viceroy

Thanks. Yes, I will be putting the busbars back in, but also going for less but bigger batteries this time. 8x 12v 260ah in 2 strings of 4. fuse on every string BMV700 monitor, and extra cooling

Yeah, I know its bad, I did change it from BBBB+ BBBB BBBB - to -BBBB BBBB BBBB + As for which battery had the worst damage it was the one in red: -BBBB BBBB BBBB+

Hmm, I think I was not very clear on the cable lengths, the cable lengths differed between the bank to each inverter. The battery interconnects were the same length, but I was not happy with how they'd connected each string, as it was nothing like your diagram, more like this image (ignore battery voltages etc). Anyway, all I wanted to know was could this type of config, perhaps with a weak cell and high temps have contributed to such a failure.

I had been monitoring the batter temps, manually, and the only time I noticed the poles getting hot was after the meltdown. I did do a quick test of the charge controller after the failure for the insurance report, and at float it was outputting the same voltage it said it was outputting. Further testing will be done as soon as the new batteries arrive to make sure it's in line. As I said, I never noticed the poles getting hot. Batteries would get warm on occasion, but never the poles. I shall Google Hawkins load tester Overcharging due to heat possibly? Temps in the garage are pretty warm and the failure was during that huge heat wave in December. One other thing which has been bugging me. My battery config was not ideal being 3 parallel strings of 4 to make up the 48v and required amp hours. However, after much research, a bussbar approach and keeping the cabling lengths exactly (within 1 or 2mm) the same would allow the strings to charge evenly. Since I run the inverters in parallel mode, I could clearly see the voltages from each inverter to the batteries was exactly the same (within 0.1V as that is the accuracy of the inverter display). When we had the panels installed, the "expert" told me my bussbar was not a good idea, and during their install which included all the breakers between batteries, inverters and PV removed the bussbar. His cabling was also not the same lengths between strings, and the voltage display between each inverter was now out by 0.1V and would fluctuate. Could the above have contributed to the issue?

The batteries werent even a year old. My setup is in the members showcase under "my newbie install" http://powerforum.co.za/topic/158-my-newbie-install/

Vision 12v 120ah (10C) VRLA

I have the opposite problem. My garage interior is way hotter than the outside ambient temps, and currently the only way I have to avoiding that is to leave the garage door open about a foot, but that's just a security risk. I like the idea of running a small AC to cool the batteries (and the inverters come to think of it), but the added load on the system is not appealing at all.

I've also been thinking about battery cooling, but nothing so dramatic. Basically just fans venting to the outside near the batteries, so the garage doesn't get so hot.

It's been quite a while since I was last on these forums, but I'm back on with a tale of woe, but with a happy ending In December last year, I came home from a lovely Sunday morning to a strange smell coming from the garage. In the garage I could hear a sizzling noise coming from the solar setup. On closer inspection, the sizzling was coming from the battery bank, where 3 of the 12 batteries were hugely swollen, so much so that they had swollen into each other and melted together. All the rest of the batteries were showing signs of warping along their tops. To say my heart sank would be an understatement. My mind was all over the show wondering how this could have happened. Was it the lightning storm we had the evening before? (Happened to fry the network card in my PC) Was it heat (we experienced a heatwave over December)? Was it just a weak cell that just let go? The official reason provided to insurance was lightning, and this is where things start to look up. Our insurance claim for damage to the batteries has been approved. So now begins the process of getting new batteries, changing the system a bit and putting in measures to possibly stop this sort of thing from happening again.

The company was Gauteng Water Heating. The first part of the install went really well, but towards the end, their quality of service dropped dramatically, so much so that I still haven't paid then the final instalment.

