Group Buy - Gigavac high voltage relays

IF YOU ARE NOT A FINANCIAL MEMBER OR YOU HAVE LESS THAN 30 POSTS AND YOU POST ANYTHING FOR SALE, IT WILL BE DELETED.
Forum rules
All may view this forum, only AEVA Members may post here.
Post Reply
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Hi all,

I am about to drop a shirtload of cash on a high voltage relay for the race bike. These relays are ideal for switching the precharge and discharge loads of most large motor controllers, as they are designed to withstand very high DC voltages without failing. Also, they are about as compact as you can get - just 38 mm across and 46 mm tall.

http://www.gigavac.com/products/relays/ ... /index.htm

I need one for my race bike, and I will eventually need one for my car. However there is a substantial price break after just five units.

G12SP-12Vdc
1-4 pcs = $607.00 each – Less 15 % university discount
5-9 pcs = $473.00 each - Less 15 % university discount
Lead-time to Ship: stock

If anyone is interested in buying one of these for their projects let me know and I can add them to the list.

Cheers,
Chris



AEVA National Secretary, WA branch chair.
Tritium_James
Senior Member
Posts: 683
Joined: Wed, 04 Mar 2009, 17:15
Real Name: James Kennedy
Contact:

Group Buy - Gigavac high voltage relays

Post by Tritium_James »

Make sure you get the variant with the aux contacts, they're not much more as far as I can remember, and they're good for those with a BMS that can use it - it means you can detect welded shut or failed open contactors.

You also want the "dual-coil" type, they have dramatically reduced power consumption once they've pulled in. Should be part number GX12SAB.
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Thanks James. I'm already using the contactors with auxiliary contacts for the high current stuff, but this relay will be used for switching the precharge and discharge circuits. It won't experience high currents, but it will cop full pack voltage. I measured the current draw for all 4 contactors and I get 2 amps. The HV relay wouldn't add more than half an amp at worst.
AEVA National Secretary, WA branch chair.
User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Group Buy - Gigavac high voltage relays

Post by BigMouse »

jonescg wrote:this relay will be used for switching the precharge and discharge circuits. It won't experience high currents, but it will cop full pack voltage.


Wow, you're shelling out $600 just for precharge?

I've designed a solid-state precharge circuit for the very reason that contactors are too big, heavy, and expensive to be used for precharge.

The most recent version of it is integrated in to my motor controller's main HV circuit board. It precharges/discharges at up to 8A through a resistor (I use 50ohm for my ~400vdc pack, can charge 2400uF in 0.6s). Voltage rating is determined by the components used. Mine uses 800vdc components. It also detects failed open/closed contacts on the main relay by measuring capacitor voltage vs battery voltage. This is necessary to prevent resistor overheating and failure from sustained high-power dissipation in the event of contactor failure (or in the case of a stand-alone application, controller trying to draw current through resistor before contactor closes).

Maybe I should sell these things as stand-alone products?

Alternatively, I've come across 450vdc relays. They're around $24 each, but only SPST N/O, so can only precharge. Part number I was looking at: Fujitsu FTR-J2AK012W and supplied by www.mpmcomp.com.au
User avatar
evric
Site Admin
Posts: 503
Joined: Sun, 20 Jul 2008, 01:57
Real Name: Eric
Location: Adelaide SA
Contact:

Group Buy - Gigavac high voltage relays

Post by evric »

{Quote]
....
Alternatively, I've come across 450vdc relays. They're around $24 each, but only SPST N/O, so can only precharge. Part number I was looking at: Fujitsu FTR-J2AK012W and supplied by www.mpmcomp.com.au[/QUOTE]

I checked out this website... How do you find info on the relays?
Prius Plug-in Conversion: http://www.evplus.com.au ...Holden Barina EV: http://www.evric.kestar.com.au
User avatar
Johny
Senior Member
Posts: 3733
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

Group Buy - Gigavac high voltage relays

Post by Johny »

BigMouse wrote:I've designed a solid-state precharge circuit for the very reason that contactors are too big, heavy, and expensive to be used for precharge.

......This is necessary to prevent resistor overheating and failure from sustained high-power dissipation in the event of contactor failure .....
You still need a contactor(s) in series with your solid state precharge(s) or it's not safe. It won't pass NCOP14.
User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Group Buy - Gigavac high voltage relays

Post by BigMouse »

Johny wrote:
BigMouse wrote:I've designed a solid-state precharge circuit for the very reason that contactors are too big, heavy, and expensive to be used for precharge.

