Recommendations for quality 40 or 50 amp PWM Solar Controller
Farmhat said
09:10 PM Aug 2, 2018
G'day.
Looking for recommendations for a quality 40 or 50 amp PWM Solar Controller please.
Joe
Peter_n_Margaret said
11:27 AM Aug 3, 2018
I have a Plasmatronics PL60 (also available in 40A) which is probably as good as PWM controllers get.
It was purchased 13 years ago and good quality MPPT controllers would now be my first choice.
Cheers,
Peter
T1 Terry said
11:41 AM Aug 3, 2018
Hi Joe, as far as PWM controllers it's hard to go past the Plasmatronics range for quality, back up service and the fact they are Australian made. As far a solar capacity, I much prefer to build a system that is open ended, not restricted by the controllers capacity but rather have the capability of having capacity added on at very little additional cost and the Plasmatronics Dingo 20/20N fits the bill extremely well for this type of system. Forget about the name tag suggesting the controller is limited to 20 amps, it has the advanced technology to control remote solid state relays making it capable of handle many hundreds of amps without and solar actually ever passing through the controller itself. The added advantage there is the solar can be run in the most direct route to the batteries possible as this is where the solid state relays would be mounted.
A controller that requires the solar to actually pass through it requires the solar to be wired through the walls to where the controller is located and then on to the battery, often not an easy task where heavy cabling would be required to limit voltage drop. Using the remote control method means the controller itself can be mounted anywhere that suits and only requires light gauge cables run through the wall between the solid state relays and the Dingo 20/20N making installation a lot easier as well. Add the fact the Dingo 20/20N is fully programmable it means you can tune the charging regime to suit your needs and suit any battery chemistry used now or in the future, it even has a generator control feature for those who still use such things :lol: or if you have more solar charging than the battery requires at any time the Dingo 20/20N has separate contacts that can be programmed to use this excess solar electrical energy for tasks such as water heating or even powering an air con if you have enough solar.
Yes I sell them but only really in systems I build, I don't have any shares or financial interests in the Plasmatronics company, nor am I paid anything by them, I just like to promote a good product and an Aussie company doing a great job.
T1 Terry
Farmhat said
02:30 PM Aug 3, 2018
Some of the PWM controllers are Positive Ground Controllers. Can this be explained to me please?
How do these work with the solar/battery systems that are negative earth in most vans ? Or don't they?
Thanks, Joe.
Aus-Kiwi said
02:57 PM Aug 3, 2018
Terri . Never thought of that ? So itâs like a relay or contactor on a high load commercial component ? Iâve checked to upgrade mine from 30 amp . But really itâs doing ok . Thought of two systems . 2X2 X 2 batteries ? But REALLY 30A with 420 watt solar is fine . Just overcast it takes a little longer . A higher rated reg possibly wonât make any difference .,
Peter_n_Margaret said
03:24 PM Aug 3, 2018
Farmhat wrote:
Some of the PWM controllers are Positive Ground Controllers. Can this be explained to me please?
How do these work with the solar/battery systems that are negative earth in most vans ? Or don't they?
Thanks, Joe.
Joe, this is only important for measuring the loads connected directly to the controller.
If any of those loads use a chassis earth return, the controller won't measure them if it is a positive earth controller. If they have their own earth wire back to the controller (which is recommended best practice anyway) or they are connected via a shunt which is monitored by the controller it will be measured properly.
The PL range are all negative earth units except for the Dingos.
Since the direct load measuring capability of most controllers is quite low anyway, it is convenient (and accurate) to use a shunt monitored by the controller. I have my fridges and lights direct to the PL60. The inverter, and the vehicle alternator (input and output to the crank) are via a 200A shunt while pumps and other power users are via a 50A shunt. All loads and external inputs are measured.
Cheers,
Peter
Cheers,
Peter
Farmhat said
04:16 PM Aug 3, 2018
Thanks guys.
Peter, as I already have all loads go through a shunt, Victron BMV700, does that make the fact that if I used a new controller with a positive ground, irrelevant if I didn't put any load through that controller. IE, solar panels only to controller to battery? Just hook up controller the same as old controller that wasn't called a positive earth controller.