Hi all, Now that my system is in and being used, I've been trying to tweak it for best performance, efficiencies and of course balancing usage of the batteries against longevity. For those who haven't seem my system, I have the following: - 2x 4kW (8kW total) Axpert MKS inverters with integrated MPPT charger - 12x 265W SolaireDirect panels (These were supposed to be Rensola 250W, but when on the roof getting a closer look, I saw the change) - 12x 120Ah 12V AGM Vision HF batteries. Anyway, I've got the inverters set that solar output takes priority over grid except if one of these two conditions is met: - Solar not available. - Battery Voltage reaches my programmed minimum voltage (set at 1V increments which is disappointing as I would have preferred 0.1V increments) currently to 49V Charging priority is what I've been fiddling with but currently, the batteries are charged by a combination of solar & grid using constant voltage method (56V absorb, 54V float) up to 30A (specified by battery documentation, although I've seen other battery documentation that says any amperage providing its constant voltage) Now my real question: - So I've set the minimum battery threshold to 49V so when the batteries reach that level, the system automatically switches to grid bypass until the batteries are fully charged. This switchover takes place when the batteries are under load, so the 49V under load could be 50.x V under no load (ie, when the load suddenly stops and switches to grid. How exactly should I be setting this so that the batteries don't really discharge below 60%? Should the value be the load value or the no load value? I really hope the above makes sense.

I had a company install the panels onto the roof, and they assisted with fuses and breakers for the batteries and will be supplying the electrical compliance certificate, but everything else was DIY. I'll do a complete photo update of the install when its 100% And will also add my thoughts about what I think I should have done differently.

Made a small change to the system this weekend. Turned the 3 panels on the flat roof 90 degrees to take advantage of the morning sun. Made a huge difference. Previously at around 8am, I was seeing between 250 and 300W from PV. This morning, that figure was around 880W.

I'm in JHB, Fourways. The house sits about 45% from north, the panels facing NW and the Evacuated tubes facing facing NE. I'm thinking about rotating the 3 panels on the flat roof to face in the same direction as the Evacutated tubes to take advantage of the morning sun. I'm not sure exactly what's being generated. The inverters by themselves don't store a log, and I'm still fiddling with the supplied software, but it's not the most useful and only displays PV voltage when the inverters run in parallel. However, since the panels went live, our daily consumption has dropped from 20kw/hr/day to 9kw/hr/day, so guessing 11kw/hr/day from the panels as a rough guess. I have trunking ready and waiting to be installed. Just waiting on a proper battery cabinet and cable layout to be finalised before I install. Yep, got a 100A/60VDC amp fuse for each inverter. I was thinking of putting a terminal fuse on each battery, but not sure if that's overkill?

Hi, Actually, both inverters have a parallel kit each. Yep, the 5kva (4kW) MKS Anyway, you can connect the PV as you like, either all on one inverter or split between each inverter, so long as each inverter only gets a Max on 3kw of PV. There is a setting on the inverter where you set this up

Pics have been uploaded Nope, no special software required to run the axperts in parallel. They already had the parallel boards installed so it was simply a case of plugging in the communication and power sharing cables and that was it. The pics are showing only one of the inverters running though. I did make a VERY stupid mistake of mislabelling the AC cables and blowing the inverter which has been sent in for repairs. Still turned on, but throwing an error about a soft bus start error. I should be connecting the replacement in this weekend.

