Seplos Mason DIY Kit - Ancillaries - Advice
Posted by: @makia2023I'm told 48v as the cut off is the best options as that is approx 10% soc. Is this your view and can you provide any advised values for me to confirm what I've read (or not).
Also, I'm assuming Pylontech setting for the inverter should work with the seplos BMS?
Let's deal with the BMS settings first.
Very few people seem to question what is meant by an assertion that a BMS or inverter is somehow compatible with a product from a different manufacturer.
It might be referring to the voltage settings which are required for the connected devices...
... or it might be that data is being transferred across a CANbus or Modbus communications link.
That would enable measurements made by the BMS get reported/recorded by the App issued for the Inverter, or vice versa.
It may have nothing to do with protecting your precious batteries.
So beware!
There are also many views across the internet as to the 'best' parameters which you should apply to your LiFePO4 cells.
Will Prowse, who has been publishing hundreds of You Tube tutorials on inverters, solar panels and batteries over the years, currently suggests:
48V LiFePO4 Battery w/ BMS
- Absorption: 58V
- Float: 54.4V
- Inverter Cut-off: 42.8V-48V
Individual 3.2V LiFePO4 Raw Cell (for individual cell capacity testing)
- Absorption: 3.625V
- Float: 3.4V
- Low voltage disconnect for capacity testing: 2.5V
Whoever you choose to believe, the basic principle remains the same.
The Inverter/Charger parameters are those which you set to define the voltage envelope within which your batteries are charged and discharged.
The BMS parameters are set outside of those.
The BMS acts rather like a fuse. If there's a fault, or an error in configuring the inverter, then it will step in and disconnect the battery before any damage is done.
Putting it the other way around; The inverter parameters are inset from those of the BMS.
Here are the absolute maximum and minimum voltages you should consider using: with a LifePO4 cell.
The inner pair of voltages are those which are set in the inverter (or charger) per cell.
A cell should not fall below 2.6v, nor be charged higher than 3.55v
which equates to a range of 41.4v to 56.8v for a 16S battery (sixteen cells in series).
The outer pair of voltages are applied to the BMS.
If the charge/discharge system fails, then the BMS prevents any cell falling below 2.35v or rising above 3.65v
You might suppose that equates to a maximum voltage of 16 x 3.65v (58.4v) for a 16S battery.
But that's not so.
Remember, the BMS has sense wires across each individual cell.
It will cut off the charge-current as soon as the first cell in that battery rises to 3.65v.
In practice I wouldn't configure my inverters and battery BMS units to these absolute minimum and maximum values.
But everyone will have their own opinion on how much they wish to inset from those extremes.
Save energy... recycle electrons!
@robl when i assembled mine last year around June time i think it was, i used a piece of 18mm melamine (kitchen cupboard shelf) in the bottom, i used EVE 280AH cells and ignored the plastic strips but used the foam between the cells. Using 18mm melamine meant that i could then hold the cells in compression.
some others have 3d printed a mesh type support that fits neatly in the bottom of the case. i have also recently heard that Seplos have now sorted the issue ....?
- 24 Forums
- 1,426 Topics
- 29.9 K Posts
- 40 Online
- 1,211 Members
Join Us!
Latest Posts
-
RE: Is this a bad installation and is there something wrong with my Samsung heat pump?
@transparent that controller was moved from the loft an...
By David999 , 5 mins ago
-
RE: Noise problems with newly installed Samsung 8kW ASHP
@sjn i felt exactly like you when I heard my colleagues...
By Lokisam , 46 mins ago
-
RE: Observations on my Ecodan's estimates of energy consumed and delivered
yes ours is set exactly as you stated. 72W for pump4. Z...
By SUNandAIR , 47 mins ago
-
RE: Additional ASHP kW for DHW cylinder?
We're in a similar boat to you with a hodgepodge of dif...
By Mars , 2 hours ago
-
Insulation of flow and return Heat Pump piping
I know mention has been made of ties on insulation runs...
By Toodles , 2 hours ago
-
RE: Heat Pump Truth or Myth#2 - Cycling uses a lot of power and ruins your COP
@jamespa Possibly a load of hot air then?😉 (Sor...
By Toodles , 2 hours ago
-
RE: No-code, plug-and-play monitoring for your heat pump
Anyway, so far we have all missed the main protagonist ...
By Toodles , 2 hours ago
-
Rising Damp – Production Recommendation
We've noticed some rising damp around a window after th...
By Mars , 3 hours ago
-
RE: Bivalent (or even trivalent!) system design options for a new GSHP installation
Right, back to the topic at hand. To answer some of you...
By Algienon , 16 hours ago
-
@editor I sent an email to these people a few months ba...
By Toodles , 20 hours ago
-
RE: Are Octopuses Slowing Consumer Adoption of Heat Pumps?
@ivanopinion Im in the same team as Ivan. I think for a...
By bontwoody , 22 hours ago
-
RE: ASHP Cut-off Temperatures: What's Your Setting and is a Your Heating Still On?
@technogeek Our Homely controller turns the heating on ...
By Toodles , 1 day ago
-
RE: Issues with Vaillant connectivity via the MyCONNECT gateway
@drew-pa I don't know about hard work! It is pretty cl...
By dr_dongle , 2 days ago
-
RE: Are Solar Diverters Necessary for Homes with ASHPs and Solar PV?
@editor No, I made one 😀 Loft insulation all...
By Andris , 3 days ago
-
@hughf Thanks for that. Ah so they are talking about ...
By IRMartini , 3 days ago
-
RE: Ecodan software update. Real or scam?
@abernyte, hmm, must have been a major disruption if 40...
By Mars , 3 days ago
-
RE: Installing your own ASHP - DIY
I’m in the DIY camp, completed the install last Septemb...
By HughF , 3 days ago
-
Riello / Midea - modbus set flow temp
Hi, I’ve got a Riello NXHM 8kW HP with emonHP, all wo...
By stuartornum , 3 days ago
-
RE: Say hello and introduce yourself
@irmartini Oh! That’s a great shame.😳 Toodles.
By Toodles , 4 days ago
-
RE: New Fogstar 15.5kWh upright solution
@robl I've added the screens. Li-Bms screen is accur...
By GGW , 5 days ago
Latest Topics
-
Insulation of flow and return Heat Pump piping
By Toodles 2 hours ago
-
Rising Damp – Production Recommendation
By Mars 3 hours ago
-
Additional ASHP kW for DHW cylinder?
By Project_Electrify 17 hours ago
-
By IRMartini 3 days ago
-
Riello / Midea - modbus set flow temp
By stuartornum 3 days ago
-
Ecodan software update. Real or scam?
By Morgan 4 days ago
-
Noise problems with newly installed Samsung 8kW ASHP
By Lokisam 6 days ago
-
Central heating inhibitor with ASHPs
By IRMartini 6 days ago
-
Advice on potential HW Cylinder size
By JWilliams89 7 days ago