___ Posted April 17, 2019 Share Posted April 17, 2019 1 hour ago, phil.g00 said: But, it isn't about watts, it's about voltage, open circuit voltage is 0 watts by definition. If you push the voltage too high the MOSFET breaks down. It's known as Avalance breakdown, but a MOSFET can handle some of this, as long as the energy value is low enough. The energy is however proportional to the square of the current, so you don't need much current to damage things. Many modern MPPTs will also attempt to protect themselves by turning the low-side FET on (on synchronous buck converters) and shorting the PV modules to lower the voltage. So there is a little bit of wiggle-room, but the question remains: Do you want to take a chance with a an expensive piece of hardware? Coulomb 1 Quote Link to comment Share on other sites More sharing options...
VisN Posted April 18, 2019 Share Posted April 18, 2019 So after all the posts here are we any closer to what the minimum temperature setting should be for the highveld? I'm about to go with this to negate any overvoltage issues. Quote Link to comment Share on other sites More sharing options...
phil.g00 Posted April 18, 2019 Share Posted April 18, 2019 52 minutes ago, VisN said: I'm about to go with this to negate any overvoltage issues. What price are these and where? Quote Link to comment Share on other sites More sharing options...
VisN Posted April 18, 2019 Share Posted April 18, 2019 10 minutes ago, phil.g00 said: What price are these and where? https://thepowerstore.co.za/products/jinko-300w-eagle-mono-perc-maxim-smart-module-silver-frame One online store. I'm sure better prices are available with a bit of shopping around. Quote Link to comment Share on other sites More sharing options...
phil.g00 Posted April 18, 2019 Share Posted April 18, 2019 3 minutes ago, VisN said: One online store. I'm sure better prices are available with a bit of shopping around. It appears as if these are an MPPT chip instead of a bypass diode. I'll have to find out more. ___ 1 Quote Link to comment Share on other sites More sharing options...
VisN Posted April 18, 2019 Share Posted April 18, 2019 9 minutes ago, phil.g00 said: It appears as if these are an MPPT chip instead of a bypass diode. I'll have to find out more. https://cdn.shopify.com/s/files/1/1776/7837/files/Maxim_Residential_Flyer.pdf?6284092317569249418 https://cdn.shopify.com/s/files/1/1776/7837/files/Datasheet_EN_Eagle_PERC_MX2_60M_280-300W-40mm-compressed.pdf?11414400420435099991 I have @SilverNodashi to thank for bringing these to my attention. Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted April 18, 2019 Share Posted April 18, 2019 12 hours ago, DeepBass9 said: But at that time of the morning your panels will be producing zero. In winter on the highveld you won't produce any power before 8.30, where you might get a few measly watts. Really? Does your panels not produce any power before 8:30? I normally have about 400W in summer by 7:30 Quote Link to comment Share on other sites More sharing options...
___ Posted April 18, 2019 Share Posted April 18, 2019 1 hour ago, SilverNodashi said: Really? Does your panels not produce any power before 8:30? I normally have about 400W in summer by 7:30 13 hours ago, DeepBass9 said: In winter on the highveld you won't produce any power before 8.30 Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted April 18, 2019 Share Posted April 18, 2019 4 minutes ago, plonkster said: /facepalm. But this morning the system produced 338W at 7:30. Summer is better though. ___ 1 Quote Link to comment Share on other sites More sharing options...
___ Posted April 18, 2019 Share Posted April 18, 2019 Summer vs Winter. In summer I discharge my batteries over night to make room for solar the next day. The sun is up by 6AM and making at least some power already. I am often still asleep at this point, since school is only at 07:45 and I've been in that special timezone that engineers inhabit ever since leaving high school. In winter I can get up, and if the sky is clear, I tell the inverter to start discharging (full speed). By 9 I have room for the day's PV Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted April 19, 2019 Author Share Posted April 19, 2019 So I installed a small weather system today, one that has been lying in the cupboard for the past 4 years. Yipp. Not a typo. Fell over it when I took out a pair of pliers. Actually wanted to see what is happening in my db. After some pulling and tugging I managed to clear the spiderweb of cables, and with some help from the family I manage to label most of the wires. All but 2 circuit breakers which are connected to a red wire leading somewhere unknown. Going to leave them off and perhaps someome will raise a concern some time... Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted April 23, 2019 Author Share Posted April 23, 2019 So I had an entertaining weekend and only manages to shock me 7 times due to my own stupidity, and I thoroughly tested the Earth-breaker-switch. Took a long time labelling all the cables, and still have no idea to where the one cable feeds power (lights), and then extending some of the very short cables to something that I can work with. Changed the walled-in DB to a surface mounted structure. I still need to go and buy an additional 10A CB for the bottom (solar) row, that will only service lights and the lounge (TV, PC) for now. Clint and Jaco De Jongh 2 Quote Link to comment Share on other sites More sharing options...
