# Cab heater relay/contactor advice



## EVfun (Mar 14, 2010)

The usual choice is the KUEP-3A15-12 relay. Though the current can be a bit over the ratings they seem to work well for this in EVs up to 156 volts.


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## Yukon_Shane (Jul 15, 2010)

EVfun said:


> The usual choice is the KUEP-3A15-12 relay. Though the current can be a bit over the ratings they seem to work well for this in EVs up to 156 volts.


Thanks!

I was starting to think there weren't any reasonable priced options and I'd have to break down and buy an oversized contactor. That being said my pack will be 160v nominal so this relay may be a bit undersized...


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## Yukon_Shane (Jul 15, 2010)

Any thoughts on this relay?
http://www.futurlec.com/Relays/SSRDC200V40A.shtml


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## EVfun (Mar 14, 2010)

Might work if you mount it on a heatsink and put that in the airflow from the heater fan. I'm not a fan of SSRs (Solid State Relays) for power application because when the fail they usually fail ON. 

You can help the KUEP handle a little extra voltage (it is rated for 150 vdc) by putting a capacitor and resistor across the contacts. I'm not sure what values I'd pick, the exact values aren't to critical. I usually pick an EEs head to get approximate values.


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## mora (Nov 11, 2009)

I've burned at least three of those solid-state-relays. Ones I got don't get hot with 20A flowing through them. I use heat sinks on them though. I believe failures had something to do with low operating voltage (less than 10V). I have never had problems with them when I apply at least 12V on "coil". Less than that and they seem to quit working too soon, even they are advertised as 3-24V.


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## Yukon_Shane (Jul 15, 2010)

You certainly hear alot of stories about the SSR's burning out early.

I'm thinking more and more that I should just go with a full pack rated contactor but I really don't want to spend $150 just to switch my heater on and off.

I think I'll give the SSR with a heat sink a try and watch for a used contactor in the classifieds...of course if it fails closed and kills my battery pack I will surely not have saved anything by going that route....

Given how common cab heaters are in EV's I'm supprised that there isn't a more universal solution. I'm finding that building an EV is full of these sorts of challenges. There seems to be certain areas of the installation that require the use of products that are just not ment for this application and the work around is to either:

1) install products which are known to have a high failure rate so you just deal with it, or
2) if you have the resources (and the inclination) then you can way overbuild

I guess it's all part of the fun


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## bluefxstc (Dec 29, 2007)

I have been using one of these for my heater with no problems. #M30A-12D 
http://www.surplussales.com/Relays/mercury_con.html. I have 45 SE 180s so 144 nominal with a normal output in the 155 VDC range. It might not be a good option of it gets really, really cold where you live but works good for my climate. About the coldest it gets here is 0F. You would have to look up where mercury becomes a solid to find out if it would work for you.


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## Yukon_Shane (Jul 15, 2010)

bluefxstc said:


> I have been using one of these for my heater with no problems. #M30A-12D
> http://www.surplussales.com/Relays/mercury_con.html. I have 45 SE 180s so 144 nominal with a normal output in the 155 VDC range. It might not be a good option of it gets really, really cold where you live but works good for my climate. About the coldest it gets here is 0F. You would have to look up where mercury becomes a solid to find out if it would work for you.


This looks like another good option. I did a quick websearch and it looks like mercury freezes at around -38C (or -37F). We definately get that cold here but I don't think I'd drive my EV at that temperature so it would probably be fine.

Anyone else have experience with these mercury relays in a cold climate?


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## rwaudio (May 22, 2008)

I just went the safe way and bought a couple of EV200's you can find them on ebay pretty cheap if you have a week or two to watch for a low priced auction.
http://www.ebay.com/itm/Kilovac-EV200-Tyco-EV200AAANA-500-A-12-900V-Relay-/300607272942?pt=LH_DefaultDomain_0&hash=item45fd96f7ee#ht_4604wt_1226

Based on the total conversion price a couple of contactors is a drop in the bucket for reliable long term switching. I think I paid about $80-90 Shipped for a pair of EV200's.


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## Yukon_Shane (Jul 15, 2010)

rwaudio said:


> I just went the safe way and bought a couple of EV200's you can find them on ebay pretty cheap if you have a week or two to watch for a low priced auction.
> http://www.ebay.com/itm/Kilovac-EV2...ltDomain_0&hash=item45fd96f7ee#ht_4604wt_1226
> 
> Based on the total conversion price a couple of contactors is a drop in the bucket for reliable long term switching. I think I paid about $80-90 Shipped for a pair of EV200's.


