ebike key switch

[Footie]

Does anyone know where I can get an ebike key switch?
I am thinking about the imminent arrival of my new battery, but I think I would like to have two batteries for my bike.
I'm thinking about making up a second battery case with the new battery. The switch has to go into a circuit that is 36 volts and that has a maximum drain around 20-25 amps. Maplins are 12 volt so no good.
Any pointers, anyone?
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[john]

The maplin switch is rated 10A at 12V, 4A at 240V. So for 36V it will be somewhere in-between. I would say that these are currents that it can switch rather than it can carry. As you will be swtiching before you activate the controller, your switching current would not normally be more than 1A.

My guess is that if it will switch 10A it will be able to carry a fair bit more and you may be ok with it. You could check with Maplin but they probably won't no any more than the spec.

 

[Footie]

Thankyou John - I have never been good at electrics

So if I understand you correctly, you’re saying:

at 12 volts the switch can take 10 amps,
at 42 volts the switch can take 9 amps,
at 80 volts the switch can take 8 amps,
at 118 volts the switch can take 7 amps,
at 156 volts the switch can take 6 amps,
at 194 volts the switch can take 5 amps,
at 240 volts the switch can take 4 amps.

So at 36 volts the switch should be able to take 9.5 amps (roughly).
And as you say, "designing on the plus side" should mean the switch would take a bit more.
Providing I don't try to switch it when at full throttle (unlikely) it should be ok.

I will get one and give it a try.
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[Ian]

I agree with John in that the switch rating is it's switching capacity, rather than it's carrying capacity which will be higher. The lower current rating at higher voltage is a result of arcing that will take place when the switch interrupts the current, but in this application the switch won't be turned off while carrying current so there is no need to de-rate it for 36V.. in other words it should be good enough.

Does it have to be a key switch though? Apart from the ability to physically lock the battery in place, which is not relevant in this case, I often thing key switches serve little purpose on bikes. After all, the lack of a key is not going to stop a thief riding the bike away.

 

[Footie]

Does it have to be a key switch though? Apart from the ability to physically lock the battery in place, which is not relevant in this case, I often thing key switches serve little purpose on bikes. After all, the lack of a key is not going to stop a thief riding the bike away.

I suppose, it does not have to be a removable key switch.
However, a switch with a removable key serves two purposes (for me).
1. It will ensure the power is turned off when stopped - leaving the key could mean it's stolen. So it's good reminder for me.
2. Turning it off and removing the key means no one can turn it back on while it's left locked up and unattended or mess about with it.
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