Joe
T1 Terry said
04:18 PM Aug 3, 2018
Aus-Kiwi wrote:
Terri . Never thought of that ? So itâs like a relay or contactor on a high load commercial component ? Iâve checked to upgrade mine from 30 amp . But really itâs doing ok . Thought of two systems . 2X2 X 2 batteries ? But REALLY 30A with 420 watt solar is fine . Just overcast it takes a little longer . A higher rated reg possibly wonât make any difference .,
The regulator only needs to be big enough to pass all the solar can supply through to the battery. Good quality ones can current limit so the system can be oversized to get the most when it's winter or overcast but not allow the full amount through when conditions are good.
By using the solid state relay remote control method the maximum limiting is removed along with any losses due to voltage drop along the cable run. An example, 30 amps with a 2v drop means 60w of the solar gets used up as heat in the wires, much more useful charging the batteries.
The reason for using quality solid state relays is their ability to switch on/off/on very quickly to stabilise battery voltage but not eat up part of what was supposed to go to the batteries as heat inside the solid state relay. The cheap crap ones on evil bay are so bad they would be better used for supplementary water heating, at least the heat generated would go to some use.
T1 Terry
T1 Terry said
04:23 PM Aug 3, 2018
Farmhat wrote:
Thanks guys.
Peter, as I already have all loads go through a shunt, Victron BMV700, does that make the fact that if I used a new controller with a positive ground, irrelevant if I didn't put any load through that controller. IE, solar panels only to controller to battery? Just hook up controller the same as old controller that wasn't called a positive earth controller.
Joe
Peter has sort of got it right, maybe just a bit twisted though. The PL series and the Dingo 40/40 switch the negative side of the solar and negative side of any loads connected to the load terminal, the Dingo 20/20N switches the positive from the solar and the positive on any loads connected to the load terminal.
Because all solar should be connected via a 2 cable run, both positive and negative, it makes no difference which switching method is used. It does make a different for any loads the controller has connected via the load terminal however so care must be used when connecting this section up if you do actually use it.
T1 Terry
Peter_n_Margaret said
05:00 PM Aug 3, 2018
Joe, as you already have a Victron BMV700, why do you propose a 40-50A PWM controller.
My suggestion would be to install 2 smaller, good quality, MPPT controllers which would give you a better result than PWM, plus some security in case of a controller failure some time in the future.
Solar panels need to be well matched to the battery charge voltage to give best results. This is how Terry gets good results. MPPT will allow panel voltages that are less than ideal to perform better.
Cheers,
Peter
Farmhat said
05:51 PM Aug 3, 2018
Peter_n_Margaret wrote:
Joe, as you already have a Victron BMV700, why do you propose a 40-50A PWM controller.
Cheers, Peter
Because currently in place is a 30A PWM with max panels for it. I would like to add more panels and that would be too many for the 30A necessitating a larger controller.
As far as I understand it, I can't see what bearing having the Victron BMV700 has on having a PWM or not. (But I am learning)
Joe
-- Edited by Farmhat on Friday 3rd of August 2018 05:52:20 PM
Peter_n_Margaret said
06:13 PM Aug 3, 2018
Farmhat wrote:
Peter_n_Margaret wrote:
Joe, as you already have a Victron BMV700, why do you propose a 40-50A PWM controller.
Because currently in place is a 30A PWM with max panels for it. I would like to add more panels and that would be too many for the 30A necessitating a larger controller.
As far as I understand it, I can't see what bearing having the Victron BMV700 has on having a PWM or not. (But I am learning)
Joe
Does not have a bearing on PWM Vs MPPT, but it does mean that a simple, high quality controller without sophisticated "reporting features" will do the job for you.
1. But why PWM?
2. Simply add a second small good quality controller to the new panels rather than chucking the existing one away. Two controllers will happily play together.
Cheers,
Peter
Farmhat said
06:18 PM Aug 3, 2018
Thanks Peter. I can see some sensibility in that.
Joe.
T1 Terry said
02:00 PM Aug 4, 2018
Peter_n_Margaret wrote:
Joe, as you already have a Victron BMV700, why do you propose a 40-50A PWM controller. My suggestion would be to install 2 smaller, good quality, MPPT controllers which would give you a better result than PWM, plus some security in case of a controller failure some time in the future. Solar panels need to be well matched to the battery charge voltage to give best results. This is how Terry gets good results. MPPT will allow panel voltages that are less than ideal to perform better.