$45-50 for a contactors is absolutely reasonable. the best I've seen these on ebay for is $150 each but then I was just look at the buy it now price. I've never found the auctions saved much but it sounds like I'm wrong in this case.

Any reason why you got 2?


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## rwaudio (May 22, 2008)

Yukon_Shane said:


> $45-50 for a contactors is absolutely reasonable. the best I've seen these on ebay for is $150 each but then I was just look at the buy it now price. I've never found the auctions saved much but it sounds like I'm wrong in this case.
> 
> Any reason why you got 2?


I want to have the option of powering my cabin/battery heaters from wall power after charging is complete but before I unplug (both heaters are actually designed for AC use), so I will need to disconnect both +/- terminals so that I'm not connecting anything from the wall to my pack. I will then use cheap SSR's to turn on the AC power as a "car starter" type functionality. I haven't implemented it yet, but I'm looking at the idea of having the negative of both the cabin/battery heater connected to the pack by one EV200, then the 2nd EV200 turns on only the + to the cabin heater and then a relay switches on the battery heater as it will only be about 1 amp. I may simply start with them in parallel since if I need heat the cells could probably use it too or vice versa. (I am aware of the safety requirement that won't allow the heaters to be connected to both the wall/pack at the same time in effect connecting my pack to wall power directly, IE 12v AC/DC supply that activates a NC relay that would disconnect the turn on signal wire to the EV200 not allowing it to turn on any time that the car is plugged into the wall)

http://www.ebay.com/itm/Kilovac-EV200-Ser-Contactor-Tyco-EV200AAANA-Lot-2-/200665327015?pt=LH_DefaultDomain_0&hash=item2eb895e5a7#ht_500wt_1287

The above link isn't a bad price for a pair if you have a use for two. I was in no rush when I bought mine so I watched auctions for a few weeks before I found the good deal.


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## Yukon_Shane (Jul 15, 2010)

rwaudio said:


> I want to have the option of powering my cabin/battery heaters from wall power after charging is complete but before I unplug (both heaters are actually designed for AC use), so I will need to disconnect both +/- terminals so that I'm not connecting anything from the wall to my pack. I will then use cheap SSR's to turn on the AC power as a "car starter" type functionality. I haven't implemented it yet, but I'm looking at the idea of having the negative of both the cabin/battery heater connected to the pack by one EV200, then the 2nd EV200 turns on only the + to the cabin heater and then a relay switches on the battery heater as it will only be about 1 amp. I may simply start with them in parallel since if I need heat the cells could probably use it too or vice versa. (I am aware of the safety requirement that won't allow the heaters to be connected to both the wall/pack at the same time in effect connecting my pack to wall power directly, IE 12v AC/DC supply that activates a NC relay that would disconnect the turn on signal wire to the EV200 not allowing it to turn on any time that the car is plugged into the wall)
> 
> http://www.ebay.com/itm/Kilovac-EV2...ultDomain_0&hash=item2eb895e5a7#ht_500wt_1287
> 
> The above link isn't a bad price for a pair if you have a use for two. I was in no rush when I bought mine so I watched auctions for a few weeks before I found the good deal.


 
That's a great plan. I'm just starting to get my head around the battery heating but I might have to copy that


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## Dennis (Feb 25, 2008)

Yukon_Shane said:


> I'm starting to plan my cab heater and I'm looking for some advice on the heater relays/contactors.
> 
> In reading through past threads it seems as though the consensus is to avoid ac relays and probably the best approach is to us a contactor that is rated to pack voltage.
> 
> ...


With high voltage, high current DC you are pretty much screwed in regards to using AC relays for DC use. Not all is lost though because you can buy 80 amp contactors for $50 or less. 

Here is one that will fit your application perfectly:

http://www.tecknowledgey.com/catalog/product_info.php?cPath=57_58&products_id=1883

Be sure to select the following parameters:

Coil type: Continuous
Coil Voltage: 12 volts
DC or AC coil: DC
Aux. Switch: No
Protected: Yes
Blowouts: No


I chose double pole because it will provide a greater degree of isolation of the high voltage pack from the heater section when the heat is off. \


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## Yukon_Shane (Jul 15, 2010)

Dennis said:


> With high voltage, high current DC you are pretty much screwed in regards to using AC relays for DC use. Not all is lost though because you can buy 80 amp contactors for $50 or less.
> 
> Here is one that will fit your application perfectly:
> 
> ...


