# MES-DEA RM4 as parking heater with Webasto remote



## rwaudio (May 22, 2008)

Is your RM4 connected to mains (240v AC) or your battery pack?


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## KeeBee (Oct 24, 2014)

I don't know yet, i just got the car last week. I think it's connected to the battery pack since it's also working while driving.


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## rwaudio (May 22, 2008)

I'm doing something similar with an RM3, the one thing to consider is that if you remotely turn on the heater after the charger has completed you won't be replenishing from the wall. This is what happens in my car, when I want to preheat off wall power I have to turn on the heater, give it a few seconds to bring the pack voltage down, unplug the charge cord and plug it back in. Then the charger almost keeps up with the heater draw.


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## KeeBee (Oct 24, 2014)

I thought of that, but didn't test it yet. If the charger doesn't start automatically when the heater is switched on, I want to use a timer(clock) to switch a 63A relay. If I let the timer switch the main power off and on again just before the heater is switched on I guess the charger will also be active.
Would be nice if I could trigger the charger to kick in when the heater is switch on. Unfortunately I have no information about any of the components used in my car. It's a prototype of Detroit Electric based on the Lotus Elise.


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## rwaudio (May 22, 2008)

You'll want the charger to kick on after the heater, otherwise it will likely terminate instantly because the pack is still "full".
That's how my Brusa works anyway. I believe many chargers will kick in once the voltage drops too low, but it's meant to save a pack that's being stored for many months, I doubt any charger would kick in when the voltage drops slightly.

Nice little car, hopefully you get everything working well.


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## KeeBee (Oct 24, 2014)

My initial setup did work but if the battery pack was fully charged, the heater would use energy from the battery instead of the charger. I found out that I can start the charger by supplying +12v to a dedicated pin on the charger connector. 

Update on the schematic, the 1A fuse was to small and needs to be 2A.


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