Coulomb Posted April 23, 2019 Share Posted April 23, 2019 I don't think that your daisy-chain of what looks like 2.5 mm² cable will handle the combined loads safely. Though it looks quite neat,especially compared to the old mess. Can you get some of that snappable insulated copper bar that is designed for the purpose? ___ 1 Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted April 23, 2019 Author Share Posted April 23, 2019 Yeah. I did not get a bussbar when I bought the Hager CBs, thinking that I can use my existing bussbar. When removing I saw that the CBI BB does not fit, and went to Builders to get another, which also didn't fit, so I drove to ElectraHertz today to get some 16mm wire and the correct bussbar (R150 ... ). Quote Link to comment Share on other sites More sharing options...
Shockin Posted April 30, 2019 Share Posted April 30, 2019 Hi, where did you get the db board from? Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted May 3, 2019 Author Share Posted May 3, 2019 I bought it at ARB in Menlyn. I have to add that it is not that sturdy as it appears on the pictures, perhaps because I cut out most of the back. Ar almost R800 it is also not that cheap. I have seen better (or in my opinion) boards at ElectraHertz in Silverton. Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted May 10, 2019 Author Share Posted May 10, 2019 I would appreciate it if you guys can check my design. They delivered my equipment on Wednesday, but I still have not received my design. But, looking at my planned installation and the equipment that was delivered, I think I do not have the correct stuff. The plan is to use 2x 150/45 MPPTs together with the 12 solar panels. Each MPPT to be fed by 6 panels (3 in series, with 2 strings in parallel). I did not get cables as the quote included 4 mm wire which I thought may be too thin. I ordered 6 mm PV cable to be delivered. 1. The panels to be connected in series with the supplied MC4 connectors (on the PV Panels). 2. I will connect the 2x series panels (3 each) with MC4 Y connectors. They are rated at 60A (ordered, 6 mm). 3. Using 6 mm cable, reported to manage at least 60 A. I will either use 50/45 A fuses or circuit breakers before the MPPTs. Is this really required? 4. Using the same 6 mm cable between the MPPTs and combiner box (to be bought / made) with 50/45 A fuses. 5. 35 mm wires leading from the combiner box to the batteries and invertor. 125 A fuses between combiner box and batteries. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted May 10, 2019 Share Posted May 10, 2019 What size are the panels? Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted May 10, 2019 Author Share Posted May 10, 2019 They are 330W Canadians. After drawing the design I decided to remove the fuses before the mppts and change them with 2-pole circuit breakers. Quote Link to comment Share on other sites More sharing options...
Coulomb Posted May 11, 2019 Share Posted May 11, 2019 7 hours ago, MorneDJ said: I decided to remove the fuses before the mppts and change them with 2-pole circuit breakers. I would replace them with fuses on each string. Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted June 17, 2019 Author Share Posted June 17, 2019 Can anyone assist in telling me what cable is required between the multiplus II and the venus GX ? Is it a normal network cable (UTP)? Quote Link to comment Share on other sites More sharing options...
seant Posted June 17, 2019 Share Posted June 17, 2019 59 minutes ago, MorneDJ said: Can anyone assist in telling me what cable is required between the multiplus II and the venus GX ? Is it a normal network cable (UTP)? Yip that's what I used Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted June 23, 2019 Author Share Posted June 23, 2019 Had some time and finally connected everything, and it was a failure. The solar panels is generating power, it is powering the MPPT, and it appears that the Venus is running. It reports that the batteries are flat, so I am leaving the system to charge the batteries. But ... the moment I switch on the Multiplus II the earth switch trips on the main board. I see that there is two markings on the "on" switch, something like: " II O I ". When the invertor is on the " I ", the green invertor light burns but my main earth switch trips. Problem is with none of these the invertor is not sending power to the house? When I put it on " II ", no light is on but it does not trip the earth switch. Can anyone tell me what is the " I " and " II " switch options are for. Cannot find anything in the manual. Up to date I have done everything myself so, if possible would like to sort this out before approaching a professional installer. Quote Link to comment Share on other sites More sharing options...
MorneDJ Posted June 23, 2019 Author Share Posted June 23, 2019 And fixed, although I do not know what the " I " and " II " switch is for. Still waiting for https://vrm.victronenergy.com/ to verify my email so that I can register the equipment and update the firmware on the MPPTs. Quote Link to comment Share on other sites More sharing options...
Jaco De Jongh Posted June 23, 2019 Share Posted June 23, 2019 2 hours ago, MorneDJ said: something like: " II O I ". Normally 1 is On, 0 is off and II is charger only. 2 hours ago, MorneDJ said: the moment I switch on the Multiplus II the earth switch trips on the main board. I know @plonkster had the same issues, he had to change his RCD to a better one that could "Handle the Inverter" . Plonk please help out here? I cant find the thread nor can i remember the specs of the RCD. Quote Link to comment Share on other sites More sharing options...
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