Part of our yearly maintenance activities for remote solar powered telco customers was S/C current and O/C voltage test in full sun. They sparked but never appeared to show any signs of damage. I was often amazed how well these panels performed after 20+ years of service or in overcast conditions. Infact I never found a faulty one (unless torn off by cyclones or burglars) Justin On 17 December 2012 08:45, Brent Brown wrote: > On 17 Dec 2012 at 12:56, IVP wrote: > >> Hi all, >> >> I have an acquaintance, a menace I've mentioned before, who has >> come up with another way to surprise me >> >> He's just installed four 200W solar panels to power his house via >> 24V batteries and an inverter >> >> He rang me this morning and asked a question that I wasn't able >> to answer except to say it didn't sound safe. I Googled then and >> now but didn't find any relevant information >> >> Apparently the 24V panels he ordered are actually 12V, which >> he's going to sort out with the supplier >> >> But in the meantime, he's connecting the panels directly to the >> batteries, bypassing the charger, as he says in full sunlight the panels >> put out 26V which is "enough to keep the batteries topped up" >> >> What concerns me is that he says he connects the panels only when >> their output is over 24V and sees a spark. The supplier has suggested >> he not do this, which sounds reasonable to me. 'menace'claims (based >> on what, I don't know) that this spark will do the panel no harm, and >> rang me for reassurance that he is correct. To my mind, a spark when >> a power supply is connected to a load means something is under stress, >> for better or worse, and if they were my panels I'd not be tempting fate >> by blowing an internal connection, thereby getting lumbered with a non- >> returnable damaged panel >> >> Am I right to right to advise that panel damage is possible and that >> basically what he's doing is an intuitively stupid thing to do ? (for >> various reasons) > > Yes, sounds like a fair call. Taking him at his word that he actually has= 4 x 12V > panels (but intended them to be 24V) and 24V batteries and a correctly sp= ec'd 24V > solar charger, then a safer interim solution might be to suggest he wire = the 12V > panels in series pairs to provide 24V and use the solar charger. > > -- > Brent Brown, Electronic Design Solutions > 9 Titoki Place, Pukete, > Hamilton 3200, New Zealand > Ph: +64 7 849 0069 > Fax: +64 7 849 0071 > Cell: +64 27 433 4069 > eMail: brent.brown@clear.net.nz > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .