Thread: Using relays for a latching circuit

Originally Posted by BradC

It would. If you search hard enough you might even find one less than 6” in diameter and worth less than the car. A PWM motor controller will be smaller, much cheaper and more reliable.

I'm curious as to why it'd have to be so big?

I was under the impression that a seat heater element is about 5 or 10w max. IIRC I've seen 3w element kits.

I think back when I worked for truck companies, they want 4am starts and Melb winters/autumns/springs can get a bit frosty, and D1 heater took some time to heat themselves up. So I sold the D1 ...

Nah, I looked into fitting heated elements after I replaced seat spring and foams on the drivers side and was quite easy to do in the end, so had me thinking.
... and thinking and thinking .....

Years later did nothing, sold D1 and moved to a colder region in autumn/winter/spring!... much hotter in summer tho.

But back then with my expectation that the element is about 5w or so, I thought that using a 15w pot would suffice(easily available at Jaycar). It's only 40mm in diameter, and less than $20.

Any reason why you wouldn't use something like that?
I'm definitely no electrical expert, I just thought that as long as the pots capacity is greater than the element capacity, it would be durable.

Haven't had a look at your circuit in detail, but I wonder if this would help.

Originally Posted by AK83

I'm curious as to why it'd have to be so big?

I was under the impression that a seat heater element is about 5 or 10w max. IIRC I've seen 3w element kits.

The D3 seats are ~66W on high and ~36W on low.

3W isn't enough to keep my coffee warm let alone my backside.

I'll check the resistance across the heater element and work out the current, might be a useful starting point. Probably won't be today, picked up a virus. Back to bed.

Originally Posted by POD

I'll check the resistance across the heater element and work out the current, might be a useful starting point. Probably won't be today, picked up a virus. Back to bed.

Get well quick Pete
See if you can find a good nurse.