Battery Isolator Switch

[Reeflodge]

Sorry if this has been mentioned before.
I want to add an isolation switch between the battery and controller box, I know it will be high ampage so will need quite a heavy duty switch.
At the moment every time I connect the 2 connectors together it makes a large spark.
Would this switch be ok to use and if so do I connect it in-line using the live or negative wire?

Disconnect Rotary Isolator, Sunwan Battery Switch Power with 12V, for Car Van Truck Boat https://www.amazon.co.uk/dp/B0823HFQSC/ref=cm_sw_r_cp_tai_k3WnEb7QQ3K3C

 

[Nealh]

All you need is simple push button on off switch which can handle the voltage, no amps flow when wired on the V+ side.
All current flows through the untouched V- wire.
I do just this and use a simple pane mount latching push switch.
With my battery holder I had the room on the base part to simply drill a 12mm hole and insert the panel mount switch on the V+ side ensuring the soldered joints are insulated.
I use these on all my batteries and also for the BMS switching.

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[Reeflodge]

All you need is simple push button on off switch which can handle the voltage, no amps flow when wired on the V+ side.
All current flows through the untouched V- wire.
I do just this and use a simple pane mount latching push switch.
With my battery holder I had the room on the base part to simply drill a 12mm hole and insert the panel mount switch on the V+ side ensuring the soldered joints are insulated.
I use these on all my batteries and also for the BMS switching.

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Find many great new & used options and get the best deals for 10pcs Mini On/Off Latching Latch Push Button Switch Locking Car 12mm 12V Black at the best online prices at eBay! Free delivery for many products!

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I already have a push button switch on the handle bar, but it doesn't prevent the spark when I am connecting the battery to the controller connector.
I want to isolate any discharge coming from the capacitors in the controller to prevent a spark when connecting the battery to it.

 

[Woosh]

don't add that switch.
If you have a mechanical switch, you simply move the spark to the switch which adds to wiring and is less accessible than your battery's contacts.
Batteries with switch have a FET based soft switch (google soft power switch) which prevents oscillations when the current flows through the junction.
If the sparks bother you, add a tiny smidgen of grease onto the contacts to reduce them.

 

[Reeflodge]

don't add that switch.
If you have a mechanical switch, you simply move the spark to the switch which adds to wiring and is less accessible than your battery's contacts.
Batteries with switch have a FET based soft switch (google soft power switch) which prevents oscillations when the current flows through the junction.
If the sparks bother you, add a tiny smidgen of grease onto the contacts to reduce them.

Surely if the power is isolated on the controller side it will not spark if it is turned off when I connect the battery?

 

[Woosh]

Surely if the power is isolated on the controller side it will not spark if it is turned off when I connect the battery?

Yes, that's true but you need to realise that the controller works with 3 voltages, 36V battery that feeds the motor, 14V FET drivers to drive the CPU and the FETs and 5V for sensors and signalling. The 14V and 5V are produced inside the controller from the 36V that you want to switch.
The on/off switch on your LCD or LED panel switches only the 14V line. You have to switch on the battery before you can switch on the LCD or LED panel, that's when the inrush current to the main capacitor causes the sparks.
If you don't have a soft electronic switch, you will hear the spark from your additional switch which is not any less unpleasant.

 

[Nealh]

I already have a push button switch on the handle bar, but it doesn't prevent the spark when I am connecting the battery to the controller connector.
I want to isolate any discharge coming from the capacitors in the controller to prevent a spark when connecting the battery to it.

The power button on the handle/bar display only stops the led/lcd from powering up, it doesn't prevent power direct between the battery and controller.

 

[Reeflodge]

The power button on the handle/bar display only stops the led/lcd from powering up, it doesn't prevent power direct between the battery and controller.

That’s why I wanted a switch to cut the battery power.
Every time I leave the bike to go in shop or pub people can mess about with it unless I disconnect the connectors every time which is a pain.

 

[Reeflodge]

Unless I can change the thumb throttle to one with a key?
My current thumb throttle with 3 led power indicator and on/off switch has a 6 pin connector, the key throttle one with a key and voltage meter has 5 wires, how can I change it?

 

[Reeflodge]

You've convinced me not to go with switch but I am going to fit Anti Spark connector instead.

 

[lenny]

 

[saneagle]

Old thread, but needs clarifying. Firstly, your battery already has a switch to switch off at low voltage or over-current. It's dead easy to hack into that with a manual switch to switch off the battery whenever you want.

Secondly, most anti-spark connectors are a waste of time. All they do is shroud the spark so that it doesn't scare you. The contacts still burn. To avoid the burning, you need a charge resistor that limits the current until the inrush has finished. That's a lot of unnecessary messing about and expense, compared with adding a switch to the battery. Some anti- spark connectors have the resistor.

If you like nerdy things, you can make a solid state soft start switch with MOSFETs, which is basically making an external version of what's already in the battery. Instead of adding the switch to the external version, it's just as easy to add it to the internal one, which is easier, simpler and cheaper. Maybe that's why his capacitor blew, and nothing to do with sparks.

Lastly, that guy in the video hasn't a clue. He has his battery the wrong way round so that the capacitor will explode.