Seplos CAN BUS RS485 48v 200A 8S-16S BMS

Firechief

New Member
Anyone already tested this BMS?

Seplos CANBus/RS485 48V 200A 8S-16-BMS

Looking to make a Solar storage battery bank with 16 x LiFePo-4 280Ah cells in a 48VDC config giving me a capacity of around 13,5kWh and it would be great if it can communicate with either Victron or Fronius inverter. This BMS has RS485/CANBus com on board and could communicate with a second and more battery bank when needed.
I'm new to this battery stuff, but want to learn more. Since Belgium has changed the rules for reversing meter, I'm looking for a affordable solution/DIY Project to store the produced energy during the day and consume this during the night. I was thinking of a micro-grid system with Victron products.
I live in Belgium as mentioned before and have a 3 fase 400V+N 32A grid connection and looking for as less consumption as possible. I have 5740Wp (14x410W Canadian Solar panels in 2 strings) pointed 220° & Fronius Primo 4.0 Single fase inverter. Daly household consumption is about 15kWh with a max peakload around 5000W. If i can get this to work i'll get a similar second battery bank increasing the capacity to about 26kWh.

I'm open for discussion and advise.

Thx in advance
 

snoobler

Solar Honey Badger
Low temperature (cell) warning: 2℃
Low temperature (cell) warning recovery: 5℃
Low temperature (cell) protection: -10℃
Low temperature (cell) protection recovery: 0℃

The above is a great way to trash a battery. protection should occur at and preferably above 0°C.
 

Ampster

Renewable Energy Hobbyist
This BMS has RS485/CANBus com on board and could communicate with a second and more battery bank when needed.
I would ask Seplos to give you examples of communication with Victron or Fronius. I would not assume all CANBUS or 485 devices can communicate with each other unless you are an engineer who is familiar with those protocols. There is a user here who has successfully communicated with a Victron and an Orion BMS.
 

Firechief

New Member
Low temperature (cell) warning: 2℃
Low temperature (cell) warning recovery: 5℃
Low temperature (cell) protection: -10℃
Low temperature (cell) protection recovery: 0℃

The above is a great way to trash a battery. protection should occur at and preferably above 0°C.
At the beginning of the list:

All the following parameters is configurable through upper computer system.

So I think it's configurable
 

Firechief

New Member
I would ask Seplos to give you examples of communication with Victron or Fronius. I would not assume all CANBUS or 485 devices can communicate with each other unless you are an engineer who is familiar with those protocols. There is a user here who has successfully communicated with a Victron and an Orion BMS.
on their site they mention:
3. Compatible inverters:

  • Victron
  • Growatt
  • Goodwe
  • SMA
  • Pylontech
  • Luxpower
  • Sofar solar
  • Deye
  • Sermatec
  • Fox ESS
  • Victronic power
  • Renac

So I think it should work, but i will contact them for an example, thx for the advice.
 

cinergi

1.21 Jigawatts
I'd be worried that their long list of compatible inverters just means the inverter will run (a marketing technique), not that it will properly pay attention to the CANBUS. Each inverter has completely different protocol specs and the BMS would need to be explicitly configured to indicate that a particular type of inverter is connected to it (so it can configure the CANBUS protocol properly). It will be interesting to hear if Seplos says that the inverter will pay attention to the CANBUS signaling (e.g. max charge/discharge current, charge voltage, etc).
 

Ampster

Renewable Energy Hobbyist
@cinergi understands that layer of networking and the importance of protocol specs. "Compatable" is a term that could be easily mean a dozen different things. A simple example is my Skybox and my BMS are compatable but despite the well defined CANBUS specs of my BMS there are none for the Skybox. So I have to use a contactor to turn off DC to my inverter when the BMS senses an issue.
 
Last edited:

Bjorn

New Member
Anyone already tested this BMS?

Seplos CANBus/RS485 48V 200A 8S-16-BMS

Looking to make a Solar storage battery bank with 16 x LiFePo-4 280Ah cells in a 48VDC config giving me a capacity of around 13,5kWh and it would be great if it can communicate with either Victron or Fronius inverter. This BMS has RS485/CANBus com on board and could communicate with a second and more battery bank when needed.
I'm new to this battery stuff, but want to learn more. Since Belgium has changed the rules for reversing meter, I'm looking for a affordable solution/DIY Project to store the produced energy during the day and consume this during the night. I was thinking of a micro-grid system with Victron products.
I live in Belgium as mentioned before and have a 3 fase 400V+N 32A grid connection and looking for as less consumption as possible. I have 5740Wp (14x410W Canadian Solar panels in 2 strings) pointed 220° & Fronius Primo 4.0 Single fase inverter. Daly household consumption is about 15kWh with a max peakload around 5000W. If i can get this to work i'll get a similar second battery bank increasing the capacity to about 26kWh.

I'm open for discussion and advise.

Thx in advance
Hello,

this bms looks promising!
Are you able to order this? I see that the minimal order quantity is 1000.

Ps. I also live in Belgium😀
 

Firechief

New Member
Hello,

this bms looks promising!
Are you able to order this? I see that the minimal order quantity is 1000.

