Safe power shut off.

[trimixdiver]

Hi guys I'm putting another battery pack together its a Sanyo 18650 Li-ion Battery pack 14.8V 5200mAH 4S2P going to be using a Protection Circuit Module For 7.4V (2S) Li-Po/Li-ion Battery ...https://www.dropbox.com/s/478vbu8wv6uxwhk/Battery Pack detail for Dive Light.PNG?dl=0
I'm not sure how long to discharge the pack for , wouldn't want to ruin the pack.

Tony

 

[trimixdiver]

Anyone?

 

[RetroTechie]

Protection circuit not intended (or even suitable) for a 4S pack?

 

[lucca brassi]

don't understand why such protection module ?

Pack is normally discharged with value same as charged that mean 20% C which is in your case 1 A ( talking for smart charger/ discharger )

Direct (rapid ) discharging depends on battery properties ( inner resistance) and is marked on battery

 

[arek98]

Are you building pack yourself from loose cells? Make sure they have similar performance - same brand, type, capacity (nominal and actual), age.
You need protection circuit for 14.8V pack. Get one with balancing function.
You need to solder balancing wires at each end and between each pair of cells (5 total - 2 at the ends will go together with charging wires).
Balancing wires can be thin but not to thin (AWG 22 would be probably my choice), they allow protection circuit to control voltage of individual cell (2 cells in parallel are threated as single higher capacity cell) and push smaller charging current when balancing cells.
I would not go for pack without balancing for more than 2 cells in series.
Something like this
If you get circuit without balancing you should still solder balancing wires and add connector. Then use balancing charger as often as possible.

 

[trimixdiver]

Guys I'm looking from the cut of voltage using that protection module.
Never mind found out.

 

[lucca brassi]

I'm not sure how long to discharge the pack for , wouldn't want to ruin the pack

≠

Guys I'm looking from the cut of voltage using that protection module