davida Posted August 21, 2020 Share Posted August 21, 2020 Good afternoon all, Been m/homing 7 years and now onto my fourth van. First time with Solar though and have a problem I cannot solve. Last year I installed a 150w panel with Votronic MPP 165 regulator, directly into the EBL 30 solar input block.. Seemed to work well and served its purpose during a 6 week France tour last summer. Problem I’m having now is the regulator is struggling to output much more than 13.5v, despite the batteries requiring 14.4v to charge, and so the batteries are not charging. Measured at the regulator output terminals and shown on the Votronic Solar Computer S. The solar panel has an open circuit voltage of 30.1 and 25.5 under load. Despite mostly white cloudy conditions I measure between 22 and 24v at the regulator input terminals. I do not understand why the available 20 plus volts will not translate to the required 14.4v to charge the batteries. The charge programs on the Votronic and the EBL are set correctly. Any help is very gratefully appreciated! davida Link to comment Share on other sites More sharing options...
buddy Posted August 21, 2020 Share Posted August 21, 2020 I believe that about 14.4 volts or more is normally the charging voltage when first on charge, if the battery needs it, which dropped to a float charge of around 13.5 volts when the battery was fully charged. You could check this by putting a load on the battery to run it down a bit and then see if the readings increase to replace the losses. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Buddy thank you. That’s right, mine is set at 13.7v float. The batteries have a decent load with a compressor fridge and are in need of charge. davida Link to comment Share on other sites More sharing options...
BruceM Posted August 21, 2020 Share Posted August 21, 2020 Firstly, have you carried out any electrical maintenance such as disconnecting the leisure battery recently? If not then I’d suggest you check the 15A Solar fuse on the Electroblock (continuity test). Link to comment Share on other sites More sharing options...
buddy Posted August 21, 2020 Share Posted August 21, 2020 Have you have disconnect any of the solar system and failed to connect the battery side of the regulator before the input side from the solar panel as is required ? If not, it could be the regulator is faulty, perhaps the supplier of the Votronic unit could help in how to test it or is it still maybe under warranty. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 No I don’t think so, During testing i have disconnected the panel from the regulator leaving the regulator still connected to the battery, I don’t think that causes s a problem? I’m thinking possible faulty regulator too, though otherwise seems to function OK, and all the LEDs on it seem to indicate normal operation. Now see if I can remember where I bought it! Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Bruce, thank you. It seems ridiculous I haven’t checked that fuse. I checked the 15a one in the regulator. Off to check it now. Link to comment Share on other sites More sharing options...
buddy Posted August 21, 2020 Share Posted August 21, 2020 If you find the fuse you are checking is ok I assume that the reading you are getting at the regulator output is also the battery voltage , which would be the reading I would expect with a a fully charged battery . Link to comment Share on other sites More sharing options...
Paul- Posted August 21, 2020 Share Posted August 21, 2020 Have you checked it first thing in a morning when it should be doing its bulk charge, my controller runs at 13.7 during the day after its done its bulk charge at 14.5v Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 The fuse is good, although was slightly charred so I’ve replaced anyway. Made no difference. Whilst I am measuring battery voltage at the regulator output, it does increase from around 12.5v when I connect the solar to 13 odd vaults, varying depending on the number of amps currently received (shown on the Solar Display) then reverting to the battery’s 12.5v when solar is off. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Paul- - 2020-08-21 4:03 PM Have you checked it first thing in a morning when it should be doing its bulk charge, my controller runs at 13.7 during the day after its done its bulk charge at 14.5v Thanks Paul, I have, that’s when I’m most expecting the 14.4 and I’m not getting it. Also takes time to get up from the 12.5v battery voltage even to 13 odd vaults Link to comment Share on other sites More sharing options...
BruceM Posted August 21, 2020 Share Posted August 21, 2020 Hmmm . . what solar current does your display indicate is being supplied? Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Between 12 and 13.5 usually. When on hookup it does display the 14.4v. davida Link to comment Share on other sites More sharing options...
spospe Posted August 21, 2020 Share Posted August 21, 2020 davida - 2020-08-21 4:08 PM The fuse is good, although was slightly charred so I’ve replaced anyway. Made no difference. Just a thought, but if the fuse is, "slightly charred", that points to high resistance in either the fuse, or the fuse holder. If it is the fuse holder (caused by the heating effect), then could this be the source of the problem? Link to comment Share on other sites More sharing options...