 
Now where was this contactor hiding when I was doing my original web searching!

That's exactly what I'm looking for: a reasonably priced, appropriately spec'd contactor.

Man, I thought I was pretty good at finding products on the web but between your post and RW's I'm realizing I have alot to learn. 

thanks


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## mora (Nov 11, 2009)

Dennis said:


> http://www.tecknowledgey.com/catalog/product_info.php?cPath=57_58&products_id=1883


Datasheet tells maximum recommended contact voltage is 96V. Doesn't this pose a problem when 160V nominal pack voltage is used?


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## Dennis (Feb 25, 2008)

mora said:


> Datasheet tells maximum recommended contact voltage is 96V. Doesn't this pose a problem when 160V nominal pack voltage is used?


The 96 volt rating would be if he is pulling 80 amps of current. I highly doubt with a heater system at 160 volts would use that much current. Maybe more like 10 to 20 amps or so. He can always select the option to get magnetic blowouts as an option which would allow it to break arc overs when the contactor opens.


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## Yukon_Shane (Jul 15, 2010)

I'll be using two 1,500 watt ceramic heaters so the contactor shouldn't see much more then 20 amps. 

Sounds like this contactor would work well. I've also followed RW's recommendation and am seeing if I can't get a kilovac EV200 on ebay for around the same price. If I can then I'll go with the kilovac but if not I think this albright unit will be just fine.

thanks everyone for your help.


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## m38mike (Dec 27, 2008)

Yukon_Shane said:


> I'll be using two 1,500 watt ceramic heaters so the contactor shouldn't see much more then 20 amps.


Shane, what kind of ceramic heaters are you using? Are they AC units that you're simply powering up with DC? Here in the Colorado high country we've already gone down to 8 degrees F, and the half hour ride into work is getting chilly. I'd like to learn about what you're doing and perhaps copy your success.


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## Yukon_Shane (Jul 15, 2010)

m38mike said:


> Shane, what kind of ceramic heaters are you using? Are they AC units that you're simply powering up with DC? Here in the Colorado high country we've already gone down to 8 degrees F, and the half hour ride into work is getting chilly. I'd like to learn about what you're doing and perhaps copy your success.


I can sympathyse, it's 14 degrees F here today and -4 degrees F when you factor in the wind chill

I'm a little ways away from implementation but what I'm planning is two 1,500 watt ceramic heaters from off the shelf AC space heaters. Based on some of the anecdotal evidience I've read it sounds like a single 1,500 heater is just not enough in cold climate such as ours and I have a sneaking suspicion that even 3,000 watts won't be enough on a really cold day. 

I've got the ceramic heaters and I've ordered the contactor so now I'm just trying to figure out fusing, etc.

I'll definately post pictures and progress on the forum and let you know how it works.


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## dillond666 (Dec 27, 2010)

I am going down the route of twin hairdryers set for 120v operation. On my 156v pack that gives about 2Kw. I have a circuit in mind that will use an IGBT to do the switching. The circuit will be a 1mA drain on the traction pack all the time but I can live with that. There is optical isolation built in for safety. I am posting my schematic for your info but it will not be tested for another day or two.

EDIT: schematic is tested ok now.


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## Yukon_Shane (Jul 15, 2010)

dillond666 said:


> I am going down the route of twin hairdryers set for 120v operation. On my 156v pack that gives about 2Kw. I have a circuit in mind that will use an IGBT to do the switching. The circuit will be a 1mA drain on the traction pack all the time but I can live with that. There is optical isolation built in for safety. I am posting my schematic for your info but it will not be tested for another day or two.


I've heard of folks using hair dryers but haven't actually seen how this approach is implemented. 

Are you using the dryer fans as well or just the heating element?


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## dillond666 (Dec 27, 2010)

I am using the whole hairdryer. I have bypassed the thermal cut out and removed the on/off switch. I also disconnected the motor from the element so that I have two wires poking out for the motor and two for the element. The only reason I brought the motor out separately was because I was worried about the motor diodes getting 100% duty cycle rather than 50%. 
I have the circuit working but the IGBT isn't saturating properly and gets too hot. I'll review my component values and amend the schematic when I'm happy.


