Natures Heaven Posted July 20, 2016 Share Posted July 20, 2016 Hi everybody New in the solar business, spend the whole day on the forum, very good input and lots of ideas, we need some help as we are totally of the grid. Our system (still very small) 5KW Axpert Inverter 2 x 260 watt Canadian solar panels 4 x 105 AH batteries 1 x 2.5 Kw Generator After buying all the correct appliances we use about 300 watts continuously sometimes spike to 500 w - one problem our system dies every morning around 3am, we then start the 2.5kw generator to charge the batteries, but we do use the generator a lot when using power tools and while we use it it helps the solar to charge the batteries. What do you think we need to do, get more PV panels or more batteries or both as we chat to lots of suppliers and every guy has a different story. Could someone give us the correct settings for our inverter for this scenario also please Thank you in advance Energy-Jason 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 20, 2016 Share Posted July 20, 2016 Hi Nature, Welcome to this forum. Yes we can help. You said: 5 hours ago, Natures Heaven said: .. we chat to lots of suppliers and every guy has a different story. ... we use about 300 watts continuously ... Let me explain to you with maths, what 300w load means. The 500w I take as peak loads, that are not on for more than a few minutes at a time? Lets say from 8am you start generating enough solar power to not use the batteries till about 5pm(?). That means your batteries need to power 300w for 15 hours of no sun. = 4500watt hours per day. = On a 48v system that = 315ah battery bank (3 strings of 4 x 105ah batteries which is a problem in itself) = 12 x 105ah batteries, discharged to 50% DOD (Depth of Discharge) with 1 days backup in reserve for next day no sun. So you effectively use 25% more or less per night. OR 4 x 105 down to 50% DOD with maybe 6 hours backup - which is fine if you have Eskom or a generator, but it is very bad for the batts at 50% ito life. Pray tell you do not have maintenance free batteries? The ones where you cannot add water? If you did have them, you may get 260 cycles, less than a year, maybe 7 months before they are dead. To recharge just the batteries, you need 8 x 260w panels, for it is taken that you have 5.5 hours of good sun per day, to recharge at 10% of AH. The above panels excludes the load you want powered during the day. How does this compare to the advice's you where given to date? Also want to add, if it was me, 300w load peaking at 500w, I would have gone for a 12 or 24v system and a 800w inverter. Quote Link to comment Share on other sites More sharing options...
___ Posted July 20, 2016 Share Posted July 20, 2016 Without getting into the math, your system is half the size of mine (in PV and battery terms) and your loads are similar. My system isn't big enough to be fully off-grid (which is fine, I'm a city dweller). So the answer is both: You need more PV and more battery. Those 105Ah batteries are usually not real deep cycles, and since you're killing them every day, they will not see next winter. The first thing I would actually do is try to get that baseline load down. TTT did a whole lot of maths already and it sounds about right. Without even looking at that, just sucking me thumb here, sounds like you need 7kwh generated per day (minumum!) and 14kwh storage (for 50% DoD, better battery life). You have maybe 3kwh and 4.8kwh storage at the moment. If you double the batteries and PV and get your baseline down it might work, but you'll need to run the generator on rainy days. Natures Heaven, Weasel and viper_za 3 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted July 21, 2016 Share Posted July 21, 2016 What loads are running overnight? Is it possible to drastically reduce those, switch off fridge for example. ___ 1 Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 Thank you all So they sold me the wrong batteries from start, I got a pm from Mike and he said I need to look into the Trojans batteries Just to be sure If I add 6 more 260watt panels and get 8 x 205ah batteries, I should be ok (with genie as backup) Thank you TTT for the explanation and no they did not explain it like that to us Thank you Plonkster - with tight budgets we have to grow with the system, so I will first add one more bank and double the PV's for now as soon as we are on 8 panels we can change batteries to the Trojans and run tests Thank you DeepBass - we have not tried to switch of fridges but we do disconnect all other stuff - we did get A++ fridges and freezers. This is our appliances and usage Internet 19,2 24 19,2 24 VoIP Phone 12 24 Laptop 1 45 4 Laptop 2 45 4 Radio 14 12 Cell 1 charging 10 2 Cell 2 charging 10 2 Cell 3 charging 10 2 Tablet Charging 10 2 Fridge and Freezer 313 KWh per year each At least we are in the right direction now as it is very confusing when you hear different stories Thank you Regards viper_za 1 Quote Link to comment Share on other sites More sharing options...
