dax021

Any updates on this project? I have been following with interest and would like to see it completed.

Thanks Jason. Ok, so he is around, I must have just missed his posts

Whatever happened to Chris Hobson? He used to be very active, but I have not seen him for ages.

Thanks so far. Yes, I should have said KWh. His heaviest load will be a kettle, but I'm sure he can change this to gas. Otherwise his load is an office with about 6 or 7 staff. It is a computer retail/repair outlet.

Hi all, it's been some time since I have posted here as my 3Kva off grid system seems to be ticking away nicely and doing what it is supposed to. I have now been asked by a friend to help with installing a system at his workplace, to try to offset the high Eskom charges. He has bought an Axpert RCT-AXMK2-5K-48V and is in the process of buying 10 x CNBM 6P330, 330W panels. He already has 4 x 102 Ah batteries which he intends to use in the meantime while he saves for a Pylontech. His intention is to run off solar during daylight hours and is then happy to use Eskom at night when his load is very low. On average his daily consumption is about 15Kw (08:00-16:00) and less than 1Kw (16:00-08:00) Would such a setup work, and if so what does it entail to install? Your advice would be greatly appreciated. Thanks, Peter

Thanks for the answers. I am no electrician, although I have wired a few houses, and I always put the supply at the top. My landlord, on the other hand, always puts the supply at the bottom. (Notice I have steered far away from terms like "bottom entry", gives me the grills). He says this is the standard in the UK, but as I wouldn't trust him to wire a 12V light bulb, I am not sure if this is the case. At least it would appear that it makes no difference to the function of the CB, wired either way.

Does it matter which way the supply and load get connected to a CB? In other words, does it make any difference whether one feeds the supply in the top or bottom?

I second that. After 3 hip replacements, I realize it's a bit of a hit and miss affair. Right hip replaced 2001 and redone in 2010, still not lekker. Left one done in 2003 and I cannot tell the difference from the original

Thanks All, I have learnt something. The seller also replaced the faulty battery with 3 x 8V Trojans. Haven't connected them up yet, tomorrow will tell. I'm also kicking myself as when I reinstalled my old batteries this morning, I added my newly aquired battery balancer (thanks Chris) to see what transpires. It is now almost 21h00 and my old bank is sitting on 50.1V. Maybe I don't need new batteries after all.

Thanks Plonkster, that clears it up for me. Still amazes me that an 8V battery can show -36V. I have gone back to my old bank till i can sort this thing out.

Howzit Jaco, thanks, i'm going to see the dude tomorrow and see if he has another one. If not, i'm going to insist on getting a full refund. Luckily he lives just around the corner and is actually a decent bloke. He is workshop manager in a golf estate, so gets quite a few batteries. I dream of Pylon's every night, same as I dream of winning the Lotto, but unfortunately it aint gonna happen until i rob a bank, or meet a rich chick, which at my age is also very unlikely. Why the negative voltage though, that confuses me? I have about 10 dud batteries lying around. Not sure if the scrap value will even pay for the fuel to get to the scrap yard.

Just when I thought my battery problems were solved I hit a storing, which has broken my spirit and pocket. My 12V Willards have been dying slowly to the point that I removed 4 (out of 8), now the last 4 are shot to the point that I have to cut my load as soon as the sun sets (off grid). I scored a luck and bought 6 x 8V used Chinese batteries for R500 each. Their voltages all checked out at 7.96/7.95 so i connected them up in series and got 47.6 odd volts. Hooked up to the Axpert, and nothing happened, dead, nada. Checked volts again, down to 4. something. Checked each battery and found one is at -36,6V. As soon as I break the circuit, that battery reads 7.8 V again. I suspect that battery is shot, but these are very weird symptoms in my limited mind. Any suggestions, other than trying to swap it with a good one, which might not be possible? I do have a backup genie, but don't really want to run it just for a fridge and a few lights. I have a 12V backup light circuit, so luckily I'm not completely in the dark. Thanks in advance, Peter

Surely Mr. DIY's generator will just trip, trying to supply the whole suburb with power?

That' not a 3 way switch, that is 3 switches. It is highly illegal, and unwise to have DC and AC running in the same conduits or boxes.

To get back to the original question. Electricity (electrons) apparantly run on the outside surface of a wire so a multistrand cable can carry multiple "paths". In a 220V circuit this is not crucial as the PD is high. That is why multistrand is generally used for DC cables as they are generally of a lower PD and your losses are therefore minimised. And just to stir the pot. "Screwits" are brilliant to work with, but I hate them as I find if there is any vibration, they do work loose. A solution is to wrap them with insulation tape, but that in itself becomes a pain as it gets all sticky and crap to work with thereafter. Not insulting anyone, just my experience working on fuel bowsers

Sorry, haven't visited this post for some time. Fans come on day or night regardless. I don't think it's panel related, one reason being I only have 1200W of panels

Cool, thanks for the answers. The noise doesn't bother me at all, inverter is in the kitchen. Must still blow it out though, and see if any difference.

