Heated Sargent seat repair

[mpgscott]

The staples in my air stapler are quite small, it’s a bit late now but if I remember tomorrow after work I’ll check in my garage and reply.

Glad you have the electrics now sorted. A bit of high temperature upholstery trim fix spray and it will be as good as new.

Did you put anything back in place of the like clingfilm that was there? Take it this is like waterproofing?

Thanks

 

[Pukmeister]

Staples are Tacwise 71 Series at 4mm (5/32”). They are about 8mm width and 4mm deep so will penetrate about 3mm which is just about deep enough to penetrate into the plastic seat pan. They are about 8mm lot smaller than the OE staples but the gun can get into tighter corners being an upholstery air stapler/nailer.

I added a thin layer of soft clear plastic to seal the seat last time I upholstered it, though I can’t recall where I found it.

 

[mpgscott]

So I just got the parcel and the new heat pad is a perfect size but unlike the Sargent element that is two-wire and 8 Ohms, the carbon fibre element is three wire (two-stage wiring) at 16 Ohms across one stage and 31 Ohms across the other. One is common ground, a relay switches the 12V feed between the other two wires for low/high heat. Unsure yet if the higher resistance is due to an inline resistor or more heating windings, some testing needed.

Looking at the wiring as best I can tell, it switches between the two circuits via the relay (which I will test later). I may end up just wiring whichever wire the full heating circuit is across the Sargent heat boss controller and testing it/measuring the amp draw which is supposedly 1.5 Amps.

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Any joy with getting it fitted as yet?

 

[Pukmeister]

No I'm too busy at present, got too many juggling balls in the air (as is usual) to deal with it right now.

Perhaps over the weekend ?

 

[Pukmeister]

Looking at the pad it looks like there are two heating element circuits, left and right, 16 ohms each . These would be switched between series and parallel operation by the relay giving you either an 8 ohm or 32 ohm resistance, which tracks with the quotes 1.5A max current.
Full heat would connect one leg the supply (+ve) to the outer two wires together and the other leg (-ve) to the centre.
Low heat would be connecting the supply to the outer two wires only.

You are spot on and I doff my hat to you Sir.

I made a rudimentary sketch of the wiring and it seems exactly as you say. At low heat it is a full single element and at high heat it it two smaller halves in parallel split down the middle.

It’s parallel resistance is 8 Ohms which is the same as the Sargent heat pad, so I intend to wire it up that way by linking the outer two wires as common live, with ground as the centre and controlling the heat output variably via the Sargent heat controller.

Will test fit using choc block strip and try it out, hopefully no fuses pop and it performs heating functions as normal. Then I can assemble properly and reupholster the seat.

 

[Pukmeister]

A quick functional test completed.

Initial heat boost mode (double-flashing LED) gives 12VDC and 1.45A

Heat Boss controller steady output (fixed or slow pulsing LED) ranges from 0.28VDC to 7.79VDC. Heater draws between 0.21A and 0.89A which drops slightly as the pad warms. It’s fused at 2A as the system can heat two pads if required.

Using P = V x I that is around six Watts which should be bugger all heat but it actually warms quickly and seems around blood heat to touch so hot enough without burning my ass through the vinyl seat cover. I’m hoping the flexible carbon heater pad is less prone to failure than the original nickel based wire element.

Time to wire it up properly reupholster the seat.

It all powers down nicely about 45 seconds after turning off the ignition.

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[mpgscott]

A quick functional test completed.

Heat Boss controller output ranges from 0.28VDC to 7.79VDC. Heater draws between 0.21A and 0.75A. It’s fused at 2A as the system can heat two pads if required.

Using P = V x I that is 5.85 Watts which should be bugger all heat but it actually warms quickly and seems around blood heat to touch so hot enough without burning my ass through the vinyl seat cover. I’m hoping the flexible carbon heater pad is less prone to failure than the original nickel based wire element.

Time to wire it up properly reupholster the seat.

It all powers down nicely about 45 seconds after turning off the ignition.

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You still using the old Sargent controller to vary the voltage?

I’m sure when I measured mine it was 13.9 ohms when the suspect wire was removed. I did shorten my element by around 5”

Got my fabric adhesive and stapler today.

Thanks
Mark

 

[Pukmeister]

Yes, it’s a brand new controller for £170 !!! The original went pop in the rain and is obsolete. Last time I repaired the broken Sargent seat element it was exactly 8 Ohms, as is this newer one.

The new controller works exactly the same as the last one, giving a 12volt initial boost output on start up then dropping down to 7.8 volts.

Problem now is I can’t find the scrap vinyl I was intending to glue onto the seat cover underside edges as reinforcement where the staples have split it. Probably an eBay/amazon purchase needed for some more.

 

[mpgscott]

Yes, it’s a brand new controller for £170 !!! The original went pop in the rain and is obsolete. Last time I repaired the broken Sargent seat element it was exactly 8 Ohms, as is this newer one.

The new controller works exactly the same as the last one, giving a 12volt initial boost output on start up then dropping down to 7.8 volts.

Problem now is I can’t find the scrap vinyl I was intending to glue onto the seat cover underside edges as reinforcement where the staples have split it. Probably an eBay/amazon purchase needed for some more.

That’s weird mines up at like 14ohms.

