Jocklandjohn Posted March 9 Share Posted March 9 I've noticed since the weather got sunny in the last few weeks I've been getting an overvoltage warning on a battery system monitor. This has been flashing when I go to use the van after its been parked up outside the house so obviously not occurring when driving. The vehicle alternator was replaced with a new one last autumn, also two new batteries installed, one starter one leisure, so I'm pretty sure none of them are at fault as its all been working fine over the winter, starting and charging as expected. And the solar panel was replaced last autumn because the previous one died completely (after many years of solid and reliable use). When driving, the various LCD monitors have always showed the alternator output being within normal charge range. However today the voltage went up when driving, to 15.5V. I switched on heater blower and lights to add a load and got the overvoltage warning to go off and the indicated voltage in the system came down and showed 14.5V So having recalled this was only recently happening and seemed to be when NOT driving I assumed it could be the solar panel. So I disconnected the solar input cable from the charge controller and immediately voltage dropped to normal. I left the vehicle for a while, watched voltage drop and stabilise - all as expected 12.75V on both batteries. Started vehicle and measured voltage at alternator 14.4V or thereabouts and similar at both battery’s terminals. Took a drive about - all as expected, no overcharge warnings and indicated voltage normal. Reconnected the solar input to the charge controller and voltage immediately went over 15v and up to 15.5v eventually, so disconnected it again and it all returned to normal. Any suggestions as to what might be going on and where I should start looking for a cause? Panel? Charge controller? Wiring? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 9 Share Posted March 9 Charge controller controls the voltage, so I would start there. That said, some of these controllers have a higher voltage/frequency mode to help maintain the battery, often run just once a month, it could have been that? Worth checking the manual, I would think. Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 9 Author Share Posted March 9 33 minutes ago, Bowie69 said: Charge controller controls the voltage, so I would start there. That said, some of these controllers have a higher voltage/frequency mode to help maintain the battery, often run just once a month, it could have been that? Worth checking the manual, I would think. I wondered about the charge controller, but the "higher voltage/frequency mode to help maintain the battery" point hadn't occurred to me. So thats a good shout. All its other functions are spot on - the diagnostics and voltage tracking etc all seem perfectly normal. Curiously the charge controller has an overvoltage warning via Red LED but that has not lit up at all. The overvoltage warning I oobserved was via a separate device, so bit peculiar the charge controller didn't pick it up....unlesss...its doing as you suggest. I shall dig deeper. First thing I'll do is disconnect and reconnect all the wiring I think. An chance a dodgy MC4 solar connector could cause this? Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 Hello fella, I actually live off grid got solar and wind running different parts of my plot, I had the same problem and naturally thought its going to be the charge controller, after doing a bit of research it turned out, in my case anyway that I needed to fit one directional diodes in the live to stop it power returning to the panels, apparently, and I'm only spouting off what someone told me, if the power end up tracking back it will give you allsorts of readings, I've sent some photos of what they are with the number on it but it's so small I had to take two, hopefully you can work it out from the pictures, I think you buy 10 for pennies, Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 1 Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 9 Author Share Posted March 9 23 minutes ago, stevebus said: Hello fella, I actually live off grid got solar and wind running different parts of my plot, I had the same problem and naturally thought its going to be the charge controller, after doing a bit of research it turned out, in my case anyway that I needed to fit one directional diodes in the live to stop it power returning to the panels, apparently, and I'm only spouting off what someone told me, if the power end up tracking back it will give you allsorts of readings, I've sent some photos of what they are with the number on it but it's so small I had to take two, hopefully you can work it out from the pictures, I think you buy 10 for pennies, Thanks Steve that a useful observtion too. I went into the 110's solar setup with a fair degree of interest becasue I wanted to explore the possibilities of doing what you're doing at some point and be off grid, and as I use the van for working out of anyway, it made sense from that point of view as well, as that has given me real world experience of being away from mains power. I have an alternator-side management setup, which prioritises starter battery & when its fully charged switches to send surplus to the auxiliary battery. And on the solar side the charge controller is prioritising the auxiliary battery and sending a trickle charge to the starter battery. Vendors of both systems said there would be no issues with them operating in this manner. The solar charge controller has four sets of terminals: two separate battery-out circuits for main & aux batteries, one circuit for solar-in, and one for a load which has a low-draw compressor fridge on. The overvoltage state was apparent on each battery so that suggests the charge controller was responsible for causing it. I think I need to experiment with my voltmeter and figure out what readings I'm getting and where, starting with the soalr panel leads and see what coming off that and take it from there. Certainly without the panel connected all is back to normal so that narrows it to the solar side I think. Thanks for the input. Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 No worries, good luck with it all, the only thing more I'm going to say is I found that keeping the alternator side of this completely separate from the solar side worked better for me, basically what started the wagon started the wagon and what ran the inside, TV, stereo and lights just did that, all the best 1 Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 My set up, looking at the picture upside down probably portrays how it all is here😁 1 Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 9 Author Share Posted March 9 Excellent! Compact and bijou as they used to say! I flipped it for you to save others turning their monitors upsde down! Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 Thanks, useless with anything techy, 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 9 Share Posted March 9 Show us a pic of your solar controller and ideally the wiring - otherwise we're just guessing. Any even vaguely decent solar controller should be protecting against reverse voltages and cutting off the charge at a set voltage. Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 Not that I'm going to get into a dispute about it, I was told this by Marlec, and this is my case only, all a controller does is basically short circuit when the battery is fully charged, and stops gasing and frying them, to get rid of the dump, is to either get a hot water element (which is a good one) or some sort of zenor diode like you use to get old British motorcycles, the controllers you get don't do that, all the while your solar panels are up there doing their thing it's going nowhere other than trying to get somewhere, if that make sense and the power can go back to the panel and fry it, which then creates false readings, basically all the while the sun is shining that panel is taking it, giving out grunt and going nowhere, the diode will protect your panel and send it one direction, the dump, hope to god that makes sense Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 9 Share Posted March 9 Sorry to go on, another thing you can do is add another battery to your solar side, that'll help Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 10 Author Share Posted March 10 (edited) 16 hours ago, FridgeFreezer said: Show us a pic of your solar controller and ideally the wiring - otherwise we're just guessing. Any even vaguely decent solar controller should be protecting against reverse voltages and cutting off the charge at a set voltage. Here you go. Wired in accordance with instructions, using appropriate gauge wire. All run in protective plastic tubing to batteries. As indicated on the device left to right - Battery 2 is starter Panel is solar (wire with tape on it is disconnected earth) Battey 1 is Auxiliary/leisure battery Last one is Load (conencted to a fridge, Wiring to fridge is switched and fused, switch is currently off) LED's are currently: Green indicating all is functioning as it should, the two batteries I've just metered when I took picture show 12.7V (at rest overnight) Panel LED is unlit because disconnected, Load LED is Green becasue its indicating sufficient charge to run a load if needed. Steca's vendor advised choice of whether Battery 1 is starter or leisure is dependent on how I want it set up, however if only connecting one battery to the system it MUST be connected on terminal 1 Main. Because I have a separate manager on the alternator system, an IBS I fitted 25 years ago, which is prioritising the starter battery this combination should mean each battery is maintained and managed appropriately. All the led light combos designed to fault-find show no issues and that all is running as it should Vendors of both systems were consulted and both said there was no issues with me connecting a system in this way. I metered the panel output when I took the photo, 8.40AM overcast and weak sunlight and it was delivering 3.6V so its working ok. Edited March 10 by Jocklandjohn 2 Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 10 Author Share Posted March 10 Just had a thought - I think I will try switching the Steca battery termnals and allow the solar to prioritise the starter rather than auxiliary battery - the net result should still be the same - the starter gets prioritised (as per alternaotor-side system), and the surplus goes to the auxiliary and the overall energy management/storage will remain the same. This might remove an unforeseen electronic 'hurdle' that may be causing issues. Will report back! 1 Quote Link to comment Share on other sites More sharing options...