Ps. I also live in Belgium😀
Bjorn,

Minimum ordering quantity is 5, but i didn't order yet. maybe contact them to see what's possible? I'm looking for people who use these to see if they can communicate with the Victron Energy equipment. But do let me know if you order or intent to.

Kind regards
 

anschluss

Solar Enthusiast
Hello,

I am rather interested in this BMS. It could be either complete trash or the "philosopher's stone" to DIY an inexpensive 48V battery back capable of communicating with low and mid-tier brand solar inverter/chargers. From looking at specifications and videos about the BMS, I extracted some information which I am going to check with Seplos via e-mail. Here's my tentative summary:
  • Different BMS models (8S-16S) have built-in charge and discharge mosfets with current limits between 50A and 200A
  • Two RS485 ports
    • for intercommunication between parallel battery packs
    • for parameter programming and monitoring via computer and Windows software
    • potentially (I don't fully understand this) to connect inverter/chargers without a CAN bus port
  • A CAN bus port to connect to inverter/chargers
  • Switchable CAN bus protocols - as indicated in a youtube video, the BMS can apparently
    • emulate a pylontech battery
    • use a manufacturer protocol (visible are Growatt, Sofar, Victron, Luxpower)
      • Bildschirmfoto 2021-05-18 um 13.00.03.png
  • On their homepage, they indicate a minimal order quantity of 5
  • On their alibaba page, two BMS models (8S/24V 200A and 16S/48V 150A) are offered with a MOQ of 1
In a comment to another video, they announce a complete DIY battery case set for 16S 280Ah LiFePo4 cells:
...Please stay tuned. We're planning to design the new case for 280 Ah cells."
Any other important information I may have missed? I am planning to write a message to Seplos inquiring about the feasibility of a DIY assembled ~13.5 kWh battery pack for use with a Sofar HYD series or a Sungrow SH5K-30 inverter.
 

Ampster

Renewable Energy Hobbyist
CANBUS is nice but there is no garanty that a particular inverter will speak the same language as the BMS. It is not plug and play like Ethernet. If not, can it control a contactor or provide a contact closure that can control a relay?
 

anschluss

Solar Enthusiast
CANBUS is nice but there is no garanty that a particular inverter will speak the same language as the BMS. It is not plug and play like Ethernet. If not, can it control a contactor or provide a contact closure that can control a relay?
I am aware of the CAN bus conundrum; this is why I am intrigued by this BMS. I am not interested in contractor control because the inverter/chargers I would like to use don't even have any simple contacts to be controlled - they need CAN bus or RS485.
 

cinergi

1.21 Jigawatts
I am aware of the CAN bus conundrum; this is why I am intrigued by this BMS. I am not interested in contractor control because the inverter/chargers I would like to use don't even have any simple contacts to be controlled - they need CAN bus or RS485.

It's still important to have a contactor in case the CANBUS communication fails or fails to be acted upon. That's the setup I have - both a contactor and CANBUS (Orion BMS). Yes, you can physically get away with it, but I don't recommend it.
 

anschluss

Solar Enthusiast
It's still important to have a contactor in case the CANBUS communication fails or fails to be acted upon. That's the setup I have - both a contactor and CANBUS (Orion BMS). Yes, you can physically get away with it, but I don't recommend it.
The Seplos BMS has internal MosFETs.
 

anschluss

Solar Enthusiast
Ah, I guess I misunderstood; so all current must run through the BMS and the BMS can interrupt the circuit?
Yes. I am inferring this from the sections titled "Overcharge protection and recovery" and "Over discharge protection and recovery". The manual is available in the Resources section of this forum. I may have misunderstood the information presented there - I'd be happy if others could read it and report about their own conclusions.

The charge/discharge protection mechanisms are separately explained:
  • Overcharge protection and recovery of individual cell
  • Overcharge protection and recovery of battery pack
  • Over discharge protection and recovery of individual cell
  • Over discharge protection and recovery of battery pack
  • Charging over current protection and recovery
  • Discharge over current protection and recovery
I don't know how this could be implemented without built-in interruption circuits. I also like that the BMS can auto-recover from protection states without requiring a manual reset.

I am surprised there hasn't been more mention of this BMS even though the manual has been available since July 2020. The English is rather good and the text is easy to read. Even if the BMS communication shouldn't turn out to be 100% compatible with the proprietary inverter protocols, it could still be a versatile, inexpensive solution to building a DIY 8S-16S battery pack if you don't need the ubiquitous bluetooth connectivity. The manual lists configurable parameters galore - there's even a "Heating function (At low temperature)" so I guess it could perhaps be configured to have circuit for a heating pad. Am I missing any hidden drawbacks? I am inclined to just buy and try out the 8S version. The Seplos seems simpler to use than the Ant BMS which I bought but never felt motivated enough to hook up to my spare set of 100A cells.
 

houseofancients

Solar Addict
on their site they mention:
3. Compatible inverters:

  • Victron
  • Growatt
  • Goodwe
  • SMA
  • Pylontech
  • Luxpower
  • Sofar solar
  • Deye
  • Sermatec
  • Fox ESS
  • Victronic power
  • Renac

So I think it should work, but i will contact them for an example, thx for the advice.
victronic.. they probably mean voltronic, which include MPP solar .. would be very hopefull
 
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