BruceM Posted August 21, 2020 Share Posted August 21, 2020 davida - 2020-08-21 4:44 PM Between 12 and 13.5 usually. When on hookup it does display the 14.4v. davida That's the voltage. I understand that your Votronic Solar Computer will also display instantaneous current and instantaneous watts? It was the current that I was after although watts will do as an alternative. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 I did wonder about the charring, and so I will keep my eye on the replacement. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Sorry Bruce, not paying attention. The amps of course varies depending on cloud coverage, today it’s been between 2 and 8amps on the display. Does it need a minimum amps for the 14.4v? The input voltage from the panel varies less, I haven’t seen it below 22v even at 1 or 2 amps. I am still learning! Link to comment Share on other sites More sharing options...
BruceM Posted August 21, 2020 Share Posted August 21, 2020 davida - 2020-08-21 5:18 PM The amps of course varies depending on cloud coverage, today it’s been between 2 and 8amps on the display. Well if that’s the current being drawn it indicates to me that both your solar panels and regulator are working and providing a lot of the power needed by your fridge. What happens to the battery voltage reading if you turn your fridge (and anything else on the 12v circuit) off? Also when did you last clean your solar panels? Presonally I aim for every 4 weeks when in use. Like with cars, rain is not enough on its own especially given that the solar surfaces are horizontal. Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 BruceM - 2020-08-21 5:26 PM davida - 2020-08-21 5:18 PM The amps of course varies depending on cloud coverage, today it’s been between 2 and 8amps on the display. Well if that’s the current being drawn it indicates to me that both your solar panels and regulator are working and providing a lot of the power needed by your fridge. What happens to the battery voltage reading if you turn your fridge (and anything else on the 12v circuit) off? Also when did you last clean your solar panels? Presonally I aim for every 4 weeks when in use. Like with cars, rain is not enough on its own especially given that the solar surfaces are horizontal. Bruce, I cleaned them 3 weeks ago before coming on this holiday. When I turn the fridge and other loads off the voltage increases by a tenth or two. Link to comment Share on other sites More sharing options...
BruceM Posted August 21, 2020 Share Posted August 21, 2020 OK – as I see it With the compressor fridge turn on and whilst off EHU : The solar regulator appears to be putting out anything between 2A and 8A according to the solar light levels The habitation battery voltage is not rising above the regulator battery float voltage as measured at the regulator output terminals and also according to the solar computer even first thing in the morning when we’d expect the batteries to require recharging (I assume that you’re not plugging into EHU overnight?) Turning off all 12v drain only effects the solar output voltage by approx 1/10thV . If that summary is correct then to me it appears to be that the solar regulator thinks that the batteries are already fully charged and is only supplying current according to the load applied to the 12v system (ie fridge, lights etc). That being so, I’m a bit stumped. Whilst the regulator may have developed a fault it strikes me as a strange one. The possibility that the ‘charred’ fuse connection on the EBL is an issue indicator may be worth investigation – maybe clean the fuse contacts as suggested previously? Possibly the best test to determine if that is having an impact would be to run two wires from the solar regulator output directly to the habitation battery (having unplugged the solar from the EBL and temporarily covered the solar panels) and see what effect that has. Link to comment Share on other sites More sharing options...
mikefitz Posted August 21, 2020 Share Posted August 21, 2020 Connecting direct to the battery would be a useful test. The voltages for solar input and currents of 3 to 8 amps suggests that the panel is working OK. Ideas that may be causing the problem. With a compressor fridge, a 150 watt panel is a bit marginal unless you have ideal solar conditions, it maybe that the battery is not having power via the solar to get to full volts. There may be issues with the leisure battery preventing correct charging . The fuse problems suggesting overheating point to issues with the EBL fuse holdet or internals. I suspect you may find a significant volt drop between controller terminals and battery when high currents are flowing. There have been a number of failures of the Votronic MPP so that cannot be discounted. Examining all cables amd interconnections between the controller and battery on both positive and negative cables may find the cause of the 'missing volts'. Mike Link to comment Share on other sites More sharing options...
