A Couple of Odd Questions About Heated Seats.

2018 R1200rt. I never use the heated seat and was thinking of using the output to the seat to control a pair of driving lights. I realize the lights might over power the ECM so I would add a solid state relay and pull power off the battery. I am not interested in buying a Can Opener or similar item. I have the lights wired in with a switch and will leave them the way they are if my wacky idea won't work

First off, does anyone know if I can buy just the seat side of the electrical connector, preferable with a short length of wire? I looked around but failed.

Second, does anyone know if the output is pulse wave modulation? And if it is PWM, is it fast enough that it could control a set of LED lights to control the brightness without causing a flicker?

Interesting idea. I'm not an electrical engineer so I could be way off base here but I think it sounds plausible, and you can find terminals in a number of places that match the BMW style, I usually do a quick Google search and pick the best price, or you could try Vizi-Tec, he does not have them on his website, but it's worth sending him an email.

PoorUB said:

... I would add a solid state relay and pull power off the battery. ...if it is PWM, is it fast enough that it could control a set of LED lights ...

Click to expand...

If you are talking about repurposing the multi-controller on your left grip to turn your lights on and off, then you have a couple of issues here. First, yes, the power to the rider's seat is PWM. The pillion has a switch for high and low power, and I'm not sure how they achieve that.

But since you have decided to use a relay, then the PWM would not be a factor for the LEDs, I think. Rather, the question is at what power setting would the relay activate? And then, would the relay be reliable when the input is near its switching voltage? The output from the relay would be on or off. You don't want it to be rapidly switching on and off.

It seems to me that you might get this to work if you just leave the multi-controller set to full duty-cycle. That should activate a relay. And the lights will go on and off in response. But is that what you want?

If you want to use the multi-controller to continuously dim the driving lights, then that is another problem. You can design your own device to use the multi-controller input to drive a power circuit to the lights -- but why would you do that? The EzCan is that device, and you can buy it knowing that somebody else spent their effort making it work reliably, developing an app to control it, adding some additional circuits in case you need them, and providing you with a warranty that it will assure you that you haven't wasted your money when you buy it. Do you think you can do all that yourself for less effort and money?

I am a big fan of penny-tech do-it-yourself projects. I get a lot of satisfaction from them. But this is a case where unless you just really enjoy the process, you should buy an EZCan. In my opinion.

Cap

I have a solid state relay that activate with a wide voltage range, something like 4 to 39 volts DC. A solid state relay will work fine with the PWM as being electronic it will open and close thousands of times a second. My only question is if the PWM is fast,like in hundreds of cycles a second, or slow like one cycle a second. With PWM you will get a full 12 volts, and then off again, but only for a tiny portion of a second, maybe 100 or even 1,000 times a second.

The tail/brake light on the newer R1200RT works like that. On and off about 1/2 the time for tail lights, full on for brakes, plus it only will work with LED bulbs as they will react fast where and incandescent bulb works slowly.

I know with my heated jacket the controller is PWM, but it cycle maybe once a second, just longer on times when I turn up the power.

I probably will have to get out the test leads and just try it. I wonder what the rider's heated seat draws for amps. I might be able to wire the lights direct. The lights I have draw only a couple amps each, might be inline with what the heating elements in the seat draws.

I am probably on my own on this one!

I am a big fan of penny-tech do-it-yourself projects. I get a lot of satisfaction from them. But this is a case where unless you just really enjoy the process, you should buy an EZCan. In my opinion.

Nope, not going to happen. I will not spend the coin for an EZCan to run the lights. If i can't make it work I will just leave them on a simple off/on switch.

You might be on your own but you have many watching with great interest.

I had some time today, finally! Went out to the shop and started messing with the heated seat, trying to see what kind of power is coming out to feed it. First thing I tried was to test for voltage, I couldn't read any! Hooked up a small LED bulb and tried it, it wouldn't light up. Tried it with just the power on, and the engine running, heated seat controls set to all settings. Tried it with the seat connected and disconnected. Now it has me wondering if BMW did something in the programming of the ECM so the bike has to be moving or something weird.

I have pretty much given up, maybe some other day when I have more time and patience!

Was the engine running when you tested the heated seat voltage? Power works when engine is running, in case you did not know.

Engine running. I couldn't read any voltage at the connector.

I haven't tried just turning on the heat and see if the seat gets warm. I should verify that first, then do some voltage tests.