Surplus solar diverter + battery storage issue?

[lakelandfolk]

• 
• Members
• •  107
• Location: Tarleton

• Author

 

Fitted a PV Mate solar diverter today and our batteries are 100% fully charged.   The PV MATE is showing circa 1.5kwh + is being diverted to the immersion heater, however multi test meter on immersion heater shows only circa 140volts AC is being delivered. I note that page 3 of instructions says "installation must be in the immediate vicinity of the water heater"  Our PV MATE is about 15 meters from the cylinder via a 2.5 cable, then spur outlet then .5 metres of 2.5 heat resistant flex. Could the 15.5 metre cable run be causing such a big voltage drop??  Confused because when we use the boost function then the normal 230v AC is delivered yo the immersion.     Despite the immersion element receiving only 140v ac it does appear to be performing OK.   In about 1 hour the cylinder water temp has increased from 43 to 55 degrees. Very confusing.        Any ideas/observations would be much appreciated. 

 

•  
• Quote

[sharpener]

The diverter probably supplies a chopped waveform very far from being a simple sine wave. So a multimeter will not average it correctly using the root-mean-square method unless it is an expensive "true rms" type.

 

This also may explain why they specify a short cable run, to reduce the risk of radio interference from the chopped waveform.

 

Also it can cause problems with screw connections, I have had to replace even a high grade (MK) fused spur box  because of this, make sure they are all very tight.

[lakelandfolk]

Is the current set up safe?  Should I consider a plan B?   I could re site the diverter unit alongside the cylinder but that would be 15 metres and 3 walls from the ct clamp in the meter box and the transmitter might not be able to pair with the diverter unit.  In that case I could extend the ct clamp cable, which I think will be CAT5, by the necessary 15 metres and fit the transmitter alongside the diverter in it's new position.    ie Cylinder, diverter unit and transmitter side by side, a little bit of work but I can do it myself. I'm 85 but do enjoy a project. 

[sharpener]

It's generally best to have a short mains cable and long CT cable as the latter is low voltage and will neither radiate nor pick up interference.

 

I looked at their website and it seems a reasonable product (I built my own diverter and am familiar with some others).

 

If it is working OK (and it sounds from your first post it is), nothing is overheating or causing radio interference then you could just leave it as it is. I would perhaps check if the transmitter will cope with the extra range, if not I would leave it be rather than bother extending its cable. Your choice. Bonne chance.

[RobLe]

We had a solic 200 pv diverter to our immersion for a few years.  Similarly it lived near the fusebox, with a short CT cable, and then a long (7m) cable to the immersion.  Never had any trouble with it, didn’t notice any interference generated by it.  
As has been mentioned, you’ll only get a full mains waveform out when it’s really sunny, most of the time it will be ‘phase controlled’ and lower rms voltage, which is it working correctly with the available spare solar power.

[lakelandfolk]

Many thanks everyone, I have spotted a flaw in my suggested plan B.  The proposed new position, next to the cylinder, is in a lean to conservatory which of course gets very hot when the sun is shining. I know diverters can suffer from over heating  issues so the conservatory would not be a happy place for it.  The current set up appears to be working OK so I will leave it as is and and just keep an eye on things.  Once again, thank you for your advice.