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OomD

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OomD last won the day on July 24 2016

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  1. I did not, no. I'd prefer any available solar power to charge the batteries before using it for load. Timer settings are all set to 30% SOC with no charging from grid or gen. I can see how your suggested change can make a difference, just confused as to why it did not reduce charging to help the load, as it did at about 10:00. Edit: Come to think of it, your suggestion makes absolute sense. Thanks!
  2. Hi guys, Haven't been here for a long time. Just installed an 8Kw Sunsynk to replace my Axpert, and while monitoring the charging today I noticed the inverted used from power from the grid while charging the battery from PV. I want to know how I can completely stop the inverter from using the grid unless the batteries are below 30%. Heres a pic of what happened. At 11:35 a load (probably kettle) was switched on, PV generated 3.2Kw, batteries charging with 1.8Kw. The load was 2Kw, so why did the inverted add another 688W from the grid, if the PV watts were enough to carry the load and the battery charging simultaneously? Or, if the PV watts was not strong enough, why did it not lower the charge watts to accomodate the load? Around 10:00 there was also a load, but during that time the batteries were used to help the PV sustain the load, the grid was not used. I don't understand the difference between these two scenarios? My system mode is set such that the battery is set to 30% the whole day, in my mind it means it must run from batteries until it reaches 30%, then switch back to grid? Thanks!
  3. Thanks guys, appreciate the feedback. I'll keep an eye on it over the next few weeks.
  4. Yep, 6 full cycles since I've added the new battery, as can be seen on the screenshot. Strictly speaking, if stronger batteries give more current then the SOC should remain the same for all. But things are obviously not always in proportion, I understand. What baffles me most is how come the stronger battery draws less current during charging? I would expect the "flattest" battery to draw the most current. But, this is with "dumb" batteries in parallel, perhaps the built-in battery manager in these are the cause of it. Some fancy algorithm they use to distribute the charging amongst all the batteries? I dunno, just thinking out loud here.
  5. About a year ago I got rid of my lead acids and switch over to Pylontechs. I placed 3 x US3000 in parallel, with a Raspi and ICC software monitoring the whole lot. All went well. Recently I added another pylontech ot the mix. I hooked up the new pylontech and allowed the four batteries to reach equilibrium, so to speak, before connecting back to the inverter. Now I expected the older ones to discharge first, but it appears to be happening the other way around. The new pylontech is the master. See the screenshot from my ICC while the batteries are charging, the new one is way lower than the other 3, and is drawing less current. For the same current draw I would understand the new one being lower during charge, as it's capacity will be higher and thus needs more current to fill up. But why would there be such a great difference in SOC, and why would the new one charge with less current than the rest? And, why would it discharge before the rest? I've even seen the ICC software report a SOC of 101%! (In the pic, the blue circled number on the left is the total SOC). Could this be due to a firmware difference between the old and new ones? I'm not even sure if these batteries' firmware can be updated? Any input would be appreciated!
  6. Had them running for a year, so I'm guessing around 200 to 250 cycles.
  7. I've used these for about a year, then upgraded to Lithium. Average DOD was 20%, I had ICCSoftware on a Raspi controlling the lot, and a BMV702 monitoring them. Never had balance alarms or the like. In Centurion area, I'm thinking around R5K for the lot. Oh ate too, 8 0 3, 2 four 7 1.
  8. OK that clears it up a bit. But... sorry to be nitpicky, I just need to understand the consequences of using it like this. If set to 54, with bulk set to 56.4 and float set to 55.2, this will cause the inverter to switch to batteries while the batteries are still in bulk phase. As the battery voltage ramps up, and crosses over 54 for about a minute, then the load is switched to battery. This creates the possibility of the batteries never really being fully charged, depending on actual load and solar availability. In the long run the batteries crystalise more with this scenario, don't they? Unless, off course, a periodic equalising charge is used to offset this. Note please, I am not arguing the correctness of your info, I really appreciate the feedback. Just trying to understand it.
  9. Thanks for all the replies, guys, and also the great detail Chris. I'll lower the voltage to 49V, I understand 50V is a bit high given the Axpert's (erroneous) use of it to determine SoC. @Chris Hobson I'm using 73.00b currently, not going to 73.00c yet until I decide finally what to do re parallel use of 4KW/5KW inverters (different thread). I'll adjust the back-to-batt setting to 54V, thanks for the advice. But then, should I not be lowering the float too? I mean, if float is set to 55.2V as it currently is, it will technically not get down to 54V? Or does the setting of 54V for back-to-grid mean 54V and greater? Once again, I appreciate the feedback, guys. I have purchased ICC in the meantime and busy getting my Raspi up and running, and will probably eventually hook it to the BMV as well. Just need to get the VE.Direct cable.
  10. Thanks, pilotfish. Yes I realise its high, but I want to try and maintain a 20% DOD max. Works out to around 50V. I know that the Axpert's voltage monitoring is causing the premature back-to-grid here, and not the actual SOC. I am more concerned about the fact that the inverter does not go back-to-batt again, and trying to understand the inverter's behaviour. Ultimately, I suppose, getting ICC is the better option (I simply don't get the time to finish my own SuperPV project).
  11. Thanks for responding, Chris. Absorb = 56.4 Float=55.2 Charging=OSO 12=50V 13=FUL From your questions I deduce that the Axpert did not complete the charging (even though the BMV thought it did) and thus did not go back to batt?
  12. Strange, it is Gary at Inverter Warehouse that I communicated with, who initially told me that the inverters are all 5KW now.
  13. I wonder if there is any nice document around somewhere, that describes the Axpert's thinking process. For example, I got home yesterday and the Axpert was in bypass mode. My batteries (8 x Narada) were at 51.3V, and according to the BMV712 they were at 94% SOC. The last full charge was about 14 minutes before, according to the BMW. Now, it might be that the BMV recognised a full charge, but the Axpert did not (running 73.00b). Anyway, I wondered why the Axpert was on bypass. In my mind there's only 2 reasons: 1. Overload condition. 2. Batteries reached the "back to grid" level. In my case I know its not #2, and I'm not aware of any heavy load prior to me getting home. Setting 4 is on Bypass Enable, though. What I am curious about though, is why did the Axpert not switch back to batteries again? There was no significant load (about 400W), thus no reason to stay on grid. My setting 1 is SBU, so I expect the Axpert to stay on batteries/solar until the "Back to grid" volts are reached (setting 12, mine is set to 50V). Does anyone know what conditions makes the Axpert go back to batteries, once it has switched to grid? Maybe only the next time they are charged, or there is sufficient solar?
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