# Power off BMS when not in use?
**URL:** https://foil.zone/t/power-off-bms-when-not-in-use/20810
**Category:** efoils – Electric Hydrofoil Surfboards
**Created:** [May 26, 2024, 7:44pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810 "2024-05-26T19:44:50Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@seantab](https://foil.zone/u/seantab)
#### Post date: [May 26, 2024, 7:44pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/1 "2024-05-26T19:44:51Z")
Experts, I have two questions:
Assuming I have to use BMS.
1- Should BMS get powered off when battery not in use or in storage?
2- If answer to first question is yes, then what is the correct way of powering off BMS so it doesn’t use power while in idle?
My setup consists of a 13S6P battery using Samsung 21700 cells 3 amps each, with a 100-amp BMS. I’m constructing a multi-use, multi-volt battery for an efoil and potentially other applications. The primary role of the BMS is to balance the cells, as my ESC will cut off power independently. However, in case I switch to using a 10S or 11S configuration in the future, I need a robust BMS to balance or discharge the inactive cells, which is why I opted for a higher-capacity BMS.
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### Author:  [@maninjo](https://foil.zone/u/maninjo)
#### Post date: [May 26, 2024, 8:05pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/2 "2024-05-26T20:05:50Z")
I don`t power my BMS down, and it even has bluetooth enabled all the time. The power a bms uses is very little.
If you plan on storing the battery for more than two or three months at a time, I would suggest checking the voltage to make sure the voltage hasn’t dropped to much but other than that you are fine.
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### Author:  [@Foilguy](https://foil.zone/u/Foilguy)
#### Post date: [May 26, 2024, 9:21pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/3 "2024-05-26T21:21:21Z")
> [@seantab](#):
>
> Assuming I have to use BMS.
Lots of people only use the BMS for charging so it would seem you don’t “have to” at least for the demands of efoiling.
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### Author:  [@seantab](https://foil.zone/u/seantab)
#### Post date: [May 26, 2024, 9:30pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/4 "2024-05-26T21:30:22Z")
That’s good to know. This is my first battery pack build. I ordered a 300 amp dc breaker, and 16 wire connector just in case. I will do some measurements and update later on as i finish up the build.
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### Author:  [@Toto44](https://foil.zone/u/Toto44)
#### Post date: [May 27, 2024, 6:12am UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/5 "2024-05-27T06:12:50Z")
If you need it only for balancing, why dont you use just an active balancer from the same maker?
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### Author:  [@Larsb](https://foil.zone/u/Larsb)
#### Post date: [May 27, 2024, 9:35am UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/6 "2024-05-27T09:35:30Z")
Not needing BMS… that requires the pack build to be without issues.
An example where the bms would save you from risks is a single cell in a parallel group having poor spot welds, and cell breaking loose from the thermal cycling during use or vibrations. In a large pack there can be hundreds of failure points like this. I’ve tried it unfortunately🙂
It easily happens, you can’t really see it but the effect can be a fire. I think using a bms or smart bms monitoring is always a good idea
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### Author:  [@seantab](https://foil.zone/u/seantab)
#### Post date: [May 27, 2024, 12:52pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/7 "2024-05-27T12:52:38Z")
@Toto44 initially that was my intention to only use equalizer, but decided on smart bms 100 amp to make it multi use. It’s little more effort and cost is negligible, but could save time from building another pack in future.
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### Author:  [@seantab](https://foil.zone/u/seantab)
#### Post date: [May 27, 2024, 1:03pm UTC](https://foil.zone/t/power-off-bms-when-not-in-use/20810/8 "2024-05-27T13:03:53Z")
@Larsb 100% agree and and in my case i have to use BMS because I’m branching of 9s, 10, 11, 12, and 13s. If i use 9s let’s say in another application (though less likely), then this 100 amp bms should be capable of discharging unused 10-13 s at least that’s a thought.