DIY Electric Car Forums banner

[EVDL] 12v relay to switch 70V ~10mA?

1174 4
I need a relay with a 12V coil to switch 70V at about 10mA. I have the
wiring protected with a 1/4A fast blow fuse. This is to control the
line to a CycleAnalyst. The manual says that it only draws only 7mA
but I don't know if this is referring to the standard small display
version or the large display version. For this low of a current draw
will a 12V rated relay work safely? Also, will the voltage drop across
the contacts likely be less than the 0.1V resolution of the device? As
a point of comparison I notice that the auxiliary relays in the Zivan
chargers are rated at 30VDC 1A and 110VDC 0.3A.

Thanks,

--
David D. Nelson
http://evalbum.com/1328

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
1 - 5 of 5 Posts

· Registered
Joined
·
72,624 Posts
Discussion Starter · #2 ·
As Lee suggested, you can use a relay with a high enough contact AC voltage
that will work on DC. I pick up all my relays, fuse holders, circuit
breakers, fuses, terminal blocks, chassis rated wire, wire ties, flexible
plastic black conduit and black plastic conduit fittings from my local
electrical supply house.

I have been using a Square D Plug-In Relay Class 8501-Type KU that is rated
for 10 amps at 250 vac with a 12 volt coil which is use to control two main
contactors with 180 vdc coils that draw 0.33 amps each. Uses Type N relay
sockets that can be either mounted separately or track mounted using a DIN
mounting tract which can also be use to mount any size terminal blocks, fuse
holders, circuit breakers, switches, etc. These relays now have been in use
since 1975.

I am using a 3 pole relay with only one pole being use. The other poles are
spares just in case the working pole go's bad. Never had to switch the
poles yet, so I should be good for another 70 years.

Roland




----- Original Message -----
From: "David Nelson" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Saturday, September 04, 2010 8:05 PM
Subject: [EVDL] 12v relay to switch 70V ~10mA?


> I need a relay with a 12V coil to switch 70V at about 10mA. I have the
> wiring protected with a 1/4A fast blow fuse. This is to control the
> line to a CycleAnalyst. The manual says that it only draws only 7mA
> but I don't know if this is referring to the standard small display
> version or the large display version. For this low of a current draw
> will a 12V rated relay work safely? Also, will the voltage drop across
> the contacts likely be less than the 0.1V resolution of the device? As
> a point of comparison I notice that the auxiliary relays in the Zivan
> chargers are rated at 30VDC 1A and 110VDC 0.3A.
>
> Thanks,
>
> --
> David D. Nelson
> http://evalbum.com/1328
>
> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
 

· Registered
Joined
·
72,624 Posts
Discussion Starter · #3 ·
the cycle analyst has a capacitor for its internal powersupply.

the capacitor is behind a fairly high value resistor.

so on starting it acts like a resistive load, and on opening it acts as a
capacitive load.
thats about the best possible combination there is.

so I say go for it, a 12v relay should be fine.

Matt

----- Original Message -----
From: "David Nelson" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, September 05, 2010 11:05 AM
Subject: [EVDL] 12v relay to switch 70V ~10mA?


>I need a relay with a 12V coil to switch 70V at about 10mA. I have the
> wiring protected with a 1/4A fast blow fuse. This is to control the
> line to a CycleAnalyst. The manual says that it only draws only 7mA
> but I don't know if this is referring to the standard small display
> version or the large display version. For this low of a current draw
> will a 12V rated relay work safely? Also, will the voltage drop across
> the contacts likely be less than the 0.1V resolution of the device? As
> a point of comparison I notice that the auxiliary relays in the Zivan
> chargers are rated at 30VDC 1A and 110VDC 0.3A.
>
> Thanks,
>
> --
> David D. Nelson
> http://evalbum.com/1328
>
> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.851 / Virus Database: 271.1.1/3112 - Release Date: 09/04/10
02:34:00

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
 

· Registered
Joined
·
72,624 Posts
Discussion Starter · #4 ·
Thanks for all the perspectives, ideas and things to consider. I've
decided it may be best to get a properly rated relay. I'll be mounting
this under the dash of my Gizmo so the type with the mounting tab,
like the automotive relays, is easiest. Is there a small 70+ volt NO
relay with a 12V coil and with a mechanical latch so that it can
manually turned on? I'd like to avoid having to get a mechanical
switch rated at 70V for the occasional time I want to turn on the
CycleAnalyst without the 12V system operable. In the mean time I can
verify that what I want to do works as desired using an auto relay I
have laying around or, better yet, temporarily use one of my 150V 10A
relays.

--
David D. Nelson
http://evalbum.com/1328

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
 

· Registered
Joined
·
72,624 Posts
Discussion Starter · #5 ·
Hello David,

Yes, you can add a mechanical latching mechanism to a relay that is design
for it or get one that is all set up for it. The small glass square plug in
Square D Type KA relays can be a latching relay or add a latching mechanism
to it. GE, Westinghouse, ITE, Cutler Hammer and similar companies make the
same frame size relays you can get from any electrical supply house.

Roland






----- Original Message -----
From: "David Nelson" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, September 05, 2010 2:04 PM
Subject: Re: [EVDL] 12v relay to switch 70V ~10mA?


> Thanks for all the perspectives, ideas and things to consider. I've
> decided it may be best to get a properly rated relay. I'll be mounting
> this under the dash of my Gizmo so the type with the mounting tab,
> like the automotive relays, is easiest. Is there a small 70+ volt NO
> relay with a 12V coil and with a mechanical latch so that it can
> manually turned on? I'd like to avoid having to get a mechanical
> switch rated at 70V for the occasional time I want to turn on the
> CycleAnalyst without the 12V system operable. In the mean time I can
> verify that what I want to do works as desired using an auto relay I
> have laying around or, better yet, temporarily use one of my 150V 10A
> relays.
>
> --
> David D. Nelson
> http://evalbum.com/1328
>
> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top