M star mppt 45 suitability on valence lithium cells?

jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
Im running these : valence u27 xp 12 ....
I have 8 cells wired in at 24v  4x 2 cells.
My concern is that of overcharging through the solar ....ie i cant seem to find how to limit the current / voltage accurately on the m star mppt 45s?
Do i need to hook it up to a computer? 
Its not too much of an issue here in the UK at wintertime...
Summertime is my concern...
These are 130 ah 12v cells... lightly used and just put back in to service...


  • mcgivormcgivor Solar Expert Posts: 2,404 ✭✭✭✭✭
    edited January 8 #2
    According to the specifications they can be charged with charge controllers with an AGM algorithm which may, or may not, be exactly what is required, hense the, can be charged with "MOST' disclaimer. Custom settings using a computer will enable more precise control of the parameters, however 45A maximum is on the low side of the recommended charge current for one battery, let alone four, but that figure really depends on discharge rates between charging cycles. It would appear that they are intended as a drop in replacement for lead acid each with it's own BMS, which is theoretically a good feature but the technology is reletivaly new, and I'm no expert, there are however others on the forum who are  more experienced and may provide more insight. I too am eager to read responses as I'm looking at future replacements for LA technology.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    I have a pair of 45 amp mppts mstar...a 60 amp pwm set to cut out b4 the mppts
    I get 3kw of solar in the summer and i just was looking for the simplest method of limiting the end current / voltage going in to these batteries as in summer they will be full  quite early in the day...
    I have these from  low mileage decommissioned electric vans.. i have enough to make another bank on a reserve switch... and some left over.
  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Basically im getting 120- 130 amp @24v on a sunny day incoming.
  • BB.BB. Super Moderators, Administrators Posts: 28,150 admin

    Just to be clear, those are kWatt*Hours and Amp*Hours? (missing the *Hours part?)

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Yes the batteries i have are 1.7 kwh each 130 ah and 12v. Jim
  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    I May have not been clear: 3kw is my solar array
    My bank is 8x 12v batteries wired as 4 x 24v @ 130ah
    Giving 520ah @24v
    Batteries are valence u27  12 xp lightly used cells
    My concern is setting up the charging correctly ie end amps etc ? Hvd? Lvd?
    I have 2 x mstar 45amp mppts
    1 xantrex c60 pwm
    1 outback 3kw inverter/Charger 
  • karrakkarrak Solar Expert Posts: 314 ✭✭✭✭
    Do you have the Valence BMS that goes with those batteries?

    Off-Grid with LFP (LiFePO4) battery, battery Installed April 2013
    32x90Ah Winston cells 2p16s (48V), MPP Solar PIP5048MS 5kW Inverter/80A MPPT controller/60A charger, 1900W of Solar Panels
    Homemade BMS https://github.com/simat/BatteryMonitor

  • mike95490mike95490 Solar Expert Posts: 8,013 ✭✭✭✭
    You need to use the MSView software and a serial cable to connect a windows PC to the controller.  You can then set any voltage and current limits you desire.  Converting a PC USB port to a Serial cable (with a valid power signal) is hard, only one company is known to do it properly   Tripp Lite  model U209-000-R USB -Serial  https://www.tripplite.com/usb-serial-adapter-cable-usb-a-db9-male-male-5-ft~U209000R/
    MS references this specific model as having the proper DC-DC converter chip inside to power the RS232 circuits

    You may find these links helpful
    https://www.morningstarcorp.com/morningstar-best-practices-battery-chemistry/   using MS View (it also has latest firmware for controllers in the download archive, update the controller firmware first, then adjust things. READ the instructions or you will BRICK things)

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Simon:No i dont have valences own external bms....
    Thanks mike ive ordered the cable so hopefully i can set up my charger
  • karrakkarrak Solar Expert Posts: 314 ✭✭✭✭
    The reason I asked was that it looks like Valence uses their own proprietary BMS. I would think that the battery balancing and cell monitoring  part of the BMS is contained within the batteries you have. Each individual battery BMS is connected to other individual battery BMS's and to a central control unit via a proprietary interface.

