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MG MGB Technical - Heated seats, electrical supply

Since I am fitting new leather seat covers from Pretige- UK in my Tourer. I am also thinking of fitting heated seats. My better half is addicted to them in the dayly drivers. I also have to admit that a warm back is a treat, when driving top down in the north of Scandinavia.(Which we do all year, ofcourse) The questions are therefore twofold. From where do I pick up electrical supply of 30A. It has to be from somewhere in the vincinity of the gearbox tunnel. Also preferable from a source that cuts out, when ignition is in the off mode. The second question is for any of you, that might have fitted seat heaters under leather covers before. Does the thin heating matrasses appear visuable thru the leather facings? The facings are foam quilted in the middle sections. Any feedback?

Thanks in advance.

Erik
Erik

Hi Erik.

The obvious point to take the current from is the starter motor solenoid, via a fuse. If you switch the seat heater current with a relay's contacts you could drive the relay coil from an ignition switched feed, so ensuring that the seats are off when the ignition is off.
You will need to use heavy gauge wire which you must be careful to route in a way that will avoid any possibility of chafing through the insulation.

Having said this, if the seats are going to draw 30A for a significant time, the standard alternator won't keep up, especially if you have lights, etc on.

HTH.. Don
Don

Hi Don,
I have had my doubts that my 18ACR, 43A alternator isnīt on par with the job. Iīll have to see if I can source an alternative. The SAABīs and Volvoīs has big alternators and are plentyful in brakers yards over here. Where in Cornwall are you at? Did some surfing in New Quay in the seventies.

Thanks
Erik
Erik

Hi Erik.

I live about 10 miles from Newquay, and enjoyed a visit to Stockholm a few years ago... there was open-air skating, but no surfing...

Don
Don

Erik

I have just fitted seat heaters under the leather of my fiero seats. You cannot see the heater mattress under the leather, however i do not know how this compares to the standard MGB seats trimmed in leather, but i gether noone has had problems yet.

However, the seat heatsers i use, take an 'ignition-on' circuit from under the dash - the green circuit i believe. Something like the wipers or HRW use this circuit and are reasonably close to the tunnel. However, they have their own supplied inline fuse which is only 5 amp.

Are you sure you will need a 30 amp fuse..? That would be some current to have next to your balls! ;->

Have you a particular type of seat heater in mind..?

~PHIL
Phil

Phil
I need to get heated up so I can perform during the X-mas vacation ;> The 30A fuse rating is taken from memory after seeing an aftermarket heatermatress, but Iīll have to double check. My autoelectric knoledge isīnt that good, but I calculate that it will give some 300W to play with. Donīt know if itīs overkill as y
ou
imply. But I will be glad if it would operate on 5A or approx. 50W.
Don
Did you go skating on the lake Malaren or out in the archipelago. That is something I miss from my years in the Stockholm area. Skating mile after mile on black snowless new ice. That is something...

Thanks
Erik
Erik

Phil
Went to the store and checked. The heater draws 5A per unit. The manufaturer recomends an 8A fuse for each of the seats. So I guess itīs possible to install without upgrading the alternator.

Cheers
Erik
Erik

Erik,

I've just fitted some German heater pads under MGB leather seats, they don't show through....these are dual elements, but only have 5a fuses, there is a relay in the circuit, and two feeds, one permanently live and one in ignition circuit and really neat switches.

Mike
Michael barnfather

Erik,
you ask about alternative Alternators. You could alway put the biggest single wire Delco unit available in place of your puny Lucas unit. You can go to my Alternator site and pick up a link to a Delco site for more information. There are many satisfied customers, so it is something to think about if you need the 700 lb. gorilla to heat your seats. http://hometown.aol.com/idbritcars/boschAlt.html
Bob Muenchausen

Bob, and others,

Let me take this opportunity to express again my opposition to Delco "single wire" alternators. Why?

a. you are paying extra money (a lot of extra money) for something you don't need, can't use, and are not getting.

b. you will give up the function of the alternator warning light.

Before I go further, a bit of clarification: Sadly, far too many auto parts store clerks believe that ALL Delco alternators are "single wire" units, which is not the case. The Delcos we are speaking of come in two configurations - one and three wire models. Externally, they are identical, each having 3 terminals, and in many cases, a true one-wire can be wired up as a three wire if you wish. In fact, a 1-wire is made by internal modifications to a 3-wire unit. Otherwise, there are NO differences between the two. What I'm speaking of here are the true 1-wire units.

Now back to point a: The only reason - the ONLY reason - for using a one-wire is simplicity. Supposedly, it is easier to hook up one wire than it is to hook up three wires, and you can have a cleaner engine compartment with only 1 wire to worry about. This may be true if you are building a street rod or a custom car from scratch, and don't already have a wiring system in place. This is not the case we are speaking of here. The 3 wires needed to hook up a 3-wire alternator are already in place in an MGB. To use a one-wire, you have to cut 2 of these wires and insulate them so they can't touch ground and cause a melt down. To do this, you also have to know how to do it, and which of the 3 wires you need to cut. If you know this, you also know enough to connect the 3 wires properly (if not, Bob's web site and associated links provide the proper guidance).

As for point b, whether or not you consider the alternator warning light to be of much value, why go to a lot of trouble, to say nothing of expense, to eliminate it? Plus, you will now have a non-functioning component on your dash.

I don't mean to belabor the point, but I can't tell you how many times I've been called on to solve an alternator problem, only to find that someone has installed a 3-wire as if it were a 1-wire. And I hate to see anyone spend money needlessly when they could use the money for other needed parts for their car. Typically, a 1-wire sells for 3-4 times as much as a 3-wire. Another point to consider is availablitiy - you can find a 3-wire on the shelf in most any town in the country, but a 1-wire will be a special order item most places. This can turn a simple 1-2 hour repair into a 2-3 day wait.

