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Forum Index : Solar : BETTER cheapo Solar Controllers.
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| Davo99 Guru  Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
My other thread on cheap controllers progressed into much more interesting and beneficial information so I thought I'd start again with what I have learned, or think I have, with the original question as a guide that may help others. I have a cheap PWM controller I bought some years back that had the advantage over many others I have bought since of having the voltage parameters USER settable and adjustable. Many do not and have settings that IMHO are too high for float voltage which boiled the batteries and too low in the bottom end cut off which is also not good. For my use the High flat voltages which do literaly boil the things with enough panel on them is the worst problem. They are crappy things to use though and the readouts are garbage. After much time on the net, I think I have figured the difference between the better adjustable controllers and the ones that are basically battery destroyers. This is the controller I have and love. Works perfect, easy and logical to use, been 120% Happy with it.  These appear to still be available from a Seller ( at inflated cost) but there is also a slightly differently presented version of the same thing with these units which have a model Number.  The problem I have found with these ATM is they all appear to be sold by one seller on Fleabay Oz at least whom has about 30 different seller names and equally bad reviews with endless complaints about Non delivery with all their store fronts. Fronts being an appropriate term. . So I kept looking. I found these which I had previously discounted as every controller I have had that was coloured blue which was complete and utter garbage of the "Kill your battery one way or the other " variety. But I noticed some similarities between the good one I have and the crap ones. Here is the "run for your life" type.  Here is a similar but what I believe good and decent type:  Now if you go back to the first pic of the good one I have and this one, You'll notice something... what I call the battery happy face on the LCD Display. The other one with the battery that doesn't smile ( How Rudeness!) is the "Boil or starve your battery to death" type and the one with the smiling battery seems to indicate the look on your own dial when you have one of these worthwhile types. Would be hard to come up with a graphic to illustrate the Look of frustration and annoyance I have had trying to do any settings with these other POS types that flat our more times than not just don't work properly at all. In all of the smily face types I looked at, and there were other designs of casing, They all if one delves into the Chinglish destructions, reference to the voltages for float and cut-off being " User adjustable" which is exactly what is needed. I would suggest anyone looking at these also looks at the description for this verification as well. Now this is just excited and untested hope of appearing to have something that may be worthwhile and helpful to others to contribute at this stage but I have in trepidation of actually getting them, ordered a couple of different nits with Mr. Happy battery to test the theory..... which I'm pretty confident of at this time. The advantage of the "Blue" appearance models seems to be they are being sold cheaper, sometimes substantially, than the black cased models.... for whatever reason but again I am pretty sure they are all the same controller being the happy or not so happy face Type just thrown into different casings. The other thing is I found sellers with much better feedback flogging the blue ones than some of the others but do your homework before you click the Buy button. I haven't looked at whats on the other sites but from what I have seen before, they are all the majority of the same and generally Fleabay is cheaper and there are local sellers ( supposedly) where you can get the things faster so you don't have as long a wait to be disappointed and frustrated. I am very SUSPECT on the happy face models being different amperage outputs as frequently listed. I can't find any pictures where they are marked so I'll see if my first Guess comes off and from there I might order a 60 or 100 Amp Model and see if there is any difference on the board. Actually, maybe I wont bother. There is no way on this gods green earth I can even get a 30 amp cable into those little wire connector terminals so how you could ever get a cable capeable of Carrying 60 or 100A @ 12 or 24V is well beyond me and another reason fro my suspicion. The units -MIGHT- do 20A but I reckon that's going to be about the upper limit. If anyone knows different I welcome to be corrected but I'd put money and a lot of it on the bet these things have about as much chance of doing 100A as I have of Lighting up a fart and Rocketing to the moon. I also found another interesting looking model being offered:  This controller also features Mr.happybattery and the specs say the parameters are user adjustable. The problem at this time I see with these on Fleabay is they all again appear to be from the same seller/ Drop shipper trading under a Myriad of names and all with a Pathetic amount of complaints for non delivery of goods, endless broken items which they won't make good on and general low lift sh*tfluckkery of a sellers that need to have their toenails trimmed with a Ride on lawnmower. They could be a decent unit but there seems to be a significant risk from what I looked up at length, that you would never get one to arrive to find out. BEWARE there is also a very similar Coloured looking model that has the regular battery depiction on the LCD which