Temp wire/on-off switch lws 20s40a

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Beno

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Mar 6, 2021
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Hi. I am trying to source a bit of info relating to the lws bms temp wire, can it be used as a on off switch if cut and wired to the existing switch within the case as it was on the original bms as it won't charge unless turned on.
 

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italianuser

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Feb 25, 2020
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Producer doesn't give much information http://www.lws-pcm.com/en/product/.

On laptop BMS boards I noted the same thing, without temperature sensor they wouldn't work, I suppose because it's becomes an open circuit.

What do you want to switch on/off, the whole battery pack? I wouldn't touch the temperature sensor. To disconnect the whole battery pack I have a 100A manual switch on one of the battery cables. I'm no expert on BMS boards but I always saw them as an integrated part with the battery once mounted. If I had to disconnect a BMS digitally I suppose it could be done by interrupting all of the thin wires.
 

Beno

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Mar 6, 2021
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So I took a chance and cut the wires and made a connection to the power switch and attached the charger. I had to unplug and then plug back in which switched the charge light on. So the white temp wire can be used as a on/off . I'll post an update here once I've taken it for a test run. Thanks
 

italianuser

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Feb 25, 2020
Messages
376
I'm happy with your test. But I'm not quite sure about connecting a switch instead of the sensor. I found a datasheet for a model of the BS02 family: https://asset.conrad.com/media10/ad...nitor-0-up-to-160-c-radial-lead-1-breaker.pdf (PDF attached).

That model should be a temperature&temperature dual protection sensor, see here: https://www.bto.pl/pdf/05761/seria tb02.pdf (PDF attached below, too).

What I'm saying is that that kind of sensor has an autoreset feature which, if managed by the board in any way, could possibly activate giving you unexpected behaviour.

So, ok for your test, but maybe keep it under observation for at least a week (I also found a 96 hour parameter somewhere in the net).

See you in 96 hours!

Enjoy!
 

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  • datasheet-507867-tb02-bb8d-125-temperature-monitor-0-up-to-160-c-radial-lead-1-breaker.pdf
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