weldted Posted December 10, 2018 Share Posted December 10, 2018 Whilst well aware it's December, we are currently in the South of France. Having recently upgraded my solar controls. I am disappointed at the charging gain. Previously I had a Solar boost 200 E controller, having changed it for a Voltronic 350 Mppt one. This is fed by 300 watts of panels and have fitted a Voltronic solar computer and shunt. Wiring it this way allows me to monitor both charge and discharge. Together with two new Yuasa L36-EFB 100 amp batteries. They have now done about 25 cycles down to around 80% so should be working up towards where they should be. On today's reading at midday clear sky voltage at panels 17.14, voltage at controller input 17.01, voltage at output to leisure batteries 12.7 second output to engine battery 12.85. This is having been parked up since last night no engine or mains charger input. The mppt light is on but the battery 80% or the 100% lights are off. Showing 1.8 amps charge to leisure batteries with everything off. Charged the batteries with genny now showing 95% charged taking 4.2 amps 80% and 100% lights still off. If I plug the computer into the controller it shows no volts at the batteries no current in or out. Put it back on the shunt shows all the info. Have rechecked wiring etc if engine running shows rate of charge and voltage of both batteries. Would of thought it would perform better than this suspect controller may be faulty. Earlier in the year never got more than 4 amps from it. Link to comment Share on other sites More sharing options...
Keithl Posted December 10, 2018 Share Posted December 10, 2018 weldted - 2018-12-10 4:29 PM ...a Voltronic 350 Mppt one. Ted, Are you sure it's a VOLTRONIC and not VOTRONIC? I can't find instructions for the former but can for the latter. Keith. Link to comment Share on other sites More sharing options...
weldted Posted December 10, 2018 Author Share Posted December 10, 2018 Opps Votronic!! Link to comment Share on other sites More sharing options...
aandncaravan Posted December 10, 2018 Share Posted December 10, 2018 As we have said before, those batteries, as per most batteries give the optimum cycle life versus use at about 50% Depth Of Discharge (DOD), To regularly take them to 80% will most likely result in less than half their quoted cycle life and a degraded battery? That the panel voltage is low at 17v suggests that a load is being placed on it by the Votronic, indicating the solar charger is working, but maybe not getting much current going in? The low current suggests that one or more of the panels isn't contributing? If it was me I would begin checking the current at the panels first, then working from there towards the battery. Suggest you isolate each panel in turn by disconnecting them all as close to the Solar panel as you can (so you don't disturb the existing wiring at the Votronic) and then connect them one by one to see what the Shunt shows. Long term I would suggest you maybe consider fitting a £6 Wattmeter in each Solar Panel output cable where it enters the roof followed by a fuse. You can then remove the fuses to monitor how the panels with fuses "in circuit" react. It is possible one panel can fail and not only fail to contribute, but actually draw some of the power from the other two panels. Good article here : https://www.electronics-tutorials.ws/diode/bypass-diodes.html. It is a complication that usually only arises where multiple panels are joined into a single Solar Charger. The watmeters will allow you to monitor the efficiency of each panel over time, as they are unlikely to degrade equally. Link to comment Share on other sites More sharing options...
Paul- Posted December 10, 2018 Share Posted December 10, 2018 17.01v? is it just one 300 watt panel or have you connected more than one in parallel rather than in series Link to comment Share on other sites More sharing options...
weldted Posted December 10, 2018 Author Share Posted December 10, 2018 As stated before I'm not the best at explaining the batteries were still at 80% as in I had only used 20% of their capacity not 80% discharged. I have two 90 watt panels and three 40 watt panels all in parallel hence 17 volts. They have been on this van since 2012 and with the previous controller performed well. On the day I changed the controllers over the old one was giving 11.7 amps at 14.2 volts it only took less than an hour to change over and the new one was giving 5.5 amps at 12.9 volts this work was started at 11:00 on a clear sunny day. The main reason for change was to have a second output to the engine battery. The instructions clearly state that an LED will come on at 80% and a second one at fully charged neither do so. And there is the failure to produce a reading from the solar computer when it is connected to the controller but fine when connected to the shunt. I disconnected the temp sensor from the battery in case that was giving an incorrect reading but made no difference. Link to comment Share on other sites More sharing options...
aandncaravan Posted December 10, 2018 Share Posted December 10, 2018 I would agree with you that something is wrong with the Votronic, but I would still start at the Solar panels and work towards the Batteries. Link to comment Share on other sites More sharing options...