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## dillond666 (Dec 27, 2010)

OK, added a capacitor to help charge IGBT gate faster and saturated Vce is 1.7v, much better than the 6v I was getting before.
Hairdryer draws7.5A so that gives 12.75W heat to be dissipated from the IGBT, I'll put on an old cpu heatsink and mount it near the suction draught of the hairdryer. 

I updated the earlier schematic.


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## m38mike (Dec 27, 2008)

Yukon_Shane said:


> I can sympathyse, it's 14 degrees F here today and -4 degrees F when you factor in the wind chill
> 
> I'm a little ways away from implementation but what I'm planning is two 1,500 watt ceramic heaters from off the shelf AC space heaters. Based on some of the anecdotal evidience I've read it sounds like a single 1,500 heater is just not enough in cold climate such as ours and I have a sneaking suspicion that even 3,000 watts won't be enough on a really cold day.
> 
> ...


 
Any updates for us? Pix? 

I've got a ceramic heater, and the 12v fan. I don't have my contactor yet, but I'm probably going to get an EV200 for $70 from ebay. I think I'll use a 160v 15a mini-fuse from Mcmaster-Carr between the pack and the contactor.


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## Yukon_Shane (Jul 15, 2010)

m38mike said:


> Any updates for us? Pix?
> 
> I've got a ceramic heater, and the 12v fan. I don't have my contactor yet, but I'm probably going to get an EV200 for $70 from ebay. I think I'll use a 160v 15a mini-fuse from Mcmaster-Carr between the pack and the contactor.


Not yet, I've got two ceramic heating elements, fuse as well as the EV200 contactor (managed to get this for $40 on ebay!) but now I'm starting to rethink this strategy in favour of a fluid heater that would keep the high voltage out of the car. As I'm typing this I'm realizing how much easier the ceramic heater approach would be...

so many decisions. I'll post an update soon with some pictures on what I decide.


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## m38mike (Dec 27, 2008)

I've got my heater installed now, and it's working very well. I used a 1500 watt, $20, 110vac heater, an EV200 contactor, a 160vdc 15amp microfuse, a 12vdc fan, and a 12v lighted switch. The 12v switch provides the 12v power to both the contactor and the 12v fan. I replaced the 110v fan with the 12v fan. That required some cutting on the 12v fan casing to get it to fit . I have it set for two speeds, on and off. I used the factory plastic casing to keep the ceramic heater all neat and protected. Since my vehicle did not come with a heater, I had no duct work to work with. I hung the heater in the back of the cab so it would blow the heat forward to the windshield. That also helps to get rid of frost on the glass. I put the contactor and the fuse in a 6"x6"x4" plastic junction box to protect the terminals from any accidental contact with anything else. 

I'm watching the ameter to see how much juice I'm using on my 20 mile commute. So far it looks like it uses about 10% of my power used in my commute when it's on. I don't use it all the time, or at least I haven't yet. It brings my cabin up to a comfortable temperature, then I turn it off. When the cabin cools off enough I turn it back on. I haven't had any sub-zero weather to use it in yet. But it's doing a good job keeping me comfortable when it's in the teens and twenties above zero F outside.


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## Ace_bridger (Nov 22, 2011)

Can I ask what the advantage of your circuit is over simply switching the hair dryer on by using an EV200 contactor activated by a switch in the cab?

I have just bought a 1200W hair dryer to provide warm air for the windshield and to provide some heat for the cab.

What's wrong with just switching it on via the EV200? Am I being simple?


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## m38mike (Dec 27, 2008)

Ace_bridger said:


> Can I ask what the advantage of your circuit is over simply switching the hair dryer on by using an EV200 contactor activated by a switch in the cab?
> 
> I have just bought a 1200W hair dryer to provide warm air for the windshield and to provide some heat for the cab.
> 
> What's wrong with just switching it on via the EV200? Am I being simple?


Ace, Not sure who you are directing your question to, but since it follows my message, I'll assume it's to me. I guess I was not clear in what I wrote, but I am using the EV200 to control the high voltage. The 12v switch just turns it on and off. The same 12v switch also turns the 12v fan on and off.


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## Ace_bridger (Nov 22, 2011)

m38mike said:


> Ace, Not sure who you are directing your question to, but since it follows my message, I'll assume it's to me. I guess I was not clear in what I wrote, but I am using the EV200 to control the high voltage. The 12v switch just turns it on and off. The same 12v switch also turns the 12v fan on and off.


Sorry Mike, the message was regarding Dillond's installation.

My intention is to do something similar to what you've done...great minds think alike, as we say over here in Britland!!!


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