I’m looking for solution for electric vehicle charge and power distribution system PCB. For some reasons I want to split battery to several Li-Ion packs in separated units (hulls). I see the next possible setup for me, as shown in the Fig. 1 below.

Fig 1. Functional Block Diagram for Charge and power distribution system

The main question for me is the realization of such kind of “parallel” connections of chargers and power sharing between battery units and System Load. Is this a right way for such setup? I’m understand that batteries will try to equalize voltage between the units, but it is acceptable for me. I want to use one of the Analog Devices (or another) charger IC’s and connect several chargers like as shown on Fig. 2 below. What could go wrong?

Fig 2. Charger Unit (example schematic from Analog Devices LTC4008-1 datasheet)

Also maybe there are similar on-the-shelf solutions or best ways?

  • \$\begingroup\$ re " I’m understand that batteries will try to equalize voltage between the units, but it is acceptable for me" -> It may be acceptable to you but, worst case, the batteries will add magic smoke, vent with flame and destruction. Due care is needed when parallellingh batteries that they are within suitable voltages AND that worst case current flows are both designed and allowed for. || Q: "What could go wrong?" A: "What could go wrong? !!! :-) !!!". \$\endgroup\$ – Russell McMahon Oct 17 at 1:17
  • \$\begingroup\$ Providing a "datasheet link](analog.com/media/en/technical-documentation/data-sheets/…) is always a good idea. || Why do you chain the next charger(s) past the current limit sense resistor? It's not obvious to me that that's good or useful. \$\endgroup\$ – Russell McMahon Oct 17 at 1:23
  • \$\begingroup\$ @RussellMcMahon Thank you for reply! \$\endgroup\$ – xandeer Oct 17 at 2:11
  • \$\begingroup\$ @RussellMcMahon re "batteries will add magic smoke" Ep, I'm understanding the problems of parallel battery connections and for this reason I want to separate it with discrete chargers, one charger per each Li-Ion bat pack. Probably I misunderstood example schematic, but if I connect "System Load" of 1st charge circuit to "DCIN" of 2nd charge circuit that will give me separated battery packs which haven't direct connections between each other? \$\endgroup\$ – xandeer Oct 17 at 2:57
  • 1
    \$\begingroup\$ Shared voltage SMPS are inherently unstable without complex compensation to prevent offset unbalance and burst ringing with resonance. I remember PowerOne's rackmount failures like this fixed with 10% preload and 0.2% balance. But CC mode sharing is slow BW so the trick is to make a bus with exceptionally low ESR and ESL. and similar rated mOhm Caps. to result in high SRF (MHz) There must be a global and local current sense for ratio metric sharing. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Oct 17 at 3:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.