hurbie Posted March 10 Share Posted March 10 a decent sollar controler can be set to different type's batterys, for example a lithium battery needs a higher voltage then a lead acid one . so might be that your problem is there . set to the correct battery the controler should never give more output then the "set" voltage (even with the engine running) Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 10 Share Posted March 10 21 hours ago, stevebus said: Not that I'm going to get into a dispute about it, I was told this by Marlec, and this is my case only, all a controller does is basically short circuit when the battery is fully charged, and stops gasing and frying them, to get rid of the dump, is to either get a hot water element (which is a good one) or some sort of zenor diode like you use to get old British motorcycles, the controllers you get don't do that, all the while your solar panels are up there doing their thing it's going nowhere other than trying to get somewhere, if that make sense and the power can go back to the panel and fry it, which then creates false readings, basically all the while the sun is shining that panel is taking it, giving out grunt and going nowhere, the diode will protect your panel and send it one direction, the dump, hope to god that makes sense There's some jumbled-up stuff going on in there, not sure how much of it is accurate or applicable to other controllers... I'm fairly sure (most) solar controllers do not short anything out, there's no reason that I'm aware of for doing so - when you're not drawing power from a panel you just disconnect it and it will sit there making volts that no nowhere just like a battery with nothing connected to it. A zener diode will not handle a load-dump from a solar panel or car battery - a chunky one might be able to dissipate a few watts but that's about it. Reverse protection / shorting diodes are used in multi-panel installations (panels in series) to prevent one panel acting as a blockage, or the weak link in a chain, or having too much voltage across its terminals from other panels in the chain - but I don't think that's applicable here. I'm slightly curious about your overall setup - it sounds like you've got other controllers (IBS?) in the system as well as a fair few extras wired in, more complexity equals more chances for weird interactions to happen. Most likely IMHO is either a controller that's forgotten what battery type is fitted as Hurbie says, a fault in the solar controller so it's not actually shutting off the panel, or some weirdness in the wiring / interaction with another device in the system. 1 Quote Link to comment Share on other sites More sharing options...
stevebus Posted March 10 Share Posted March 10 OK fella Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 10 Author Share Posted March 10 6 hours ago, FridgeFreezer said: I'm slightly curious about your overall setup - it sounds like you've got other controllers (IBS?) in the system as well as a fair few extras wired in, more complexity equals more chances for weird interactions to happen. Most likely IMHO is either a controller that's forgotten what battery type is fitted as Hurbie says, a fault in the solar controller so it's not actually shutting off the panel, or some weirdness in the wiring / interaction with another device in the system. Yes an IBS doing starter battery priority, with excess to aux when starter is charged. And the solar setup doing the reverse, priority to aux, delivering 90% of available solar input, and 10% to starter battery. Both vendors were asked about the ways these would interact and if there would be issues, both said no they should be ok, self managing and voltage limiting if excess detected. However as you suggest there may be either a mismatch of some sort or an actual malfunction. 6 hours ago, hurbie said: a decent sollar controler can be set to different type's batterys, for example a lithium battery needs a higher voltage then a lead acid one . so might be that your problem is there . Yes I checked that in the initial setup and its set to lead acid. But I will go back into the menus and check its all ok. Its entirely possible its reset some functions when I discnnnected it all to renew the battteries/alternator last year. There may also be a distinct set up sequence required eg attach X, then Y, etc so I'll give it a good look over. Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 19 Author Share Posted March 19 UPDATE Disconnected and reconnected the panel and solar controller, checked all the settings for 'battery type' & 'charging profiles' & 'cut off voltages' etc are correct (they were), then changed the charge ratio from 90/10 to 50/50 (unit can control two batteries, default was 90/10) and I'm not getting any more >15V readings. (The data logger in the system picked up a series of 15.5V highs across the last few weeks.) I am getting no more than 14.8V highs now and I spoke with the Steca supplier tech rep a few days ago (very helpful folk) and they advised a unit self-test which I did and the units are functioning correctly and in-spec. They think that the 15.5V highs may have been an anomaly possibly due to the LR battery box being exposed to the cold (it was very cold at ground level but with warm sun on the roof/solar panel) and the batteries low temp was having some effect on the charge profiles and that this may have triggered the highs. They did say these would have been transient highs and not necessarily continuous, and suspect that the change of the charge ratio to 50/50 has alleviated it. They suggested monitoring it for a spell to see what occurs especially if the temp drops again, but certainly the last few days have not revealed any unusual highs sufficient to trigger any over-voltage warnings. SO it *might* be resolved. Its been hovering at 2 Quote Link to comment Share on other sites More sharing options...