Cheers, Peter
As all who read these forums know, I'm not a fan boy for MPPT controllers for smaller systems, those under 1500w. If you do want to go MPPT you need a controller that senses battery voltage via separate leads rather than the controller to battery leads so you can stop them fighting each other till one shuts down. These type of controllers are out there and I'm experimenting with 6 of them in parallel to control a 10kW solar array charging a 33kWh battery pack (1200Ah @ 24v nom.) Not one of the 6 will pump out the same as the others even though they all have identical age and open circuit arrays connected to them and all are mounted side by side on the same roof with no trees to cast shadows. Because there is plenty of solar and battery capacity it doesn't matter in this case but it would with a much smaller array and smaller battery pack. Just something to keep in mind before forking out your hard earned $$.
PWM controllers with separate battery sensing wires don't suffer this problem at all and as the cable run is so short on an RV (5mtrs or less) there is very little to be gained by connecting panels in series to boost voltage for the minimal gain of reduced voltage drop to the controller, far better to run suitable cable and connect them in parallel. PWM excels in this type of arrangement, it doesn't care if the panels are a mish-mash of sizes, age or open circuit voltages, all it does is connect the solar to the battery until the battery reaches the required voltage, then rapidly turns it on and off to maintain that voltage. You can even have panels with a rather low max power voltage combined with panels with a higher maximum power voltage and use this to your advantage. When the battery is low all the panels pump in all they can provide and the low maximum power voltage panels produce higher amps for a given watt capacity/ covered area while the higher maximum power voltage panels are needed for that last bit of charging or if you have flooded cells that require rather high equalising voltages. That higher amps output is a real bonus when the solar isn't the best so a better outcome from the solar area you have available.
T1 Terry
Ron-D said
09:25 AM Aug 5, 2018
T1 Terry wrote:
Peter_n_Margaret wrote:
Joe, as you already have a Victron BMV700, why do you propose a 40-50A PWM controller. My suggestion would be to install 2 smaller, good quality, MPPT controllers which would give you a better result than PWM, plus some security in case of a controller failure some time in the future. Solar panels need to be well matched to the battery charge voltage to give best results. This is how Terry gets good results. MPPT will allow panel voltages that are less than ideal to perform better.
Cheers, Peter
As all who read these forums know, I'm not a fan boy for MPPT controllers for smaller systems, those under 1500w. If you do want to go MPPT you need a controller that senses battery voltage via separate leads rather than the controller to battery leads so you can stop them fighting each other till one shuts down. These type of controllers are out there and I'm experimenting with 6 of them in parallel to control a 10kW solar array charging a 33kWh battery pack (1200Ah @ 24v nom.) Not one of the 6 will pump out the same as the others even though they all have identical age and open circuit arrays connected to them and all are mounted side by side on the same roof with no trees to cast shadows. Because there is plenty of solar and battery capacity it doesn't matter in this case but it would with a much smaller array and smaller battery pack. Just something to keep in mind before forking out your hard earned $$.
PWM controllers with separate battery sensing wires don't suffer this problem at all and as the cable run is so short on an RV (5mtrs or less) there is very little to be gained by connecting panels in series to boost voltage for the minimal gain of reduced voltage drop to the controller, far better to run suitable cable and connect them in parallel. PWM excels in this type of arrangement, it doesn't care if the panels are a mish-mash of sizes, age or open circuit voltages, all it does is connect the solar to the battery until the battery reaches the required voltage, then rapidly turns it on and off to maintain that voltage. You can even have panels with a rather low max power voltage combined with panels with a higher maximum power voltage and use this to your advantage. When the battery is low all the panels pump in all they can provide and the low maximum power voltage panels produce higher amps for a given watt capacity/ covered area while the higher maximum power voltage panels are needed for that last bit of charging or if you have flooded cells that require rather high equalising voltages. That higher amps output is a real bonus when the solar isn't the best so a better outcome from the solar area you have available.
T1 Terry
Its hard to argue with a techie when your not one ,but on the net the consensus just a bout everywhere if you care to look supports mppt,We only travel with a large portable panel and since changing to mppt from the pwm the difference has been remarkably better,my brother in law after seeing our results has done the same ,I cant understant why you are not with the main stream on this maybe the way you build things supports old tec....
Jaahn said
12:05 PM Aug 5, 2018
Peter_n_Margaret wrote:
Farmhat wrote:
Because currently in place is a 30A PWM with max panels for it. I would like to add more panels and that would be too many for the 30A necessitating a larger controller.
