Lseat.com seat skins / covers: Review, notes, modifying for heat + ventilation

[jangell]

I’m in the need of new seat covers, and I have to replace the heated inserts I installed a decade plus ago as well. I thought about cooling, but was sure how to get perforated covers. That and I hadn’t actually figured out how to do the cooling until now. Looks like I have a fall project — this write up is going to be my template.

Any chance you can provide the gcode or mode for the vent you printed for the seat back?

— Joe

[FABombjoy]

I’m in the need of new seat covers, and I have to replace the heated inserts I installed a decade plus ago as well. I thought about cooling, but was sure how to get perforated covers. That and I hadn’t actually figured out how to do the cooling until now. Looks like I have a fall project — this write up is going to be my template.

Any chance you can provide the gcode or mode for the vent you printed for the seat back?

The STL? Maybe - let me get this setup to a full version 1.0 first
The vent does conflict a little with the battery cover so I'll have to revise it.

I hope to have both heating & cooling fully connected in the next few weeks before our fall Michigan driving tour. Based on previous years, both heat and cooling will be useful.

[jangell]

Yeah, the STL; I guess the gcode is a bit more machine specific (I’m just getting back into 3D printing and I’ve forgotten a few things). I mean, I could build my own model, but you’ve already done the hard work.

it’ll be a couple months before I do my seats, so I’ll just keep following what you’re doing until I’m ready. This thread has already been hugely helpful! I’m curious to see what you’ve decided to go with for the heaters, too.

— Joe

[FABombjoy]

I'm taking a labor day break, but in short:
-A cheap seat heater kit, cutting a million little holes in the heat pad fabric so air circulation can happen
-The heater kit switch and driver module goes in the dumpster where it belongs
-3D printer heat bed MOSFETs to drive the heaters instead (rated 30A continuous duty - total overkill which is perfect)

It would be pretty trivial to whip up a PCB for a pair of logic-level drive MOSFETs, but for $15 shipped a pair of 30A heat bed drivers is far too easy.

[jangell]

A cheap heating kit is what I have now, and what I was planning to do when going forward, so I guess I’m on the right track there.

I was wondering if drilling a couple big holes for the fans would be fine, rather than a lot of little holes. I guess it might sacrifice heating near the fans, though. I don’t actually know how the heat pads work so I was sure how amenable they’re be to having holes added to them, but it sounds like it’s fine.

I’m doing my own climate control UI so I’ll be doing the same thing with the included control hardware. Although I was just going to use MOSCETs in place of the switches; are you replacing everything downstream of the pads? My “I don’t actually know how heating pads work” thing has kept me from planning that far yet. I didn’t even know heat of drivers were a thing.

Have a good break! I’ll be spending part of mine finally installing A/C idle up on my MegaSquirt.

— Joe

[FABombjoy]

I was wondering if drilling a couple big holes for the fans would be fine, rather than a lot of little holes. I guess it might sacrifice heating near the fans, though. I don’t actually know how the heat pads work so I was sure how amenable they’re be to having holes added to them, but it sounds like it’s fine.

I have the style with carbon wires that criss cross. You can cut sections out of the middle but I just punched holes through the fabric that holds the wires in place.

If you cut only sections for the fans, the heat pad would have to go under a foam layer and they're too big for that.

You'll also see in the photos that the wires in the pad don't go totally to the edge, so I trimmed these pads a bit so they'd fit on the center sections of the seat foam form.

I’m doing my own climate control UI so I’ll be doing the same thing with the included control hardware. Although I was just going to use MOSCETs in place of the switches; are you replacing everything downstream of the pads? My “I don’t actually know how heating pads work” thing has kept me from planning that far yet. I didn’t even know heat of drivers were a thing.

I'm only using the pads. It came with a controller box and a control switch. The switch is chinsy and I don't like the look or feel of it. The driver box has 2x MOSFETs. I managed to find a datasheet for them and the specs are so good they're either made out of magic or the company is full of "it". The 30A MOSFET drivers I purchased will be super overrated for the task which should translate in to "probably shouldn't catch fire". I'll feed in a PWM control signal to set the heat level.

Have a good break! I’ll be spending part of mine finally installing A/C idle up on my MegaSquirt.

It's a nice feature to have!

[jangell]

When I take my seats apart I'll check to see what my heater pads are liked and what kind of shape they're in, but they're not terribly expensive on Amazon so I'll probably just buy a new set. My driver's side ones don't work at all right now, and the passenger one only works at one temperature, and I'm not quite sure where the failure is.

Punching holes between the crossing wires makes a lot of sense. I imagine it's just a bit tedious to do.

I take it the heaters are really simply, and applying power to them causes them to heat up? I'll get some high power MOSFETs and PWM like you're doing -- that does seem like the best solution. My touchscreen currently has four heat levels for the heated seats (including off), but I can change it into an arbitrary off-to-max scale easily enough, once I'm using PWM. Although I doubt you'd be able to tell the difference between three levels. PWM fewer components and pins not he Arduino, since I don't need to individually control the low/medium/high switch settings. Cool. I'm going to have to figure out how to modify my UI for seat coolers now, too.

As for A/C idle up, I have the MegaSquirt modification done and TunerStudio settings done, and it bench tests just fine -- I just have to hook it up between the mode switch and the low pressure switch tomorrow. I'm getting tired of stalling at lights.

-- Joe

[FABombjoy]

Even without AC idle-up you shouldn't stall like that. I know that came up in your build thread - did you post a log/MSQ of when it happens? If so send me a link and I can re-review your tune and log. That should be solvable on its own. AC idle-up shouldn't be needed to solve it.

[jangell]

It happens even without the A/C on, but the A/C makes it more extreme. I keep meaning to start a new thread about it. I was going to do that last week, but then I lost my oil vapor separator cap, which caused a huge vacuum leak and made my logging moot. Mark D was able to source a new cap for me at a junkyard, which I'm going to test drive tomorrow.

I can get the idle to drop pretty low by just shifting from R to N to D and back. When the engine has load, the idle drops down to the 600s. I have my idle at 900 RPM now just to reduce the chance of stalling, but if I'm pointing up a hill and take my foot off the gas quickly, I might stall out. I've significantly boosted the lower end of the ignition table to try to catch stalls, but with only moderate success. What I really want is a way to open the IAC more if the idle drops below 600 RPM or so, since I feel like that would be the most effective way to catch a stall (although I guess not as fast as adjusting the ignition timing), but I can't figure out how to do that. I'm running closed loop idle, but it seems like it just doesn't react fast enough at low RPMs. I'm also using the easy slider instead of manually setting the closed loop PID. I'll share the tune and some logs in a new thread later this weekend, rather than hijack this one any more than I already have. If you like I can record logs with the A/C on (and A/C idle up off) to show what happens under a heavier load (ie: make it more likely to stall).

Thanks!

-- Joe

[FABombjoy]

Sounds good!

To briefly tie ventilated seats with this megasquirt non sequitur, I briefly considered tying unused MS3X coil driver outputs to the seat fan PWM in and sending fan control commands over canbus, using the MS3 generic PWM output mapping option. I mapped it all out functionally and decided it was ludicrous to build megasquirt controlled seats