Crossy

The Saga Continues In the 18 months that the system has been operating I've bought a fair number of smaller (32650) LiFePO4 cells for various projects including our solar floodlights. The experience has shown that the quality of the cells available is somewhat "variable", ranging from "pretty decent" to "absolute carp". Even buying the same cells from the same seller didn't really guarantee anything. With this in mind I bought 20 x 105Ah "Eve" cells at 1,099Baht from a seller I've used before, my idea being to capacity test them and use the best ones, along with the existing 100Ah cells (which I would also capacity test) to make the new 2P16S pack. The cells arrived and were duly charged to 3.65V (full) and capacity tested at 20A down to 2.5V (totally empty). The results were somewhat disappointing. The cells ranged from 82Ah down to 55Ah ???? OK, so I can pair them "best to worst" with the existing cells. When I capacity tested the existing 100Ah cells I was amazed to find that they ranged from 98Ah to 100Ah!! ???? I evidently got lucky on those. Hoping to make the best of a bad job I tried ordering another 4 of the Eve cells, "no stock", even at other sellers of the same cells "no stock". It's pretty obvious that all these suppliers were drop-shipping from the same source which was now exhausted. Grrr. OK, so now we have a 2P16S pack which has cell-pair capacities of 165Ah to 182Ah, meaning that the best I can hope for is a total of 165Ah (or about 8kWh). Oh well ???? This pack is currently under test and calibrating the Seplos BMS. I also now have the LiFePOQR app (check the Google Playstore) which can decode the QR codes on the cells and give you all kinds of useful details, manufacturer, manufacturing date, capacity etc. Unfortunately, all the cells (even the original 100Ah ones) come back with "invalid data" and a suggestion that the codes are fake ???? <More Soon>

A Little History Back in June 2021 we were commissioning our Sofar hybrid solar inverter, this unit needs a battery pack in order to function correctly. So, in my innocence, I bought 16 x 100Ah LiFePO4 cells at 1,125 Baht a pop, along with a cheap (Daly) BMS, stuck them together in a pack with zero preparation and hooked them up. It worked! Slightly later I bought my first battery capacity tester and a multi-charger, these arrived too late to actually test the pack I'd made and the BMS wasn't of the "smart" type so things were operating "blind". A little later I bought 16 x 200Ah "used" LiFePO4 golf-cart cells at 1,499 Baht a pop. I spent rather a long time doing capacity tests on these. The charger could only do 6A so it was taking a day and a half to charge them, then the tester discharged at 20A. All bar one cell tested at somewhere near 160Ah (I didn't keep records I'm afraid) the remaining cell was nearer 60Ah ???? Of course it was way too late to complain so I ordered another cell which came out somewhere near the others. So I built a pack, added a "Smart" BMS (another Daly) and hooked them in parallel with the first lot, all worked reasonably well and I was storing around 9kWh in the two packs (treating them gently). Fast-Forward to This Year I bought a more decent Smart BMS (from Seplos) which could actually talk to the inverter. There are many discussions on the web as to whether there's any advantage, but in our case the Sofar inverter has a software bug, in that it defaults to a lead-acid profile if there's no comms. It's supposed to be adjustable, but basically ignores any settings so we weren't getting quite to a full charge. Along with the Seplos I added a 5A "flying-capacitor" call balancer, hooked it all to the golf-cart cells and ran the PC software (which talks to the BMS via an RS484 converter). It rapidly became apparent that, even with the balancer, one of the cells was "a bit weak", so to help it along I hooked the "spare" cell (the one that I rejected 12 months ago) in parallel with it which improved matters a fair bit, but the parallel combo still showed as being rather low capacity. Earlier This Month (Dec. 2022) The Daly BMS on the 100Ah cells went "fzzt" and let out the Magic Smoke, it was replaced by the old non-smart unit to get the pack back online. So, the engineer in me got itchy fingers and ordered another Seplos BMS to replace the fried unit and decided that adding a further 16 x 100Ah cells to the current 100Ah pack (making it a 2P 16S arrangement) was going to be good use of my Christmas money from mummy (don't tell Madam!). Meanwhile I've acquired a second 20A tester and 4 x 20A 3.65V chargers, so I can do capacity tests in a reasonable time. <To be Continued>

Are you using the App or the website??

Set it to the lowest value that will stay on under adverse weather conditions (when surges may trip the beast). The UK standard for domestic RCBOs (which are fixed) is 30mA so you're really good to go at any of the available settings.

Yeah, the simple adaptors don't swap the pins over. UK is Live on the right; Thailand is Live on the left (both with earth at the top).

Fixed after reference to the original article.

I believe that switch is a "bypass" for the RCD part of the device and should normally be "off". The idea being that you can get the juice back on even if you have an earth-leak (not something I would be recommending). You could try making an external tester using a small lamp connected L-E on a plug. Plugging it in should trip the RCBO immediately.