As far as I understand it, I can't see what bearing having the Victron BMV700 has on having a PWM or not. (But I am learning)
Joe
Does not have a bearing on PWM Vs MPPT, but it does mean that a simple, high quality controller without sophisticated "reporting features" will do the job for you.
1. But why PWM?
2. Simply add a second small good quality controller to the new panels rather than chucking the existing one away. Two controllers will happily play together.
Cheers, Peter
Hi
Generally I would not recommend that you put two controllers on in parallel. They can work OK and I have done so, but both PWM. But if you have a PWM and a MPPT together in parallel that could confuse the controllers. I would not do that and I can monitor things are happening OK.
So my recommendation would normally be to just get one controller that is big enough to do what you want and a good brand and fit it correctly with big wiring and it will be 'fit and forget ?'. Simpler !! You have the BMV700 so you can see if things are not working as you expect. Keep your old regulator for a backup.
I also suggest MPPT is a good idea. That is what I have used for the last two of my set ups. But I still use my old PWM regs for other things. They(two) still work well for casual charging with some old panels.
Jaahn
-- Edited by Jaahn on Sunday 5th of August 2018 12:11:00 PM
T1 Terry said
12:04 PM Aug 6, 2018
Ron-D wrote:
Its hard to argue with a techie when your not one ,but on the net the consensus just a bout everywhere if you care to look supports mppt,We only travel with a large portable panel and since changing to mppt from the pwm the difference has been remarkably better,my brother in law after seeing our results has done the same ,I cant understant why you are not with the main stream on this maybe the way you build things supports old tec....
Try arguing with Plasmatronics and Morningstar then, I guess you might consider them to be technically minded. Both will tell you openly that MPPT does not suit the Aust climate due to the much higher panel operating temps resulting in the need for much higher solar voltage input via mis-matched panel to battery voltage or multiple panels in series to create the higher voltage. If you consider that to be nonsense, look at the specs for the accepted NOCT (normal operating cell temperature) and tell me that matches Australian conditions, then look at the actual panel manufacturers charts that show the genuine MPV at actual panel temperatures, not ambient temperatures and see where you consider solar panel temps would be in the mid day sun.
Try reading reports for those with actual testing carried out in conditions experienced in Australia rather than Europe and the US, 40*C panel temp in the mid day is considered extreme in those climates. Also, avoid reading reports where the solar array is used for back to grid generation because that has absolutely nothing to do with battery charging, being technically minded you'd know that already
I've never changed my position because I use genuine figures when making any calculation and you can only get those by actually doing the tests in Australian conditions, Plasmatronics did the same thing and that is why they still don't manufacture MPPT controllers for battery charging use in Australia.
T1 Terry
Peter_n_Margaret said
01:44 PM Aug 6, 2018
Terry gets good results by choosing panels that closely match the 12V charge requirements. Under these conditions, PWM works erwell. But many panels are not so suitable for PWM, even those which are sold as nominal 12V ones. My 13 year old Kyoceras still provide a consistent 20V to the controller. The charge voltage is typically 14.8V. If I was wanting to use panels that were in excess of 18V, I would seriously consider MPPT.
EDIT... If you wish to use the very cheap household panels, you MUST use an MPPT controller to charge 12V or 24V batteries.
Cheers, Peter
-- Edited by Peter_n_Margaret on Monday 6th of August 2018 02:04:09 PM
Ron-D said
04:43 PM Aug 6, 2018
Seeing is believing Terry the change to the mppt has been a huge improvement over the Pwm ,you must defend your views with long scripts of reasoning, but I have a fairly new van with a good quality meter on the wall with all the charge stage indicators and this thing drives the battery into float amazingly especially under a lot of sun ,the pwm is not in this class,seing Is beleveiving, what would you have me do go back to pwm and a much slower charge rate , mate theres no chance of that happening
Aus-Kiwi said
11:48 PM Aug 6, 2018
I have more panels than required for my reg . That based on 12v . As calculation . Iâm about 5 amps over . But you NEVER get 100 % efficiency . I use microwave, two compressor fridges . On 30 Amp . Most days itâs on float made before mid day . A good sunny day by 10 oâclock . I have 3 batches of panels parallel wired . 3 X 120 AH batteries and 3 starter via VSR ., charge off alternator when driving also .
T1 Terry said
02:53 PM Aug 7, 2018
Peter_n_Margaret wrote:
Terry gets good results by choosing panels that closely match the 12V charge requirements. Under these conditions, PWM works erwell. But many panels are not so suitable for PWM, even those which are sold as nominal 12V ones. My 13 year old Kyoceras still provide a consistent 20V to the controller. The charge voltage is typically 14.8V. If I was wanting to use panels that were in excess of 18V, I would seriously consider MPPT.
EDIT... If you wish to use the very cheap household panels, you MUST use an MPPT controller to charge 12V or 24V batteries.
Cheers, Peter
-- Edited by Peter_n_Margaret on Monday 6th of August 2018 02:04:09 PM
Absolutely no argument about the need for an MPPT controller if you are using seriously mis matched panel voltage to battery voltage, otherwise you will only get the max amps specified on the back of the panel and not around 70% of its potential watt output. Keep in mind you can't get all the advertised solar in watts transformed into battery charging current, that just can't happen and simply doesn't happen, any one who tells you they get all the advertised watts from panel to battery is mis handling the truth rather severely.
If you expect much more than 70% of the solar advertised output converted into battery charging current in anything but freak conditions you will be seriously disappointed so don't be mislead by manufacturers techno-babble that sounds like you will get up to 98% efficiency. That actually means the best you will see if 98% of what comes in come out the other side, watt for watt, simply the nature of the beast, it needs something to power it.
Anyway, I believe the OP asked about PWM controllers so why has the MPPT camp hi-jacked the thread for their own preaching yet no one has said anything .....
T1 Terry
EDIT: Just something to think about Peter, that 20v you see is at zero amps, you can't use that figure to make any meaningful calculations, try the max amps you can get at what voltage by adding light bulbs in series at around mid day in full sun, this is the true Vmp of the working solar panel, now use that voltage in the equation so you really do see what you might gain by going to MPPT .....
-- Edited by T1 Terry on Tuesday 7th of August 2018 02:57:54 PM
Peter_n_Margaret said
03:55 PM Aug 7, 2018
The 20V is what the PL60 says the panel volts are while charging at 30A (or pretty much any time). If that is not the real panel volts, then someone should speak to Plasmatronics :)
Your 70% is pretty close. I typically get a tad under 30A (at a boost voltage of 14.8) from 600W of 13 year old panels. 30A X 14.8V = 444W = 74% of 600 (minus a "tad" for the bit under 30A).
Anyway, I believe the OP asked about PWM controllers so why has the MPPT camp hi-jacked the thread for their own preaching yet no one has said anything .....
I am a long time PWM user, so can hardly be accused of being in the MPPT "camp", but I do acknowledge that there are often better ways of doing things now than how I did it. Bit like those who need to bring Lithiums into AGM questions?
Cheers, Peter
T1 Terry said
05:02 PM Aug 7, 2018
Peter_n_Margaret wrote:
The 20V is what the PL60 says the panel volts are while charging at 30A (or pretty much any time). If that is not the real panel volts, then someone should speak to Plasmatronics :)
Your 70% is pretty close. I typically get a tad under 30A (at a boost voltage of 14.8) from 600W of 13 year old panels. 30A X 14.8V = 444W = 74% of 600 (minus a "tad" for the bit under 30A).
Anyway, I believe the OP asked about PWM controllers so why has the MPPT camp hi-jacked the thread for their own preaching yet no one has said anything .....
I am a long time PWM user, so can hardly be accused of being in the MPPT "camp", but I do acknowledge that there are often better ways of doing things now than how I did it. Bit like those who need to bring Lithiums into AGM questions?
Cheers, Peter
Are you measuring the solar in voltage at the PL60 while the battery is charging at the 30 amps with a multimeter or pressing the button to scroll through to solar panel voltage? Check the 2 different measurement methods and see if they both come up with 20vdc. I think you will find scrolling through the PL60 menu items will show that the solar voltage is open circuit voltage and not charging voltage
From the owners manual, page 16
6.6 SOLV (Solar Voltage Display)
This screen displays the solar panel voltage (open
circuit).
Note that the charge current to the battery is
turned off while the PL is displaying this screen,
but if the view is left on the SOLV screen, the
panels will be reconnected when the screen goes
to sleep (failsafe) after 16 minutes.
T1 Terry
Peter_n_Margaret said
05:09 PM Aug 7, 2018
..........panels will be reconnected when the screen goes to sleep (failsafe) after 16 minutes.
