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Forum Index : Solar : Going off grid
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| windlight Guru  Joined: 03/03/2007 Location: AustraliaPosts: 331 |
To your wonder fillm, my system back in WA I had a vent in the flat ceiling of the battery room enclosure (over the batteries) which was inside a garage, had trunking up to a whirly, I wasn't there long enough to see any negative results. The installer wanted to place the batteries (lead acid) under the inverter and his man was quite indignant when I said it was not acceptable, he claimed they had done 50+ installs like this, yea OK, they had to move them, all equipment was within the 3x2.7M room. Over here everything is in the 6x9M garage with a plywood separator between batteries and inverter, and an open window above the batteries, rain is straight down here , mostly. 
I personal spent 22 years in a coal power station where all 8 units were hydrogen cooled, we made the hydrogen on site, and my level did all isolation's and gas testing, when we could not find a chemist. There were procedures for working on each units hydrogen control panel and for any hot work in the vicinity of the generator. Most interesting situation I found was a small blue flame on a test point fitted to the side of a generator, this was behind a small door, a check back to the last hot work permit issued revealed that it must have been burning for 6 months. If I was not such a sticky beak it probably would still be burning. In battery rooms I would be more concerned with the corrosive nature of the vented gas than the hydrogen, but it does go bang with quite spectacular results. A of J "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Well I'm going to take the advise of other forum members and have decided to move the battery bank outside. I bought a cheap garden shed for $185, its about 2m high, 1.8m wide and .8m deep. Lots of ventilation holes around the roof, it's as air tight as a open window. Here's a pic of it nearly assembled, I still need to fit the door. Mongrel of a thing to put together, but what do you expect for the price. 
I'll mount it next to the workshop shed on some timbers ( I'll make a concrete slab for it later when I'm sure on its final location ), and run the battery leads through the back of the garden shed into the workshop shed to the inverter. With the batteries outside I wont have to worry about explosive gasses or corrosion. I figure if I get 5 years out of it I've done well. Nothing else much to report on the off grid build. My new shed is up, but the house it taking bloody forever  , lots of waiting for council paperwork, owner builder stuff, insurances, surveyors, inspectors, approvals, etc, etc. Moving in a 2nd hand house is just like building from scratch, and I would never take on a project like that again. Taking too long and financially killing me. And they wonder why the building industry is slowing down?
But I did install a single solar panel and small battery bank in the new shed. It powers a couple of yard lights that switch on at night. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Well done Glenn .. Reading back from the start , a lot of good advice concerning the safety aspects of batteries.. I agree with all of them . I'm installing those new fire alarms over my batteries with a remote alarm in my bedroom . I,ve made my battery boxes out of fibro cement sheeting and the fujitsu one is completly steel. I do have carpet under all the batteries and all my boxes are ventilated . All my batteries are valve regulated absorbed matt lead acid , have had no problems with them ,except one has small crack in top of casing ,(this particular bank I pay special attention to as it dies fairly quickly compared to the rest . I guess it's the drying out maybe because of the crack) plenty of cartridge and mcb fuses in my system .. Bruce Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thanks Bruce I was thinkig of building the battery shed from scratch using a timber frame, but the kit seamed like a cheaper quicker option. Maybe not in the long run. For now I'll just be sitting the batteries on a plank of wood with some rubber matting, but will build a frame to get them off the ground once I settle in. Yeah I've got fuses everywhere. A 160A to the inverter, a 50A from the charge controller to the battery bank, and each panel pair has a 10 amp fuse. I have 6 panel pairs, as I call them, 2 24v 175w panels in series, so I end up with 6 power leads from the array. I also included blocking diodes for each panel pair, and some 90v gas arrestors going to ground. The arrestors are after the fuse, so the fuse should pop before the charge controller is damaged. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Glenn , ---Those "gas arrestors" .. I've two Krone blocks full of them sitting around waiting for a home. I'm thinking they may be for 48v telecom equiptment,or were ,before my sticky fingers grabbed them,lol. So, would they be ok for our 48v gear , reckon so??. If I remember (thats a laugh) , the line or + side went to one leg and the other side went to the - side . The body or middle was earthed in the krone block .. I could have this arse about , but a bit of Googling and a call to my ex-workmates could clear this up . Diodes,, blocking ,, would you install these to stop feedback from the batteries at night ,, or do the solar panel blocking diodes do this job ??. I have some of those big block diodes-around 75 mm X 20 x 25mm on a chunky heatsink. bruce. Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Bruce Yeah I had a bunch of these little gas arrestors from a krone block too, but I cant find them, they would be deep in a box of junk somewhere, so I ended up buying in some new ones from RS Components. The 48v telecom gear uses a 90v arrestor. Telecom lines run at 48vdc for normal on hook, and 75vac for ringing current, so the 90v rated arrestor is designed to protect the equipment and not trip at those voltages. For a 48v battery bank that may creep up to 60v from time to time, a 90v arrestor will suit just fine. My panels have bypass diodes built in, and they are mono-crystalline so dont really need a blocking diode, but I did a test anyway. I connected my variable powersupply across one panel in its box ( dark conditions ) and it drew about 20mA at 24vdc. With 6 panel pairs, thats about 120mA ( 6 watts ) loss at night, not a lot, but still a loss. Also having a blocking diode in series with each panel pair does provide some protection to the rest of the array if one panel pair develops a short in its feed cable. There is a loss in having a blocking diode, but for a 48v system its tiny, more of a concern for a 12v system. EDIT: the 90v arrestors were not suitable, see the next page, need a higher voltage arrestors. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
More progress. Positioned the "Battery Room" next to the workshop. 
