Kobus van der Watt Posted February 22, 2018 Share Posted February 22, 2018 Hi Does anyone know what will the optimal settings be on an Axpert in the following scenario: We have installed two 5kva Axperts in parallel with each 3kW of panels. But only one set of Sonic 250ah batteries. How will we get the best out of solar panels without really using the batteries, is this possible or do we need more batteries. Thanx Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted February 22, 2018 Share Posted February 22, 2018 6 hours ago, Kobus van der Watt said: . How will we get the best out of solar panels without really using the batteries, is this possible or do we need more batteries. The efficiency of the panels on an Axpert is purely down to load. Your setup reminds me of Dolly Parton. You have 6kW worth of panels and only 250Ah of batteries. Your batteries must enter float fairly early in the morning and your panels idle through the rest of the day. My system was similarly unbalanced but I only had 1 Axpert with 3kW of panels. I try ensure that on a sunny day we maximise our usage. Being a farmer this is fairly easy and there is usually someone to delegate to to switch on/off pumps geyser etc if we are not ironing baking etc. A bigger battery bank would give your inverters more to do but hard to justify just to make your inverter more efficient. If you need more batteries that is anopther story. I would be hesitant to hae such a small battery bank couple to such a large PV array. The Axpert's tendency to overshoot bulk voltage is well documented and may be exacerbated with a smaller battery bank. PaulF007 1 Quote Link to comment Share on other sites More sharing options...
___ Posted February 22, 2018 Share Posted February 22, 2018 19 minutes ago, Chris Hobson said: The Axpert's tendency to overshoot bulk voltage is well documented and may be exacerbated with a smaller battery bank. Off topic, but a Lithium Ion battery has a far worse tendency to "elbow" and suddenly shoot up. Solar chargers that overshoot and don't pull back fast enough will trigger BMS protection relays or damage cells. Only writing that because I've had a few days of fighting with a similar overshoot issue. Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted February 22, 2018 Author Share Posted February 22, 2018 Thank you for the responses, much appreciated Quote Link to comment Share on other sites More sharing options...
pilotfish Posted February 22, 2018 Share Posted February 22, 2018 8 hours ago, Kobus van der Watt said: Hi Does anyone know what will the optimal settings be on an Axpert in the following scenario: We have installed two 5kva Axperts in parallel with each 3kW of panels. But only one set of Sonic 250ah batteries. How will we get the best out of solar panels without really using the batteries, is this possible or do we need more batteries. Thanx If you add more intelligent control to your system then I think your will be able to accomplish what you ask above; Hook up a PC or RasPi and install ICC software to monitor and control the Axpert system, Add a Victron BMV to monitor the battery state of charge correctly, Set the battery charge to SOL (solar only), In ICC go to Axpert Settings and set [To Grid SOC = 75%] and [To Solar SOC = 90%] If you do the above then in the morning your home will run on grid until the batteries reach 90% SOC (probably around 9 > 10am) and then switch to solar, on sunny day your system will continue to use solar and charge the batteries to 100% if excess PV available (use heavy loads between 9am and 3pm). At night you will run off battery until you reach 75% SOC then switch to grid untill your batteries next reach 90%. Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted February 22, 2018 Author Share Posted February 22, 2018 3 hours ago, pilotfish said: If you add more intelligent control to your system then I think your will be able to accomplish what you ask above; Hook up a PC or RasPi and install ICC software to monitor and control the Axpert system, Add a Victron BMV to monitor the battery state of charge correctly, Set the battery charge to SOL (solar only), In ICC go to Axpert Settings and set [To Grid SOC = 75%] and [To Solar SOC = 90%] If you do the above then in the morning your home will run on grid until the batteries reach 90% SOC (probably around 9 > 10am) and then switch to solar, on sunny day your system will continue to use solar and charge the batteries to 100% if excess PV available (use heavy loads between 9am and 3pm). At night you will run off battery until you reach 75% SOC then switch to grid untill your batteries next reach 90%. Thank you for that info, that is what I meant by optimal settings. What is the difference between SOL and sbu on setting 01. Quote Link to comment Share on other sites More sharing options...
pilotfish Posted February 22, 2018 Share Posted February 22, 2018 Sorry I used the incorrect term, I was referring to the charge settings (program 16) where I recommend [OSO] only solar for a grid assisted system, whereas an off grid system should be set to [Cut] to facilitate charging by generator. The reason i recommend this setting is because charging batteries is not 100% efficient and so should be done with free PV power and not costly grid power - this is easy to do if you have reliable grid available. Program 1 should be [Sbu] and not [SOL], apologies for any confusion created. Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted February 23, 2018 Author Share Posted February 23, 2018 No confusion, that is how I set it up, just wanted another opinion. I will just check the Program 16 parameter. Thanx Quote Link to comment Share on other sites More sharing options...