viper_za Posted July 21, 2016 Share Posted July 21, 2016 If you can for now try to get the panels on 6 and 9 later as it is better to run them in strings of 3 panels per string with the Axpert 5kVA. Arandoza and Natures Heaven 2 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 Here is the load, right, based on actual figures given? Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 That gives us, 20% DOD and 1 days backup, which is good, but then you need a 48v 450ah bank = 16 x T105RE's. Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 And that means, to recharge the bank with 5.5 hours, every day, you need 6 x 260w panels. And check the inverter size required for average load = 300w. BUT we know fridges / Freezers have startup peaks, not bad on A+ and A++ devices, so I would guess min 1000w inverter that can handle surges up to 2000w will be more than sufficient. Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 I would consider L16RE-B 370ah batteries? And I will consider 50% DOD with 1 days backup, this is off grid. Then you need 8 of then for 48v. Now to just put it out there, on a 12v system, you would only need 4 of them. Massive reduction in costs on batts and panels. What am I missing guys? Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 @viper_za, my most constructive critic re. 48/12v, what say you on such a nice little small load, off grid with gennie backup? Quote Link to comment Share on other sites More sharing options...
viper_za Posted July 21, 2016 Share Posted July 21, 2016 33 minutes ago, The Terrible Triplett said: @viper_za, my most constructive critic re. 48/12v, what say you on such a nice little small load, off grid with gennie backup? Okay, yes it will work. But now all of the sudden the R/$ takes another dive oil shoots back up to $110 a barrel (currently +-$48) This would make running my gennie even less affordable. I want to rely on my solar more, heck even running on the bank is cheaper than running the gennie. Now the 48v bank is more efficient and hammers the battery bank a lot less when running the higher loads. This is something Chris did, he just needs to use the gennie when the need arises. The other reason he is living off-grid and as money allows he can upgrade his panels to start running more and more luxury items. Microwave, kettle, iron, vacuum etc (can use less gass if he only uses a gas stove, another saving during day time) Only expense now would be the the panels and cables since he already makes use of a big enough inverter He already uses the 5kVA inverter Mark, Chris Hobson and Natures Heaven 3 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 Thanks Viper! Now Nature, in my opinion, has the best of both worlds to contemplate. The moment you start talking luxury items, if Nature wants, like electric kettle, geyser, then do not go 12v. But there is something I think we should also point out to newbies on solar. You are going to upgrade / change for you cannot possibly "understand" what is coming unless you have lived it with the wife. Only once the wife has experienced solar's limitations, can she give her qualified and experienced input and if you are good, get her approval. Nirvana for any solar system is the wife's approval, for once that is obtained, you, the electricity provider, has learned a hell of a lot. You are then a Grand Master on Solar - with her permission, support and blessing. And now I am going to use the cheapness of Axperts to the benefit of my side of the discussion! Axperts are cheap I am constantly told. Yet we all know batteries are not. So get a cheaper 12v inverter and keep the cheap 5kva Axpert around just in case you change your mind earlier than anticipated. I would, with a first system, go as cheap as I can knowing full well that I am going to change in 1-3 years, I am going to run the batts into the ground learning. So I buy wisely that I could re-use the smaller parts afterwards like for example for lights and other light loads so I do not really "waste", just re-allocate the school fees already spent. The moment you start off with electric kettle, geyser, vacuum cleaner, you really first need to consider needs versus wants, for they have vastly different price tags. And lest we forget, like me being "off-grid" Eskom my "gennie". Going for day 3 now with insufficient sun. Lowest batts have been early this morning was 61% SOC. Yes, it is fine. It is good to now and then push them to 50% ... my supplier told me ... then bring them back up to 100% and do a equalise. Good stirring of the juices in other words. O wait, Axperts cannot equalize Trojan's, sorry! Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 33 minutes ago, viper_za said: This would make running my gennie even less affordable. Forgot to add, the 12v system calcs, needs no gennie for 1 day. So if you are careful you could stretch to 2 days. All about managing the load to avert using the gennie. FWIW, if I was on a farm with a diesel gennie, I would look very hard into biodiesel. Quote Link to comment Share on other sites More sharing options...
