superdiy

Cobus, what do you mean with "it reaches bulk at around 13:00 but remains in bulk until around 16:00"? Charging always start off with Bulk, being constant current until the set "Bulk" voltage is reached, then it goes into Absorption mode, where a constant voltage is applied and the current gradually drops off. Lastly it goes into Float mode after the current in Absorption mode was below a pre-configured value for a pre-configured amount of time. I assume you meant that it goes into Absorption mode at around 13:00 and stays in Absorption mode until the sun goes down. What is the current at say 15:00 or 16:00? Is it quite low, e.g. around 1 A? Mine is configured to go into Float mode after the current in Absorption mode stayed under 0.7A for more than 1 hour. Since you have increased you bank's size quite a bit, you might have to adjust that "go into float current setting" to be a bit higher than what it was before, since the bigger bank will now draw more current in Absorption mode than what was drawn by the smaller bank.

Hi Chris, I cannot remember if I've ever seen such a setting. I don't think the "4 batteries" thing can be changed either - they assume 12V batteries are used and on a 48V system you would have 4 of them. I don't think the tail current is bought into account when charging either. The thing is, the 3KW infini can only charge up to 25A, so on a bank of up to 250Ah, that would be the recommended 10% of the Ah rating of the bank and it would take x amount of time in the absorption stage before the charger switches to float. You have now increased your bank to 500Ah and effectively it will only be charged @ 5% of the Ah rating of the bank and therefor, if you start off at the same SOC for both banks, the larger battery bank will take much longer to become fully charged than the time it took the smaller bank to get to 100%.

Cells, not batteries. Could not resist.

The kettle in the pic is plugged into a mains outlet. The one in the link is 12V.

OK, I was afraid that this would be your problem. The voltages of the panels are similar, that means that they will perform much better in parallel, but all connected in parallel would be way to low for the MPPT to work properly - you need between 60V and 115V. You have not mentioned the MPP current, only max current, the MPP current will just be a bit lower for both panel types, but with 1 serial string you will be limited to the current through the smaller panels which would be 8.33A under short circuit condition and a bit lower at MPP - the +- 6A you see looks in line if you keep in mind that your tilt angle is way too low, especially for winter. I don't think you really have any other option than to tilt the panels more or to add more panels and configure them differently. Any serial / parallel combination of the current panels will leave you with either the same amount of losses or a too low total pv voltage, which would be too low for the MPPT to work effectively.

I am not saying that it is the case, but what they usually do is to only change the duty cycle on "lower" power settings. In other words (ignoring efficiency and power used by controlling circuit, display etc.) if you set it to 2100W, it will draw 2100W all the time. If you set it to 1400W, it will draw 2100W for 67% of the time and draw 0W for 33% of the time. If you set it to 800W, it will draw 2100W for 38% of the time and 0W for 62% of the time. The switching rate (from full on to full off) might be at 2 times per second or 100 times per second, I don't know, but the point I want to bring across is that the power is not necessarily varied, but in most cases the duty cycle is varied. So the problem with induction cookers is where someone want to power it from an inverter, the inverter will have to be able to handle the full 2100W and not only the 800W or 500W you've set it to. A microwave oven works on the same principle, if you set a 1000W oven to a power setting of 700W, it outputs 1000W for 70% of the time and 0W for the other 30% of the time. In microwave ovens the duty cycle is just much lower - few seconds on, few seconds off, few seconds on, few seconds off.

Hi Fritz 2 things here... If your panels are fixed, in other words the tilt angle is not adjusted seasonally etc., then it should be tilted at more than 15° to get the most from them - 19° for Mussina, which is the most northern place in SA and almost 30° if you are in the most southern place in SA. solarpaneltilt.com The one serial string consisting of different panel types worries me a bit. If all your panels have the same (or very close) voltage at maximum power point, the total current flowing through them will be limited to the current flowing through the 150W panels and effectively you will lose at least 120W or more at MPP on a good day (4 x (180-150) = > 4 x 30W => 120W). Please post specific model numbers or datasheets for all the panel types you are using, maybe we can suggest a different configuration which might have better results.

The thinner cable will have higher resistance. With higher resistance you will have a higher voltage drop over the cable. The higher resistance in the thinner cable will cause the cable to get warmer and because of the higher voltage drop on the thinner cable, the speed-heat will be less effective because some of the power goes to waste in the cable supplying the speed-heat. If the cable is too thin it might get so hot that the insulation melts, which will cause a short-circuit, which might cause a fire etc. etc. By using the 2.5mm2 cable, it might not overheat, but your speed-heat will not be able to heat the water as quick as it would have using thicker cable. The incoming water temperature differs all the time, so you might not even notice the effect of the thinner cable. If you are OK with the power going to waste, it should be fine to use the thinner cable. I won't skimp on that - I prefer to over-compensate and would have used 6mm2 cable for that 5KW speed-heat, even if the distance between the DB and speed-heat was less than 4 meters, but that is just me.

Hi Tropman, have you actually measured the wattage at the different settings or is that what they indicate on a dial / display?

Hi haider There is no way you can "increase the charging" on your infini - the maximum charging current is 25 A and according to your settings in the screenshots, you have it set to 25 A already and you are charging the battery by PV and grid and are using the grid when pv is not available and if the battery voltage goes below 50 V you start to recharge it from the grid. All of the above indicates that your battery should be charged and that that is not the problem here, unless your grid fails a lot or if you are switching off the grid connection to the infini permanently or at night perhaps - please let us know if you have the infini connected to the grid permanently and if the grid is available most of the time. The only other reason why it might trip as you said when the grid fails is because it supplies a load of more than 3 KW while the grid is available and when the grid fails the inverter is overloaded and trips.

