Iam obviously no expert,but everything I have read and believe me I studied every bit of information available stated that mppt Was the way to go. Theres a solar expert on the panel who is dead against mppt and fair enough ,I have hooked up a modern mpp to my set up and the difference between its performance and the PWM is amazing...
If you have a setup that is fully charged by midday then who cares, as it will be charged well anyway. If you need all the help to get charged by the end of the day then MPPT does provide some extra current but mostly when the batteries are down and the voltage is lower. It can use the higher panel voltage and convert it to extra battery current.
MPPT is also better when you have panels which are not regular 12V charging panels but put out a higher voltage. The MPPT again will convert a higher panel voltage into more current at the battery voltage. Some advantages there in using sometimes cheaper "house" panels.
However there are lots of fake MPPT regulator/controllers on the market. Because they are regarded as better, lots of cheap ones sold are labeled as MPPT but do not actually do that and have no parts inside for that function. If you want genuine MPPT then only buy a known good brand. Otherwise just buy a good brand PWM unit.
If you are upgrading then I hope you are upgrading the wiring too. The extra power gained by MPPT will not be realised if the resistance in the wires and connectors from the panels to the reg/controller wastes the power in losses.
Cheers Jaahn
PS all roof top solar charge inverters use MPPT as the industry standard. That will tell you something.
-- Edited by Jaahn on Tuesday 13th of March 2018 10:28:47 AM
You know all this discussion about different regulators is really moot in my opinion. At the end of the day all that is needed is a good charge on the battery and a regulator that can handle the current from the panels. Now I admit, I know little about this subject so I may be way out of line here, BUT thats all I see as being important.
I have also noticed the great price differential in regulators. I refer back to my first comment in this post.
Cheers
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Homebase is Murray Bridge Tourist Park (in a cabin). New Horse.. 2020 Ford Everest Titanium, Jayco swan for touring.
if you can't follow all this just ask me to explain it better, I don't mind a bit. I tend to get over technical some times but hopefully those that can't quite follow it will ask for more explanation, better than boring those who do understand some of it to the point where they don't read any more and maybe miss something that will expand their knowledge. Hopefully those that don't agree will be constructive in their criticism rather than attack for the sake of it
It really depends on the solar panels you plan to use. If they are all roughly the same capacity as far as watts, have a voltage significantly greater than the battery voltage you want to charge, then MPPT is the way to go. Ideally with all the panels connected in series, positive from one into negative from the next till you have only one negative at one end of the chain and one positive at the other end of the chain, and this total open circuit voltage is less than the max input voltage of the MPPT controller and that controller can output the total that can be extracted from this combination, then go that way and you will be happy with the outcome. If you can not make a solar panel single series string with an open circuit voltage less than the max voltage the MPPT controller can handle, then you need to connect all the panels in parallel. This means all the negatives together and all the positive together to add up to the max amps the controller can handle. So you need to look at both the input max voltage and the output max current to be sure you choose the right controller for your set up. No matter what anyone suggests, forget about trying to make 2 series strings to keep the voltage down and feed that into one controller, the end result is a poor functioning system. The same goes for multiple MPPT controllers or multiple charging devices working along with an MPPT controller unless they are the top of the line linkable type or you have a degree in cabling/ rewiring and programming to trick the individual controllers into becoming master slave controllers. Yes, it can be done, by the average punter ..... highly unlikely to get it to work without ending up paying for someone to sort it. The chances of the user understanding how it works so they can explain to the repair man when it stops working .......?????? Not the best situation to end up in when you are out on the road eh.
