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Sonoff Power Meter Modification - Apache 700

413 Views 4 Replies 3 Participants Last post by  Scotjimland
Hi everyone,

New to the forum. I am a big VW fan and have contributed many DIY projects to similar forums. Hope I can contribute in the same way here.

My first DIY will be the fitting of a power meter to our Apache 700 Sargent EC500 cupboard.

The device I have purchased is a Sonoff POW elite. This will be inserted in the wiring between the EHU (orange cable normally) and the Sargent EC500.

I will use genuine JST connectors for the insertion before the Sargent so the wiring can be reverted to factory if I ever decide to remove the Sonoff.
(There maybe a couple of holes to fill on the vertical panel if I decide to remove).

Advantages of having a power meter: -
  1. Real time indication of watts being consumed by MH - takes the guesswork out of consumption.
  2. Historical usage data for 6 months.
  3. Resettable kW hours of electricity used.
  4. Indication of incoming voltage.
  5. Remote control / isolation of EHU supply via mobile application.
  6. Scheduled on/off EHU.
  7. Set power limit, Sonoff will disconnect at a set power (saves embarrassing EHU MCB trips).
So, if I find the where the DIY mod pages are I will be posting progress and images.

I have already received the Sonoff and am playing with it now.

Cheers :)

I have bought the 20A version of this: -

Do I need to pay to use this forum in a meaningful way? If that is the case I may have to relocate...
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Welcome to the forum noonoo. That sounds like an interesting project but as a 12v (or any electricity really) nincompoop I just trust to the person who did whatever he did to my MH to make the solar work, apparently.
Some years ago I fitted an OWL power meter in my USRV when we were living in it full time .. as you say, useful for monitoring and not tripping the EHU ..

No install required, just a simple clamp over either Live or Neutral incoming supply cable.

Would I fit in my present campervan...?
No, not worth it, we rarely use EHU and when we do am savvy enough to know how may amps we are pulling with mental arithmetic.. it's not rocket science even for a non-electrical person.

You don't need to pay for this forum.. but these are the benefits ..
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Thanks for your reply, I did see your install dating back to 2012 IIRC? Nice (y)

I did look at all available smart meters that use the current clamp, none of them gave me the features the Sonoff offers so despite the wiring I am happy to go ahead.

If I decide to remove it will be a simple unplug job of the JST VL 2x2 4 way connectors. It will leave a few holes of course.

As we are newbies to MH life I think we will be mainly on EHU for the foreseeable future so it should have a useful lifespan.

Also, just out of curiosity I'm interested to see the ec500 battery charger and water heater consumptions. Certainly the battery charger is a big variable (0-300W)?
I think the water heater is 850/1250W or close to those numbers depending upon the switch setting - this switching in/out as it needs to.

At least it puts a max consumption on my misses hair dryer ;)

Cheers :)

The other big thing is validating energy consumption, I am aware some sites now charge per kwh? Nice to be able to check...
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The other big thing is validating energy consumption, I am aware some sites now charge per kwh? Nice to be able to check...
yes indeed ..
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