Painted and mounted a 2400*1200 sheet or 12mm plywood onto the workshop wall. This is where I'll mount the inverter, power board, controller, etc, etc. 
This is the solar panel lead in box. 
It has the fusing, gas arrestors and blocking diodes. Yes, its built into a plastic lunch box. It also has a couple of extra diodes to monitor the solar panel voltage independant of the charge controller, and a LED just to let me know I'm getting power to this point. The solar panels are connected up into 3 groups, the first group has one panel pair, the 2nd has 2 panel pairs, and the third has 3 panel pairs. These groups can be switched ( in the charge controller, more on that in a later post ) in combinations from 1 to 6 panel pairs. The idea is the charge controller can match the solar panel input to the inverter load, by switching in and out different combinations of panels. This is to avoid cycling the batteries too much once they are fully charged, not a big issue, but something I wanted to play around with. The two little diodes are to provide a night time / low light sensor input to the charge controller, so it can tell if the panel voltage has dropped below battery voltage, and go into night mode. In night mode it switches off the control relays, saving a few watts. It also means I didn't really need the blocking diodes, since the controller will open circuit the panels at night anyway. But they still offer protection if part of the panel is shadded. Things are starting to move along now. My house will show up next week, weather permitting, so I need to get this system finished in a couple of weeks. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Glenn,, Nice to see you are moving along , like your big workshop . I'll keep an eye on your progress, one day I'll take a trip up that way and we'll have a cuppa .. Cheers Bruce Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Pretty much finished the solar controller. Its based on a Maximite computer, and build ito a small tool case. The screen can display setup, basic view ( shown ) and detailed view, where it displays watts and watt hours, peaks, relay state, etc etc etc, and a cool graph of the last 2 minutes/hours/days of battery current. The display is a little composite reversing monitor, and the keyboard is a numeric type with PS2. 
Mounted a couple of the solar panels on the roof of the shed. These are just get some power into the batteries and keep the system ticking over. I'll mount the other 10 panels in a couple of weeks. Pic of my brother giving me a hand. 
The batteries are connected up. I used 19mm copper pipe flattened out with some push bike inner tube as a insulator. 
Mounted the inverter and power box, and gave it a test, all working fine. 
Getting there. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Looking Good! I am amazed yet again at the level of regulation and monitoring etc you have built into that box. Well done, Glenn. You can move in now. Trev @ drivebynature.com |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Glenn , I like the set-up , you are yonks ahead of me on the monitoring side. I have my batteries on float at present , the panels are nearly ready for connection .. Looks good , your Bro needs a prayer mat !!! Bruce. Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
It's using a CGMMSTICK Trev, its like a mini PC, a Maximite clone. It measures battery voltage, panel voltage ( so it can shut down at night ), current into the battery from the panel, and current from battery to inverter. That way it can track watt hours in and out of the battery bank, making it easier to keep track of the state of charge. It logs the data to a SD card. It drives 3 relays to switch the panels in and out as needed. Originally I was using MOSFETS, but was having problems with leakage so changed to relays as I needed to get the controller into service as soon as possible. Once I've settled in I'll expand on its software to add more functions, like remote display, battery equalisation, etc. Yeah its a good photo Bruce, he's actually holding a loop of wire but looks like he praying to the sun god. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Another little update. Installed the controller and got the system going. 
This is a photo of the controller screen. 
The graph shows the rise and fall of watts as clouds passed overhead. With the two panels installed, the system will have enough capacity for my power tools, lights, etc while I finish the house and start moving in. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn Looks good mate, love the little display keep up the good work. All the best Bob Foolin Around |
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Wombat Regular Member  Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Hi Glenn, Very tidy, nice. I really like what you've done with your CGMMSTICK. Hope to do something similar with a maximite myself. [:) Watching with great interest. Russ P.S. What battery's are you using there? They appear to be all in series.  |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
"a CGMMSTICK" New word to my vocabulary! Thanks for explaining but doesn't gel in my brain. What is a maximite? I have heard of "marmite", and "vegemite" and "promite". Is maximite something like a black paste too? Trev @ drivebynature.com |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
This is the Maximite. http://www.thebackshed.com/windmill/articles/Maximite.asp Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Russ Cant remember the make off the top of my head, the invoice is buried in paperwork, but they are a deep cycle 230Ah 6v battery. 8 in series to give 48 volts. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Hi Glenn, Your system looks great. I like your display - where did you get it, and what was the cost approximately? Greg |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Its a 4.3' TFT LCD reverse Rear View Car Video Monitor, model CZ7. Search eBay for "CZ7 Monitor" and you'll find heaps for under $25, brand new. It accepts PAL and NTSC. In PAL mode or the Maximites NTSC mode, most of the screen area is used, but there is a blank border around the edge. Not really a problem, as you can see in my photo. The DuinoMite running version 2.7 had a NTSC mode thats fills the screen much better, with a higher resolution then the Maximites NTSC mode. Current draw it tiny! About 100mA from memory. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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