I will need to check, it was definitely heating up nicely

 

[mpgscott]

I checked tonight and my resistance jumps around if I put pressure on the seat. So sitting on it the resistance is 36ohm, my old and aging seat wiring must be toast.

I’ve got it all back together and will try it out.

Failing that a seat pad like you will be getting installed, I’ll wait for your feedback on your new seat heat pad.

Thanks

 

[Pukmeister]

The reason I went for the EBay heating kit to use its element is twofold.

Firstly, I’ve used a kit on my scooter for over two years and it’s brilliant yet it costs just a fraction of the price of what Sargent charges.

Secondly, as it’s a flexible carbon element rather than a stiffer and more brittle spiral wound nickel alloy wire, I hope it will last longer.

 

[mpgscott]

A quick functional test completed.

Initial heat boost mode (double-flashing LED) gives 12VDC and 1.45A

Heat Boss controller steady output (fixed or slow pulsing LED) ranges from 0.28VDC to 7.79VDC. Heater draws between 0.21A and 0.89A which drops slightly as the pad warms. It’s fused at 2A as the system can heat two pads if required.

Using P = V x I that is around six Watts which should be bugger all heat but it actually warms quickly and seems around blood heat to touch so hot enough without burning my ass through the vinyl seat cover. I’m hoping the flexible carbon heater pad is less prone to failure than the original nickel based wire element.

Time to wire it up properly reupholster the seat.

It all powers down nicely about 45 seconds after turning off the ignition.

Sent from my iPhone using Tapatalk

Excellent, so the wiring you have there is the red and brown outer two as common to the +12v from the controller then it looks like a darker shade of red as the common to the other side of the Sargent controller?

Just want to check as I’m sure il be pulling my old seat apart in the future and this will be good to come bank to this thread.

Thanks for taking the time to detail this. Even throw up a pic of the sketch you made that be helpful I’m sure

 

[Pukmeister]

The middle wire is the negative, in my case coloured red with a purple stripe. The two lives are a red and a black, which you pair up and connect to the feed from the controller.

Hopefully my vinyl cloth sheet arrives today from Amazon so I can glue repair the seat cover edges.

 

[mpgscott]

The middle wire is the negative, in my case coloured red with a purple stripe. The two lives are a red and a black, which you pair up and connect to the feed from the controller.

Hopefully my vinyl cloth sheet arrives today from Amazon so I can glue repair the seat cover edges.

I tried my repaired Sargent seat today and it’s working well for now. However I’m not holding out much hope of it lasting.

Be interested to know the vinyl cloth you got is like.

 

[Pukmeister]

Cloth arrived, some thin faux leather vinyl from Amazon. It’s exactly the right thickness and flexibility, so I cut out a panel for the front staple area like a tongue, plus along 15mm strip for the hem around the cover and glued them on with spray contact adhesive and left to dry overnight. Will staple the cover back on today, then it’s job done.

 

[mpgscott]

Cloth arrived, some thin faux leather vinyl from Amazon. It’s exactly the right thickness and flexibility, so I cut out a panel for the front staple area like a tongue, plus along 15mm strip for the hem around the cover and glued them on with spray contact adhesive and left to dry overnight. Will staple the cover back on today, then it’s job done.

Just something like this?

Amazon.co.uk

Thanks
Mark

 

[Pukmeister]

Yes, I used something similar.

Seat now re-covered and fitted, works like a charm. Managed to drop my four tiny mounting ring bolt spacers down onto the engine/frame/fourth dimension somewhere when loosening the fuel tank panels to run the cable so had to spend hours removing the whole fuel tank and panels to retrieve them, ran the new heat controller cables and refitted the tank, what a bastard of a job on a 1250 (the Hexhead with its single plastic tank is way easier to do).
Found my power supply wire to my bike “dashcam” had become unplugged so sorted that, plus I fitted my new Option 719 style billet mirrors.

Yet another busy weekend spent flat out doing jobs, also managed to fix the wife’s car telephone system (telematics module failure) then my elderly Mums fridge was leaking water (blocked evaporator drain) and my downstairs loo flush inlet pipe fitting was weeping yet again (rejointed) so I’ll be glad to go back to work tomorrow for a rest.

 

[mpgscott]

Yes, I used something similar.

Seat now re-covered and fitted, works like a charm. Managed to drop my four tiny mounting ring bolt spacers down onto the engine/frame/fourth dimension somewhere when loosening the fuel tank panels to run the cable so had to spend hours removing the whole fuel tank and panels to retrieve them, ran the new heat controller cables and refitted the tank, what a bastard of a job on a 1250 (the Hexhead with its single plastic tank is way easier to do).
Found my power supply wire to my bike “dashcam” had become unplugged so sorted that, plus I fitted my new Option 719 style billet mirrors.

Yet another busy weekend spent flat out doing jobs, also managed to fix the wife’s car telephone system (telematics module failure) then my elderly Mums fridge was leaking water (blocked evaporator drain) and my downstairs loo flush inlet pipe fitting was weeping yet again (rejointed) so I’ll be glad to go back to work tomorrow for a rest.

As with everything in this world and I don’t know how many times I say it.

Why does everything need to be more complicated.

Good job, you’ll be pleased with your work..