Has anyone sourced or used alternative CTs of same specification to those supplied with VM-3P75CT energy meter successfully?
The 10mm diameter is fine for smaller cables e.g. 16mm2, but for larger 25mm2 or 35mm2 a 16mm or 24mm frame size CT would be great. I would suspect they exist but there isn’t much to go by with lack of specifications.
Surely Victron could release some speciations of the CTs supplied?
Accuracy: 1%
Ratio: 3000:1 ?
Rated primary current: 80A?
Secondary Current: 16.67mA ?
Saturation current ?
Load resistance?
Burden Resistor?
I would surprised if it’s a bespoke CT. Surely must be standard off the shelf CTs that will work.
The new Victron energy meter model that will support standard 5A CTs, but also different current ratings is highly welcome. I hope it will be available soon.
It does seem challenging to find a similar alternative with bigger diameter. However I see in the same Kemet model range a 120A CT is available with 16mm diameter.
This outputs a higher 400mV @ 120A primary current, however based on the charts in the datasheet it would appear at 80A primary current load it should output similar voltage as the Victron supplied CT, following similar linear curve, so should be fairly accurate?
Worth getting a sample and testing I think.
I wonder within the energy meter, can the ADC circuitry support input beyond 270mV and thus is there capability to meter beyond 80A, or would damage occur? I notice with the 80A CT upto 120A is possible and with the 120A CT upto 150A is possible, subject to design of the energy meter.
Has anyone exceeded 80A measurement with the VM-3P75CT?
@guystewart. It would be nice if Victron can advise if the C/CT-1216 can be supported or not with the VM-3P75CT
Upon looking where to procure a sample I do notice one of your UK ‘Authorised Distributors’ is selling it.
For your application there is a new version: the VM-3P5A. Basically the same meter with a generic CT input. Any CT that has a nominal secondary current of 5A is applicable (and that is a big pool!). In the setting you can set the primary current.
The news has been out since about 2 months. I’m not sure if it’s available yet.
I believe Victron originally suggested a release in Q1 of 2026. That’s clearly been and gone, so has Q2 so I’d imagine it’ll be pretty soon.
regarding the kemet clamp, I’ve been using it for a while and it performs identically to the supplied clamp as far as I can tell. I do not exceed 80amps so can’t advise how the meter responds in that scenario.
My last information is July, so basically now, but it’s not in the Q3 price list and not in e-order for distributors.
I guess there is another delay for a few weeks.
Unusual that the direction K>L appears reversed based on the split format.
Have carried out some preliminary testing. Installed the new CT on separate meter, and clipped onto same cable (Load) to compare accuracy of readings with a Victron supplied CT.
Can certainly conclude the CT works fine up to the Victron meter rating of 80A.
Did some short testing beyond 80A load, upto around 95A. After 80A, the readings on the meter become inaccurate and max out in high 80s.
Can therefore conclude there is hardware/software limitations within the current meter, and it is indeed just designed to meter upto the 80A specification.
Either way this CT solution is ideal for standard supplies, and solves the problem if you have larger cables / meter tails.
In the UK the CT is available from both RS components and Farnell.
@Victron feedback on whether this is approved for use would be appreciated.
The tech specs and the manual state that for that model it is rated for 75A 80A max. Thata pretty official statement as the the device limits. What more is needed?
If the reading is close to accurate seems to be working ok then it should be ok to use if the gauge wire is the issue. But the reading limits are definitely mentioned at 80A.
It would better if Victron sold the VM-3P75CT without CTs, at a lower cost, as it’s a waste having lots of spares, particularly if only using the kit for single phase. In the above setup I used 3 of the larger frame CTs and thus the 9 CTs supplied are unused.
It was a worthwhile test bench testing beyond the 80A limit to see what was the limiting factor actually was, as no one had the answer on whether it was the meter hardware or the CTs. Now we know. As Victron supply the kit with CTs suitable for 80A, of course the datasheet would have to state 80A max.
More is needed hence why the VM-3P5A is being launched for higher current requirements.
In the interim until it becomes available will just have to use compatible Carlo Gavazzi or ABB meters that support higher current.
When the VM-3P5A is released, I would like to think it will be sold by Victron without 5A CTs so you can choose appropriate ones and quantity needed to requirements.