ebrsa Posted February 23, 2018 Share Posted February 23, 2018 @Kobus van der Watt I also have 2 Axperts in parallel but with 2.3Kw panels and a battery bank of 450Ah, 2 strings of 8 Trojan T105's in parallel. Base load is around 700W during the day and about 550W at night. I use a Pi 3 with ICC software and a BMV700 to control the system. The BMV702 would be better. My batteries are also balanced by HA02 balancers. Unlike @pilotfish who runs his ICC set to state of charge, mine runs based on time. The reason is that I want the batteries to charge to 100% during the day and not disharge lower than 80% DOD. It is my understanding that lead acid batteries should be charged to 100% SOC after a discharge. I also want to optimise on solar usage. Now, in summer, ICC is set to switch to grid at 17:00 and to solar at 01:00. I have flashed my Axperts with @Coulomb and @weber ''s 72.70c firmware which works very well and has some usefull additional features. Check this forum at Internet of Things>Axpert Firmware and also download their Aussie manual to read about all the extras. If you use ICC for control, you will find that the program will change parameter 1 to SBU when switching to solar so whatever you set it to manually will be changed by ICC the next time it switches. That said I change the setting if I have to refill my T105's to recharge them fully if they are not at 100% SOC before rewatering. With your 6Kw panel capacity and depending on your base load, you would benefit substantially with a larger battery capacity. That raises the issue of using long lasting storage like Pylontech LFPo batteries which can be discharged almost totally. Dicharging your Sonics to 80% for maximising lifetime would give you 50Ah or 2.4Kwh. One unit of Pylontech can supply 2.2 Kwh and the price is about the same. Perhaps you should consider selling the Sonics and replace them with Pylontech or similar. I would also seriously consider it if I was younger but at my age the T105's will in all likelyhood outlast me. Recently @Chris Hobson installed a Pylontech unit so he may have information to share. I hope this helps but there is no doubt that you would benefit much from a larger battery bank assuming you don't use most of your 6Kw solar generation during the day. Edit 4 Mar 2018 @weber has kindly pointed out that the direct link to his and @Coulomb 's firmware is http://forums.aeva.asn.au/viewtopic.php?p=66664#p66664 so rather follow that link instead of the one on Powerforum described above, which is a roundabout way of getting to the "CWA" (Coulomb/Weber/Aussie) software. CWA does stand for Cost and Works Accountant but I would submit may be a good acronym for identifying their super firmware for us Axpert owners. ibiza 1 Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted February 23, 2018 Author Share Posted February 23, 2018 Thanx-a-million for the advice and detail. I will definitely look into that. Thanx Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted February 23, 2018 Share Posted February 23, 2018 Pylontechs are brilliant and I have it on good authority that Manie has cracked the BMS and will feature in ICC. Quote Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2018 Share Posted February 23, 2018 6 hours ago, ebrsa said: ... lead acid batteries should be charged to 100% SOC after a discharge. At least once a week. Quote Link to comment Share on other sites More sharing options...
___ Posted February 23, 2018 Share Posted February 23, 2018 49 minutes ago, Chris Hobson said: Pylontechs are brilliant and I have it on good authority that Manie has cracked the BMS and will feature in ICC. The canbus spec is fairly easy if you know what to look for, but I assume Manie went for the RS485 one instead? Quote Link to comment Share on other sites More sharing options...
Sidewinder Posted February 23, 2018 Share Posted February 23, 2018 The charge, discharge or both? Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted February 23, 2018 Share Posted February 23, 2018 9 minutes ago, plonkster said: The canbus spec is fairly easy if you know what to look for, but I assume Manie went for the RS485 one instead? I am not sure we will have to wait and see. Quote Link to comment Share on other sites More sharing options...
PaulF007 Posted February 23, 2018 Share Posted February 23, 2018 On 2/22/2018 at 3:02 PM, Chris Hobson said: Your setup reminds me of Dolly Parton Bahahha nice one @Chris Hobson almost went by unnoticed! @Kobus van der Watt as most said here the way you handle your system will ultimately determine how efficient it runs. You have the added benefit that on cloudy days you will still have some power. One other option is to get some wall timers ( I had quite a few running in the beginning). You can the setup stuff like phone/table chargers ectr only to be working in the day and at night they are all off. You will be amazed how low your base can get by shutting down the "silly" power hogs that you dont need. Just be aware that it can get quite addictive if that bug bites you!! Kobus van der Watt, ibiza and Chris Hobson 3 Quote Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2018 Share Posted February 23, 2018 55 minutes ago, PaulF007 said: Just be aware that it can get quite addictive if that bug bites you!! Or the wife hits you. Quote Link to comment Share on other sites More sharing options...
