I had the iboost fitted as in summer we will have way over the solar power we need, and the boiler could be turned off, today it tells me I have exported 9.2 kW hour, better to use it. However noted it was working before my battery was fully charged, not that much of a problem, but not ideal, then tonight I realised it was at 9 pm discharging my battery to heat the DHW, so flicked the switch. And send an email. I have not touched the settings, one reason is they did not leave a manual on how to use it, found one on internet, but not sure right one for the unit. I will guess the CT unit and sender are too far away, but would have expected some screen report, where fitted I need a mirror to read the screen so not easy, but seems to say "Heating by Solar 0.57 kW Htr1" which looking at manual means "Solar iBoost+ is diverting energy to the hot water tank. The instant value of energy being diverted is shown together with an indication of the immersion heater currently being supplied (if two heaters are connected will switch between Heater 1 and 2). When energy is diverted the blue symbol flashes:" so I am leaning towards a faulty unit?
I don’t worry about instantaneous readings - the system will be shooting about all over the place. Look at the daily totals instead.
It takes approx 14 kWh to heat up 40 gallons of water, the tank will stay warm for a few days, but I can see using 6 kWh on good days to keep the water hot, today exported 9 kWh so if the water is heated at the right time that would be more like 3 kWh and today my use was low, dishwasher, washing machine and tumble dryer not used. So if the iboost works as the instructions say, my export will likely be 3 kWh on good days, and many days zero, but if the iboost runs off the battery it is costing me money.
Solar generation will vary wildly so really difficult to predict anyway. Can be close to zero on dim days in December and January, 6kWh or even more per kWhp capacity installed in June/July.
Surely, as the batteries reach full charge the charging will slow down and there will be a gradual switch over by the Iboost to heating the water, not a sudden change over, because the Iboost is measuring what would be going to the grid on the tails and holding it to zero?
They usually work on an export threshold which should be configured in a complimentary way between the two, ie battery set to reduce export to eg 100W and iBoost set to start consuming at 150W (since the batteries are more effective storage than water, usually it’s better to have them charged first) and an EV charger if enabled with export related functionality set to 200W. If they are all set to the same, ie 100W they will be constantly fighting each other, eg the iBoost starts absorbing causing the battery to flick to supporting the load and whilst the iBoost continues to draw without having time to see hence the battery providing the illusion of excess solar generation.
The weather today means very little from panels They can hardly supply the house never mind charge battery, never seen so bad since they were installed.
Electric vehicles require a minimum charge rate of 6 amps, so charging an EV from PV is even more problematic. Option 1: Just charge the car at full rate. Option 2: PV surplus only, but the car may not charge. Option 3: Charge at 6 amps plus any additional PV surplus to boost it above the 6 amps.
At some point there really needs to be manual intervention to prioritise what gets what if you have PV that’s supposed to be supplying appliances in your home as well as charging a storage battery, charging your car, heating hot water and exporting any surplus into the grid, though exporting to the grid to sell electricity seems a bit over optimistic given everything else that’s being supplied.
The system will still export as the “the good days” come in blocks across the summer and it’s impossible to use and store it all.
Option 2 will only work if the PV surplus is more than six amps. Option 3 will use any thing that is available from the panels and top it up from the grid as and when required, so is the best option.
I think I have found the problem? However not really up to date with directional CT clamps, the instructions for the iboost+ say the CT clamps need to be at least 100 mm apart, the iboost+ CT clamp was pushed hard against the meter which will also have a CT clamp inside it, and is hardly 100 mm from the CT clamp for the inverter, and it does not look easy to get the clamps with the required gap between them. The main problem was they went off with the instructions for the iboost+ and I in error downloaded the instructions for iboost I had not realised two versions. On DIYNOT it was pointed out that on the new version one can set when the iboost+ cuts in starting at 100 watt then in 50 watt increments, this resulted in my realising I had wrong instructions and one I found the right ones I realised the CT coils are too close. However down to nitty gritty I should not have needed to fault find, one wonders how many other installations are wrong?
Talked to the installer today, promised to get back to me to sort out the problems. Also have an EPS (UPS) supply which is not RCD protected, and the guy doing the test for the earth rod, tested the wrong wire, which may be why no RCD fitted as he got 0.37 ohms.
If it makes you feel any better, the situation you’ve described closely resembles my own experience. My previous experience with MCS accredited heat pump installers was no better on the electrical side (they weren’t too good at plumbing either). It leads me to suspect that the MCS scheme may not be fit for purpose. The UPS output might have its own RCD in the inverter itself btw. Circuit(s) served by it obviously need RCD one way or other not least because MCBs will do nothing at all since the PSCC is so low on battery.
Yes it did thanks No I down loaded the instructions as I had same thought. I have just started a thread on isolation, as I have realised I don't know how to turn off the EPS supply to swap the FCU for a RCD FCU, I do not think it comes from the new consumer unit they fitted, as if it did they would have used a RCBO for all 5 outlets. So I think it comes from here. But I can't reach it as there is a battery in front of it. Good point about the PSCC, one I had missed, not sure what is required to rupture a 13 amp fuse? Seem to remember 2.42 ohm for loop impedance so 95 amp PSCC is required. Am I working this out correctly? As yet no paper work except for the compliance certificate which arrived before the work was completed.
Well the iboost changed the storage offset from 100 to 200 watt and now it seems to be doing as expected. So I will change the FCU for a RCD FCU myself and that should be it.
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