Well, there could be a big loss of power for the unwary?
Cheers,
Peter
T1 Terry said
05:18 PM Aug 7, 2018
Peter_n_Margaret wrote:
..........panels will be reconnected when the screen goes to sleep (failsafe) after 16 minutes.
Well, there could be a big loss of power for the unwary?
Cheers,
Peter
Well, at least you only lose 16 mins of charging so not too bad and a nice failsafe fall back built in by the Plasmatronics technical people. Hats off to them, they are easy to talk to if you ever need assistance and even the person on the reception phone can guide the caller through a lot of the stuff, even for where the "lock" function is when you get lost just which menu it's in temp does appear in more than one menu after all, well that's my excuse anyway :lol: even if it was me that locked it in the first place
G'day.
Looking for recommendations for a quality 40 or 50 amp PWM Solar Controller please.
Joe
It was purchased 13 years ago and good quality MPPT controllers would now be my first choice.
Cheers,
Peter
A controller that requires the solar to actually pass through it requires the solar to be wired through the walls to where the controller is located and then on to the battery, often not an easy task where heavy cabling would be required to limit voltage drop. Using the remote control method means the controller itself can be mounted anywhere that suits and only requires light gauge cables run through the wall between the solid state relays and the Dingo 20/20N making installation a lot easier as well. Add the fact the Dingo 20/20N is fully programmable it means you can tune the charging regime to suit your needs and suit any battery chemistry used now or in the future, it even has a generator control feature for those who still use such things
Yes I sell them but only really in systems I build, I don't have any shares or financial interests in the Plasmatronics company, nor am I paid anything by them, I just like to promote a good product and an Aussie company doing a great job.
T1 Terry
Some of the PWM controllers are Positive Ground Controllers. Can this be explained to me please?
How do these work with the solar/battery systems that are negative earth in most vans ? Or don't they?
Thanks, Joe.
Joe, this is only important for measuring the loads connected directly to the controller.
If any of those loads use a chassis earth return, the controller won't measure them if it is a positive earth controller. If they have their own earth wire back to the controller (which is recommended best practice anyway) or they are connected via a shunt which is monitored by the controller it will be measured properly.
The PL range are all negative earth units except for the Dingos.
Since the direct load measuring capability of most controllers is quite low anyway, it is convenient (and accurate) to use a shunt monitored by the controller. I have my fridges and lights direct to the PL60. The inverter, and the vehicle alternator (input and output to the crank) are via a 200A shunt while pumps and other power users are via a 50A shunt. All loads and external inputs are measured.
Cheers,
Peter
Cheers,
Peter
Thanks guys.
Peter, as I already have all loads go through a shunt, Victron BMV700, does that make the fact that if I used a new controller with a positive ground, irrelevant if I didn't put any load through that controller. IE, solar panels only to controller to battery? Just hook up controller the same as old controller that wasn't called a positive earth controller.
Joe
The regulator only needs to be big enough to pass all the solar can supply through to the battery. Good quality ones can current limit so the system can be oversized to get the most when it's winter or overcast but not allow the full amount through when conditions are good.
By using the solid state relay remote control method the maximum limiting is removed along with any losses due to voltage drop along the cable run. An example, 30 amps with a 2v drop means 60w of the solar gets used up as heat in the wires, much more useful charging the batteries.
The reason for using quality solid state relays is their ability to switch on/off/on very quickly to stabilise battery voltage but not eat up part of what was supposed to go to the batteries as heat inside the solid state relay. The cheap crap ones on evil bay are so bad they would be better used for supplementary water heating, at least the heat generated would go to some use.
T1 Terry
Peter has sort of got it right, maybe just a bit twisted though. The PL series and the Dingo 40/40 switch the negative side of the solar and negative side of any loads connected to the load terminal, the Dingo 20/20N switches the positive from the solar and the positive on any loads connected to the load terminal.
Because all solar should be connected via a 2 cable run, both positive and negative, it makes no difference which switching method is used. It does make a different for any loads the controller has connected via the load terminal however so care must be used when connecting this section up if you do actually use it.
T1 Terry
My suggestion would be to install 2 smaller, good quality, MPPT controllers which would give you a better result than PWM, plus some security in case of a controller failure some time in the future.
Solar panels need to be well matched to the battery charge voltage to give best results. This is how Terry gets good results. MPPT will allow panel voltages that are less than ideal to perform better.
Cheers,
Peter
Because currently in place is a 30A PWM with max panels for it. I would like to add more panels and that would be too many for the 30A necessitating a larger controller.
As far as I understand it, I can't see what bearing having the Victron BMV700 has on having a PWM or not. (But I am learning
)
Joe
-- Edited by Farmhat on Friday 3rd of August 2018 05:52:20 PM
Does not have a bearing on PWM Vs MPPT, but it does mean that a simple, high quality controller without sophisticated "reporting features" will do the job for you.
1. But why PWM?
2. Simply add a second small good quality controller to the new panels rather than chucking the existing one away. Two controllers will happily play together.
Cheers,
Peter
Thanks Peter. I can see some sensibility in that.
Joe.
As all who read these forums know, I'm not a fan boy for MPPT controllers for smaller systems, those under 1500w. If you do want to go MPPT you need a controller that senses battery voltage via separate leads rather than the controller to battery leads so you can stop them fighting each other till one shuts down. These type of controllers are out there and I'm experimenting with 6 of them in parallel to control a 10kW solar array charging a 33kWh battery pack (1200Ah @ 24v nom.) Not one of the 6 will pump out the same as the others even though they all have identical age and open circuit arrays connected to them and all are mounted side by side on the same roof with no trees to cast shadows. Because there is plenty of solar and battery capacity it doesn't matter in this case but it would with a much smaller array and smaller battery pack. Just something to keep in mind before forking out your hard earned $$.
PWM controllers with separate battery sensing wires don't suffer this problem at all and as the cable run is so short on an RV (5mtrs or less) there is very little to be gained by connecting panels in series to boost voltage for the minimal gain of reduced voltage drop to the controller, far better to run suitable cable and connect them in parallel. PWM excels in this type of arrangement, it doesn't care if the panels are a mish-mash of sizes, age or open circuit voltages, all it does is connect the solar to the battery until the battery reaches the required voltage, then rapidly turns it on and off to maintain that voltage. You can even have panels with a rather low max power voltage combined with panels with a higher maximum power voltage and use this to your advantage. When the battery is low all the panels pump in all they can provide and the low maximum power voltage panels produce higher amps for a given watt capacity/ covered area while the higher maximum power voltage panels are needed for that last bit of charging or if you have flooded cells that require rather high equalising voltages. That higher amps output is a real bonus when the solar isn't the best so a better outcome from the solar area you have available.
T1 Terry
Its hard to argue with a techie when your not one ,but on the net the consensus just a bout everywhere if you care to look supports mppt,We only travel with a large portable panel and since changing to mppt from the pwm the difference has been remarkably better,my brother in law after seeing our results has done the same ,I cant understant why you are not with the main stream on this maybe the way you build things supports old tec....
Hi
Generally I would not recommend that you put two controllers on in parallel. They can work OK and I have done so, but both PWM. But if you have a PWM and a MPPT together in parallel that could confuse the controllers. I would not do that and I can monitor things are happening OK.
So my recommendation would normally be to just get one controller that is big enough to do what you want and a good brand and fit it correctly with big wiring and it will be 'fit and forget ?'. Simpler !! You have the BMV700 so you can see if things are not working as you expect. Keep your old regulator for a backup.
I also suggest MPPT is a good idea. That is what I have used for the last two of my set ups. But I still use my old PWM regs for other things. They(two) still work well for casual charging with some old panels.
Jaahn
-- Edited by Jaahn on Sunday 5th of August 2018 12:11:00 PM
Try arguing with Plasmatronics and Morningstar then, I guess you might consider them to be technically minded. Both will tell you openly that MPPT does not suit the Aust climate due to the much higher panel operating temps resulting in the need for much higher solar voltage input via mis-matched panel to battery voltage or multiple panels in series to create the higher voltage. If you consider that to be nonsense, look at the specs for the accepted NOCT (normal operating cell temperature) and tell me that matches Australian conditions, then look at the actual panel manufacturers charts that show the genuine MPV at actual panel temperatures, not ambient temperatures and see where you consider solar panel temps would be in the mid day sun.
Try reading reports for those with actual testing carried out in conditions experienced in Australia rather than Europe and the US, 40*C panel temp in the mid day is considered extreme in those climates. Also, avoid reading reports where the solar array is used for back to grid generation because that has absolutely nothing to do with battery charging, being technically minded you'd know that already
I've never changed my position because I use genuine figures when making any calculation and you can only get those by actually doing the tests in Australian conditions, Plasmatronics did the same thing and that is why they still don't manufacture MPPT controllers for battery charging use in Australia.
T1 Terry
Terry gets good results by choosing panels that closely match the 12V charge requirements. Under these conditions, PWM works erwell.
But many panels are not so suitable for PWM, even those which are sold as nominal 12V ones.
My 13 year old Kyoceras still provide a consistent 20V to the controller. The charge voltage is typically 14.8V.
If I was wanting to use panels that were in excess of 18V, I would seriously consider MPPT.
EDIT... If you wish to use the very cheap household panels, you MUST use an MPPT controller to charge 12V or 24V batteries.
Cheers,
Peter
-- Edited by Peter_n_Margaret on Monday 6th of August 2018 02:04:09 PM
Seeing is believing Terry the change to the mppt has been a huge improvement over the Pwm ,you must defend your views with long scripts of reasoning, but I have a fairly new van with a good quality meter on the wall with all the charge stage indicators and this thing drives the battery into float amazingly especially under a lot of sun ,the pwm is not in this class,seing Is beleveiving, what would you have me do go back to pwm and a much slower charge rate , mate theres no chance of that happening
Absolutely no argument about the need for an MPPT controller if you are using seriously mis matched panel voltage to battery voltage, otherwise you will only get the max amps specified on the back of the panel and not around 70% of its potential watt output. Keep in mind you can't get all the advertised solar in watts transformed into battery charging current, that just can't happen and simply doesn't happen, any one who tells you they get all the advertised watts from panel to battery is mis handling the truth rather severely.
If you expect much more than 70% of the solar advertised output converted into battery charging current in anything but freak conditions you will be seriously disappointed so don't be mislead by manufacturers techno-babble that sounds like you will get up to 98% efficiency. That actually means the best you will see if 98% of what comes in come out the other side, watt for watt, simply the nature of the beast, it needs something to power it.
Anyway, I believe the OP asked about PWM controllers so why has the MPPT camp hi-jacked the thread for their own preaching yet no one has said anything .....
T1 Terry
EDIT: Just something to think about Peter, that 20v you see is at zero amps, you can't use that figure to make any meaningful calculations, try the max amps you can get at what voltage by adding light bulbs in series at around mid day in full sun, this is the true Vmp of the working solar panel, now use that voltage in the equation so you really do see what you might gain by going to MPPT .....
-- Edited by T1 Terry on Tuesday 7th of August 2018 02:57:54 PM
The 20V is what the PL60 says the panel volts are while charging at 30A (or pretty much any time).
If that is not the real panel volts, then someone should speak to Plasmatronics :)
Your 70% is pretty close.
I typically get a tad under 30A (at a boost voltage of 14.8) from 600W of 13 year old panels. 30A X 14.8V = 444W = 74% of 600 (minus a "tad" for the bit under 30A).
I am a long time PWM user, so can hardly be accused of being in the MPPT "camp", but I do acknowledge that there are often better ways of doing things now than how I did it. Bit like those who need to bring Lithiums into AGM questions?
Cheers,
Peter
Are you measuring the solar in voltage at the PL60 while the battery is charging at the 30 amps with a multimeter or pressing the button to scroll through to solar panel voltage? Check the 2 different measurement methods and see if they both come up with 20vdc. I think you will find scrolling through the PL60 menu items will show that the solar voltage is open circuit voltage and not charging voltage
From the owners manual, page 16
6.6 SOLV (Solar Voltage Display)
This screen displays the solar panel voltage (open
circuit).
Note that the charge current to the battery is
turned off while the PL is displaying this screen,
but if the view is left on the SOLV screen, the
panels will be reconnected when the screen goes
to sleep (failsafe) after 16 minutes.
T1 Terry
Well, there could be a big loss of power for the unwary?
Cheers,
Peter
Well, at least you only lose 16 mins of charging so not too bad and a nice failsafe fall back built in by the Plasmatronics technical people. Hats off to them, they are easy to talk to if you ever need assistance and even the person on the reception phone can guide the caller through a lot of the stuff, even for where the "lock" function is when you get lost just which menu it's in
temp does appear in more than one menu after all, well that's my excuse anyway :lol: even if it was me that locked it in the first place 
T1 Terry