pilotfish Posted February 23, 2018 Share Posted February 23, 2018 2 hours ago, The Terrible Triplett said: Or the wife hits you. Seems TTT may be admitting that he is addicted to being beaten by his wife, Is this a 4th personality rearing it's head??? Quote Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2018 Share Posted February 23, 2018 15 minutes ago, pilotfish said: Seems TTT may be admitting that he is addicted to being beaten by his wife, Is this a 4th personality rearing it's head??? For the newbies. We've all been through the phases, where we hunt each and every watt, chasing them down mercilessly, to the utmost horrendous frustration of the family. As Plonkster said "... quite addictive if that bug bites you." Once settled, then we have the phase where "someone" switches things on against the advised regulatory rules and regulations laid down with such passionate care and understanding, and the system trips yet again with the resultant loud disapproval screamed from various fronts at the most inopportune moment. Obviously, during this loud exchanging of disapproval, we off course have died 10 times of fright thinking what the hell happened? Was that because of the last change I made!? Then we move to the phase where they all operate around the system with caution and wisdom. This is the quiet phase before all hell breaks loose. The last phase occurs after yet another tripping - probably caused by her, or one of her siblings, obviously(!), in your absence - when SWAMBO, not the wife, SWAMBO, goes ape on your a...e , rears up out of the distant blue saying in her most silent but violent tone of voice: You. Will. Take. The. System. Out. Right. Now! -as you enter the door, having had to move the gate manually, and open the garage doors by hand. That is the level I am referring to. Obviously, there is an alternative. The the TERRIBLE triplett way. Me Myself and I, we would skip all the above phases and just bow down, dig in, steadfast like a rock, non-negotiable, "onwrikbaar in ons oortuiging" and stare them down with ice in our veins threatening the utmost violence with our cold icy stare if any rules and regulations are not adhered too, to the LETTER of the law, as laid down by us. Note: Please do not try this at home! It can result in substantial additional costs. Hospital costs. You could try and claim it under Solar Expenses if you want. Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted February 24, 2018 Author Share Posted February 24, 2018 14 hours ago, Sidewinder said: The charge, discharge or both? Both Quote Link to comment Share on other sites More sharing options...
___ Posted February 24, 2018 Share Posted February 24, 2018 I think I'm past all that. First, one of the big issues in my house is that the wife likes light. Everything must be bathed in ample levels of lumination. Lights are turned on in bright daylight to add just a bit more light to things. And lights are left on... it will go unnoticed all day. Besides, having to turn it on and off every time you enter a room is so much work... To me this idea is completely foreign. I grew up on a farm where we had a 36V battery system and the lamps were 60W incandescents. You turned them off and that was that, no questions asked. This city things where come 7PM you turn on all the lights you might need (not just the ones of the rooms you are in) is completely new to me. So what I did is installed LED lighting so I can stop worrying about it. The inverter is a hybrid, so no tripping. The wife has already grasped the value of having power when everything else is out. In fact, I probably have her blessing to upgrade to a 3kva unit... because then her hair drier can work during an outage. You'd be amazed how often you have a power failure starting right after 8AM on a Sunday morning, with Church starting at 9. Barezzi 1 Quote Link to comment Share on other sites More sharing options...
Gabriël Posted March 28, 2018 Share Posted March 28, 2018 On 2/23/2018 at 9:50 AM, ebrsa said: Unlike @pilotfish who runs his ICC set to state of charge, mine runs based on time. The reason is that I want the batteries to charge to 100% during the day and not disharge lower than 80% DOD. hi @ebrsa, trying to tune my system i stumbled on this post of yours. although my setup is different from yours my object is the same, i.e. having full batteries as the sun sets and running as many things as possible during daytime from the panels. is this achieved by setting icc as per image? regards g Quote Link to comment Share on other sites More sharing options...
Kobus van der Watt Posted March 28, 2018 Author Share Posted March 28, 2018 I have no idea what the relation between battery voltage and percentage SOC is, so i have no idea what the voltage should be at 70% SOC Quote Link to comment Share on other sites More sharing options...
pilotfish Posted March 29, 2018 Share Posted March 29, 2018 16 hours ago, Kobus van der Watt said: I have no idea what the relation between battery voltage and percentage SOC is, so i have no idea what the voltage should be at 70% SOC It is not a straight forward relationship so there is no accurate answer. A big instantaneous difference will come about when switching from charging to discharging or vice versa, also your battery terminal voltage will jump up/down with amps drawn as a result of internal resistance of the battery. Internal resistance will increase as battery condition deteriorates with age, so this relationship will change over time SOC as offered by the BMV (not voltage based SOC as per Axpert) will rise and fall smoothly which is why it is a MUCH better method to control your switching states. But to try and answer your question I have attached my Battery Trend graph below. While delivering +/- 1kW of power the voltage is +/- 50V at 90% and +/- 49.5V at 70% and +/-48.5V at 60% where I switch USING SOC as per BMV. You can see the voltage dips on the middle graph as amps spike with fridge starting etc, and the smooth slope of SOC by comparison. Quote Link to comment Share on other sites More sharing options...
Gabriël Posted March 29, 2018 Share Posted March 29, 2018 46 minutes ago, pilotfish said: smooth slope of SOC by comparison hi @pilotfish, what i cant figure is why my battery soc slopes downward over the last 24h.... i suppose there is a bmv702 setting which can set this. i also attach batt settings on my icc and dash image Quote Link to comment Share on other sites More sharing options...
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