So, my install is nearly done, basically just some tidying up, and finalising parameters on the inverters. Before starting on this "little" exercise, I knew absolutely zero about this sort of thing, and mostly getting info through Google and Youtube, I got to the point where I was comfortable to proceed. My primary goal with this install was to lower my reliance on Eskom, get relief from the increasingly worse load shedding, and basically try do my bit for a greener future. The main components of my system are: - two RCT Axpert MKS 5kva inverters. I did a lot of looking at different inverters and these seemed to be best value for money overall. - twelve Vision HF 12v 120ah batteries. Probably not the best choice, but for the time being, they seem to be working fine. I guess time will tell. - twelve Rensola 250W PV panels. - Retrofitted 18 evacuated tube system for my 200L Kwikot geyser. A little while ago did some renovations on the house which included converting the existing garage into a TV/entertainment room, and building a new garage directly in front of it. The one downside to this is that the main DB board was no longer located in the garage, but in the one room where we spend most of our time at home. Since I wanted to do this install (mostly) by myself, I didn't want the expense or inconvenience of making changes and pulling extra cabling to and from the DB board. Luckily for me, there is a box where Eskom power comes into the property with a main breaker. This proved to be in an ideal spot to break away to the inverters. I mounted the inverters on the wall in the garage, bought 2 surface mounted DB boards, and a whole lot of cabling and lugs. The first DB board sits between and above the inverters and is where I have placed the breakers leading to and from the inverters. Main reason for these are so I can isolate the inverters individually or together from either the grid or the house or both as required. The second DB board was stripped out, a nice piece of wood installed into it and converted into the bussbars to combine the batteries to connect to the inverters. I had an old steel cabinet in the garage near the inverters where I housed the batteries. Worried about off-gassing etc of the batteries, I removed a door. The cabinet was not ideal as the shelves were not up to the task of holding up 120+ kg of batteries per shelf so I had to add some wood struts. I ran like this, using the inverters as a battery backup for the house in case of load shedding for about 5 weeks. About 3 weeks ago we had the evacuated tubes fitted to the geyser, and results were good. I set the geyserwise controller to turn on twice a day for 20 minutes each time just to top up the temps to 55C if required. Since then, Citypower installed new meters, which seemed okay at first, and pretty cool as they come with their own little monitors which could be used to track power usage. I already had an Effergy monitor, so this was not really needed, just cool nonetheless as I didn't need to upload Effergy data to my PC to get daily usage. This week was an exciting one as we had the PV panels installed. The installers only arrived at 12pm which was not ideal as they didn't have time to complete everything, but they did enough to get the panels connected to the inverter. Wife was very impressed the next morning when she woke up to the power monitors showing zero consumption from Eskom. Right now I'm still deciding on output and charging priorities for the inverters, but I think I'll run off panels during the day, and grid at night, and the batteries will be my reserve for when there is no solar or Eskom. Anyway, this is what I have so far, and any comments or suggestions are welcome. I'll upload pics this weekend (hopefully)

That's why I want something like your little doohickey. The busbars are only there as it seems the most efficient method of connecting to stop some batteries not being used/charged as much as others.

Did some more research into this, and if we didn't have a maid using water thoughout the day, a DC titanium element would have been fine, since it would slowly heat up the water during the day, and maybe only needing a bit of a jolt from eishkom in the morning. Having a maid using water throughout the day ruins this as the tank would never be able to get up to temp. Have now decided to go with vacuum tubes retrofitted

@Wetkit, I also read the same thing about multiple strings, but I think it's how you wire everything up. My setup is going to have 3 strings and each string will connect directly to busbars, and from the busbars to the inverter/chargers. @Superdiy I want!

Well replacing a string would be easier financially than replacing everything. Hopefully nothing goes wrong battery wise for the next 5 or so years.

Thanks for the answers. Another question on replacing cells. Whats the consensus on this. What are the dos and donts with replacing cells in a battery bank.

My two Axpert 5kva inverters arrived this morning, so next step is to start looking at batteries. I'm on a bit of a budget so looking to get the best bang for buck. My first question is which is better and why. 6v * 8 = 48v or 12v * 4 = 48v Not taking into account that you usually get more ah from the 6v batteries, which configuration is better?

I've been watching thread for a while now, and have decided to go with two Axpert MKS 5kva inverters in parallel before the DB board. Will be adding to this either 8 or 12 120ah batteries configured for 48v, and six 300w panels (for now). Geyser element will be replaced with a titanium element and I'll be adding vacuum tubes in a split system configuration to lower consumption further. Still undecided on going to a gas hob, but that might come sooner than later. In addition, will be installing a 2500l water tank and pump for those regular water interruptions we have. Only problem now is sourcing the inverters for a decent price, but I should have them before the end of March (I hope).

I'm looking to start converting my home to run mostly off Solar, and I've seen adverts for converting a std. geyser to use a titanium element which can run on AC or DC and uses much less power than a normal element. Apparently running one of these off 3 panels and a few batteries is a cost effective way to go. Any insight on this would be greatly appreciated.