Paul- Posted December 10, 2018 Share Posted December 10, 2018 If it was mine the 2x90w would be coupled in series on one mppt controller and either get a second controller of the same make and type for the 3x40w and couple those in series, or, and it may be a cheaper option, to sell the 3x40w and get another 90w and have 3 in series. Link to comment Share on other sites More sharing options...
plwsm2000 Posted December 10, 2018 Share Posted December 10, 2018 The fact that when you changed the controller, the power output dropped by more than half should have rang alarms bells.(11.7A * 14.2V = 166W for the old setup vs. 5.5A * 12.9V = 71W for the new setup). I also don't understand why the voltage dropped from 14.2V to 12.9V 17 volts seems very low and suggests there is something wrong with your panel wiring or you have a faulty panel. Do these have blocking diodes fitted? If not, you should try to find out the published voltage at max.power (Vmp) for each of your panels - I would expect these to be at least 18V even for the 40W panels. On the Votronic controllers, you cannot connect the -ve of the solar panels to anything other than the Votronic controller (it must not be grounded). I would also be wary about connecting anything else in series with its output to the hab battery. In the datasheet for the MPPT controller, it states it has "automatic compensation of voltage losses on the charging cables". This may be upset if you have anything else between the controller output and the battery (apart from a fuse). Link to comment Share on other sites More sharing options...
weldted Posted December 10, 2018 Author Share Posted December 10, 2018 The panels are connected directly to the controller just as they had been previously, the + from the controller output goes directly to the + terminal of the hab batteries. The - from the controller goes to the Votronic shunt onboard side together with all the negative connections exactly as per the instructions and the outboard side of the shunt goes to the - terminal of the leisure batteries Link to comment Share on other sites More sharing options...
Basher Baz Posted December 10, 2018 Share Posted December 10, 2018 Do you still have the old controller? Maybe worth re-fitting it. If its a panel fault then you're amperage will be significantly lower than before. If not then looks like issues with the new controller. As your using different size panels I tend to agree with the remark regarding blocking diodes. Its not a problem with same size panels and it may not be the main problem at the moment but you could be losing some amperage into the other panels if you don't have these fitted. After all, we all want to max out electric that's going free. If its any help i run 2 x 100w panels lying flat on roof through a single MPPT controller and usually get 8 -9 amps at 13.7 v bulk charge on a sunny day. Link to comment Share on other sites More sharing options...
weldted Posted December 10, 2018 Author Share Posted December 10, 2018 Many thank for all the input, all the panels have blocking diodes fitted, but will separate the panels when We get back to the cottage next week and start from there. Link to comment Share on other sites More sharing options...
Alanb Posted December 10, 2018 Share Posted December 10, 2018 Paul- - 2018-12-10 7:34 PMIf it was mine the 2x90w would be coupled in series on one mppt controller and either get a second controller of the same make and type for the 3x40w and couple those in series, or, and it may be a cheaper option, to sell the 3x40w and get another 90w and have 3 in series.While connecting panels in series has advantages, before connecting in this way, it would be wise to check the maximum input voltage of the controller.Alan Link to comment Share on other sites More sharing options...
weldted Posted December 11, 2018 Author Share Posted December 11, 2018 Been up on roof this morning, panel make Sunpower rated 17.5 volts. 5.2 amps.Max open circuit volts 20.5 Maximum voltage for controller 50 volts. Link to comment Share on other sites More sharing options...
spirou Posted December 11, 2018 Share Posted December 11, 2018 Victron has a useful calculator for voltage/amperage for various solar panel and regulator combinations since it also includes temperature effects. Obviously aimed at victron equipment but if you set up your own presets with the data off the panels and regulator it will calculate those just as nicely. Then you can play with series/parallel combinations to come up with the optimal setup. https://www.victronenergy.com/upload/software/VE-MPPT-Calc-1_9.xlsx Link to comment Share on other sites More sharing options...
weldted Posted December 11, 2018 Author Share Posted December 11, 2018 Thanks for the info, but I still have concerns re the controller as it doesn't give any output to the solar computer? I have emailed the maker for advise. Link to comment Share on other sites More sharing options...