is not Mr. Happy battery (or owner) and is the same LCD display as all the crappy units that are NOT settable on voltages. I got to say, I looked through a LOT of listings and the amount of Neg feedbacks on nearly all the people flogging these things is BAD. I didn't see many pertaining specifically to solar controllers but a lot of other crap these sellers Flog relating to non delivery and broken on arrival. Some of it I look at and think why would you want this crap in the first place but the thing is people do, they pay their money and then get screwed over by these dog sellers. When multiple people in a month complain they didn't get something, That to me is a worry and an insight to the sellers attitude and puts me off. Yeah, it may only be $30 but I'm over the hassle of dealing with these Low life Mongerels to get nothing out of it so prefer to hedge the bets with someone that APPEARS more creditable. Fleay feedback is as rigged as a US electsham though. I have left neg feedback for dodgy products more than once and it's disappeared and some of the local Non asian sellers have been the worst.... Not mentioning Mills trading/ Edison's.... SCAMMING THE SCAMMERS.... This is how you get back at these professionally dishonest con merchants. One of the controllers I bought is listed as being MPPT. I think everyone here knows what a crock that is but for those whom may not be regular participants here, ALL these cheap, low end controllers are PWM. From what I see, anything under about A$70 is guaranteed to be PWM. PWM isn't terrible but you don't want to pay for a Rolls Royce and get a Kia With RR Badges on the thing and passed off as something it's not and you paid extra for the quality model. PWM works Fine but is not as efficient or flexible as PWM... if that's what suits your needs best. For what I want, adjustable PWM works very well. The controller I bought ( or one of them,) is described as MPPT in the title, the detailed description and multiple references. No where could I find mention of PWM which it really is. When the thing arrives, I'll simply put in a " Not as described" claim and ask for my money back. The seller will go through the usual scamming POS lowlife routine of wanting a picture and asking dumb questions in an effort to make it all too hard and probably offer something insulting like $2 refund and a line like they will get in trouble from their boss if they refund it all and other Crocks designed to pull on the heartstrings of the stupid westerners. Ya! I will go straight to a neg feedback. Beware that fleabay will often side with the scammers if you make a " threat" in your correspondence like "If you don't refund , I'll leave neg feedback" so watch that one. I say something that works in my favour like " I trust you are a reputable seller ( while I try not to vomit in my own mouth knowing they are scamming filth) andyou will do the right thing and I won't have to go through the procedure of getting ebay involved which will lower your seller rankings with them." Looks good to the Bots later when they read this and makes me seem a buyer they want to keep onside... like they give a rats... I DO leave the neg feedback if I don't get a rpomt refund and that does most of the time tend to get them to take notice and if they do care at all, they will often ask If they refund will I change the feedback. Yes! Of course I will. I'm not unreasonable nor dishonest. I want satisfaction and if they do the right thing I will too. If they refund me I'll change the Neg feedback and add that they refunded. NO, I'm not going to change it to pos feedback. They tried to scam me like they do thousands of others I'm sure and if I have had to jump hoops to get my money back, that in no way is a positive experience to me. I'll revise the feed back to say they refunded which fulfils my promise and that's it. I always agree to REVISE or UPDATE the feedback, I never agree to change it to positive Feedback as they will ask. To do so in my book would be dishonest because if I had to go to this trouble it's not a positive experience. That's simply get what I ordered which was as described and this is not. They miss the detail in the response every single time. If they come back and ask me to change the feedback I either ignore them or just add that they refunded for the not as described product. If they won't Refund or continue with the excuses/ BS then I'll just open a case with Fleabay. It's important to send the pics the seller asks for, be coperative and be very clear in your messages to the seller ( I repeat it's not as described and why more than once) because that's the first thing fleabay or their Bots look at when you put in a claim. You MUST be Polite and non threatening. That done, I haven't missed with these claims and the Bot or the person if you get one, usually issues the refund then and there AND you keep the item. Convid has been a great excuse for not returning something ..." I'm in lockup and not allowed out my house". That worked several times over the last couple of years. Keeping the item which is good but not as described is part of the payoff for your time. Getting the dodgy sellers is the best bit for me... not that they ever change their scamming ways, the refunds are just cost of doing dodgy and profitable business to them. I have done this enough now that I know where to find all the well buried ebay Links for claims ( and they ARE well buried) and can do it all pretty quick. I like getting free stuff as well and like in this case, often LOOK for these things which are misleadingly described so I can get back at the sellers and cost them some money. I ( with others) have complained to Fleabay and shown irrefutable proof of things being sold over months by dodgy sellers we already got refunds for being not as described but fleabay do jack about it. Suits me. I got more sets of LED driving lights for nothing than I can count and they work fantastic for lighting the big tree out the front with for Christmas. Thank you scamming little fleabay parasite sellers. So that is my, at this Time theory with the Cheapo Solar controllers. The one I have you can set exact voltages you want has been brilliant and If this theory holds up with these other ones I have coming, there is still cheap and workable units around. I'll probably get some more and take them to my father and hook them up to some of his toys like the Tractor, Chipper, especially the log splitter that sits unused for months and other things to keep the batteries from running down and getting ruined. I'll update when the Happy face units arrive and see how clever I am or am not.  |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Dave can understand your frustration with the plethora of alcheapo crap controllers being sold. Most are cloned rubbish and not even suitable for keeping a car battery topped up for a long period of time. Here is a link to one that I have used in the past, it has adjustable user settings when a LifePo4 battery is selected. Link I had it on a temp 12v Lifepo4 battery for 6 months before designing my own, its rated for 30 amps and will do that for about 2 minutes.... there is a temperature sense diode inside the case and the case interior isn't ventilated, so inside the air temperature gets up to 75c and heats up the diode causing the voltages to move about. The pcb tracks inside get really hot. Solution don't exceed about 12 amps and drill a series of 8mm holes around the case edges to allow air to circulate, other than that it works well and will work ok keeping mower batteries etc topped up when driven from a small 20-100w panel etc. Little used LA batteries don't like being keep on any sort of charger for long periods, best option for them is to have a small fixed power supply set for the batteries "Bulk" setting voltage about 14.5v depending on type; put it on a timer that charges it for a day then turns off for a week and repeat. This will allow the battery to self discharge a little so its actually chemically working. Perhaps we need a simple analog small PV charger (no CPU) just some pots for setting various voltage trip points that can charge up to 10A or so for ever reliably. What sort of charge current and voltages do you want to use? Cheers Mike |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I think I may have seen some of those chargers like you linked on fleabay but I wasn't paying a lot of attention. There are others that look the same but are just the non settable type. For what -I- want, mainly something that will top up batteries that were slightly discharged under load and keep them floating till needed again. I run some LED lights which are connected all the time so the batterys are cycled but not very discharged as the draw is minimal. 10A would be fine for this as long as they could be put on regular household panels. Some of these cheap controllers are not compatible with the higher voltage (40Voc) panels I guess because the amps created in the differential voltage is too much for them to handle. |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
You can hook up a 40v panel to a 12v battery, the panels voltage will just pull down under charge load to the battery voltage, max current will be what ever the panels output current is. The 40 volts no load input probably will blow up any of those cheap controllers designed for 12-24v if they are using components not rated for the voltage which is probably the case. I will have a think about the most basic controller that will do the job reliably, others on the forum may also have constructive ideas.... |
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Technophiliac Regular Member  Joined: 18/12/2020 Location: New ZealandPosts: 92 |
What high (and if you have noted the low ones) float voltages are these controllers running batteries in your experience, to cause this issue? Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 455 |
I have had a few elcheapo controllers over the last 40 years. Some only come with a very thin aluminium backing plate that is used as a heatshink. To get anything like their rated current I have bolted decent heatsinks to the back of them, it appeared to help. At the moment I have two elcheapo 30 amp controllers that have been reliable, Their brand sounds like a dating site ( Perfect Suitor) before them I had a couple of white controllers that the manufacturers were too ashamed to put their name to. They did not last long. I also have three Victron 50 amp controllers on the house supply and and so far for the last 4 years they are doing a fine job. Pete |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
One of the controllers Arrived today, the larger one Marked MPPT. It IS adjustable on the float and load voltages which I set however was holding the small 9 Ah battery at 14. 2 which it lists as the Equalisation charge but makes no other mention of that as to how long it runs or any setting for it. I left the thing several hours and it was still gassing the battery when I came back despite me setting the float voltage to 13v just to see if it would hold at that. I swapped out the little battery for a 90 Ah I ran down a bit trying to get the old Mower to Fire. Think the fuel pump is a bit sad on that so it did take some cranking and pull some Juice out the battery. The Controller said 12.2v when I put it on which was late so I'll see how it goes tomorrow. Giving the thing the hopeful benefit of the doubt that maybe the other battery was too small for the thing to work against but No idea what this equalisation charge time is set too but clearly too long for the little SLA. The thing also has battery type settings B 1-4 but NO indication what each number pertains to as far as battery Type. Might have a bit more ammunition for the refund on this besides it being not as described. May be unfit for Purpose as well although I am hoping it is OK in that regard. See how I go tomorrow with the thing and how it handles the Big Battery. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Well, I can't make head not tail of this damn thing. I put a meter on the battery and not much to my surprise found the voltage on the controller reads .8V Low to what the battery really is. Then it doesn't. Reads pretty much correct. Then it doesn't again. I tried different battery setting programs in the B1 B@ etc which resets the float voltage you manually set. The lowest setting on the controller is 13V but it appears if you set a Lower voltage than what the battery is currently at, the controller has a wig out. The LCD fades and gives stupid readings like the battery is at 16V. If you go into the battery program and then go to say B2 and then back to B! again where it was, the thing reboots, the display contrast comes back and it seems to work again.... Untill you set the float voltage too low again. I drained the battery a bit, rest and the thing seemed to work OK... for a while and then was doing I don't know what. It got cloudy this afternoon and a bit late so maybe the output was a bit low from the panel but the controller did show 2.3 A going into the battery at one stage and the voltage went up so whatever it was outputting was enough to add charge. And this has been my over all experience with some of these things. They are just a pain in the arse to use. I can cope with the things being inaccurate in there read out but the problem is this one like others is Inconsistent. Seems to do one thing one minute, something else the next so there is no chance to bias the error to get what you want. See if I can figure any more out tomorrow and get my old one out to compare in case I have forgotten or got something wrong with that. |
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| davef Guru Joined: 14/05/2006 Location: New ZealandPosts: 499 |
Hi SolarMike, For the controller in your link ... how long will that unit stay on 14.4V before dropping to float? Thanks, Dave |
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| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 92 |
MPPT controllers all seem to have 3 hallmarks, 1) They stop charging completely while they figure out their preferred parameters (I assume) for variable lengths of time and frequency and conditions (which IMO is wasted energy...small point!) and 2) their charge currents commonly exceed the solar panel side current a little (before arriving at float conditions) and 3) the panel voltage runs at higher levels than PWM (again before floating. What I am not clear on is what the parameters you are running, what panel power, voltage, battery voltage, plainly you are swapping different batteries but the scale of your setup(s?) seems relevant to selection of controller to me. FWIW I've trying various controllers, I've been using Jaycar "200A DC Power Meter with Anderson Connectors" on each side (Between panel and controller, and between controller and battery) along with analogue volt and ammeters in series on the solar side as well. The digital meters usefully save some maximum values as well. I wouldn't want to make judgements about controllers with anything less. Those digital meters seem reasonable for measuring voltage current and watts (that means consistent between meters) but their time and Ahr readings are not IME so reliable. Also they need a minimum voltage (around 5 or 6V) to save their settings until reset. With the onset of night time the solar side / voltage turns off, they lose data for the day, and are a pain starting up the following day - they do not like the slow voltage rise of a new day, and fail to start properly. These issues are addressed using a couple of LiIon batteries (~8V) plugged into their DC pins, they then last about 3 weeks between charges, save data and reliably restart the next day. Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
I haven't used that controller for several years, sorry cannot remember, located the manual that came with it and had a read..... the 14.4v bulk setting bit just says "for a short period" before switching to float. I will connect it up to a 12v battery and test it, get back to you. Cheers Mike |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
There are two common algorithms commonly used for an automatic three level "smart" lead acid battery charging. 1/ Bulk charge up to some specified voltage such as 14.2v. 2/ Absorb charge, either for a specified time (rare), or more commonly until the current falls below some minimum set value. That might be something like 10% of the chargers maximum design bulk charge current. 3/ When absorb charge finally terminates, it switches down to a specified float voltage such as 13.8v If the voltage is pulled down below the float setting because of some applied discharge load, the charger then reverts to condition one, Bulk charge. The charger may get confused initially when first powered up, especially if the battery is very small compared to the charger capacity, or totally dead flat, or badly sulphated up. An automatic "smart" charger can only function properly and cycle properly between modes with a completely healthy battery. Cheers, Tony. |
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| davef Guru Joined: 14/05/2006 Location: New ZealandPosts: 499 |
