BMS On/Off switch wires?

Batteries, Chargers, and Battery Management Systems.
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rg12   100 kW

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BMS On/Off switch wires?

Post by rg12 » Jan 10 2017 5:33am

Hey Guys,

I got this BMS that has two white thin wires coming out of it and it says that it's the On/Off switch.
Why do I need an On/Off switch? the switch for the battery is in the lock while off it's cutting the red wire from the bottom part of the battery to the battery itself.
Where do I connect those thin wires?
It looks like these two white wires in the middle (not the same BMS though):
Image
24S 17.5Ah 25R, Greentime Controller, QS203 5KW

Joachim   1 kW

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Re: BMS On/Off switch wires?

Post by Joachim » Jan 10 2017 6:46am

this is a 13s bms?
You have 13 sense wires for B+1 up to B+13 and number 14 for B-
One side of the bms you have 2 wires open and this wil be the on/off switch for the bms.
The white in the middel is the temp sensor.

Just put these 2 wires that are open togheter and the bms in always ON(so not the 2 wires to the temp sensor)

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rg12   100 kW

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Re: BMS On/Off switch wires?

Post by rg12 » Jan 10 2017 7:40am

I soldered the two together (it was a switch for sure, not the temp sensor wires) so the BMS will be on and I thought that I did something wrong since the battery has a random problem that when the switch is turned on the voltage that comes out below the pack either is constant like it should be or goes away after a second.
I first thought it was a switch problem but I wiggled the key in every switch position, pulled on the wires inside to try to make it happen at will and it didn't so it seems that it's something with the BMS.
24S 17.5Ah 25R, Greentime Controller, QS203 5KW

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Ykick   100 GW

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Re: BMS On/Off switch wires?

Post by Ykick » Jan 10 2017 7:59am

Have you tried pushing a charge into the pack through BMS?

Some of the BMS with on/off switch I’ve used needed a brief charge current to “activate” the circuit.

Dunno why but that’s how the BMS w/switch behaved for me?
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

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rg12   100 kW

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Re: BMS On/Off switch wires?

Post by rg12 » Jan 10 2017 8:15am

Ykick wrote:Have you tried pushing a charge into the pack through BMS?

Some of the BMS with on/off switch I’ve used needed a brief charge current to “activate” the circuit.

Dunno why but that’s how the BMS w/switch behaved for me?
What do you mean by a brief charge? connecting the switch wire to the + wire or something?
24S 17.5Ah 25R, Greentime Controller, QS203 5KW

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Ykick   100 GW

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Re: BMS On/Off switch wires?

Post by Ykick » Jan 10 2017 8:21am

rg12 wrote:
Ykick wrote:Have you tried pushing a charge into the pack through BMS?

Some of the BMS with on/off switch I’ve used needed a brief charge current to “activate” the circuit.

Dunno why but that’s how the BMS w/switch behaved for me?
What do you mean by a brief charge? connecting the switch wire to the + wire or something?
No.

On/off wires should be ON (switch closed) and then apply a charge to the charge port or discharge port if they're the same.

Just like you would normally charge the battery pack. In my experience, the BMS w/switch required a brief charge for the BMS to work normally.

I dunno if BMS is the same but simple thing to try?
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

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rg12   100 kW

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Re: BMS On/Off switch wires?

Post by rg12 » Jan 10 2017 8:50am

So before every ride I have to stick the charger in?
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Ykick   100 GW

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Re: BMS On/Off switch wires?

Post by Ykick » Jan 10 2017 9:11am

rg12 wrote:So before every ride I have to stick the charger in?
No. The BMS I've used with on/off switch worked normally as expected after the initial connections to the battery and a shot from a charger.

But if you ever disconnect the battery from the BMS it will require a shot of charge before it will work again. That happened to me out riding one time and fortunately I also had a range extending pack so I just swapped out packs and continued on until I got home to the charger.

No guarantee it will work for your BMS although the on/off switch versions I've used, that's how they behaved.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

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rg12   100 kW

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Re: BMS On/Off switch wires?

Post by rg12 » Jan 10 2017 12:24pm

I have charged it for the first time through the BMS up to about 90% charge and that auto switching off thing happend afterwards...
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kuririkura   10 mW

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Re: BMS On/Off switch wires?

Post by kuririkura » Jun 29 2019 8:14am

Sorry guys, i know this an old thread,
But i just got my battery pack and it's included with a switch, the seller says that this a bms switches.
Should I always keep it on, or should i turn it off when i'm not use the bike?

And should I turn it on/off while charging?

hemo   100 W

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Re: BMS On/Off switch wires?

Post by hemo » Jun 29 2019 6:07pm

Switch on when charging and off when not in use.

kuririkura   10 mW

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Re: BMS On/Off switch wires?

Post by kuririkura » Jul 04 2019 8:54pm

hemo wrote:
Jun 29 2019 6:07pm
Switch on when charging and off when not in use.
Thanks!

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Matador   10 kW

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Re: BMS On/Off switch wires?

Post by Matador » Jul 13 2019 8:39am

rg12 wrote:
Jan 10 2017 5:33am
Hey Guys,

I got this BMS that has two white thin wires coming out of it and it says that it's the On/Off switch.
Why do I need an On/Off switch? the switch for the battery is in the lock while off it's cutting the red wire from the bottom part of the battery to the battery itself.
Where do I connect those thin wires?
It looks like these two white wires in the middle (not the same BMS though):
Image
That white rectangel connected to the white wire is most likely a THERMAL on/off switch... So that the BMS shuts down if the battery ever overheats... That would be my guess.

Matador

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