30a ON/OFF switch

[Scooter]

Can anyone direct me to a place that has DC 30a switches?
I have a project bike and I need a switch to cut the juice when the bike is not in use. I do NOT have the standard aluminum case (with switch). I have mounted the battery without the case (for size reasons), and the down-side is I cannot find a switch to handle the Vector and a 48v/20ah LifePo battery. (the motor draws 30a continuous power, yes?)

thank you

[Bikemad]

I would use a double pole 16A switch and simply link the two poles together so they switch together in parallel and should therefore be able to carry 32A.

Alan
 

[Scooter]

Hmmmm...so it's okay to use an AC switch for DC? I'll give it a try.
Thanx

[Hastings]

I have given up on on off switches after "welding" a few heavy duty ones it is the thunges inside that will be heated they will stop working after a while.  I now use a Anderson SB style connector instead.  My weakest link then moved to my fuse holder that gave up repeataly without blowing my 30 amp fuse. The first  sign before stutering to a stop would be slower speed than normal on a full charge. I have given up on off switches after "welding" a few heavy duty ones it is the tongues inside that will be heated by the constant high current and they will stop working after a while.  I now use an Anderson SB style connector instead.  My weakest link then moved to my fuse holder that gave up repeatedly without blowing my 30 amp fuse. The first sign before stuttering to a stop would be slower speed than normal on a full charge. So now I use Maxi fuses and holders with a high contact surface such as this http://www.littelfuse.com/products/fuses/automotive-passenger-car/specialty-products/fhma.aspx.

I think the best idea  if you want an on of switch would be a heavy duty relay  then you could use a micro switch if you want
e Maxi fuses  and holders with a high contact surface. http://www.littelfuse.com/products/fuses/automotive-passenger-car/specialty-products/fhma.aspx.

I think the best if you want an on of switch would be a heavy duty relay for instance a 24 v 100 a  then you could use a microswitch if you want....

[Bikemad]

The arcing together of the switch contacts usually occurs when the power is first turned on as the short burst of high current charges the capacitors in the speed controller in a fraction of a second.

A simple resistor can be used to limit the current precharging the capacitors prior to operating the main power switch which should completely eliminate the high current surge.

A momentary push button in series with a 100 ohm resistor can be connected across the across the main switch contacts.
To use, simply press for about a second before operating the main power switch.
This will prevent the burning of the switch contacts that is usually responsible for early switch failure.

Alan
 

[Scooter]

Thanx Hastings and BikeMad,

I'm going to run down to (sucky) Osh and pick up a standard home light/flip switch. I had used one for a long while (over a year) on my MP3 with a 48w/10ah battery without a problem...I believe I used the little guy--the 15a/115v. I don't know for sure as it was a while ago. I took it off after someone put fear in my consciousness regarding AC/DC currents. So, with the 48w/20ah and MP4 I'll use the double pole 20a and do a bridge thingy between the poles, as per BikeMad. The "huge" downside is the goofy "look" of having a home electrical box and light switch dangling off the bike frame. (somewhat kidding--I can hide it). I did order a few rocker switches via the link you sent, BikeMad. Much cleaner look. It'll take a while to receive them.
I'll report after a while of the AC light switch set-up.

Oh, and still another thing--is there someone specific I can request a 20" extension cable for the MP4 (control harness)? I'm building another custom frame (recumbent) and I loathe cutting and soldering longer wires in between the existing "joints" (as the Chinese call them).

Thanx!

[Morgen 3Eman]

Hi Hastings,

Hey, I have to tell you there is a reason some current interrupters are called "Switches", and others are called "Connectors".  Switches are typically  design rated for millions of operations, while connectors are designed for a few thousand operations.   I have been using a 100A rated battery isolation switch, but if you look at my battery connection contacts, there are clear signs of damage from arc sputtering, and I would guess yours is the same.   The tin coating on the contacts is easily sputtered by the high current of initial contact.  If you can get some gold plated contacts, that would be a better choice as gold does not sputter well.  Small sized gold plated high current connectors are available from hobby shops that deal in electric model racers,  drones, etc.  Hobby King is where I got mine on line.  I don't remember the brand name. 

TTFN,
Dennis

[Morgen 3Eman]

The connector I used was a 250A PolyMax.

TTFN,
Dennis