747 Posted September 20, 2020 Share Posted September 20, 2020 I have a 100 Watt panel on the roof and I also carry a 90 Watt panel in the garage for times when there is not much Sun or the days are short. I plug the freestanding panel into a junction box which the solar wiring from the roof also runs through (the panels are wired in parallel). The solar regulator is quite old, it is a Schaudt LR1218 and it feeds the power via the Reich Ebox controller to the Leisure and Van batteries. For a number of reasons, Covid only being the latest one, the van has not been used for trips for around a year. After our first couple of short trips lately, I thought the batteries were not charging up correctly. The weather was dry with some cloud. I thought that possibly a bit of regular charging/discharging might sort them out as they have stood fully charged for 12 months. We attended a weekend rally with the C&CC this weekend and I had both panels connected and a 12 volt ammeter in the line to check on charging rates. After getting back from walking the dogs, I checked on the progress of the solar to find that when the Sun was behind a cloud, I was getting nearly 5 amps into the batteries. The Sun came out while I was checking and in full Sun, the output dropped to 1 amp. 8-) This happened every time the Sun disappeared and reappeared. I unplugged the freestanding panel and normality returned. I removed the fuse to the roof panel and plugged in the freestanding panel and again, normal operation (eg, more Sun, more Amps, less Sun, less Amps). I have checked the wiring and found no problems. I checked the Diodes on the freestanding panel and they are OK. I am now wondering if it is the Schaudt regulator at fault, it is around 10 years old. I know it has handled both panels in the past when for a short time they were both freestanding and could output up to 11 Amps at times. Does anyone have any other ideas as to the problem please? Link to comment Share on other sites More sharing options...
StuartO Posted September 20, 2020 Share Posted September 20, 2020 I remember reading somewhere about solar panel cells causing back voltage when some are in shadow, thereby compromising output. Perhaps the way your two panels are wired (in parallel, without protecting diodes where they are connected together) is causing this problem. Clearly there is something causing back voltage somewhere. Link to comment Share on other sites More sharing options...
colin Posted September 20, 2020 Share Posted September 20, 2020 Are you overloading the ammeter? Link to comment Share on other sites More sharing options...
747 Posted September 20, 2020 Author Share Posted September 20, 2020 Thanks for the replies so far. The panels were either fully in the Sun or fully shaded by clouds. The Ammeter has been reliable so far, I actually checked the van as I thought I carried a spare battery for it but could not find one (it needs a small battery for the LCD display) The tester is this type, originally bought from Maplin. https://www.amazon.co.uk/Sealey-TA120-Automotive-Current-Tester/dp/B001SBFZK0/ref=sr_1_5?dchild=1&hvadid=80745423568056&hvbmt=be&hvdev=c&hvqmt=e&keywords=car+current+tester&qid=1600629750&sr=8-5&tag=mh0a9-21 Link to comment Share on other sites More sharing options...
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