......This is necessary to prevent resistor overheating and failure from sustained high-power dissipation in the event of contactor failure .....
You still need a contactor(s) in series with your solid state precharge(s) or it's not safe. It won't pass NCOP14.


What part of NCOP14 would it not be in compliance with?

EDIT: I think I found it: "Disconnection of the traction pack from the rest of the traction circuit must be by a contactor operated by the ignition switch."

Well, the 450vdc relay may be suitable anyway.
Last edited by BigMouse on Thu, 10 Jan 2013, 12:35, edited 1 time in total.
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Yes, I know it's expensive, but I will know the relay is rated for the voltages it will be experiencing. Even at low currents, high voltage sparks can cause damage to regular relays. If it were to weld to the contacts you would have a big spark when the resistor finally popped.

So far, it is the only relay I can find which is rated for switching high voltages (up to 8000 VDC). No other relay is rated this high. Likewise my precharge and discharge resistors need to be rated to 700 V or higher.

$400 each is surely better than $600 each!
AEVA National Secretary, WA branch chair.
User avatar
Richo
Senior Member
Posts: 3737
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Group Buy - Gigavac high voltage relays

Post by Richo »

Mmmm sounds over engineered.
I'd go with 2 Kilovacs and resistors.
Probably all less than $200

When do you plan on getting an 8kV pack?
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Yeah, that would probably work fine, I don't have the room on the bike unfortunately.
AEVA National Secretary, WA branch chair.
User avatar
Richo
Senior Member
Posts: 3737
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Group Buy - Gigavac high voltage relays

Post by Richo »

This is only because of the racing rules - right?
Does the Controller need precharge?
Do you know what the controller capacitance is?
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Yeah, the rules state that when shut down, the battery must be completely isolated from the controller and motor and that the capacitors inside the controller must be discharged to below 50 V within 5 seconds. Leaving a resistor across the contactor would keep the controller charged up.

The controller has 560 uF of capacitance, so yeah, it needs precharge. I have ordered two 50 W 1kR resistors from RS which should do the job. It should be 97% charged after 2 seconds, and discharged to below 20 V after 2 seconds. I'm thinking I should delay it to 3 seconds to be safe.
AEVA National Secretary, WA branch chair.
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Hi Guys,

Since I worked out that I don't need the DPDT relay, I can instead use a SPDT, I have got a price from Gigavac for these little HV relays:

http://www.gigavac.com/products/relays/ ... /index.htm

GH3 1-4 pcs = $274.00 each.

They are only 23.5 mm in diameter and 36 mm in total length, with the M14 threaded part is 13 mm long. If anyone needs one of these for managing their high voltage precharge switching (like over 300 V DC) they are pretty space efficient for the money.

AEVA National Secretary, WA branch chair.
User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Group Buy - Gigavac high voltage relays

Post by BigMouse »

What about these relays I mentioned earlier?

FTR-J2AK012W Datasheet

450vdc rated, 10A, $24 ea

EDIT: fixed link
Last edited by BigMouse on Tue, 15 Jan 2013, 15:37, edited 1 time in total.
User avatar
jonescg
Senior Member
Posts: 3615
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Group Buy - Gigavac high voltage relays

Post by jonescg »

Here is the datasheet to said relay: http://download.siliconexpert.com/pdfs/ ... ftr-j2.pdf

It looks good for anyone running a sub 450 V system. A few things to note is the maximum switching voltage is rated to 600 VDC, which is a fair bit more than 450, but still not enough for 700 V. It would probably work, but for how long?   Also, they recommend a diode rated to 3 times the maximum switched voltage, which in my case is 2100 V. Maybe this is where Gigavac justifies the cost?

AEVA National Secretary, WA branch chair.
User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Group Buy - Gigavac high voltage relays

Post by BigMouse »

Ah, you're running 700v. Yeah, wouldn't work for that. But for the majority of conversions (non AC at least), it should be good. Also, I can't find anywhere it described a diode of 3 times the switched voltage. It does describe a varistor of 3 times the coil voltage rating though, in parallel with the coil terminals. This would be a 36v device for a 12v coil. Very doable.

Check the schematic on page 6 of the datasheet. The note on page 2 "3 times the value of the power source voltage" is a bit vague, but it makes more sense looking at the schematic and the associated note there:

"Note 2: Please use varistor as surge protection device. If varistor will not be used, the electrical
life need to be derated.
Note 3: Varistor surge protection device should be connect parallel to coil(s). Suitable
voltage of varistor is 3 times the coil voltage."
Post Reply