Power relays?

[ShreddinPB]

Hey guys, I have a little problem I am trying to solve. I have a electric trike I built. I added a key switch to it. The trike is 48V 1000W. So in order to switch on and off the power to the motor, I need a pretty beefy relay right?

I had this one laying around, and wired it up and it works fine (havnt put the 48v thru it yet but tested connections)
http://www.amazon.com/gp/product/B008BGLM02/ref=wms_ohs_product?ie=UTF8&psc=1
Will this actually work? The output connection rates at 5A and 40~480VAC, but I need to use DC? or does that matter?

if that one wont work, can I use this?
http://www.amazon.com/Amico-Green-I...d=1377049698&sr=8-9&keywords=24v+80a+relay+dc
Its 24V but rated at 80A, since 48V 1000W is 20.8A, can it take the 48V thru it?
Can it take a 48V input? I have a seperate 12V system on it for lights and the such.. can that switch it?

Sorry I am new to Relays

thanks guys!

 

[bowlofsalad]

Maybe I don't understand. Do you know what a relay does exactly? I am not trying to offend you when I ask this question. If you aren't absolutely certain, how do you know you need it? I am not sure you need it, because I might not understand what you are trying to achieve.

https://en.wikipedia.org/wiki/Relay

"Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal."

I think you are looking for something other than a relay. Most controllers have a either an on/off switch on it or wires to which you can connect a keyed switch to. http://endless-sphere.com/forums/viewtopic.php?f=2&t=52206 This thread might give you a tiny bit of insight into other options.

 

[ShreddinPB]

Maybe I don't understand. Do you know what a relay does exactly? I am not trying to offend you when I ask this question. If you aren't absolutely certain, how do you know you need it? I am not sure you need it, because I might not understand what you are trying to achieve.

https://en.wikipedia.org/wiki/Relay

"Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal."

I think you are looking for something other than a relay. Most controllers have a either an on/off switch on it or wires to which you can connect a keyed switch to. http://endless-sphere.com/forums/viewtopic.php?f=2&t=52206 This thread might give you a tiny bit of insight into other options.

Well yeah, a relay is what I was asking for then. I have a small key switch
http://tncscooters.com/index.php?route=product/product&path=49&product_id=201
I dont think those little wires can handle 48v up to 20.8A.. so I was looking for a way to use that key switch to cut off battery power for the whole thing.
So a relay is in order right?
I use the battery for other things also and would like the key to completly shut it off

thanks!

 

[ShreddinPB]

As a side question, if I do want to just cut the controller off with the key switch, which wire do I splice into? THe +, -, or the throttle? I assume any one would work?

my controller
http://www.tncscooters.com/YK43B.php

 

[shenzhen_ex]

I am very interested in this thread but unfortunately I cannot offer much tech support.

I recently added a $5 contactor rated at 150A on my Ebike (link to contactor thread). It connects and disconnects the battery without sparks.

I still don't know if that contactor was necessary... but i like it.

 

[CroArcher]

Four relays rated 12V=48V in series;four contacts of these relays 20A=80A in parallel,cheap and bulky but works

 

[d8veh]

Well yeah, a relay is what I was asking for then. I have a small key switch
http://tncscooters.com/index.php?route=product/product&path=49&product_id=201
I dont think those little wires can handle 48v up to 20.8A.. so I was looking for a way to use that key switch to cut off battery power for the whole thing.
So a relay is in order right?
I use the battery for other things also and would like the key to completly shut it off

thanks!

Most controllers have a key-switch connection or ignition wire. It's that one that you connect your key-switch to, This method cuts the power to the controller. The battery is still connected, but nearly all the power is blocked.

If you don't have this wire, you can do it with FETs rather than a relay. There'es a thread running here how to do it.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=52701

 

[ShreddinPB]

Well yeah, a relay is what I was asking for then. I have a small key switch
http://tncscooters.com/index.php?route=product/product&path=49&product_id=201
I dont think those little wires can handle 48v up to 20.8A.. so I was looking for a way to use that key switch to cut off battery power for the whole thing.
So a relay is in order right?
I use the battery for other things also and would like the key to completly shut it off

thanks!

Most controllers have a key-switch connection or ignition wire. It's that one that you connect your key-switch to, This method cuts the power to the controller. The battery is still connected, but nearly all the power is blocked.

If you don't have this wire, you can do it with FETs rather than a relay. There'es a thread running here how to do it.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=52701

I posted a link to the controller I am using and I dont believe it has that connection?
It only has power in, motor out, and a 3 wire from the throttle, with, throttle, +, -.

I ordered the FETs but they wont be here in time for me to put it together for this weekend.. oh well will juts be plugging it in

 

[dnmun]

you can put a switch on the circuit current in the BMS and turn off the BMS in order to connect the controller without a spark.

 

[ShreddinPB]

you can put a switch on the circuit current in the BMS and turn off the BMS in order to connect the controller without a spark.

That would require taking my battery box completly apart, which at the moment is not an option.. need it for this weekend

 

[alsmith]

It depends on exactly what you are wanting to achieve.

The simplest way is to add the key switch into the power lead to the throttle. No signal to the controller so no throttle, and you're switch would be ok without relays.
If you're wanting to disconnect the battery then you're relay/FET or some kind of large mechanical switch is the way to go. Or you could add a removable plug into one of the power leads that would need to be in place for the bike to operate. Not many people will have a loopback connector, and if out of sight....

Or both?