Bill Meadwell Posted August 21, 2006 Share Posted August 21, 2006 We've recently bought a Hymer with 2 fairly large solar panels, approximately 600 x 400 with 36 cells in each. They are wired to the leisure battery through a control unit. However, if I check the voltage going into the control unit on a sunny day, I only get 9 volts, and the same coming out of the control unit with the wires connected back up. Obviously this is not enough to charge a battery, and I would be grateful for any help/information that anyone can give as to what voltage I should expect, and how to attain it. Many thanks! Link to comment Share on other sites More sharing options...
johnsandywhite Posted August 21, 2006 Share Posted August 21, 2006 :-D Hi Bill Meadwell. I think your panels are around 30 Watts each with a total of 60 watts. The reading even on a dull day should be MUCH more than 9 volts. The voltage from the Solar Panels should be between 15 VDC and can go as high as 18 VDC on a cold day. Have you checked to see if the panels are cracked/broken? Link to comment Share on other sites More sharing options...
Don Madge Posted August 21, 2006 Share Posted August 21, 2006 [QUOTE]Bill Meadwell - 2006-08-21 3:01 PM We've recently bought a Hymer with 2 fairly large solar panels, approximately 600 x 400 with 36 cells in each. They are wired to the leisure battery through a control unit. However, if I check the voltage going into the control unit on a sunny day, I only get 9 volts, and the same coming out of the control unit with the wires connected back up. Obviously this is not enough to charge a battery, and I would be grateful for any help/information that anyone can give as to what voltage I should expect, and how to attain it. Many thanks![/QUOTE] Bill, I've got one 60watt solar Panel. On a good day I'll get 3.2 amps, this keeps my two 100AH leisure batteries and the engine battery topped up. :-D On a dull overcast day I'll sometimes get 0.2amp. Make sure you keep the panels clean. Don Link to comment Share on other sites More sharing options...
colin Posted August 21, 2006 Share Posted August 21, 2006 We get up to 18v on sunny days, solar panels do deteriate with age, usualy cracking cells. Can you sepperate panels and check each to see if they are both down on voltage. Link to comment Share on other sites More sharing options...
Clive Posted August 21, 2006 Share Posted August 21, 2006 Almost certainly you have a broken connection. Measure the output voltage at the panel terminal block directly to be sure. Solar panels have a life expectancy measured in tens of years and after several they will be down to 80% of what they were when new. If you throw them away then throw them at me. Good luck C. Link to comment Share on other sites More sharing options...
getaway Posted November 22, 2008 Share Posted November 22, 2008 I have an Exide 12v BatterySaver Pro 15W mounted on the roof of my Autohome Wayfinder. The leads go into the leisure battery box but are not connected to anything. With a voltmeter across the leads on a sunny day I get a no volts reading. If the panel is defective, what would be the likely cause and would it be repairable? The Towsure catalogue recommends a voltage regulator for 18W panels, but not for 10W, should my 15W be regulated? And another thing, measuring the volts across the terminals of the battery I get 17 volts! is this OK or is my meter U/S? many thanks for all the advice and tips relating to panel and battery matters, I intend to fit a "Clive" bridge twixt vehicle and leisure batteries. :-D Link to comment Share on other sites More sharing options...
George Collings Posted November 22, 2008 Share Posted November 22, 2008 Clives initials -CMGB must stand for Collects Most Good Bits. Link to comment Share on other sites More sharing options...
Clive Posted November 22, 2008 Share Posted November 22, 2008 Take more water with it George! Link to comment Share on other sites More sharing options...
Paul- Posted November 26, 2008 Share Posted November 26, 2008 Most panels will provide between 15 to 21 volts, usually about 21 volts this to help prevent power loss, so you do have a problem. Maybe it’s the wires... or the connectors? Have a look at the panels to see if there is any visible problem, cracked glass, or fogging. Try the connector on the panel & see what's coming out, then trace the wire back down to the regulator. I would think it's likely to be a dirty connector that needs replacing Link to comment Share on other sites More sharing options...
davenewellhome Posted November 26, 2008 Share Posted November 26, 2008 Its worth pointing out that you will only see 19-21volts on the panel output if its open circuit, i.e. NOT connected to the regulator and batteries. when connected fully the load (the reg and batteries) pull the voltage down. D. Link to comment Share on other sites More sharing options...
hymer1942 Posted November 27, 2008 Share Posted November 27, 2008 Can someone clarify, My meter like Dons shows charging in Amps. Dull day .02. Not in volts. Link to comment Share on other sites More sharing options...
Mike H Posted November 27, 2008 Share Posted November 27, 2008 I have just checked my charging monitor. I shows a charge of 0.4 (sunny/overcast) and the batteries charged to 14.7v. It is an 80 watt solar panel. Hope this helps. Mike H. Link to comment Share on other sites More sharing options...
mike 202 Posted November 27, 2008 Share Posted November 27, 2008 Mine is the same size as Mike H, but the regulator seems to keep maximum voltage to 14.4 Volts. Overcast but bright is 0.4 -0.6 amps with about 4 amp max in sunny Spain. As batteries become more charged the current Amps reading drops. Back EMF and all that effectively reduces the difference between the supply voltage (solar panel) and the battery voltage so that if they became equal then charging amps would reduce to zero, thereby stopping the battery from cooking. Link to comment Share on other sites More sharing options...
Paul- Posted November 29, 2008 Share Posted November 29, 2008 [QUOTE]mike 202 - 2008-11-27 4:22 PM Mine is the same size as Mike H, but the regulator seems to keep maximum voltage to 14.4 Volts. Overcast but bright is 0.4 -0.6 amps with about 4 amp max in sunny Spain. As batteries become more charged the current Amps reading drops. Back EMF and all that effectively reduces the difference between the supply voltage (solar panel) and the battery voltage so that if they became equal then charging amps would reduce to zero, thereby stopping the battery from cooking.[/QUOTE] A good 3 stage Series design regulator will carry on charging in pules mode as it attempts to equalize the cells in the battery. Paul Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 30, 2008 Share Posted November 30, 2008 [QUOTE]getaway - 2008-11-22 8:46 PM And another thing, measuring the volts across the terminals of the battery I get 17 volts! is this OK or is my meter U/S? [/QUOTE] Assuming you've got nothing putting 17 volts into your battery when you measure the voltage across its terminals, then your meter must be inaccurate (or you are using/interpreting it wrongly). One would expect a fully charged 12v battery, at rest and off-load, to provide an across-terminals voltage reading of between 12.7v and 13v. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.