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  #1  
Old 01-28-2020, 03:34 PM
KatanaPilot KatanaPilot is offline
 
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Location: Locust Grove, GA
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Default Seat heaters

OK I need a EE for this.

Is it acceptable to use a PWM dimmer (say 8A capacity) for a resistive load like a seat heater (6 amps)?

Use of dimmer would allow variable control and elimination of the relay normally used for low/high switching.

It's times like this I wish I had studied EE and not AE.
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  #2  
Old 01-28-2020, 03:52 PM
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blueflyer blueflyer is offline
 
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There is a Goodyear seat heater that is a cig lighter connection (6 amps) and has a high and low setting. They are about $40. I bought one on impulse last month.
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  #3  
Old 01-28-2020, 04:07 PM
gblanck gblanck is offline
 
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Location: Redwood City, CA
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Yes- I used the 7A PWM dimmers from pilotlights.net with heater inserts from flyboys. Works nicely. I've had some mechanical reliability issues with the dimmers- suggest using the "remote" version so it's easy to replace the supplied variable resistor when/if it breaks.
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  #4  
Old 01-29-2020, 07:15 AM
KatanaPilot KatanaPilot is offline
 
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Greg, do you think the reliability issues might be due to a PWM dimmer not being ideally compatible with the type of load from a seat heater?
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Krea Ellis

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  #5  
Old 01-29-2020, 07:23 AM
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N941WR N941WR is offline
 
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Before you install a seat heater, please google "seat heater fire".

They are surprisingly common.
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  #6  
Old 01-29-2020, 07:25 AM
lr172 lr172 is offline
 
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Quote:
Originally Posted by KatanaPilot View Post
Greg, do you think the reliability issues might be due to a PWM dimmer not being ideally compatible with the type of load from a seat heater?
PWM is definately compatible with resistive devices and should work well in that application, assuming they are rated for the current. For reliability, you would be wise to have extra headroom. 7A rating may not provide the same reliability as a 10A for a seat heater that may draw 5-6 amps.

Be sure you understand how the heaters work, electrically. They typically route power in two different paths/configurations to generate two different levels of heat. You will want the PWM circuit connect the same as the high current routing.

Larry
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Last edited by lr172 : 01-29-2020 at 07:29 AM.
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  #7  
Old 01-29-2020, 08:31 AM
skydiverlv skydiverlv is offline
 
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Location: kansas
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I installed seat heaters with only the low circuit wired direct to switch thus eliminating the need for relays and extra wiring. My wife has found that sufficient for her, the reason for installation.
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  #8  
Old 01-29-2020, 09:46 AM
gblanck gblanck is offline
 
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Quote:
Originally Posted by KatanaPilot View Post
Greg, do you think the reliability issues might be due to a PWM dimmer not being ideally compatible with the type of load from a seat heater?

The reliability issue's I've had are all mechanical- the rheostats physically coming apart after a while. Likely just from vibration and the way they're mounted with the weight of the dimmer PCB supported by the nuts on the shaft / cover of the rheostat which is just held together with a few soft metal tabs.
-Greg
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  #9  
Old 01-29-2020, 12:27 PM
KatanaPilot KatanaPilot is offline
 
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Default Thank you!

I appreciate the information.
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