Thanks Mike and Tony. The issue is that I have been using the type shown in the 3rd image at the top of the thread for 2-3 years and wondered why they never seemed to come off 14.4V for sealed lead-acid. I think that explains why a fairly new deep-cycle battery in the caravan went "south" ;( |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I thought the little battery may be too small to impose a big enough load on the charger especially seeing it was full when I connected it. The larger battery was somewhat discharged and I noticed the charger recorded 14 AH put into it. Just seemed erratic on the float charge and wandering around. I made sure the connections on everything were good and would give it a load with a Couple of 50W lights to see how it handled some load but didn't make a lot of difference to the stability of the thing. This is what I meant about the other one being good to use. There is no stuffing round with it. You tell it what you want and it does it. The display is accurate on voltage and although the interface, buttons and functions appear the same, The old one doesn't stuff around like the new one does. You set it and that's what you get. Ran it for 6 Months and never had to change a setting but if I did to experiment, that's what I got. This thing is like it has a goddam mind of it's own. I looked up some Vids on the new one but they are pretty useless. Things like where which wire goes and what the settings are not how to set it or if the thing does what it's told. A couple exposing that it is NOT MPPT which I'll reference in my refund claim. Looks like the thing wont really be worth having anyway. The battery is certainly healthy enough far as I can tell. I picked up up from outside a factory unit where it was dumped by the garbage. Thought it was worth collecting to get a few bucks for scrap. Brought it home and tested it and seemed good. Put it on the charger and it came up fine. Been using it about 6 Months to start cars, mowers, the tractor and everything else and it seems a very strong battery. Came at the right time because finally the Mercedes/ Varta battery the brother in law gave me when it was 10 Years old finally fell over. It was almost 13 on the label date. NEVER had a battery go near that long and would have had trouble believing one could. This battery has Land/ Range rover stickers on it but no manufacturer but looks very similar to the Varta battery and I'd be pretty confident that's whom its made by. No date on this one however. I bought one of those battery testers that Clockman or whoever recently recommended in another thread for my father. Had to run him through using it but he got the hang and loves it. Went and tested the batteries on the scrap pile and found 2 that came up good. Paid for itself straight off. As he suspected his old load tester was not giving good readings. I'll order another one for myself. Went out yesterday and didn't get back till late so didn't get to look at anything but I'll go out now and have a play. It' is completely overcast and raining but the panel this is running off is flat so still should be good for a couple of amps and there are 2 other panels on the roof that run my inverter fan I can take the output off as well. Brought my original much loved controller down so I'll hook that up and see what it does for comparison to the new one. |
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| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 92 |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
This Charger is very Frustrating. It never seems to do the same thing twice or be consistant. Let me preface the rest of my gripes with a possible reason.... Been overcast all day here today and rain to Drizzle. For what ever reason, 3 panels I check I was pulling power from were all giving out way high open circuit Voltage. The 270 which is rated at 39 Voc was doing 54 and the 2 X 190W that should do 32 were about 50. I know about cloud edge effect but that was ridiculous. When I first checked I thought I must have had a Fritzed meter so I went and got another one and got the same readings! I noticed on the controller there is a sticker max DC input 50V so - maybe- that explains the erratic behaviors but.... Really was all over the shop and made no sense. I was reading high battery voltage on the LCD ut the multi meter sid it was pretty much where I put it. Then it would trad correctly.... Then the thing would shut down when I re set it and tried to turn it down lower than the voltage the battery was at. then it wouldn't.... AGGGHH! Didn't know if it was me loosing my mind or the thing is a total POS. So I hooked up my old one. One funny thing I noticed with it was I had to keep going back into the settings to get the float voltage to go down 1/10th at a time. I'd go in, get it into setting mode, Press the button and it would do down a 10th but no more. Go through the menu again, Back into float setting and it would go down another 10th but no more. Anyway, got it low to test it and sure enough, battery floated 2/10ths above the read out and stayed there. I dropped a load on the Battery and the thing supplied more amps till it overshot the 2/10Ths and did that every time. Beautiful. I then found another controller of the very cheap and nasty Non smiley face type that I have had trouble with before. Hooked it up, Set the thing and bugger me if it didn't work perfect as well! Set it low at 13V and the thing tracked at 13.1 every time even when I hooked in the 3 panels together. Would ramp up with the load till the battery topped off and sat there. It had a 50V max input sticker on it too. IF I bypassed the controller the battery voltage would shoot up to 15V+ quickly so it wasn't that there wasn't enough power to push the battery higher. The combined panels were doing about 4.5A short circuit. I am totally confused with this new controller. It has to be the same setup as the old one, the menus and setup is identical to the