Remote control power switch

danielrlee

danielrlee

10 kW
Joined
Mar 29, 2013
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506
Location
Wiltshire, UK
I have recently been looking into ways to implement remote power switching into my electric bike. Browsing through ebay listings, I came across these and wondered if either would be suitable. They appear to be based on the same relay, but differ in board design.

http://www.ebay.co.uk/itm/400649497789

http://www.ebay.co.uk/itm/171188670543

I want to switch a 50VDC 23A load and was hoping that somebody with a much better knowledge of electronics than I (there are many of you) could tell me with confidence.

Thanks in advance for your assistance.

EDIT: I recognise that there may be better ways to implement this functionality involving contactor's, SSR's, SCR's and probably other methods, but the solutions in the above links appeal to me because they are fully integrated and probably easier to implement.
 
I had looked at doing something similar myself, I was going to remotely switch the controller off via its on off circuit. The 72v 40a Infineon based controller from ebike.ca has no current draw from the pack when switched off. The problem I needed to over come is where to power the remote circuit from, it will always have some current draw?
The solution I came up with is to have both the std on off rocker switch on the controller to isolate the pack and the remote switch fitted after this, so the remote can break the circuit for security when out and about but the current draw from the relay board can be eliminated manually by the switch when the bike is garaged, if this caused the relay to open too that would be good requiring the remote to be activated after turning the switch on to get everything live.
Doing it this way with the remote relay board integrated inside the controller someone would need quite extensive knowledge to bypass it.

I don't know of a solution that can handle the whole systems current draw.
 
DC variants are available, but none that I can find which would cope with my power requirements. Having done a bit more research, it seems that the most commonly favoured switching method is using a contactor. Would I need to do the same at 50v?

My requirements are (in order of importance):

1) Security - l already have a handlebar mounted cutoff, but this can be fiddled with by anyone while the bike is left locked and my turnigy watt meter is left powered. Also, I don't like the idea of a hidden switch.

2) Keyless - I don't want to be faffing about with another key lock.

3) Power consumption - Obviously any radio circuitry would remain powered when locked, but additional power drain while the bike is running needs to be kept to a minimum. Long term parasitic drain isn't a concern since my charging routine involves disconnecting the battery and I charge after every use at the end of the day. I would be happy with a solution being powered from the main battery, or a small auxiliary battery.

4) Robustness - I don't want to have to replace components too soon due to arcing.

5) Ease of installation.

Putting together a solution using an off-the-shelf radio control circuit and a suitable switching component shouldn't be difficult, but why should I favour, say a contactor over a solid state relay, or a thyristor, or even a regular relay?
 
I believe the contactor is used because it can safely switch high voltage current from a very low voltage signal.
I would have a separate battery powering the receiver circuit...it wouldn't need to be much...probably a 9V would be all you'd need to run the RF circuit and toggle a contactor.
 
ev tocak said:
you could use something like this
http://www.ebay.com/itm/Car-Remote-...Parts_Accessories&hash=item35cb45304f&vxp=mtr
,also u would need latching relay and 12v dc-regulator to power it ,

or this http://www.ebay.com/itm/5pcs-4-CH-4...ion_Controls_Touchscreens&hash=item1e71874dda then you could use normal relay of 30A
Click to expand...
Cheers. Yeah, the second link is along the lines of what I have been looking at so far. A second channel could also be used for an alarm :)

Not so sure about using relays though. I'm starting to look into using MOSFETs for the switching, but some of this is new to me and I'm still trying to weigh up the pros and cons versus other methods.
 
You can use any RFID module to operate it:
http://www.ebay.co.uk/sch/i.html?_odkw=rfid+switch&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR1.TRC0.A0.Xrfid+module&_nkw=rfid+module&_sacat=0

Then you need to make one of these to switch the power. The RFID unit goes where the switch is shown in the schematic. I use these power switches on nearly all my bikes:



 
Dave, that is fantastic! Thank you. You always come to the rescue when I'm in a pickle. My knowledge of electronics is still fairly elementary, but it looks like the gate is bought up to voltage gradually and the resistor alters this timing. Is this correct?

Are RS Components a safe bet for genuine 4110's?
 
d8veh said:
You can use any RFID module to operate it:
http://www.ebay.co.uk/sch/i.html?_odkw=rfid+switch&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR1.TRC0.A0.Xrfid+module&_nkw=rfid+module&_sacat=0
Click to expand...
I like the idea of using RFID tags, but I'm not sure the range of those low power tags will prove to be practical. How about a higher powered transponder used on keyless cars? If the power requirement isn't too great, that could be a good solution. Failing that, I'm still happy to use an RF transmitter. Either way, I think I've found my solution :) Thanks again.
 
danielrlee said:
...that is fantastic!
... My knowledge of electronics is still fairly elementary, but it looks like the gate is bought up to voltage gradually and the resistor alters this timing. Is this correct?
Click to expand...
This parallel FET switch concept is the topic of more than one thread here...
Discussion of various switching, loading, and component considerations are to be found in these threads. This post has a calculator for selecting FETs for various current loads.

And although you have rejected the idea - here's a thread on an integrated RFID solution.

You need to search more....
 
Thanks. You're right though. I clearly DO need to search more. As with all search engines, results are often dependant on the specific keywords used, and I'm still learning here. Thank you for taking the time to compile that list of threads for me. I've got a lot of reading to do.....
 
Giovanni LiCalsi said:
It's an iPhone. You can use an Android phone, as well. Doesn't get any better than that. You can use your phone or tablet for the switching and also the dashboard gage cluster, then take it with you.
Click to expand...

Got a real link?
 
Giovanni LiCalsi said:
It's an iPhone. You can use an Android phone, as well. Doesn't get any better than that. You can use your phone or tablet for the switching and also the dashboard gage cluster, then take it with you.
Click to expand...
What if your phone battery runs out? Mine does. Often.
 
Mmm...put a USB charge port on the bike, powered off your traction pack?

I guess you'd have to have that not switched by the remote switch, though, in case the phone is dead when you come up to the bike to go somewhere.

However, a simpler method would simply be to have a bypass switch somewhere physically on the bike...which I guess could defeat any security-purposes you have for the remote. :(
 
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