hurbie Posted March 19 Share Posted March 19 no to sure what battery's youre running , but 14.8 seems to be pretty high for a lead acid battery , most you read is 14.4 to max 14.7 but maybee you have different battery's and i'm talking nonsens 😉 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 19 Share Posted March 19 56 minutes ago, hurbie said: no to sure what battery's youre running , but 14.8 seems to be pretty high for a lead acid battery , most you read is 14.4 to max 14.7 I thought the same, I still think the "smart" parts are not being as smart as they claim to be or are getting confused / fighting each other. Setting it to 50/50 may be masking the problem not solving it. 1 Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted March 20 Author Share Posted March 20 18 hours ago, hurbie said: no to sure what battery's youre running , but 14.8 seems to be pretty high for a lead acid battery , most you read is 14.4 to max 14.7 but maybee you have different battery's and i'm talking nonsens 😉 Apparently with AGM batteries this is ok as they require a different charging profile and up to 15V can be seen during charging. I dont have AGM and the solar controller is not set to AGM type batteries - I checked that. 17 hours ago, FridgeFreezer said: I thought the same, I still think the "smart" parts are not being as smart as they claim to be or are getting confused / fighting each other. Setting it to 50/50 may be masking the problem not solving it. You might be correct. Its sunny today and the hand held voltmeter is showing 19+V coming into the charge controller off the panel and the charging V to each battery sitting at 14.75. There might be less 'smart' going on here than I thought. I did change the battery priority to suit the existing IBS unit so they shouldn't 'fight' each other, but thats no guarantee they want to play nice! I'm giving the tech rep I spoke with an update in a few days so will see what he's got to say. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 20 Share Posted March 20 59 minutes ago, Jocklandjohn said: I dont have AGM and the solar controller is not set to AGM type batteries - I checked that. >14.6v feels quite high for a system set to normal lead-acid mode, this page suggests <2.45v/cell which puts you at 14.7 max: https://batteryuniversity.com/article/bu-403-charging-lead-acid The graph here about low-temperature charging makes me wonder if one of these smart chargers thinks it's colder than it is and is bumping the voltage up: https://batteryuniversity.com/article/bu-410-charging-at-high-and-low-temperatures Although that wouldn't account for the much higher voltages seen earlier. Quote Link to comment Share on other sites More sharing options...
simonr Posted March 20 Share Posted March 20 Something worth mentioning here is your Volt Meter (Multimeter). The accuracy of a mid-range meter can easily be +/-1.5%. Cheap ones, even worse. Even a high-end meter will only be +/-0.3V DC Volts just after it's been calibrated. I would never rely on it to be better than +/-1%. A mid-range meter showing 14.5V could actually be anything from 14.3V to 14.7V. (On a high end meter, 14.35V to 14.65V) Thus I shouldn't worry too much about such small apparent voltage differences. Quote Link to comment Share on other sites More sharing options...
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