I don't know exactly how they are doing it, but they are maybe transmitting real-time 50 Hz mains data from the clamp to the receiver, which is connected to mains. By doing that they should be able to determine power flow direction.

Since you have to power the controller by connecting it to the AC line, you can effectively measure direction of power flow as well. A clamp is actually a transformer where the primary winding is the cable onto which it is clamped. The direction of the current flowing through the secondary winding of the CT / clamp will mimic the direction of current flowing through the primary winding (the cable onto which it is clamped). Being AC, the direction of current flow will change 50 times a second (at 50 Hz), but if you take the L & N connections into account you can measure the power flow direction. When a meter is not connected to L & N directly, e.g. if the meter is powered by an AC/DC transformer or power supply or is battery operated, the power flow direction can not be determined by the clamp only.

OK, it used to be available from reuk.co.uk, but the circuit etc. has been removed and they have replaced it with a description and a link to a commercial product: Pictured above is a product which comes with a clip-on current measuring device which measures the instantaneous net current (solar generation minus domestic consumption) being exported through the electricity meter. It supplies only this amount of power to the (standard 3kW) immersion element automatically to make best use of surplus PV solar generation. This device is called Solar iBoost and is available here: buy Solar iBoost from around £180.

It is available in kit form in the UK - try a quick google - I'll post the link if I can find it. That should also not be the only option out there.

First thing that jumps to mind is the huge battery bank you are trying to charge with the 25A from the infini. The standard charging current should be about 1/10th of the Ah rating of the battery bank - you have a 750Ah battery bank and it should be charged at about 75A - you are charging it at 25A max, which is 1/3rd of the recommended / standard charging rate for your battery bank. Your inverter will really struggle to get the battery bank charged. It might work if you only discharged it say 10 to 15% every night and have good sunshine the next day, but if you drain the battery bank more than that every night, the inverter will not be able to recharge it to 100% during the day and after a few days of this, the battery bank will be dead - that said, this is when you have disabled AC charging and runs from the battery bank at night. If you are charging from PV and AC and runs the load from the grid at night it is OK, because then the battery bank will eventually be charged after a day or more depending on the DOD. You also mention that the inverter trips when the the electricity goes (grid fails); does that happen during the day when you have enough sun (incoming PV) to cover the load or does this happen at night when the inverter has to fall over to the battery bank? What is the total load supplied by the inverter when it trips? Keep in mind that if your total load at any time is more than 3KW while the grid is available, the inverter will trip when the grid fails and the load is still more than 3KW, no matter if the incoming PV and / or battery is enough - the inverter can only supply a load of up to 3KW when the grid is not available. When you say "my requirement is to gentrate 3kw for home use for max economy" I suspect that your total load might be more than 3KW at certain times and that is why the inverter then trips when the "elecrticity goes".

My next door neighbour from a few years ago was an aircon installer and he told me that the power supplies of the inverter aircons fail a lot because of loadshedding and the unstable grid. I have only one inverter aircon, a 30000 BTU jobbie, which I keep switched off at the DB and only switch on when we want to make use of it for the reason mentioned above. The main reason why I went for the inverter type instead of the non-inverter type when I had it installed was for the fact that the startup current on the 30000 BTU non-inverter aircon of the same brand was almost 80 amps and that meant that I had to have my main breaker upgraded to at least a 100A and that would have had an enormous effect on my monthly connection fee. So I went for the inverter type, with a startup current of less than 20A and I could keep my 40A main breaker and much lower monthly connection fee as is. The other advantage is the lower claimed running current. According to the product information stickers on the aircons, the 30000 BTU inverter aircon's maximum consumption / running current is less than the maximum consumption / running current of each of the 18000 BTU non-inverter aircons I have.

One of 3 possibilities... Neutral and Earth never accidentally touched while you worked on it You have a double-pole isolator in the line to the speed-heat and it was switched off, either close to the speed-heat or in the DB feeding it - I'm not sure about the regulations and requirements for the double-pole isolator, but since you have to have one within (I think) 1m from a geyser, the same regulation maybe applies to a speed-heat. The earth wire running to the speed-heat is faulty / not connected at the other side (DB).

You'll have to pop in for a coffee at least.

No, I cannot remember. I did draw up a diagram of the shunt and the components on the shunt pc board and the associated wires to the monitor, but I'll have to really dig deep to find that - it is somewhere in my piling system in the garage. Basically you have the power to supply the monitor, the voltage drop across the shunt and the midpoint or temperature probe reading.

Ouch, the frequency ranges are a bit tight / limited.

I've made up a longer cable and used 4 pair cable instead of the original 3 pair cable and had to run certain wires in parallel, because the voltage drops on certain wires have an effect on mostly the voltage reading. If you are going to make it shorter it might have the opposite effect or you might not notice it at all depending on the final length of the cable. When I did my testing I noticed a voltage drop on the 20+m cable and then experimented the round-robin way to determine which wires I had to double up to reduce the cable's resistance and associated voltage drops. It is NOT "just a data cable", the shunt does not contain anything digital e.g. A-D converters etc. The cable between the shunt and the actual monitor / display unit carries analogue voltages which are converted inside the monitor.

Sorry, missed this one. A true hybrid is able to combine sources to power loads.

Yes, that would be 4mm2 per conductor.

OK, then I stand corrected - seems that it is indeed a true hybrid.

That's what I suspected. Not a true hybrid either, as I understood it is just possible to feed back to the grid and charge batteries at the same time, the rest is similar to the Axperts.