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Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 04:57am 13 May 2022
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I have seen some articles here about home made MPPT controllers, they look very complex to me. I need to replace my damaged controllers and want to control the following. 24 volt battery bank 90 volts DC panel voltage 60 amps or above current from the controllers to the battery.
Many years ago I saw some stuff that was being done by Oztules on home made regulators. Just wondering if anyone here knows of a simple circuit to use for this purpose and where I can get circuit boards made in Australia. I have a board design for a project that Oz did but it is only a .png or pdf file. Do any manufacturers work from pdf files? Hope someone knows Thanks Pete
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 05:09am 13 May 2022
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Hi Pete, The PCB manufacturers usually require Gerber files.
My home made MPPT controller to Poida's design works very well with a 40A current limit. At 60A you start looking at expensive 2oz PCB's.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 10:25pm 17 May 2022
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HI Murphy, thanks for the reply. I have been working my way through the giant article on Poida's regulator. There seem to be lots of revisions, is there a page where the end design is shown. I would like to have a go at building a couple myself. The victron regulators I had are dead and the company decided to pot them in epoxy which makes them non repairable. The agents in Tassie said that their tests showed that the internal fuse is blown, this according to them means the battery was reversed at some stage. Total gobblegook the agent said normally there are fuses on the input side of them when they are installed and they should have blown first. Well mine had circuit breakers and they did not trip. Potting things to make them non repairable is a rotten practice in my mind. So if there is a final design, which I am guessing is the one you made , I would like to have a go. Thanks Pete
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1432
Posted: 01:27pm 20 May 2022
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I have had good results with 2 oz copper boards. The firmware is mature now. My home system uses 2 of the mppt regulators. I have tested them at 45 Amps for hours on end with no problems. Peak power testing at 3kW into a nominal 1 Ohm load just makes some pcb traces warm.
efficiency testing always showed they were about 95% +/3% but likely 92% near the high power levels. It's hard to get even 5% accurate using cheap clamp meters etc. All I know is they don't get very warm at all so they are efficient.
my last post at the mppt thread was a victory lap showing 5MW.hr total energy from the 2 mppt controllers. I am very proud of this.
building these is easy. In your situation I would not build one for the 60A load. I would build two, assuming you can split the input into two similar sized power inputs. Maybe you can not. Nicks has run his at those sort of power levels.
I can not give you the Gerber files for PCB manufacture since they are not mine. They are Nicks's. I am sure he will be OK if I send you them after I ask him (or you ask him.) If I do not ask him first then that would be rude
Nicks's board is just as good as Wiseguy's board in my opinion when looking at efficiency and reliability.
so the steps forward are: get a few PCB made using Nicks's design buy a few parts. make a couple of chokes. Get some good 100V 470 or 1,000uF caps you don't need as many as the PCB has footprints for. Get a handful of Arduino Nanos 2x 12V-12V isolated dc converter modules 2x TLP250 etc. see the BOM
Building them is easy. programming the nano is simple configuring the mppt/nano is easy and must be done (your battery needs your charge regime)
I am happy to help you (and anyone else) with making their mppt controllers.wronger than a phone book full of wrong phone numbers
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 10:07pm 20 May 2022
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Thanks for the reply poida. Sounds good. One thing is that my system is 24 volt, is it just a matter of changing stuff in the nano program or are there other considerations? I have 4 different arrays at the moment so would make at least 4 of them. I will pm Nick and ask him for the gerbers. Thanks Pete
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 07:03am 21 May 2022
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Pete, sad to hear that you too are a victim of those dreadful Victron solar regulators.
If you have trouble with obtaining nick's Gerber files you can try mine, they are OK for a 1oz copper board & 40Amps continuous. They also fit a cut short Aerosharp heat sink. Before you start, check if you can buy the Allegro current sensors, a builder here could not find a supplier and is designing his own which will fit my PCB. Poida was keen to re cycle the sensors from the Aerosharp but I found them too fiddly so they will not fit on my PCB. I used a small DC/DC module to get the 5V for the Nano. I used re cycled capacitors from scrapped inverters. The choke *is* important, if you get it wrong it will be noisy and get hot. Check my MPPT build for some ideas.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 06:00am 22 May 2022
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Just wondering, I have box of 1000 uf 63 volt caps, would it be fine to series them up. That way i figure I would have 500uf 126 volt caps. As I already have them, it would be great to use them. I like the idea of through hole components so the mind is still ticking over. Pete
Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1162
Posted: 11:31am 23 May 2022
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Only if they have identical capacitance, most have a +-20% spec, so the smallest cap in the series string will have a higher voltage developed across it; so may exceed its rating.
Cheers Mike
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 03:37pm 23 May 2022
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The other thing to consider is the extra space required on the PCB. Since there are quite a few big capacitors there already I think doubling their number is not a good idea. All the capacitors I used were recycled high voltage types from junked inverters. You need to modify your soldering iron tip so that you can heat both pins at once, then their removal is quick and easy.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 10:02pm 23 May 2022
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Thanks for the advice Murphy and Mike. I do have a GTI inverter in the shed that I can look at for parts. I also have one of those old soldering irons that are basically a big lump of copper on a handle that I heat up with a gas torch. It is fantastic for removing and replacing parts on very big tracks. Pete
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 06:53am 24 May 2022
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Hello again, so I would like to get hold of some of Murpy's friends boards. Can you tell me where to get the gerbers and where a good place to get a few made is. I will work on getting all the parts first, then do as poida suggested and build one to get a handle on how they are set up. Then my plan is to change my regulators over from commercial ones to the nano ones. That will mean me making 5 of them in all. Thanks for your help folks Pete
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 10:19am 24 May 2022
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Hi Pete, With the international electronic parts shortage, the hardest part to find would be the two Allegro current sensors. My boards were made by JLPCB in Hong Kong, they come in multiple's of 5 or 10 and were not expensive. The shipping is the killer if you want the board in a hurry, if you are prepared to wait 4 weeks its reasonable.
Send me a PM with your email address and I can sent you the schematic so you can decide if you like it and organise parts. The Gerber files can also be sent via email, if you have never ordered boards before we need to discuss that procedure.
If you want just one board to start with, I may have a spare.
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 10:34pm 24 May 2022
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Thanks Mr Murphy's friend will send a pm. I found the Allegro sensors at Element 14 (previously Farnell) they are around $19 each but drop to less if you but a few more. Also Digikey australia has them listed as being in stock as well. Thanks Pete
Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 530
Posted: 10:43pm 24 May 2022
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Hello Murpy's friend, something strange happens when I try to pm you. The message appears but I cannot get the software on the site to transfer your username into the address box. Murphy's friend shows up in the member search but clicking on it does nothing. The address still stays blank. Pete
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 09:03am 25 May 2022
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Pete, that PM has me stumped too, the old one worked a lot better. Anyway, I sent you a PM so check your inbox.
I'm looking with interest the MPPT subject, due to in this moment I am in the same situation that my MPPT can't not repaired and I taken the decision to build one, but with your agreement I am happy to have the final version of gerber files and arduino soft.
Thank you very much for your help.
nickskethisniks Guru Joined: 17/10/2017 Location: BelgiumPosts: 462
Posted: 11:59am 04 Jun 2022
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You can use other current (hall)sensors too. You just need a 5V compatible sensor. You can callibrate them with the software, I think Hall has compatible sensors.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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