Hi Jaco, thanks. I guess rather dof of me as I didn't think of that. Will definitely give it a try

Is it normal for the fans to come on whenever a load is applied? The only loads that are connected permanently are a clock radio, fridge (100W) and a few 7W LED's when needed. Like this everything seems to run fine, but as soon as I connect the washing machine, the fans come on and stay on till the washing is finished. This has only been so for the last couple of months, previously the fans only came on when I used the microwave, and that I can understand as it pulls about 1800W. According to the Axpert, the load at the time is only around 260W. Axpert is mounted on a wall and has a free flow of air all around, albeit not 500mm as specified in the manual, closer to 200mm. I have also reversed the fans so they blow upwards. Model is "Sol-1-Ax3Mplus48" Is this a bad thing? Will it lead to premature failure of the fans? Is there anything that I could check for a possible fault? Thanks in advance, Peter

Just been rereading the whole post. To Chris H, the 3KvaPlus can't do "snu" in prg 16, it is not an option for some reason. The genny seems to work fine in either APL or UPS mode. It is a SR2 with Hoffberg alternator and seems really smooth. I'm too dof to connect a scope or such to check waveform.

Hi Jaco, inverter is a Mecer branded 3kva plus model. Bit difficult to get a camera in there to photo the label because of the way it's mounted, but have double checked model #, as per the decal it is "SOL-1-AX-3MPlus48". The manual you mentioned earlier is the correct one with a couple of minor differences, I guess different prints only. Axpert can definitely take 3Kwp with V range from 60-115V and VOC of 145V, so same as the 5Kva model. Panels are ReneSola JC295M-24Ab, 295W with 44.7VOC. Pilotfish, that's a good idea. I can remove 1 string and connect in parallel to my standby PWM charger. This seemed to balance them nicely previously when connected as such. Batteries are probably fubar anyway as I was given them when they stopped holding charge on the landlady's 24V Microcare system. After having them on my PWM for some time I had them tested at a battery place and they insisted that they were 100% After I've robbed my local bank I will invest in a couple of Pylontechs

Thanks to all for the great advice. I have gone through it all and deduced (not sure if correctly) that the unbalanced batteries are pulling the bty bank down and confusing the Axpert, hence the premature low bty warning. Will take pilotfish's advice and rearrange for now. Panels are working fine. The sun is shining again, at last, so switched on the microwave and observed 1.14Kw feed from the panels at 09h00 this morning. I have changed prg 1 to "uti" and although not tested with the genny, am pretty sure this will cure my charging problem. Will test during the next cloudy period. At the moment the Axpert reports the bty's at 53.6V and in float. Panels supplying 135W, my laptop is charging and fridge is running. Thanks again, Peter

Wrote them down, but can't find the piece of paper. If I remember correctly, the outer ones in each string were about 14.4V and the other 2 inners were about 12. something.

Hi, thanks for all the replies. Attached is a spreadsheet of my settings. I see a few of them are not as recommended, so will make the changes. I take note of all the all the advice on more panels etc., and agree entirely, but unfortunately this aint going happen owing to budget. I pretty much live hand to mouth at the moment. Reading another thread prompted me to check each bty V independently, and found I have 1 in each string down to 11.6V. I presume this is causing a problem . I have been in contact with Chris R, and as soon as I can, I will be purchasing 2 x HAO2's from him. My bty's are Willard Solar 105's, but are actuallly only 90Ahrs at the 20C rating. I survive on this system by really watching my loads. Fridge draws 100W while running, lights maximum of 100Wh, microwave over 1000W, but I only use for about 10min/week and only when the sun is shining. Laptop and Cell chargers, I'm guessing at 200W/day and I also try to keep to sunshine hours. Thanks again, and sorry for the belated reply. The weather has been so shit for the last 3 days that even my cat refuses to go outside and I have basically shut my inveter down and am operating on my backup 12V system for lights at the moment. the rain is pelting down on my tin roof so hard that I can't hear myself think. As soon as i can concentrate, I will go through this thread again and make changes as recommended. Axpert Prg Settings.xlsx

I have a couple of questions regarding my Axpert , which i'm hoping someone can help me with. Model is "SOL-1-AX 3Mplus48". I have 4 x 300W panels connected in 2 parallel strings of 2, and 8 x 100Ah batteries, connected in 2 strings of 4. Lister 4KW for backup, and completely off grid. 1. I very rarely see the panel input wattage go higher than 350-400 with the volts sitting around 70 - 80. Would it be better to remove one panel and just have 3 in series to get the higher voltage, as it would seem to me that the system isn't using the full panel capacity anyway? 2. The last few days have been pretty overcast and I got a low battery warning for the first time. I tried to charge the batteries via generator power, but after an hour it didn't seem to have made any difference. My load was only about 500W while the genny was running, so thought there would be plenty of juice going into the batteries. There was a trickle of panel W coming into the inverter. Reading the manual, I'm getting the impression that the genny will only supply power once the low battery level is reached or there is no solar input. In other words, I can only make use of the genny at night or if I disconnect the panels. Am I interpreting this correctly? Also, will the excess genny power not being drawn by loads, go to charging the batteries? Thanks in advance. Peter