part of a year on comms nonsense with my Pace BMS before I just accepted that the documentation is basically aspirational fiction.

One thing nobody seems to mention: check your RS232 voltage levels with a multimeter before assuming the physical layer is fine. These packs occasionally ship with the comms port outputting at 3.3V logic despite the RS232 label, which means your converter is just sat there confused. Burnt through two cheap USB-RS232 adapters before I realised.

Also worth knowing — if you're planning Victron integration, the GX devices are far more tolerant once you sort the baud rate (usually 9600). Don't bother with third-party converters if you can help it, the genuine Victron RS232 cable is overpriced but actually works.