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Forum Index : Solar : MPPT controller choice
| Author | Message | ||||
| brucedownunder2 Guru  Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
I've narrowed my choice of solar controller down to two. They are the lower budget cost ones on the market-around $200 . most of the more expensive ones are upwards of $250. My reason ,apart from my Scottish background,lol, . I am playing around with this as a hobby and my power savings are not very important. I have the type of solar panels (second hand, almost free) but they are 50 volts open circuit and because I have a 48 volt battery bank ,then these panels each pair will be in series, So that adds to approx 90-100 volts open circuit . Only the MPPT 48 volt controllers I've seen will handle this(correct me if I'm wrong). So, has anybody out there got these controllers in use and what do you think of them?.  Blue box type controller on e-bay Red and black box type controller on e-bay Sorry for the pics, I cannot attach them for the life of me, so I've described them on e-bay (solar controllers 48 volt MPPT) if you are kind enough to bother looking at them for me, sorry. Bruce Bushboy |
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| ryanm Senior Member  Joined: 25/09/2015 Location: AustraliaPosts: 202 |
I'm curious what people have to say about this. I was thinking about getting a 60A makeskyblue controller. |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
 This is the "Blue" one . Bruce Bushboy |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1022 |
Ok, Thought it best to add a little bit here. My old MPPT Charge controller (3 of them) is a PCM60X getting too expensive now. Now I have been looking at these 2 Charge controllers with interest. The Blue one as above,Blue one CPE series controller. not sue if a Wifi dongle is available for it. Seems to be strong looking unit. And the red one eSmart3 series is third generation of eSmart mppt controller, Reading about the red MPPT CC it has a few things I was interested in, mostly the ability to setup customised battery setting's (all MPPT's should have this) it was not available when I wanted it years ago. And they the ability to connect to a computer via a Cable RS485, usb and Wifi dongle, SOLD SEPARATELY, unfortunately........would have been nice to have that in the box. What is this RS485 anyway? Cable and protocol? My old PCM60X has RS232. Now has anyone had any experience with the blue one or the red one? I believe its called esmart. They are both very similar units. My apologies if I'v Stuffed something up, just difficult comparing these. Gee that address was long. Cheers Aaron Off The Grid |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
RS485 is similar in function to RS232, but it has networking functions included so you can connect multiple units on a single bus cable. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I'm in the same boat, looking at a 48v MPPT to replace my home made solar controller. The MPPT's are so cheap now. I was looking at this one Link , same price range. I did read a review where it caught on fire. I think these cheap MPPT's are probably well designed, but not so well assembled, so it would pay to pull it apart, go over any potential dry joints, check the heat sinks are tight, and look for anything else suspect. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
The red one does have a battery temp compensation probe  The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I had one of those, it lasted two days, even Warpspeed couldn't fix it. The terminals are bloody tiny as well, you're right though, production is hit and miss. I ended up spending $600 or so with delivery for an 48v 80A fangpusen from Ali, it's been fantastic for prob 18 months now. (probably blow up tomorrow now I said that). Cheers Caveman Mark Off grid eastern Melb |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
I had a generation 2 version of the esmart on a 12 volt Lifepo4 setup, it was frustratingly hopeless in that its mppt PV algorithm would sometimes track down to the battery voltage value when sun went behind a cloud, and it would bloody well stay there all day outputting bugger all current even if the sun came out full for the remainder of the day. The only way to fix was turn it off and on again, Threw it in the bin, it was rubbish. Perhaps they have figured out how to write better software now in ver 3!!. Can only say good things about the PCM60X, have three and performed faultlessly for 3 years, wouldn't like to fix it though, that's why I'm designing my own. Cheers Mike Edited 2020-04-10 07:18 by Solar Mike |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I bought a 100v 30 amp Make Sky Blue controller as a backup to my own controller after seeing Marks dead unit. Mark was dead unlucky, his crapped out after only two days. There is a very small transformer and a switching power supply that generates multiple isolated dc supply voltages. One of the 12v supplies that supplies isolated gate drive power had failed. The transformer was dipped in transformer varnish and baked into a solid lump. Impossible to dismantle or repair its so tiny. So the whole thing was unrepairable. That transformer and the microcontroller are the only two very special parts that cannot be obtained or replaced with a substitute part. Just about anything else could be repaired somehow, unless the whole thing turns into a total charred mess. Anyhow, I bought one and it works fine, and is still working very well. The whole thing is built inside a very light gauge aluminum box, and even at low power the internal cooling fan was always going full blast. That is its only real limitation, at full grunt its going to get really hot and probably fail fairly soon because there is nowhere for the heat to go. So what I did was bolt the whole aluminium box onto a massive "Inspire" heatsink and hang it on the wall. The heatsink sucks the heat right out and now the fan never comes on, and it runs cool to the touch even when running flat out. After a bit of help in the heatsink department, these work very well, and I would certainly buy another if I ever get around to installing more panels.. Cheers, Tony. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I read about the same problem on another forum. seams to only happen with 12v. Here one is pulled apart and tested, found a few issues, including the 12v erratic operation. http://skagmo.com/page.php?p=documents%2F04_esmart3_review The heat sink on the Blue Shy is a good idea, I hate noisy fans. Just how important is temperature compensation? I'm running flooded lead acid, and my ambient temp ranges from -5 to 45c, so was looking for a MPPT with a temp probe. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Fairly important Glenn. At low temperatures the chemical activity slows and battery capacity falls. You can compensate for that somewhat, by raising the charging voltage as the temperature falls and win back some of that lost capacity. At higher than average temperatures, the battery will gas much more readily, so to minimise water loss, lowering the charging voltage as temperature increases will result in less topping up for flooded cells. Its the temperature of the electrolyte that matters for temperature compensation, not ambient temperature. Sit one of the middle cells (not an end cell) onto an aluminium or stainless steel plate, and epoxy the sensor into a hole drilled into the plate. Or you could glue the sensor onto the side of one cell, but that can get tricky. Cheers, Tony. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I figured as much. I'm currently using a PL20 driving a couple of SSR's to switch 3600 watts of solar. I've limited the charge current to 30 amps, and manually adjust the boost and absorb voltages a couple of volts up for winter and down again for summer. Be nice if this was automatic, thus the want for a MPPT with a temp sensor. The PL20 does have a temp sensor connection, and just noticed they are only $33 from Rainbow Power Company, last time I looked into it they were like $150! But I do have issues with the PL20, it tends to get upset with sudden battery voltage increases and spends hours hunting up and down trying to find the correct PWM. To fix it I have to manually switch out 1500 watts of solar, so the battery voltage rise times are slower and the PL20 can lock in. On a over cast day I switch the spare panels back in, its a nuisance. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
There should not be sudden voltage changes Glenn, as the temperature of the electrolyte is going to move around very slowly. Cheers, Tony. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Its when I have the full 3600 watts connected, and only 400Ah batteries. I've watched the PWM with a CRO to work out whats going on when it plays up. Typically the problem starts when the batteries are in absorb, so not drawing much current, and a cloud passes over. The PL20 ramps up the PMW to maintain the absorb voltage, all good. Then the sun comes back out and the battery voltage rises very quickly, so the PL20 ramps down the PWM to return to the absorb voltage, I can see it stepping down every half second or so. It seams if the drop in voltage isn't fast enough, the PL20 abandons the stepping down of the PWM and just switches the PWM off altogether. It then starts from scratch and steps up the PWM to get back to the absorb mode, but steps up very quickly, the voltage goes to high, so it steps down, not fast enough, and it switches off the PWM again, repeat. The whole process takes about 10 seconds. If I have some of the panels switched out, the rise in voltage is slower and the PL20 can keep up, no problem. Its a old PL20, maybe something they addressed in later versions. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
It sounds like a software algorithm problem, not a lot you can really do about it. In absorb, it "should" be set to regulate to a constant battery voltage, it won't be MPPT'ing because the panels will be very lightly loaded and up at a fairly high voltage. It should only go into the MPPT power climbing routine in bulk charge, where the charging current is at maximum, and we don't want to load the panels down below the power peak. Cheers, Tony. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
The PL20 is a PWM only charge controller, no MPPT. Another reason to get a MPPT, especially on those days when its overcast. But yes thats what I thought, its a software issue, and wouldn't really show up unless you have to much solar for your battery AH rating. To ideally charge my batteries at 30 amps I only need about 1500 watts, not 3600 watts, so the PWM algorithm is doing a lot of thinking to keep it down under full sun. It does work, but can get confused. Regards Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1022 |
I Haven't seen any current limiting settings on the eSmart, it might have it, don't know. I have used the current limit setting on one of the PCM60X because I have 2 of them (and a 50amp pwm) running on the same lithium battery bank, but mostly the battery bank is charged enough before we get that much sunlight. When using a lot of power I prefer all the power to come from the solar panels and not the battery bank, so left the others to run to there maximum current. Cheers Aaron Off The Grid |
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