other but I still get the feeling there is something different in the programming. The old one has the B1, B2,3 setting as well and the menus and order as well as Lcd size and appearance is also identical. They function very different though. The fact the little crappy one worked fine has me stuffed. Working as it should where it never did before. I don't think I have any lower Voltage panels to try. I hooked the new and old controller off the same solar input with the old one connected first so the voltage was pulled down but that didn't seem to work either. I don't have a power supply for say 18 or 20V to hook it to to test the input voltage theory any more, I'll have to wait for a sunny day and see if the panel outputs go down as counter intuitive as that seems. I never seen panels over shoot by that much before. Seems they need Very little load across them to drag them down so I was wondering if a resistor across the panel leads may preload them enough to take down the runaway Voltage. I followed the instructions and connected the battery first and then the solar input but as soon as I did that the panel blanked down and the thing seemed to go into some protection mode. Surprise was the Little cheap arse controller. Worked perfectly and with no fuss. I am so confused. |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Those cheapo pwm controllers usually have an input over-voltage protection TVS diode, put too high an input voltage and the diode will short. When you connect the PV input, the controller will test the input with no load, then ramp up the load, perhaps the input voltage is just too high, place a 10w 24v bulb across the input, maybe enough load to bring the input down to work, or get a 10W 20V Zener diode and a suitable 0.5A load to chop off the high PV unloaded input voltage as will occur on first connection or going to float. You really need a 18V output panel or use an MPPT controller with the higher voltage panels, as its unlikely the cheap PWM controllers will use quality higher voltage components. Mike |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
The second Controller arrived today. Not what was advertised. I connected it up and the screen briefly came up, Flashed to the letter OL and then shut down. Exactly what you describe but the others haven't done that. This controller is exactly the same as one I had that is working so must have a different configuration again even though it's an Identical looking controller. Would a PWM controller accept a PWM regulated input? Watching the voltmeter on the solar or battery or the light connected to the controller output, The PWM rate seems Very slow. More like a Pulse than as I thought PWM being like 10-100 or more Hz. For whatever reason I cannot suggest, the panel output was much lower and on spec today. No Idea why, it was just as cloudy. Right on, 34 and 39V OC with the different panels. I played with the old controller and it was acting real funny. didn't shut down but wasn't feeding the battery either. It seemed to be indicating some shut down or overload. I couldn't figure why it had changed behaviour as I had the thing on household panels before and it worked perfectly.... Then I had my Duhhh/ senior moment realisation.... When I had it set up before, I had it on 2 batteries, 24V.  OOOPs! Probably why the other controller was acting up. They only tolerate so much voltage difference. All my tests so far I'll have to write off as a brain F art and meaningless. That one little Cheapo 10A controller was perfectly happy again today and held the battery at 13.2V which it showed on the LCD and was agreed with my the Multimeters. I thought that was the crap one but not so it seems. It's basic, doesn't have the readouts and ability of the others but it holds a battery where you set it just fine. I might drag the other battery down tomorrow and see how the new controller goes on the higher voltage. Pretty sure I have a panel up the back that the cover is off the diode/ lead connection so I might see what voltage 2 of the 3 segments put out and if the controllers will run a 12V Batt off that. If I had 2 panels I could make use of all the outputs and have 3 parallel pairs. If a 12V load were connected to one battery out of the series of 2, would that battery not recharge and float as normal? |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
>> Would a PWM controller accept a PWM regulated input? No, the PWM is 0-Full Volts signal, so will still be too high. >>If a 12V load were connected to one battery out of the series of 2, would that battery not recharge and float as normal? Series batteries, not a good idea to place individual loads between cells, all loads should be across the whole set, else they will seriously get out of balance. I had a think about a ultra simple maintenance charger, basically you need 5 voltage control values; 1: too low, 2: too high, 3: float, 4: Bulk, 5: float to bulk point. Then you need some time delays; 1: reach bulk then keep at that value for constant voltage charge X hours, move to float. 2: on float, if voltage drops below set level for > Y minutes then move to bulk. 3: voltage < low point for Z minutes then turn off load, sound alarm. 4: voltage > high point, turn off and sound alarm Can get more complex, especially if once a month a boost stir up the acid charge is required. It is a very tall ask to do the above with ad hoc timers and other cobbled together power supply modules etc, easiest solution is a simple CPU programmed in Basic like a 14 pin Picaxe and having it turn a mosfet on\off for charging and controlling relays. Or go and buy one; I used to build these using cmos logic gates etc, would never do it now, would take too long to get it going. Cheers Mike |
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