Super clean "ON/OFF" handlebar switch installations

[BVH]

Got my new ebike, a Commencal Meta 4.2 with BMC V3 1000 Watt motor, 51V, 30 A LiPo, temporary CLite 72V, 40 A controller. Waiting for a modded Kelly controller. I'm doing lots of tweaking so I haven't even ridden it yet. I'd like to install a handlebar mounted On/Off switch. I can't seem to find any ready-made kits. I'd rather not run full power and large wires to the bars but would rather use a remotely actuated relay/contactor. Can anyone point to ready made kits if there are any? I'd like something that looks like it came on the bike. It would be great if those who have done this could post pics and describe what they've done.

 

[rkosiorek]

something like this maybe?

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3047

many of the scooter parts stores also have something similar. like TNC Scooters or Scooterparts4less.

rick

 

[rkosiorek]

or you could Roll Your Own.

http://www.endless-sphere.com/forum...764&p=106389&hilit=+handle+bar+switch#p106389

rick

 

[TylerDurden]

You might also consider a hidden switch. With 1000W motor and a Kelly controller, keeping unauthorized users from energizing the system could save your bike (and you) unwanted trouble.

 

[BVH]

The above switch is perfect for controlling a relay - I'm making an assumption it would not handle 50 or 60 Amps? The hidden switch is also a great idea, I will do that too. Although, I never plan to leave the bike even for a minute, the best laid plans of mice and man....... Any specifics on a good relay - probably a 36 or 48 Volt actuated unit?

 

[rkosiorek]

you would have to use a relay with that to handle 50 amps.

cheapest would be to parallel up a couple of automotive relay contacts. wire the coils in series. use either a series resistor or a current limiter in series with the coils for the higher voltage. the relay coils will consume about 2~3 Watts.

rick

 

[BVH]

Thank you Riosiorek! You gave me what I need to make it somewhat easy. I will use a small, aux, 12V battery and the handlebar switch shown above to power 3 separate 20 or 30 Amp relays wired one to each of the 3, 10 AH paralleled packs. This will also solve my great dislike of the always surprising and annoying sparks I get at the Deans connectors when connecting the packs together. As long as the handlebar switch is off when connection the packs, no sparks! I still haven't figured why this happens with no loads connected. Unless it's the very minimal Voltage difference between the packs causing them to want to start equalizing upon connection.

 

[BVH]

Something i just remembered. I'm running close to 60 Volts with full charged batteries. The typical relays I've been looking at are rated at 12 Volts (both for the coil and the current circuits). I know that voltage and current go into rating an electrical device and it's usually just a matter of coming up with the size/mass of the conducting material. I wonder if I bought the 12 Volt relays rated at 60 Amps and they'll never see more than 15 Amps thruput, (and I still energize them with 12 Volts) if they would work ok? If I divide the Amp rating by 4, can I multiple the Voltage by 4?

EDIT: Found a 48 Volt, 200 Amp continuous duty relay. It says 110% of 48 Volts can be applied to the activation coil maximum. For those of you that know how to reduce voltage with resistors, what would I need to buy to lower my max 59 system Volts to approx 50 Volts? The coil circuit pulls 8 Watts. It will energize with as low as 67% of 48 Volts so no problem there.

 

[Gregte]

EDIT: Found a 48 Volt, 200 Amp continuous duty relay. It says 110% of 48 Volts can be applied to the activation coil maximum. For those of you that know how to reduce voltage with resistors, what would I need to buy to lower my max 59 system Volts to approx 50 Volts? The coil circuit pulls 8 Watts. It will energize with as low as 67% of 48 Volts so no problem there.

If the coil is using 8 watts at 59 volts then it is drawing 0.136 amps.
E /I =R
59 / .136 = 434 Ohms resistance in your coil.

You need to devise a voltage divider such that the voltage measured across the coil is 50 volts according to what you have said above. So, 50/59 is the same as 434/512. So you need a total resistance of 512 Ohms. You already have 434 in the coil so an additional 78 Ohms in series with the coil should give you 50 volts across the coil when there is 59 volts across the coil and resister combination.

You might want to double check my math as I just got up today and could have some left over 'dumb' from yesterday still hanging on.

 

[BVH]

I went back and found some more specs on this relay.

Coil resistance at 48 Volts = 336 Ohms
It uses 8 Watts at 48 Volts

I tried playing with the formula but I get a bit confused. How does the 336 Ohms change your original figures?

 

[rkosiorek]

how much is that relay worth?

while browsing ebay today i found this:

500A carry and 2000A break. only $62.00. coil works with 9 to 36V. designed for EVs just search ebay for "kilovac"

for higher voltage systems you just need a bit of a regulator.


Truly over kill but depending on the cost of that 48V relay?

rick

 

[BVH]

Rkosiorek, Great find! There's even a model that will work with my system voltage, no resistors or other mods required. I contacted the seller and am awaiting a response on the 48-96 Volt model. Thanks again!

 

[BVH]

I couldn't find the 48-96 Volt version for less than $157 so I bought the 9-36 Volt version and will split power to energize it off of one battery brick @ 29 down to 21 Volts. An added benefit is this relay draws only 1.7 Watts - as compared to 9+ Watts of the original relay so no impact on my range and no real effect on unbalancing the one brick of the two brick, 50 Volt pack.

 

[Grinhill]

Another option for a high-current contactor from a robotics source posted previously:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=10573&start=15#p162834

 

[rkosiorek]

Another option for a high-current contactor from a robotics source posted previously:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=10573&start=15#p162834

this relay also burns 8 or 9W to energise the coil. but that is the only drawback.

rick

 

[BVH]

I've decided to go with the proper Kilovac - 500 Amp capacity activated with anywhere from 32 to 95 Volts. I have the 9-24 Volt version and its is nice and small and light. A very well made relay and it only consumes 1.4 Watts at my Voltage. I also have the original White Rogers brand 500 Amp, 48 Volt that I was going to resistor down. It's really beefy, large and heavy. Hope I can use the other two in the future.