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Everything posted by JaseZA

  1. Item: Kodak VMiii 3kw 24V Inverter Age: 18 months Price: R6000 Payment Method Accepted: EFT/Cash Warranty: 6 Months of original warranty left Packaging: In original packaging Condition: Excellent used condition. Still functioning perfectly. Location: Richards Bay but visit Durban occasionally. Reason: Upgraded to 5kw 48V Shipping: Sure - For buyers account Collection: Sure Link: https://www.sustainable.co.za/kodak-vmiii-3kw-24v-solar-off-grid-inverter.html https://www.gumtree.co.za/a-generators-solar-power/richards-bay/kodak-vmiii-3kw-24v-inverter/1009522647220910040456009
  2. Very interesting, thanks for sharing! So 13S at 51V nominal = 3.92V per cell, 54V Max = 4.15V and 42V cutoff = 3.23V. Interesting seeing a chemistry that isn't LFP but NMC!
  3. Correct! In fact it turns out the Mecer 200ah is just 100ah cells in parallel!
  4. Exactly the problem with LiFePO4 - the inverter doesn't do a very good job I'm still deciding - might have another project for it. But will let you know. I have a "Smart BMS" from Ali-express (Sometimes called the 'ANTbms'). With a lot of creative programming I managed to link my rPi over bluetooth to pull the data. Then use Solpiplog to pull data from the inverter over serial and send commands.
  5. Sorry, missed your reply! As far as I know, in-rush current is the initial current the inverter pulls to fill the capacitors. In theory capacitors can fill at incredibly high currents so if there is nothing to slow the rate down, it can damage the inverter. It's why it is always advisable to connect your batteries via a resistor (can be a light blub) the first time to slowly charge the capacitors. Again, 100ah vs 200ah batteries both have very high short circuit currents versus the safe current for the inverter, so I'm not sure it would make a difference.
  6. Looking at electricity like water flow actually works very well. Pressure=Voltage, Flow=Current. Batteries in parallel are like two 100L tanks sitting next to each other, 2m above the ground. The pressure is the same at the tap except you can now allow twice as much water to flow out before it's empty (200L vs 100L). You also have two taps so your flow rate can be twice as high. Batteries in series is like having both 100L tanks at 4m but only having a single pipe! So now your pressure is doubled, you have the same quantity of water (200L) but you're trying to push that through a single tap, so you have reduced flow rate. This analogy isn't perfect though - in theory they're very thin tanks so the pressure doesn't drop very much as you drain them. Hmm, right thinking but there is an actual formula for this: P = Rho x G x H where P=Pressure, Rho=density, G=Acceleration due to Gravity and H=Height. As you can see, there is no mass - this is because pressure isn't changed by how much water, just how high it is above the ground. So Ah (Amp-Hours) is a measure of energy quantity. Basically it's how many amps can be delivered for an hour. 100Ah = 100A for an hour. Adding more batteries increases the total energy. Sorry, this turned into a lesson far more quickly than I imagined! Hopefully it's a little bit helpful. I'm also sure there are much more qualified people here to explain this! Hopefully they'll correct anything I've gotten horribly wrong.
  7. Definitely don't do that - most multimeters are only rated to 10A. If you just connect it across the battery terminals it will short the battery, allowing VERY large currents and popping the multimeter fuse.
  8. I bought a Minleaf 30V/10A PSU from Banggood - working well so far, but as I said, 10A is a bit light sometimes. But it works! And hard to beat the price. Problem is you need to accurately set the voltage to 3.6V - hard to do with an inverter I think. I've got a mix - got some from China, but that was very painful and worked out quite expensive... The rest I got from LithiumBatteriesSA. They had 120ah 2nd life cells at R750 last year which was a good price. That being said I'm busy building a DIY bank using some secondhand pouch cells I got from Mecer 12V 200ah lithiums I've been very happy for the most part with my VMiii, considering what I paid for it. It doesn't have some of the features of the fancier systems but it's been reliable for me. I am in the process of upgrading to the 5kw though - 48V is much nicer with lower currents from the batteries and while we've made 3kw work, my wife is getting a bit irritated now when I tell her to wait for the kettle to finish before she uses the microwave! But it's been over a year and we've been fine. As of last month I have saved R4744 on electricity and been the only people in our complex not worried about load shedding One thing to note - I manage my inverter and BMS through a Raspberrypi which gives me even more control than most CAN connected batteries. Without this you're relying on the inverter to figure out SoC from the battery voltage. There are quite a few threads on this and why it can be problematic. In summary, you generally just lose out on some available battery capacity. There are some BMSes available with CAN communication but you need to make sure they work with Voltronic inverters.
  9. Also, the fans will run if the unit is charging the battery. You might need to look at these settings and see what works for you. I imagine USB, ECO and BYE?
  10. That being said, even if you were to overload it, it would bypass to grid or shut down depending on your settings. But it does use energy the whole time in Line mode doing the conversion. I'm not sure if it will use the battery to power loads when in Bypass if the grid fails.
  11. Remember this is a King unit and operates differently to the MAX/VM/MKS inverters in that it has zero transfer time and does double conversion. This means it must be in bypass and not line mode to purely pass through grid.
  12. Speaking from experience, you definitely need to charge them. Or they must be right near their highest voltage when paralleling them. I bought a bench power supply just for doing this, although even that is a bit low on current. My strategy in the past has been to get them as high as possible (When the most full battery hits 3.6V) while unbalanced with my inverter charger, then connect in parallel and do a final charge with the bench power supply set to 3.6V. This being said, my cells were never hugely out of balance... And a year later they are almost still perfectly balanced.
