Iboost sender ct


Apologies in advance, im looking at monitoring a new solar panel install with an iboost diverter.

I want to log solar generated, exported,diverted and home use.

A very basic question, is it possible to connect to the iboost ct signal to obtain the export and remove the need for another ct clamp to be fitted to measure export?


Welcome, Mark, to OEM.

It might be, but I can’t identify the c.t. that IBoost uses, and without that I cannot give a definitive answer. But I strongly suspect, because the emonTx (and the emonPi is the same) needs a higher output voltage than many c.t’s can provide, the answer will be either a straight no, or yes but with impaired performance from the emonTx. Even then, the emonTx would almost certainly need modification to avoid spoiling the IBoost’s calibration. And then the emonTx itself would also need custom calibration.

The simplest is to have a second c.t. Provided the two are a few cm apart, they won’t significantly interfere with each other.

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I agree. I have an iBoost and to do what you say you would have to intercept the radio (or whatever it uses) signal between the sender and the unit.

The basic emonPi Solar monitoring setup will show you what’s generated, imported, used and exported; you are just missing the amount diverted as a subset of use.

If you really want to know how much electricity you dumped into your hot water you could:

  1. pop a CT on the wire to your immersion/iBoost (but you may then need an emonTx) or
  2. get an iBoost Buddy which tells you how much you diverted albeit not in your emonCMS.

That’s not what I had in mind. My thought was to cut the c.t. cable and T-off a cable to the emonTx to look at the voltage across the burden that is surely inside the IBoost transmitter. That way, you wouldn’t be tied to it’s sampling scheme. Because the IBoost transmitter is battery powered, there shouldn’t be any ill effects once the emonTx/emonPi’s burden is removed.

Interesting, I just have an aversion to cutting wires :joy:

I just had a look at my iBoost’s CT and there appears to be only one core; how can it tell which direction the power is flowing?

I’d be incredulous if there were more. :roll_eyes:

Take a look at “Learn” - it’s the phase of the current in relation to the voltage.
I don’t know how the IBoost detects that - it might well send a sample of the wave to the base unit, or it might rely on capacitive pickup to get a reference voltage, doing the maths inside the transmitter.

Yep, it was just that the iBoost docs talk about “cores” so I was just reporting what I found.

Done - thanks.

Thanks for information, just found out iboost has stopped diverting, so need to get this working again before trying to get another ct to the iboost

You could replace it with Robin’s Mk2PVRouter :grinning_face_with_smiling_eyes:

You’d know exactly how that works, and you could (can?) send the data you need to an emonPi.

I’ve lost track of the number of enquiries from people whose alternative power diverters have failed. Many of them have been successfully replaced by Mk2 PV Routers. To date, I’ve not heard of any Mk2 units failing in service. If one that I have supplied were to do so, I would repair or replace it without question :sunglasses: