I have just bought this 7S BMS circuit: http://www.ebay.co.uk/itm/7-cells-20A-w-balancing-Li-ion-Lithium-18650-Battery-In-Out-BMS-Protection-Board-/182198279820?hash=item2a6bdd1e8c:g:rDkAAOSwyQtVhQV3
I wanted to understand the charging process before first use, but the supplier could not help. My assumptions are:
If the charging voltage is lower than the battery pack voltage, the BMS will not allow the battery pack to discharge into the charging source.
If the charging voltage is between the battery pack voltage and the maximum allowed voltage (29.4V for 7S), the BMS will allow charge to flow into the battery pack.
If the charging voltage is higher than the maximum safe voltage (29.4V), the BMS will limit the voltage applied to the pack and fix it at the maximum (29.4V).
There will be some threshold above which the charging voltage will destroy the BMS. This seems to be a crucial parameter and is not given in the spec. How should I determine this threshold?
Any constructive comments would be greatly appreciated.