No announcement yet.

Lifepo4 BMS installation questions:

  • Filter
  • Time
  • Show
Clear All
new posts

  • Lifepo4 BMS installation questions:

    Hello Everyone,

    I am looking at installing a BMS in an 8S Lifepo4 bank. The battery is 8 x 280A/H Lifepo4 cells in series. Installing it looks very straightforward except for a couple bits I have not figured out.

    The BMS has a wire that goes to the positive post on each battery and two #8 wires (battery and load). The idea is to disconnect the negative battery cable from the battery, connect the BMS battery wire to the negative battery post and the BMS load wire the the negative cable removed from the battery. Simple!

    But..... What about the inverter and the charge controller?

    The #8 wires are NOT going to accommodate the inverter load.

    If the BMS detects a problem and disconnects the loads it will disconnect the battery side of my charge controller from the battery while leaving the panels connected to the charge controller..

    That all has me thinking that I need to connect the charge controller and inverter directly to the battery and not to the load side of the BMS.

    What is the "right" way to do it?


    Thank you.


  • #2
    You have to have the BMS control DC rated relays.
    When the battery is overfull, the PV panels get disconnected from the Controller. When too low, a relay electronically commands the inverter OFF.

    But large relays or SSR's are expensive and not included in a BMS
    Powerfab top of pole PV mount (2) | 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