This leads to why I recommend avoiding MPPT controllers if you can. If you want to get the best out of a PWM you need to have panels with an open circuit voltage 10v or less than the battery voltage you want to charge. This should mean the Vmp (maximum voltage the panel creates its max amps) should be higher than the highest voltage you expect to need to charge the battery at most temperatures. An example, a flooded cell lead acid battery wants 14.8v to reach the end of the boost charge cycle. This will probably occur close to the middle of the day and this is when the sun will be getting the panels to their highest temperature. A panel with a Vmp marked on the back of 18v says that panel at 25*C in the perfect angle to the sun will develop the most current it can produce at 18v, but, there is absolutely no chance in Australia that a flat mounted panel on the roof of an RV at mid day in full sun will be still at 25*C. Real world Vmp for that panel marked as 18v Vmp would be around 15v to 16v, could be less, but this is still more than the 14.8v required so it will do the job just fine. PWM controllers don't care if the voltage from the panels is higher, it won't extract the max that maybe could be extracted under certain conditions, but all the panels connected to the controller will put out the best they can produce as long as the cabling is up to spec. It doesn't care if one panel is a 60w and the next is a 300w, the total will still be 360w. It doesn't care if one panel produces 10 amps at up to 30v and the one beside it produces only 5 amps at up to 15v, as long as the battery voltage is less than 15v the panel mix will feed in 15 amps, when the battery voltage gets above 15v then only the 30v panel will be able to put its full 10 amps in, but the 15v panel will still be adding something. This because the 15v panel can only produce its max output at up to 15v, after that, to meet the higher voltage required to push any current out, the 15v panel will not be able to operate at its best output but it will still put out something until the open circuit voltage is reached. No one would try to charge a 12v battery to 20v or more, or a 24v battery to 40v or more, this is the voltage that a 12v nom. or 24v nom. panel can still put out some current so they don't just stop because they reached their Vmp voltage. PWM controllers don't care if other PWM controllers or any sort of chargers are trying to charge the battery at the same time, they only care about the target voltage and they will do all they can to reach it and maintain it.
So, the choice is back I your court, only you know what you have now and what you want to achieve
T1 Terry
Edited my terrible typing and tried to make it easier to read by adding a few of the words I missed
-- Edited by T1 Terry on Tuesday 13th of March 2018 03:12:15 PM
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You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
I am changing from a 30a regulator to 40a. Should I go MPPT or PWM and why.
Edit. .. I have 3X150W panels on teepee roof.
2x110AH Batteries.
-- Edited by Dougwe on Tuesday 13th of March 2018 03:14:01 AM
I run a Morningstar 30 PWM & my 2 110ah batteries are always charged by mid morning. Also my panels work well in low light, hence why I paid a bit more to get them.
Cannot fault the Morningstar; it has been brilliant & I chose it because it was highly rated repeatedly. Tested, tried & true is usually a good act to follow.
Thankyou everyone for your input. As usual everyone has come to the rescue.
T1 Terry, thankyou for such a detailed answer, I understood most of it but now have a case of information overload I have been on this for days now and my mind is spinning around and around and not cos of drinks either.
I have now made a choice. I will go with a 40a PWM. Brand still up in the air at this stage. The MPPT's are way out of my price range, for now anyway. Us old Indians have to watch our penny's ya know.
Thanks heaps again everyone.
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if you can't follow all this just ask me to explain it better, I don't mind a bit. I tend to get over technical some times but hopefully those that can't quite follow it will ask for more explanation, better than boring those who do understand some of it to the point where they don't read any more and maybe miss something that will expand their knowledge. Hopefully those that don't agree will be constructive in their criticism rather than attack for the sake of it
It really depends on the solar panels you plan to use. If they are all roughly the same capacity as far as watts, have a voltage significantly greater than the battery voltage you want to charge, then MPPT is the way to go. Ideally with all the panels connected in series, positive from one into negative from the next till you have only one negative at one end of the chain and one positive at the other end of the chain, and this total open circuit voltage is less than the max input voltage of the MPPT controller and that controller can output the total that can be extracted from this combination, then go that way and you will be happy with the outcome. If you can not make a solar panel single series string with an open circuit voltage less than the max voltage the MPPT controller can handle, then you need to connect all the panels in parallel. This means all the negatives together and all the positive together to add up to the max amps the controller can handle. So you need to look at both the input max voltage and the output max current to be sure you choose the right controller for your set up. No matter what anyone suggests, forget about trying to make 2 series strings to keep the voltage down and feed that into one controller, the end result is a poor functioning system. The same goes for multiple MPPT controllers or multiple charging devices working along with an MPPT controller unless they are the top of the line linkable type or you have a degree in cabling/ rewiring and programming to trick the individual controllers into becoming master slave controllers. Yes, it can be done, by the average punter ..... highly unlikely to get it to work without ending up paying for someone to sort it. The chances of the user understanding how it works so they can explain to the repair man when it stops working .......?????? Not the best situation to end up in when you are out on the road eh.