davida Posted August 21, 2020 Author Share Posted August 21, 2020 Bruce, Mike, Thank you, you have given me some stuff to work with there. I’ll report back. davida Link to comment Share on other sites More sharing options...
plwsm2000 Posted August 22, 2020 Share Posted August 22, 2020 Another possibility is just the lack of sunlight during the main charging phase. The main charge phase on the Votronic Duo lasts for a maximum of 4 hours when set to "Lead Acid" (I assume this is what you are using from the 14.4V you are expecting to see). At this time of year in the south of the UK, sunrise is about 6am and twilight about 30 mins earlier. My Votronic Duo switches on (i.e starts the main charge timer), around 15 mins BEFORE sunrise and finishes 6 hours later (mine is set for Gel and has a 6 hour max. main charge time). My panel has a lower open circuit voltage that yours so I would expect yours to switch on even sooner. Obviously there is not much solar power available early in the morning and it maybe there is just not enough to get to 14.4V (particularly with your fridge load). To prove/disprove this theory, just completely cover your panel for at least 30 seconds (or until the MPP LED flashes every couple of seconds) so it thinks it is night time. Remove the cover and recheck your voltages (obviously do this when there is plenty of sun around!) Also, do you have a temperature sensor connected? If this is faulty, it could make the controller think the battery temp is too high and reduce the charge voltages accordingly. Try removing the sensor if you have one. Link to comment Share on other sites More sharing options...
davida Posted August 22, 2020 Author Share Posted August 22, 2020 plwsm2000 - 2020-08-22 12:24 AM Another possibility is just the lack of sunlight during the main charging phase. The main charge phase on the Votronic Duo lasts for a maximum of 4 hours when set to "Lead Acid" (I assume this is what you are using from the 14.4V you are expecting to see). At this time of year in the south of the UK, sunrise is about 6am and twilight about 30 mins earlier. My Votronic Duo switches on (i.e starts the main charge timer), around 15 mins BEFORE sunrise and finishes 6 hours later (mine is set for Gel and has a 6 hour max. main charge time). My panel has a lower open circuit voltage that yours so I would expect yours to switch on even sooner. Obviously there is not much solar power available early in the morning and it maybe there is just not enough to get to 14.4V (particularly with your fridge load). To prove/disprove this theory, just completely cover your panel for at least 30 seconds (or until the MPP LED flashes every couple of seconds) so it thinks it is night time. Remove the cover and recheck your voltages (obviously do this when there is plenty of sun around!) Also, do you have a temperature sensor connected? If this is faulty, it could make the controller think the battery temp is too high and reduce the charge voltages accordingly. Try removing the sensor if you have one. Thanks, I fitted a switched fuse between the panel and regulator so it’s easy to turn solar off, and then back on again to replicate sunrise, if I do this midday with clear skies I still don’t get the 14.4v. No temperature sensor is fitted. Also with the 12v fridge off it doesn’t change things. On the charred fuse, it’s charred at the point where it would blow, rather than on blades, as if it did take close to its 15A limit at some point but didn’t blow. Link to comment Share on other sites More sharing options...
mikefitz Posted August 22, 2020 Share Posted August 22, 2020 The timed period for the charging cycle only starts when the bulk stage is completed. The charging process starts in the morning, when the solar input voltage exceeds the battery volts by a few volts. The first phase of charging is the bulk stage that operates with maximum current from the MPPT process, raising the voltage until the target volts, 14.4, is reached. The timed duration of the absorption stage at constant voltage follows. The time allocated by the controller depends on initial battery voltage and bulk time. Following the computed time at absorption volts the controller goes to float mode. In real life the solar energy input will not be constant and various loads may be applied to the battery. This may cause the controller to return to or stay in bulk mode for some time, perhaps all day if the the solar input cannot keep up with power demand of loads and battery charge requirements. Mike Link to comment Share on other sites More sharing options...
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