I believe our OP is looking for something like this.

Yeah, a 19-year-old me fell into that trap, it took me a long time to re-build my credit score (UK).

Task A is to contact the card provider and talk to them. The single biggest error people make is to ignore it and hope it will go away. Try to maintain a dialogue, even when out of the country. If you can make any payment at all this should keep you in their (reasonably) good books. EDIT Are you entitled to any severance? It can get quite large if you've been there for a long time (IIRC up to 10 month's salary tax free).

Meanwhile, in another thread: -

Sadly, it's not, although an increasing number of inverters are being supplied with the necessary CT (Current Transformer) and internal gubbins so that they can do it. It's certainly a wise investment to pay a little extra for an inverter with the facility. The ESP8266 based system we use to automatically enable/disable export on meter-reading days is discussed in the Solar Car Port thread.

@ThaifishYou must be one of the few members of this forum that actually WANTS a digital meter ???? I assume that your battery packs are still on hold / not happening too ???? The batteries are also a word to the wise for anyone considering Huawei inverters. Whilst they are generally excellent units, they use a specific high-voltage pack, so 3rd-party / DIY packs are difficult to impossible and genuine Huawei packs are $$$ ????

Grid-tie inverters will produce the maximum power available from the solar input. Physics ensures that your system will always supply the local load first with any excess going to the grid (disc-type meter goes backwards). "No-export" means that the inverter will reduce its output to only cover the local load so you don't send any excess energy to the grid (meter doesn't go backwards).

"Tablesaur" surely

For flip's sake guys, it's a ruddy warship!! Things get a bit "bumpy" you button up tight! But not having enough life preservers / rafts ... What The Heck!

Yeah, that would be @Thaifish. IIRC he got a bit blasé about spinning his meter backwards because he was booked for a proper export meter and his meter-man knew all about it. Enter the substitute meter reader ... ????

Of course, there's always that old adage "If it looks too good to be true ...". Should have gone to Specsavers. "You'll find a god in every golden cloister, and if you're lucky then the god's a she" (Murray Head - One Night in Bangkok). Hope you've found one of the rare ones ????

Yeah, I went direct to Sofar service in China and got excellent responses. Sadly, their initial attempt to fix what was a minor annoyance turned my beast into a 45,000 Baht brick. They did the right thing and replaced the unit with a new one at zero cost (all duties and VAT paid too). No complaints whatever about their service or warranty.

No issue with weather effects (panels are designed to be outdoors in all weathers), provided your mounting / roof are up to the load. They do get dusty, ours get the garden hose and pool brush (no soap) when I think they look dirty. To be honest it's difficult to quantify just how much output is lost due to the dirt as the sunshine is also a variable.

Not really a reliability issue. Our 5kW unit is a hybrid like the one Jas21 has. It failed (bricked) during a Sofar initiated firmware update. Sofar supplied a replacement inverter under warranty (didn't want the old unit back).

The type of system (and therefore the cost) you install depends greatly upon your intention and your usage pattern. For example: - You have a retail outlet and an EV which you can charge during the day. A basic grid-tie system whereby the energy is used as soon as it's made (running the A/C and charging the car) would make sense (even with no export/net-metering in place). At the other end of the scale. You have a home that's empty all day with only minimal daytime consumption (fridge/freezer, fish tank pump etc.), so you need to time-shift your energy. You can do this with an ESS (Energy Storage System = Batteries = $$$) or by exporting to the grid during the day and re-importing at night ** Most of us fall somewhere in between the two extremes. ** The official way of doing this is to have a Feed in Tariff (FIT) which currently pays about 50% of the retail cost for each kWh you export, of course you pay full retail cost when you re-import that kWh. Unfortunately, the restrictions on installation contractors, equipment approval and the like mean that this is a non-starter for DIY and therefore significantly increases the system cost (to the point where DIY with a decent sized ESS could be economical). ** The rather less official way of doing this (assuming you have a conventional disc-type meter) is to simply spin the meter backwards whilst exporting, you effectively get the full retail value of every kWh you export. This is of course illegal, but it's how probably millions of small systems operate in Thailand and to a large degree the authorities tolerate it. It's how we operate once our batteries are full, it's a shame to waste our excess production ???? Just ensure that you never actually end up as a net-exporter (-ve monthly use) and that the meter reader never sees the meter going backwards. I've never heard of anyone who got caught out getting more than a slapped wrist and the installation of a no-reverse meter.

Real world numbers from our DIY 10.6kWp system, you decide if it's going to be worth it. I've deliberately left the actual cost out, mainly because I've lost track. The system keeps evolving with "adjustments", but Madam is happy to see the small power bills (she doesn't see what I actually spend on hardware or my time).