BruceM Posted December 11, 2018 Share Posted December 11, 2018 Just attempting to visualise your wiring setup – would you clarify? - when you state “Voltronic solar computer and shunt” do you mean https://www.votronic.de/index.php/en/products/solar-technology/lcd-solar-computer or in fact https://www.votronic.de/index.php/en/products/measuring-display-systems/battery-computer Link to comment Share on other sites More sharing options...
Ocsid Posted December 11, 2018 Share Posted December 11, 2018 With the maximum power point of these panels just a low 17.5 volts, surely this is too low to gain the attributes of using an MPPT controller? As has been suggested earlier is there not a very much better solution to wire the like sized [Wattage] panels in series to be working the controller at a maximum power point voltage at least twice that now in use. Link to comment Share on other sites More sharing options...
weldted Posted December 12, 2018 Author Share Posted December 12, 2018 It's the second set up with the matching shunt Link to comment Share on other sites More sharing options...
weldted Posted December 12, 2018 Author Share Posted December 12, 2018 The previous Solar boost 2000E was an Mppt controller 11 amps plus was attainable in the right conditions. This has been the case for the last 5/6 years. The 2 X 90 watt panels and controller were bought from FF Solar when we were in Portugal and added to the 3 X 40 ones. All rated at 17.5 volts. The only reason for change was to have the second output for the engine battery which the old controller did not have, remove the battery mate as advised this whilst better than nothing is not the most efficient way to top up the engine battery, and protect the batteries from overcharging when van not in use. As said before the system worked fine prior to fitting the new controller computer and shunt. Link to comment Share on other sites More sharing options...
aandncaravan Posted December 13, 2018 Share Posted December 13, 2018 In another post you reported a mismatch between the shunt display, with it saying the battery was still highly charged, yet a voltmeter showed the battery right down at 70%+ DOD and about 12.2v. Could there be an issue with the shunt/display not showing the correct charge/discharge? I agree with the others that a reconfiguration of the Solar panel set-up may produce a higher solar yield, but I would suggest you first find out how much they have degraded. Some may not be working very well after all this time. Hence my suggestion of the Wattmeters as they record the amps over time so you can compare how much each panel has produced in a day, not just a single one off 5 second recording. At only £7 each they are invaluable for tracking how much the solar panels degrade over time. If you were seeing a best of only 11 amps prior to the change when 15 - 16 amps is more usual in that part of the world, it would suggest all was not ideal prior to the new Solar charger being fitted.. Link to comment Share on other sites More sharing options...
weldted Posted December 13, 2018 Author Share Posted December 13, 2018 The reported 11 amps was November central France. When the batteries are fully charged the solar computer when connected to the shunt shows the batteries at 100% after one hour of no load shows 12.6 volts. Shows engine battery similar. Turn habitation power on fire up tv shows 3.7 amps discharge. When batteries are down to 80% remaining, switch on Victron 30 amp charge display shows 30 amp charge then falls gradually. So would say it's fairly accurate. When computer is connected to the controller shows the leisure batteries to be flat no other readings show. When trying to program it say for a 200 amp hr battery bank enter 200 it then freezes and will only reset it you unplug it. Also the little image of a sun that is supposed to show on the display does not appear nor do the controller indicator lights light up other than the Mppt one. I appreciate the comment re upping the voltage by wiring the two 90 watts in series to produce a higher charge rate and buying some watt meters to check each panels output, also aware these panels are getting on a bit but if prior to changing the controller hasve had a better charge rate expected the same or a slight improvement. Luckily with my charging set up I have been able to keep the batteries topped up during our 16 days around France with out needing ehu. And again thanks to everyone. Link to comment Share on other sites More sharing options...
Paul- Posted December 13, 2018 Share Posted December 13, 2018 I don't suppose that you still have the old controller so you could try that again, its not unknown for controllers to malfunction.However it does sound like its a project to check each part of the equation, batteries, panels, controller, wiring and all the connections, from the panels through to the batteries before a definite answer will be found. Link to comment Share on other sites More sharing options...
weldted Posted December 14, 2018 Author Share Posted December 14, 2018 Unfortunately old controller is back in the UK, we are not home till around April/May. Have checked all wiring connections but no faults found, have separated all the panels the voltage is roughly the same from each panel. The company I bought the controller off have said it sounds like a fault with the controller and have emailed me a form to fill in. Just waiting for them to reply, Link to comment Share on other sites More sharing options...
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