I'll get off the soap box now.

Cheers, and holiday greetings to all!
Dan Masters

Just to add a comment, the only difference between a 3 wire and 1 wire delcotron is the regulator module which is interchangeable. You can swap a 1 wire reg into any delcotron to get a 1 wire alternator. The reg goes for $15-30 depending on where you get it, so it makes absolutely no sense whatsoever to pay 3-4 times the price for a 1 wire. BTW Dan, there is one other reason for using a 1 wire, a burned up wiring harness. Had that happen in a truck once and it made a big mess. Only reasonable cure was the 1 wire. But I didn't like it too well.

Jim
Jim Blackwood

If you *do* need a 30 amp supply for both seats combined then it should come from the solenoid. But it will have to come via a relay connected to the fused ignition supply (green) to prevent you leaving them on and flattening the battery.
Paul Hunt

Thank you everyone, for your comments on this subject. I have enough information to preceed with the project.

God Jul och Gott Nytt Aar!
Merry Christmas and a Happy New Year!

Erik
Erik

Where did you get these seat heaters? Can you give me an idea of the cost?
william fox

William
I sourced them locally here in Sweden at a cost of approx. 20USD/ pair. I donīt know about US, but we have had originally fitted to cars sold in Sweden since early eighties. If you canīt them find in aftermarket autopart stores, you will find the at SAAB or Volvo dealers as oem parts. But at a different cost I presume.
Cheers and happy Christmas

Erik
Erik

Thanks Eric...Happy holidays to you and yours too!
william fox

Erik: Can you give the name of the place you bought them? Do they have a website? I can'tseem to find anyplace that has them doing a websearch. At that price it would be worth having them shipped.
william fox

William,
http://www.clasohlson.se/WAG.asp?cp=Eq0q535q796&ic=N&sw=2037 mailto:kundtjanst@clasohlson.se

http://www.pebe.se/html/vinterartiklar.html
http://www.pebe.se/
Mail info@pebe.se

Having read the information on the sites I realise I quoted the prices a bit low.
If you are still interested, you have the emails to the two companies and they are english spoken. Their web sites are regretfully only in Swedish.

Warm wishes to you and your kin. (We have -12 degrees centigrade outside at the moment. What do you read??

Erik
Erik

38 F right now, I think it was around 50 for the high today. December in the midwest U.S. is unpredictable. A couple of weeks ago it was in the 20's. January and February is when it really hits. Thanks for the links!
william fox

William.

They turn up on E Bay fairly regularly...check 'heated seats'..I got mine from a German firm....I will let you have details if yopu like,

mike
Michael barnfather

Dan, Jim and others,
I was being sarcastic. I doubt anyone needs much more current than either a good Lucas 18ACR or a Bosch unit put out. And I agree completely, a single wire alternator has a single benefit for using it ~ apparent installation simplicity. But folks do use them, and do use alternators with way more capacity than they will likely ever use - "just to be sure".

If I were to wire up a source for heated seat pads or any other high current draw device, I would (and do) wire directly to the battery post, usually through an adapter type cable terminal as used for Super Power Car stereos and that sort of thing. The most amps in a car's electrical system reside in the battery, NOT the alternator.
Bob Muenchausen

My tip: Saab/Volvo specialist breakers (e.g. elferink.nl)

I used Saab heater pads in my roadster, even with the little thermostatic element removed, right under the (vinyl) seat covers. Cheap and effective. (Wire/switch the seat and backrest part seperately, though!)

Merry Christmas,

Jochen

BTW, the german brand is www.waeco.de
Jochen Beyer

Thanks Mike, that'll be great. I can use all the sources I can find.
william fox

William,
The firm is called Waeco, I bought mine from Germany, but they do have a UK branch, according to my search engine, they were only about Ģ30 per seat, have heated backs and bases, and two heat settings, I've had my co- driver test them indoors using a battery charger ( the seats are out of the car at present).....and she has pronounced them satisfactory.

Mike
Michael barnfather

Mike

They sound good - don't feel so guilty for nabbing the last pair of the Land Rover sets now...! And of course those were merely 'one setting' not jazzy 'two setting' sets!! ;->

I guess you roadster owners need the extra setting for those top down days!

Take some pics before you fit them, i could put a comparison on my webpage!

~PHIL
Phil

Thanks Michael....did you order these online, through a catalog, or a vendor? They sound like just the thing I want.
William Fox

Phil...

Too late mate, they're in !(and they've got fancy circular 3 position rocker switches)

William,

Bought them on E bay....but I'm sure they will sell direct...they sent me a wonderful catalogue with the seats....I can post it to you if you wish.....they do seem to have English agents.......might be cheaper to go down this route.

Mike
Michael barnfather

Michael: Send me what you can. Email is wcf59@NOSPAMhotmail.com Remove the "no spam" when you type in the address. I emailed the UK division and they told me they arent available in the US. Does the catalog give info on how to order?
William Fox

Now if you guys were talking about seat coolers, then I'd be interested.
Peter

William,

Their winter catalogue is on line at WWW.waeco.de, if you look in 'sitzcomfort' they are called Magic Heat and cost €98 plus post. they took less than a week to come to me.

Peter,

they also appear to have seat coolers which work off the cigar lighter !


Mike
Michael barnfather

PS the fitting instructions came in German, and English !

Let me know how you went on.

Mike
Michael barnfather

This thread was discussed between 15/12/2003 and 24/12/2003

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