This leads to why I recommend avoiding MPPT controllers if you can. If you want to get the best out of a PWM you need to have panels with an open circuit voltage 10v or less than the battery voltage you want to charge. This should mean the Vmp (maximum voltage the panel creates its max amps) should be higher than the highest voltage you expect to need to charge the battery at most temperatures. An example, a flooded cell lead acid battery wants 14.8v to reach the end of the boost charge cycle. This will probably occur close to the middle of the day and this is when the sun will be getting the panels to their highest temperature. A panel with a Vmp marked on the back of 18v says that panel at 25*C in the perfect angle to the sun will develop the most current it can produce at 18v, but, there is absolutely no chance in Australia that a flat mounted panel on the roof of an RV at mid day in full sun will be still at 25*C. Real world Vmp for that panel marked as 18v Vmp would be around 15v to 16v, could be less, but this is still more than the 14.8v required so it will do the job just fine. PWM controllers don't care if the voltage from the panels is higher, it won't extract the max that maybe could be extracted under certain conditions, but all the panels connected to the controller will put out the best they can produce as long as the cabling is up to spec. It doesn't care if one panel is a 60w and the next is a 300w, the total will still be 360w. It doesn't care if one panel produces 10 amps at up to 30v and the one beside it produces only 5 amps at up to 15v, as long as the battery voltage is less than 15v the panel mix will feed in 15 amps, when the battery voltage gets above 15v then only the 30v panel will be able to put its full 10 amps in, but the 15v panel will still be adding something. This because the 15v panel can only produce its max output at up to 15v, after that, to meet the higher voltage required to push any current out, the 15v panel will not be able to operate at its best output but it will still put out something until the open circuit voltage is reached. No one would try to charge a 12v battery to 20v or more, or a 24v battery to 40v or more, this is the voltage that a 12v nom. or 24v nom. panel can still put out some current so they don't just stop because they reached their Vmp voltage. PWM controllers don't care if other PWM controllers or any sort of chargers are trying to charge the battery at the same time, they only care about the target voltage and they will do all they can to reach it and maintain it.
So, the choice is back I your court, only you know what you have now and what you want to achieve
T1 Terry
Edited my terrible typing and tried to make it easier to read by adding a few of the words I missed
-- Edited by T1 Terry on Tuesday 13th of March 2018 03:12:15 PM
Doug, glad you were able to work out a way to go.
Terry, thanks for that explanation. It increased my knowledge and reinforced some of what I already thought I knew.
Cheers, John
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Where you happy with the brand you have ?? I have Morning Star 30Amp Have considered going larger ? But have no issues.. Over 30amp solar .. But never gets that efficient ..
Hi All,I have just purchased a Toyota LC Troopy V8D,its an EX Briz Hire,at this stage a good one. I would like to free camp/off the grid.
It has 2 bats front ,1 being the deep cycle.
So,thats the skeleton.
Cost is an issue,but so is running out of pwr for the fridge,which i plan to find a second 12V.
I have been looking at moreover poited to a REDARC BCDC1240D DUAL BATTERY ISOLATOR SYSTEM DC TO DC MPPT SOLAR AGM
and solar panel x1 on the firbre glass cannopy.
The numbers dollars being mentioned for the fit out is $3 to 4K.
Hi All,I have just purchased a Toyota LC Troopy V8D,its an EX Briz Hire,at this stage a good one. I would like to free camp/off the grid. It has 2 bats front ,1 being the deep cycle. So,thats the skeleton. Cost is an issue,but so is running out of pwr for the fridge,which i plan to find a second 12V. I have been looking at moreover poited to a REDARC BCDC1240D DUAL BATTERY ISOLATOR SYSTEM DC TO DC MPPT SOLAR AGM and solar panel x1 on the firbre glass cannopy. The numbers dollars being mentioned for the fit out is $3 to 4K. that will be supply and install. would welcome feedback folks Regards Paul
Hmmm Paul
If "cost is an issue" why would you look at such an expensive setup for another battery and solar panel for a fridge ?? You could possibly do that for less than a third of that if you do it yourself. Anyone could fit it for a couple of hours work too.
Yeah that's very over priced ,sorry to say, do some research and if you can't do it yourself find an autoelec that with experience that can
As an example , l bought 2 x 200w solar panels and abs mountings , cables etc for around $500 , bought a used redarc 1240 for $220 ....... even with a new redarc , the quote to get installed is was way over the top..... unless you were including the canopy??
Hi All,I have just purchased a Toyota LC Troopy V8D,its an EX Briz Hire,at this stage a good one. I would like to free camp/off the grid. It has 2 bats front ,1 being the deep cycle. So,thats the skeleton. Cost is an issue,but so is running out of pwr for the fridge,which i plan to find a second 12V. I have been looking at moreover poited to a REDARC BCDC1240D DUAL BATTERY ISOLATOR SYSTEM DC TO DC MPPT SOLAR AGM and solar panel x1 on the firbre glass cannopy.
The numbers dollars being mentioned for the fit out is $3 to 4K.
that will be supply and install.
would welcome feedback folks
Regards Paul
The catches with the Redarc all in one unit, it can only do one of the functions at a time and they are a similar price compared to 2 units that will both work at the same time. This idea is great for when you are driving or want to use the vehicle alternator as a 40 amp battery charger while the solar is still putting in at least a bit even when it's raining.
No idea just how much solar you have now, but you need around 400w if it's a normal size compressor type 12v fridge/freezer. Forget it if it's a 3 way fridge, you can't run those on battery power, only alternator power when driving.
Really need to know just what they plan to fit for that many $$, the upper price you quote could buy you a 200Ah lithium battery and 400w of solar, a quality solar regulator and DC to DC charger, a lithium control system and still have some $$ towards the install cost. You could even do a mixture of fixed panels and portable panels to get the solar you need if you don't have the roof area and still come in under that upper price you quoted.
T1 Terry
__________________
You can lead a head to knowledge but you can't make it think. One day I'll know it all, but till then, I'll keep learning.
Any links to any sites or products is not an endorsement by me or do I gain any financial reward for such links
Hi All,I have just purchased a Toyota LC Troopy V8D,its an EX Briz Hire,at this stage a good one. I would like to free camp/off the grid. It has 2 bats front ,1 being the deep cycle. So,thats the skeleton. Cost is an issue,but so is running out of pwr for the fridge,which i plan to find a second 12V. I have been looking at moreover poited to a REDARC BCDC1240D DUAL BATTERY ISOLATOR SYSTEM DC TO DC MPPT SOLAR AGM and solar panel x1 on the firbre glass cannopy.
The numbers dollars being mentioned for the fit out is $3 to 4K.
that will be supply and install.
would welcome feedback folks
Regards Paul
The catches with the Redarc all in one unit, it can only do one of the functions at a time and they are a similar price compared to 2 units that will both work at the same time. This idea is great for when you are driving or want to use the vehicle alternator as a 40 amp battery charger while the solar is still putting in at least a bit even when it's raining.
No idea just how much solar you have now, but you need around 400w if it's a normal size compressor type 12v fridge/freezer. Forget it if it's a 3 way fridge, you can't run those on battery power, only alternator power when driving.
Really need to know just what they plan to fit for that many $$, the upper price you quote could buy you a 200Ah lithium battery and 400w of solar, a quality solar regulator and DC to DC charger, a lithium control system and still have some $$ towards the install cost. You could even do a mixture of fixed panels and portable panels to get the solar you need if you don't have the roof area and still come in under that upper price you quoted.
T1 Terry
HI Paul
Suggest that you get another quote
T1 has made some good points especially about being able to use more than one charging source while travelling
I suggest you do a bit of research before you get conned into a dc /Dc charger ,that is assuming the Brix is a camper, /you will not be towing a van? So the Aux battery could be quite close to the main battery ,
Does that model have a smart alternator??
The money possibly wasted on the Dc/DC charger could be put to better use with more panels or battery capacity [ even lithiums for weight, AH capacity & space & T1 is your man for that]
-- Edited by oldtrack123 on Sunday 10th of June 2018 11:24:47 PM
Because they are regarded as better, lots of cheap ones sold are labeled as MPPT but do not actually do that and have no parts inside for that function. If you want genuine MPPT then only buy a known good brand. Otherwise just buy a good brand PWM unit.