viper_za Posted July 21, 2016 Share Posted July 21, 2016 26 minutes ago, The Terrible Triplett said: You are going to upgrade / change for you cannot possibly "understand" what is coming unless you have lived it with the wife But why should I start out with a "small" foundation to do my upgrades if I know I am going to do that. 26 minutes ago, The Terrible Triplett said: The moment you start off with electric kettle, geyser, vacuum cleaner, you really first need to consider needs versus wants, for they have vastly different price tags. Do you even dare hand your wife a broom to clean the carpets? 26 minutes ago, The Terrible Triplett said: I would, with a first system, go as cheap as I can knowing full well that I am going to change in 1-3 years, I am going to run the batts into the ground learning. I would rather do this ones and right from the start, do all the research I could and advise from the forums and start out without needing to buy the wrong stuff first. 26 minutes ago, The Terrible Triplett said: Yes, it is fine. It is good to now and then push them to 50% ... my supplier told me ... then bring them back up to 100% and do a equalise. Good stirring of the juices in other words. O wait, Axperts cannot equalize Trojan's, sorry! This is why I went with with the T105 RE's they have charge voltages that fit the Axpert well. Then because I do treat my batteries well and have the gennie/Eskom to fall back and not go below 70% SOC I can follow the following from the Trojan website "Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (>0.030) are detected after fully charging a battery." Month 7(every day down to +-80% SOC and on occasion down to 70%) almost done on my bank and my gravity readings are still 100% acceptable Natures Heaven and Mike 2 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted July 21, 2016 Share Posted July 21, 2016 Lots of your appliances have batteries of their own. I have one plug circuit on a timer which runs to fridge freezer and a plug outlet with a multiplug with a fearsome bristle of chargers. Phones etc are charged when the sun is shining. No reason to charge batteries using other batteries. Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 Thank you to every body Ok so thinking this, it looks cheaper to buy a 254V inverter 2.4KW and then more panels with 4 x batteries will that do the job, reason we bought this is just encase we do want to run luxury items one day or if we build another house on the farm. We currently use bosch gas heaters and gas stoves, so the only appliances on the system is as given, don't think we will change to normal geysers and normal kettles, there is nothing better than the smell of coffee from a gas stove with a wistle So if I want to keep the 48v, my extras is going to break the bank Just to make sure again Buy 24 volt 2.4KW inverter Buy 4 x Trojan batteries Buy 4 more 260 watt solar panels Correct ? Thanks in advance Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 Trojan T105 225Ah 6V Deep Cycle Battery Making sure this is the battery or do you get them in 12V Thanks Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 @DeepBass9 made a very good point @Natures Heaven If you can adjust that the laptops, cell chargers and tablet come off, charged only daytime, or get a extra battery packs for them for extended run-times, as well as the radio, knowing there is spare at night if need be, it gets even better. We are now on estimated 41% DOD, 1 day backup if the load is run as anticipated. I suspect the fridge en Freezer will be less at night, using 4 x L16RE-B 6v 370ah 1600 cycles to 50% DOD batteries, 12v or 24v inverter, the above loads taken off, looks like this now: Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 6 minutes ago, Natures Heaven said: Trojan T105 225Ah 6V Deep Cycle Battery Making sure this is the battery or do you get them in 12V Thanks Nope, all are 6v. I was proposing Trojan L16RE-B 6v 370ah 1600 cycles to 50% DOD batteries. If you want to use the T105RE's, not a problem, then you need 8 in total, for 12 or 24v system. And then the good news is, getting 8, you are back to using your 48v inverter, need more panels yes, but we are now at 28% DOD, which is very good, and the items that is now only charged daytime. Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 1 minute ago, The Terrible Triplett said: Nope, all are 6v. I was proposing Trojan L16RE-B 6v 370ah 1600 cycles to 50% DOD batteries. If you want to use the T105RE's, not a problem, then you need 8 in total, for 12 or 24v system. And then the good news is, getting 8, you are back to using your 48v inverter, need more panels yes, but we are now at 28% DOD, which is very good, and the items that is now only charged daytime. Sounds better, I think what I will do is try the 12 or 24 v system as we do not use a lot of load now, we can then on a later stage when all upgraded use the 48v, how many 260 w PV can a 12v handle and how many on a 24v, don't want to buy to many panels for the inverter Thanks Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 If I go for the 12v, wont my 105 AH battery give me more juice for now as then I have 4 x 105 AH = 420 AH or am I dumb now Quote Link to comment Share on other sites More sharing options...
___ Posted July 21, 2016 Share Posted July 21, 2016 Note, there are two kinds of T105 batteries, the one for golf carts, and the -RE one for renewable energy. You want the latter type. Has lower equalise and absorb voltages and better cycle life. Costs only slightly more. Sent from my GT-I9195 using Tapatalk Natures Heaven 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 21, 2016 Share Posted July 21, 2016 @Natures Heaven The load is not, if I use what you have given me, that small for off-grid. Plus, I think I said way above, the loads and times of the loads, versus batteries needed to power the load for those times, need MINIMUM the above panels just to re-charge the batteries in 5.5 hours on a good sunny day. Very important to understand that. Edit: If you want to power more devices daytime, you can double the panels. Let me ask you some questions: - Where are you based, general area? - How many panels would you like install for now, for 1 x 260w panels you can use ... but with a very small load. - Will you get a BMV battery monitor right from the start? - What battery do you want to look at? T105RE cost about R 2 652.67 per batt - 6v 225ah L16RE-B cost about R 4 833.04 per batt - 6v 370ah Or smaller? For am I right in that maybe you first want to dip your toe in and see? Quote Link to comment Share on other sites More sharing options...
Natures Heaven Posted July 21, 2016 Author Share Posted July 21, 2016 Thanks TTT and Plonkster We live in the Southern Cape Region, Wilderness, I do have 2 x 260 watt panels and 4 x no maintenance batteries 105 AH, so I can rather go buy a 12v / 24v inverter and use my same batteries and get another 2 more solar panels same size as above, then next month go get the batteries as mentioned looks like I don't have enough charging power so that looks like upgrading first, then the rest ? am I right as to get everything now is not possible Quote Link to comment Share on other sites More sharing options...
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