Where to get a 48V 40A relay

[hary]

Where to find a 48V 40A relay ?
That's to do my "project" :
http://endless-sphere.com/forums/viewtopic.php?f=7&t=19360

To connect and disconnect the battery from the controller when not in use only using a push button !
I've previously been using a 24V 7A relay using the 4 switches inside (4*7=28A) but I have to put some resistor to minimize the voltage on the relay winding !
And the fact of using four 7A switches instead of 1 good one doesn't make me feel good !

So I'd like to find a proper 48V 30A or 40A like standard car or truck relay.
http://radiospares-fr.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3080649

Could I modify a standard 12V or 24V car relay to a 48V ?

I forget the use of a static relay because of the voltage loss and heat production !

 

[deronmoped]

Just wind your own coil.

I used to work in a motor repair shop and we rebuilt motors all day long. It's not that big of a deal, the hardest part would be finding a relay that would be easy to pull the coil off of so you could rewind it. Use a drill motor and magnet wire. Count the wraps on a 12 V one and quadruple it. You would have to use smaller wire though to fit all those wraps on the same coil.

Deron.

 

[hary]

Thank you very much for your answer deronmoped

That's what I thought, but The better relay I have (a 24V 40A) has already a lot of wire on it and it will be hard to find space to do more winding !

And the wire in place is already so little, smaller than a hair, that I can hardly believe it's possible to find a smaller one ! In any case it would be extremely fragile !

any idea where to find hair wire ? or even smaller ?

 

[EVan]

It's not a huge problem to use a resistor in series is it? OK a little power is wasted..

You could use a coil economiser circuit instead - it could use less power than the directly connected relay.

Or, don't use a relay at all, just use a 12V isolator switch (tractor battery switch) -

No power use, nothing to go wrong, carries far more current than you need..

Just an idea to avoid the tedious job of rewinding

 

[AmpEater]

This is what you want
http://cgi.ebay.com/Heavy-Duty-48-V-200-Amp-Contactor-Solenoid-Golf-Cart-/390198270521?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5ad9a11a39

I have an extra from when I bought a few alltrax controllers I could sell, if $60 is too much for you.

I like to over rate contactors especially, and even moreso contactors that make or break any sort of significant load. That way you can trust they will do what you tell them when you tell them to do it.