Solar IBoost+ experience

JKenH

Last year when we had solar panels installed we also had a Solar IBoost+ fitted to heat one of the two hot water cylinders in our house. (We have a biggish house so have 2 separate hot water cylinders at each end to cut down losses from long pipe runs.)

I love the IBoost in principle but in practice there were a few shortcomings. We had trouble with the signal dropping out because of the distance from the sender (with several masonry walls in the way) and it was very noisy. (Located in our spare bedroom, visitors complained of the noise so much that we had to turn it off). I therefore had my local electrician move the IBoost onto the landing and while doing so reconfigured the water heating so the IBoost feeds the bottom elements in both our hot water tanks. (We have fitted separate timers to the top elements.) Yesterday the IBoost put over 8 kWh into bottom elements of the tanks and a bit more was added using manual control to to the top elements when we had over 3kw of spare solar.

I have recently purchased a Solar IBoost Buddy which has been a real eye opener. It gives a read out of what we are importing/exporting, receiving a signal from the IBoost which in turn receives a signal from a clamp on the incoming mains feed. Everything I have read on here about clamps being inaccurate at low wattages has been confirmed. Last night at about 8pm with lights and TV on (plus base load) we were supposedly exporting 50w! The IBoost significantly underestimates consumption when it is below 1kw. (I put on a 750w heater via a metering plug and saw about a 300w increase in consumption.)

This inaccuracy might explain why we usually record about 0.15 kWh of solar water heating overnight. My thoughts are that the IBoost is tricked by changes in current (e.g. the fridge cycling). Has anyone else experienced this?

What is also apparent is that the signal the IBoost receives/interprets suffers a significant delay (of the order of 30secs) so switching the kettle on when the IBoost is working means both can be running at the same time before the IBoost responds and shuts down the water heating. When the weather is consistent and no one is in the house the IBoost works as it should but on days of intermittent sunshine and cloud and household appliances being switched on and off there may be a significant amount of electricity being taken from the grid because of the inertia in the IBoost.

It is difficult to put a figure on it but I wouldn’t be surprised if 10% of what the IBoost saves does in fact come from imported electricity.

I still think it’s great and I wouldn’t want to be without it but it’s not perfect.

mgbond

I've just had an installation completed and I have an Iboost. at about 3:30pm last week I was generating around 250W as it was very dark and the Iboost was showing approx 120W going in to the tank. I put on the Tv and within seconds the Iboost switched off. I then turned the Tv off again and on came the Iboost. So I believe mine is working as expected.

I'm trying to get a smart meter as this should help link up with what the Iboost is doing.

Only issue I have is that its only heating the top part of my tank (see other thread).

Sterlingtimes

My iBoost has worked immaculately for some years. However, I think that its benefit is now marginal. I pay 3.21p per kWh the gas but I get paid 5.24p per kWh for export. My export is metered.

A kindly gentleman on this forum estimated for me that the real efficiency of my boiler for hot water production is less than 50%. Therefore, the real cost of hot water production is 6.42p per kWh.

JKenH

mgbond wrote: »

I've just had an installation completed and I have an Iboost. at about 3:30pm last week I was generating around 250W as it was very dark and the Iboost was showing approx 120W going in to the tank. I put on the Tv and within seconds the Iboost switched off. I then turned the Tv off again and on came the Iboost. So I believe mine is working as expected.

That does sound a bit more responsive than mine. Have you ever heard the fan going on yours after dark or recorded any water heating overnight?

I was going to try timing the delay with different loads but today we have intermittent sun/cloud so the generation is constantly changing. I did switch on the oven which is a massive load and the response time was about 25 seconds before the water heater switched off.

mgbond

No, not so far. That would sound to me that the clamp is the wrong way round on the Iboost sender unit

JKenH

mgbond wrote: »

No, not so far. That would sound to me that the clamp is the wrong way round on the Iboost sender unit

No, I am happy that the clamp is the right way round. The Iboost goes into “heating by solar” mode when the sun comes out and shuts down when the house load gets too high - for instance turning on the oven. Were it the wrong way round the reverse would happen.

mgbond

I don't understand why it would show heating at night. unless there is some capacitance somewhere that leaks current back to the grid or maybe the clamp is a bit to close to the meter. I did read that it should be at least 5cm away?

ajbell

Your iboost is faulty, I have had 3 already and yours is showing the same symptoms my faulty ones had.
My iboost buddy is spot on and I know how much power should be going to the tank and its spot on.
Current going to the tank when no power is being generated is a bad sign and should not happen.

JKenH

ajbell wrote: »

Your iboost is faulty, I have had 3 already and yours is showing the same symptoms my faulty ones had.
My iboost buddy is spot on and I know how much power should be going to the tank and its spot on.
Current going to the tank when no power is being generated is a bad sign and should not happen.

Ah, that’s helpful, thank you. I will have to get in touch with the manufacturer as I doubt I will get anywhere with my installer. Did you have any problems getting yours replaced?

ajbell

Yes, I had a few problems but you need to contact Marlec who make them, they will ask a few questions about how its wired up and whats connected.

JKenH

ajbell wrote: »

Yes, I had a few problems but you need to contact Marlec who make them, they will ask a few questions about how its wired up and whats connected.

I had a look at the Marlec website for contact details and noticed their troubleshooting page and particularly their comments about positioning the clamp relative to the Henley block. From there I went to look in the meter cupboard and moved the clamp - it had been positioned by the installer between the Henley block and the consumer unit - not between the Henley block and meter.

Now it is in the right place the readings are far more acccurate and last night there was no solar heating taking place so that was significant progress. I am grateful to those who commented on here.

I just need to resolve the noisy fan issue now. Apparently the fan should only work intermittently. Mine is on all the time that heating is taking place.