|
|
Post by quaysider on Aug 11, 2016 18:20:20 GMT
|
|
|
|
Post by PaulG2 on Aug 11, 2016 19:21:38 GMT
Buying seven-year-old solar technology seems counter intuitive, but if they work as promised the price is right....
Someone please correct me if I'm wrong, but looking at the specs on these and doing some simple maths it seems like on a sunny day he could get around 30 amps at 15 volts to charge his batteries. Is that correct?
|
|
|
|
Post by quaysider on Aug 12, 2016 15:43:31 GMT
I'm hoping for little more but yes ... not far off - in "My sums" I've used 14.5v but with the mppt, it should/might work out +34amp. On a sunny day that should/might do nicely .
As to the fact they're 7 years old - the spec suggests they'll still be working to 95% of their original capacity and to us right now, Money is SO tight, it was them or 390 quids worth of new ones...
Time will tell of course.
I've just plugged them together as test and voltage wise they're reading 44 (ish) each in the bright sunlight. I've no load I can connect to them so I can't check the current.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Aug 12, 2016 15:55:27 GMT
Be careful! 44V won't kill you but 55 might!
|
|
|
|
Post by PaulG2 on Aug 12, 2016 17:38:19 GMT
I'm hoping for little more but yes ... not far off - in "My sums" I've used 14.5v but with the mppt, it should/might work out +34amp. On a sunny day that should/might do nicely . As to the fact they're 7 years old - the spec suggests they'll still be working to 95% of their original capacity and to us right now, Money is SO tight, it was them or 390 quids worth of new ones... Time will tell of course. I've just plugged them together as test and voltage wise they're reading 44 (ish) each in the bright sunlight. I've no load I can connect to them so I can't check the current. Kinda makes you wonder how much solar technology has progressed other than to bring the cost down. |
|
|
|
Post by Telemachus on Aug 12, 2016 18:08:46 GMT
I'm sure they will be fine. Bumble do similarly priced second hand panels that are well received. Just a point on the expected output, I doubt you will get too near the max since if you read the fine print on the spec of most panels it quotes the output at a particular level of sunshine (unlikely to be achieved in the temperate latitudes of the U.K.) and at a particular temperature. Solar panel output decreases significantly with increasing temperature. So to get the rated output you need equatorial sun with a panel temperature of (say) 25C. Never going to happen! Feel how hot you boat roof gets on an averagely sunny UK day.
|
|
|
|
Post by quaysider on Aug 14, 2016 17:57:51 GMT
This afternoon - thanks to Amazon prime my budget mppt and monitor arrived so I cobbled together the panels I bought the other day to see how they faired. Before doing so, I had to flatten my camping battery buy stringing up 3 headlamp bulbs and leaving it connected for about 2 hours ... at about 5pm, I connected it all together and this was the result.     Not too bad a result given the time of day I suppose... and the fact the connectors were only kind of "wedged" into position. I'll box it back up and leave it in the attic until the boat arrives - looking at w/e 23rd October now :-( which seems an age away! |
|
|
|
Post by JohnV on Aug 14, 2016 18:00:37 GMT
that looks pretty good to me
|
|
|
|
Post by peterboat on Aug 14, 2016 19:14:10 GMT
97 volts can kill be careful!! I have 9 x 97 watt panels, 3 in series 3 times, and then in parallel back to the controller, and then to the batteries it keeps the voltage down and seems to be better than when it was all in series.
|
|
|
|
Post by loafer on Aug 17, 2016 13:13:29 GMT
97 volts can kill be careful!! I have 9 x 97 watt panels, 3 in series 3 times, and then in parallel back to the controller, and then to the batteries it keeps the voltage down and seems to be better than when it was all in series. I re-wired my 3x100W panels to series after being paralleled for a year. In parallel, I found the 30A fuse installed as the cable came into the boat had partially melted, although the fuse remained intact. Placing them in series meant that only 6A max could possibly come through the cabin-top (6A being the short-circuit current for each panel) Problem solved, now with reduced heat losses! |
|
|
|
Post by tadworth on Dec 17, 2016 0:24:06 GMT
Bimble solar are selling 285 w used panels at £85 each.
|
|
