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Thank you for the great forum, Safe Driving over the weekend. Sincerely Jason


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viceroy last won the day on December 12 2019

viceroy had the most liked content!

About viceroy

  • Birthday January 4

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    Broadacres, Johannesburg

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  1. Thanks all. Looking back through the history, it's tripped 4 times, 42A, 49A, 26A, and yesterday at 27A. Not a great record for one month. Definitely looking like it's faulty. Breaker is warm to the touch when I've been there to catch it. Going to play it safe and replace the breaker, and the wiring for that section.
  2. I have 3180W of PV panels configured to output between 80v and 100V. At peak output the voltage is around 86V. The peak Wattage I see is 2800W, but usually closer to 2500W. When I redid my system recently, I installed an Onesto 250/500VDC 6kA 63A double break circuit breaker. I had nothing previously and this one seemed the closest match to what my panels put out. Since then, the breaker is tripping, usually late morning, and not every day. Not only is this annoying, as I'm at work and can do nothing about it until I get home, but is wasting precious solar to charge my batteries. Looking through ICC outputs, I can't see anything unusual. I've even lowered the PV charging amps in case there was some sort of overload causing the issue. The attached image is from today when the CB tripped. As you can see, looking pretty normal until the sun suddenly disappears out of the sky. Any ideas?
  3. I sold mine to Battery Center in Roodepoort. Got R11 per kg.
  4. I also saw this sort of thing happening at the low end of the charge scale too. Batteries got down to 21% and stayed there. I didn't wait more than 5 minutes to let it get to 20% so ICC could switch to grid and start charging. Would hate for this to happen to someone, and their batteries accidentally drain down to 0% because the BMS was still showing 21%. I have since set my min battery switchover SOC to 25%.
  5. Thanks very much. I didn't use to have the luxury of putting everything right by the DB board, only about 5m, but the wires were already there so that's what I used. Only now that I've gone from 500kg of AGM batteries to 60kg of LiFePO4 can I make it all fit in that corner. That's great you are getting such good use out of the batteries. Sadly, where mine were before was in the garage, where temps are pretty much always above 40C...a real battery killer, so I'm happy to have gotten 4 years out of them. The labels are just printed on my laser printer and scotch taped to the inverter. It's kinda temporary. Will be getting some decent adhesive vinyl labels made up soon. A lady near where I live, has all the materials and printers to do it nicely. She already made my warning labels...
  6. When connecting batteries in series, you add up the voltages, so 4x 12V 105Ah batteries gives you a 48V 105Ah string. When connecting batteries (or strings) in parallel, the voltage remains the same, but the Ah increases., so 2x 48V 105Ah gives you 48V 210Ah. Not recommended to go with more than 2 strings in parallel. To get the really big Ah capacity battery banks, the easiest way is big Ah batteries with low voltages, so a single string of 24x 2V 500Ah batteries = 48V 500Ah in a single string.
  7. It's either 12V * 210Ah or 24V * 105Ah, depending on whether the batteries are connected in series or parallel. Regardless though of how they are connected, they still contain the same Wh, ie. 2520. Question 2. You would add another string of 2 batteries that are identical to what you have now. The new batteries would be connected in parallel to your current string (which are connected to each other in series btw). Question 3. With a 5kva inverter, you would be able to supply 5kW of power to devices, ie. 2x 2.5kW kettles, or 5x 1000W microwave ovens. Your batteries determine how long you can power the load for. Having 8x 105Ah batteries would give you a total capacity of 210Ah @ 48V (2 parallel strings of 4 batteries (connected in series)) which is 10080Wh total. You shouldn't really be drawing more than 50% of that if you want the batteries to last, so 5040Wh. With 5040Wh, you can power 5kW of devices (remember the 2x kettles, or 5x microwaves) for 1 hour, or you could power 1x microwave for 5 hours, or you could power something using 350W for nearly 14.5 hours. Not answering the other questions as they have been answered already.
  8. Basically interlocked change-over switch, physically disconnects one source before connecting the other. Safer, with almost no chance of failure in such a way that both sources are connected. Reverse flow blocking relay, doesn't really disconnect either source, but rather blocks flow from one to the other. Less safe, and a much higher chance of both sources being connected in the case of a failure.
  9. It is something to consider, but in my house, aside from the stove and geysers, the only circuits still in the main DB powered only by grid are the kitchen counter, and garage/patio. The loads applied to these circuits all high amp draw and/or inductive, and I don't really want these with a direct connection to the Axpert. Can you imagine, the gardener cutting the grass, while at the same time the maid has the dishwasher going, the washing machine going and needs to heat something up in the microwave. The poor Axpert is going to switch to bypass mode, or just trip (if bypass disabled). Yes, I know it's a bit of an exaggerated situation, but one entirely possible, and despite being more expensive, a hybrid inverter solution would simply add grid power to assist the PV. The Axpert wouldn't know about any excessive loads, and everyone would be happy. If loadshedding happened, a DC transfer switch, would move PV over to the Axpert, and again, everyone happy.
  10. It would be great if you could provide a list of parts you used to achieve this?
  11. About the most comprehensive answer I got was along the lines of: The negative has the same potential as the positive, and even with the positive disconnected, its possible to have current flow through the negative (in a problem situation), so better to fuse both than just the one. While I haven't done it just yet, I am going to install my second fuse onto the negative cable. Rather safe than sorry.
  12. I may actually be over complicating things too. Doing like you suggest, and leaving the panels on the hybrid inverter, I'd still essentially be charging the batteries from solar. Only if the grid goes down, would I then move the panel output to the Axpert if required.
  13. No, as the system stands now, the batteries are fully charged by 11am, from that point on, the essential loads are drawing maybe 200W until the kids get home at 4pm and start using computers, tv, etc...quite a waste I think. By switching the panels over to a hybrid inverter at the point the batteries are charged, their power will be blended with grid power, but giving precedence to the panels, in effect allowing me to maximize their use during the day. Yep, from when I was looking at the various hybrid inverters, their startup volts seem to be around 100/120V while my current string configuration is between 85 and 95V. So you are correct that, I'd need to reconfigure the string to provide higher volts, and get a separate MPPT charger. --edit-- I see the Kodak i2.5 has a startup voltage of 60V, but nominal is still 250V, and I don't see any locally.
  14. At the moment, yes, the panels are only charging the batteries and running the critical loads, and yes, critical loads are off grid, although the Axpert will switch to grid if the batteries get below 40% (setup in ICC). Together with the gas stove, and evacuated tubes for the geyser, it's working well...BUT...once the batteries are charged, the panels are 90% wasted during the day, and I've also started investigating adding a hybrid inverter. My first thought was to split the panels between what I have and the hybrid inverter, but this solution is inflexible, and at times wouldn't fit my needs. Seeing your post and the possibility of switching the panels between inverters really appeals, as I could have 100% of the panels dedicated to the grid tied inverter while the batteries are being charged, and then switch them over to the hybrid to run the house for the house for the remainder of the day. Could also get a bit more complicated as I'd also want to bypass the grid-tied inverter and run all loads through the hybrid inverter during the day, making as much use of the panels as I can. There seem to be a few automatic switches locally, but I'm not sure at the moment if all or any would be totally suitable. http://www.giga.co.za/ocart/index.php?route=product/product&product_id=423 <- drop shipping https://www.epicsolar.co.za/Items/Transfer-switches-and-DC-distribution https://www.atisystems.co.za/electrical-enclosures/normand-automatic-manual-transfer-switches-ats-mts <- actually looks like it could do the trick
  15. Hi, Yes, a DC transfer switch would be what you are looking for, simplest (cheapest too) being a manual switch, and then an automatic being more ideal, albeit at a higher cost. Who told you this? Most residential installations of Axpert inverters have it connected to the DB board. In my setup, I have a main DB which contains breakers for all the non-essential loads, and this feeds through to a sub-main DB, where I have breakers to and from the Axpert, as well as an AC changeover/bypass switch, and then all the essential loads which are normally powered from the Axpert. This is the main DB, please excuse the gaping hole. Pic was taken during installation. This is my second DB which is connected to the Axpert.


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