How to switch off BMS ?

[gedong]

Can anyone help me on how to switch off BMS ? ( zero draining power for long term storage) ?

at the moment, i'm gathering information about building battery pack, and i 'm a little bit confused about which BMS should fit my needs..
the battery case have 2 switches, button and keylock.. i guess the keylock is the switch for BMS on/off , and the LED button is for BMS current circuitry.
it also has +5V USB output for charging, this will required separate DC-DC module LM2596HVS to supply the USB module.

here's the connection diagram and inside battery case.



and, here's the assembled battery pack, surprise how small the BMS are. the specs are Max 20A discharge ?
i asked this picture from some seller in chinese aliexp***


if i want above switch to functions , do i need special BMS ? or any BMS maybe can be modified ?
here's similar BMS which have switch off

this BMS from elifebike supposed to have on / off switch, but i don't see any connector..
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2014-3C-MR54.027KF

and, anyone have experience with elifebike ? i live in Indonesia, so it's kind of difficult to find reliable resources with decent price..
sorry for my bad english, and thanks in advance.

 

[dogman dan]

Unplug the BMS from the balance wires. In the pic above, it's the plug with 9 white wires. Looks like it's glued in place though.

That should de power the bms. However, it's still possible that very tiny trickle shorts could exist elsewhere on the battery. Only an issue if the storage is for a very long time.

Or you could have a cell that self discharges very slowly, but you never knew when it was in use, since you charged it often. So no guarantee that a battery has no problems when stored for really long periods, like a year or more.

If you will be around, you can just store the battery fully charged. Then every 2 weeks or so, put it back on the charger overnight to get a fully balanced charge.

In the other pic, I am not sure if the keylock switches of the bms power use, or if it just switches off the main discharge circuit. So just switching off the key may or may not de power the whole bms. It would be a great design if it did completely de power the bms.

 

[gedong]

hi Dogman,

Thanks for your input.
yes i understand, that there's couple way to completely disconnect the BMS completely from the cells, one is from disconectting the balancing cable, or make switch from the cells before going to BMS board. but this will required hi Ampere switch.

but since i already had the switch built in onto the case, and 18650 batteries ready for assembly, i just need to find the right BMS board that works with the switch..

can anyone enlighten me by "switching off current circuit" ? what current circuit ? how do i know where is the current circuit ? are every BMS has this feature ? or only custom made ?
thanks

 

[dogman dan]

I'm not near technical enough to answer that one. But I have seen batteries with an on off switch, and presume some of them switch the bms, rather than the main wires.