  13. I would happily leave it at 20A - that's only 0.1C for a 200ah battery. I intend to charge mine at 50A or 0.25C. Most lithium recommendations I've seen are around 0.5C max for continuous and 1C max intermittent. I generally like having the inverter DC low cut off higher than the battery BMS. This way the inverter cuts on it's own terms rather than there being a chance the BMS might cut first. This is unlikely though as there is almost always some voltage drop across the cables from battery to inverter, so the inverter tends to read lower. Raising this value will reduce your total capacity but increase the life of your battery.
  14. Hmmm, I think the best option here would be 2 strings, each with a 265W + 335W + 335W. Your 335W will have their output current reduced to 8.66A though, so probably only give you max 329W. Your Voc total is 129.9V which is in the save range of your inverter. Total current will be 8.66A x 2 = 17.32A which should again be safe.
  15. Thanks for the feedback! I still haven't had a chance to update mine...
  16. These are the specs I can find - it would be best if you confirm these. Looks good for Canadian Solar 395W Poly panels - 10 x 47V = 470V which is less than 580V. I don't have personal experience but my understanding is that unbalanced MPPTs are fine. Be aware that this inverter has a current limit of 11A per string. Not sure but you might be over that with the 460W mono panels.
  17. The thing is the inverter controls the current. It determines the load, not the battery. Plus, most normal deep cycle LA battery can deliver in excess of 1000A in a dead short anyway. I have no idea why your UPS doesn't like 2 batteries in parallel. If they are well matched it should just see it as a single larger battery.
  18. My understanding is that the inverter has no idea how big your battery is. All it sees is the voltage between the terminals and all it can do is apply load and pull current. As long as the battery supplies that, it doesn't mind what the source is. Differences in batteries are far more applicable when it comes to charging voltages and currents. But this is generally to the detriment of the battery, such as charging too slowly for a large capacity battery or over charging if the charge voltage is too high. Something that could have happened here is one of the cells in the battery went high and the battery BMS disconnected it. Inverter might have taken exception to that and popped a fuse or something worse. Sounds like the damage occurred when the battery was close to or fully charged? Unfortunately the loud bang and smell of burning don't give me much hope it's the fuse.... There are many examples of people running these inverters with these Mecer lithium replacements with no problems (mybb forum has lots, my brother has been running a very old 24V for a few weeks), so I think you either got unlucky or something else has happened.
  19. On mine the exact same data is accessible by the USB port as by the RJ45/Serial port. I've used both in fact but the serial proved to be more reliable. I'm quite surprised SMH can't work with the serial data... and would personally be tempted to try with a converter just in case it did work. But I don't know the ins and outs of the system. Hopefully you can find a USB board!
  20. I just had a look on the hubble compatibility list - unfortunately it's not great... Voltronic Axpert - Serial - Requires ICC Raspberry PI Basically it's not compatible in a true sense and requires a third party to interface between the inverter and battery.
  21. Great if the Kodak supports them! You may need to get a specific cable to go between them though. For LiFePO4 type batteries (which almost all off-the-shelf solar lithiums are) you have a cell voltage range between 2.5V and 3.65V. 2.5V is completely dead and you shouldn't go there regularly. 3.65V is almost completely full and again, you don't want to be there regularly either to prolong cell life. 24V battery packs tend to be 8s - meaning 8 cells in series. 48V tend to be either 15s or 16s. 8 x 2.5V = 20V 8 x 3.65V = 29.2V To complicate matters, LiFePO4 doesn't have a very uniform curve and is instead quite flat through most of the range with a rapid increase in voltage near full and a rapid decrease in voltage near empty. That's why they tend to have BMSes that monitor current to keep track of energy in and out of the battery. I personally run my bank between 3.0V and 3.45V per cell to increase longevity of the pack. Ultimately this probably isn't a big concern as you can control a lot of these parameters on the inverter - charge voltage, cut-off voltage, back to grid voltage etc.
  22. That's strange - how old is your inverter? Mine came with an RJ45 to serial cable. I combine this with one of the linked converters to get USB into my laptop/raspberrypi. What ports do you currently have on your inverter as I'm sure there will be a way to convert to USB. I've never seen or heard of a replacement USB board...
  23. https://www.takealot.com/all?_sb=1&_r=1&_si=2bec3b091e95f52e621f36a73700b2a2&qsearch=serial to usb I personally have a Mecer one - so can't comment on the others....
  24. Currently Kodaks (Voltronic inverters in general really) are only compatible with Pylontech as far as I've seen... But Hubble should be able to confirm that for you. There may have been a firmware update allowing more though.
  25. Little bit more info needed - which inverter exactly? Seeing this is 3S4P wired I'm guessing one of the 145V max solar options? It's possible shading is an issue, but you also need to check you're not over-voltaging now with the cooler winter weather. Or that it's just a normal difference in winter with lower angles and less Sun time. I get 12kwh a day in summer (1.6kw peak) and 8kwh in winter (1.2kw peak). But my angle is 18° which is better suited for summer power (works well for me in KZN where I run Aircons all summer!) Looking at your photo - no chance you can shift the panels slightly further from the wall? Can't see what's on the other side there. Oh nevermind - just saw they were mounted to the wall! I imagine you'll still get better production from semi shaded 3S4P than the next alternative which is 3S3P.
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