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7S Li-ion BMS

Charging & BMS · 29.4 V 40 A

Daly 7S 40 A common-port · 7S Li-ion · 40 A continuous, trips at about 120 A (1 ms), short circuit about 240 A (250 µs) · over-charge 4.25 V/cell (29.75 V pack), over-discharge 2.7 V/cell (18.9 V pack) · balancing 30 mA from 4.18 V

7S Li-ion BMS on the simulator's bench

Try it on the benchThe lab drops it on an empty bench and opens its datasheet card.

Typical part: 7S Li-ion BMS — modelled on Daly 7S 40 A common-port

Pins

Ratings and limits

ProtectionDaly standard Li-ion BMS
Cells7S Li-ion
Over-charge4.25 V per cell after 1 s · release 4.15 V
Over-discharge2.7 V per cell after 1 s · release: connect a charger (or the cells recover above 3 V)
Discharge current40 A continuous · over-current trip about 120 A after 1 ms
Short circuitabout 240 A · 250 µs · release: remove the load
MOSFET resistance3.8 mΩ (150 mV and 6 W at 40 A)
Balancingpassive, 30 mA from 4.18 V
Temperature protectionnone: above its continuous rating it heats, and its MOSFETs can fail shorted

How to use it

Wire B− to the pack’s negative end, B1…B6 to each junction between cells in order, B+ to the positive end. The load and charger go on P+ and P−: the board switches the negative side with back-to-back MOSFETs. Connect the balance leads in order, B− first: a lead connected out of order can destroy the board.

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