    This statement from their website
    "Our battery modules are energy storage devices that can be configured in a variety of ways to meet the particular requirements of an application. To do so requires a properly configured Valence Battery Management System (BMS) for the system parameters and contactors. Generic or non-Valence BMS units are not suitable for use with Valence batteries. For safety reasoning, configuring of a Valence BMS needs to be performed by Valence or its authorized reseller. We do not support Valence products that have not been purchased directly from Valence or through an approved reseller."

    and the lack of detailed information about their BMS on the website make me think that you wont get much help from them to get the BMS in the batteries working properly.

    What are your plans to implement the two important functions performed by the BMS
    1. Keeping the individual cells in the individual batteries balanced and the batteries balanced relative to each other.
    2. Making sure that the cells are kept within their safe operating voltage,temperature and current zones.
    Off-Grid with LFP (LiFePO4) battery, battery Installed April 2013
    32x90Ah Winston cells 2p16s (48V), MPP Solar PIP5048MS 5kW Inverter/80A MPPT controller/60A charger, 1900W of Solar Panels
    Homemade BMS https://github.com/simat/BatteryMonitor

  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Hi simon thanks for raising those points...ive just managed to get hold of the valence software which apparently opens communications.. i need a converter cable which im in the progress of sorting out to enable connection from pc to battery...im unsure of the best way to progress in terms of bms... i was looking at the batrium system which seems to be in use by some folks using these cells ...
    What is the point of an internal bms if it does nothing?
    Is it just if the battery is in single use application?
    Any ideas greatly appreciated?Thanks James
  • karrakkarrak Solar Expert Posts: 314 ✭✭✭✭
    Do the battery BMSs communicate directly with the PC software or do you need the Valence U-BMS as well?

    I would be interested in any links to information on people using these batteries for DIY.

    Have you seen this Youtube video that documents removing the BMS supplied with the battery and installing a Batrium BMS instead? If you can't get the Valence BMS working this is probably the best way to go. Other BMSs that you could look at in place of the Batrium BMS are the Orion Jr and the unit from Zeva Australia 

    Internal BMSs come in several flavours.
    • Fully self contained: where all the circuitry necessary to balance the individual cells and disconnect the battery from the outside world if there is a fault is within the battery case. These batteries are marketed as drop in replacements.
    • Self contained but need external circuitry to stop charging or discharging: Same as fully self contained but need to connect to external circuitry or to the charger or load to stop them or disconnect them in the event of fault.
    • Master/Slave configurations: Where there is some of the BMS circuitry within the battery that talks to a master controller outside
    It is possible that the balancing circuitry within the Valence batteries you have will be able to balance the battery autonomously however this is only the case if the balancing circuitry works by removing charge from the individual cells by placing a load (usually a resistor) across the cell. This is known as passive balancing. The other form of balancing is called active balancing and works by moving charge from one cell to adjacent cells. If the Valence battery uses active balancing the batteries have to be daisy chained together to allow the transfer of charge from one battery to the next.

    Off-Grid with LFP (LiFePO4) battery, battery Installed April 2013
    32x90Ah Winston cells 2p16s (48V), MPP Solar PIP5048MS 5kW Inverter/80A MPPT controller/60A charger, 1900W of Solar Panels
    Homemade BMS https://github.com/simat/BatteryMonitor

  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Hi simon...thanks for your detailed reply.... ive yet to get the software open due to the pc (software only runs on xp) needing updates and cleaning.... also i have to go to a wifi connection... it doesnt seem to pick up the phone signal from my android hotspot....i believe the battery bms communicates directly with the software (which im happy to share) ... as the guy who i bought the batteries off was able to show me cycles logged and other info on the pc once connected.
    Yes i saw the batrium route conversion video...thanks for that... i haven't looked in to the other ones but i shall...
    Many thanks James
  • jimbob01jimbob01 Solar Expert Posts: 63 ✭✭
    Hi simon....ive now got the software up and running and it initiates an active balance at the top end ie when the voltage is 14.6 ...
    As far as i can see
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