Solar The Solar Panel Thread

Boots in Action

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No need to apologise @Boots in Action, this is a learning and sharing forum and we are all doing that with these posts.

I’m still a litttle confused as to why you would connect the load terminals on the powertech controller to the setec battery output terminals.

If I understand correctly, the batter output terminal would be to supply power from the battery via the setec to Power 12 devices.

The load terminals on the controller, be it Topray, Powertech or even my Eperver are to supply 12v to supply power to devices but coming from the door directly.

If you connect the load and battery output terminals together I suspect you’ll see smoke.
Hi again @Bellbirdweb , thanks for your kind words of encouragement to this "upstart tech head". Sometimes I need pulling into line!!!
The matter about connecting the load terminals to the solar controller is I think a very important one. As you are no doubt aware, most of the better controllers incl your Epever and my LD MPPT controller have "user adjustable" settings for LVD and LVR (amongst others) to allow us to set our own levels of protection for our very important and expensive AGM or GEL battery. Unfortunately, a lot of the cheaper solar controllers have a fixed setting for both, set at factory, which may or may not be suitable - most are not!! And to make matters worse, were you aware that on a Setec (mine at least), has a fixed setting of 10.00V plus/minus 0.2V for LVD?? (refer specs manual) At that voltage, the battery would be "stuffed" and probably beyond proper recovery. It certainly did NOT protect my Daughter's battery!!! And I do not want my setting THAT LOW. (refer SOC chart).
The advantage of connecting the LOAD wiring to the solar controller, means that the solar controller senses the low voltage setting BEFORE the SETEC does, and disconnects the load at whatever setting is on the solar controller (fixed or manually set). I note that on the Topray, the LVD is 10.7v plus/minus 0.4 , which to my mind is far too low, but better than depending on the Setec at 10.00 volts!! All or most of the members on this forum are, or should be aware of the need to keep battery charge state above 50% if possible and definitely try to use no more than 70% if full recovery of battery is to be achieved. I have included a SOC table once again for AGM batteries.
But I digress. If the load wiring is NOT connected through the solar controller, the LVD defaults to the Setec at 10.00 volts - far too late!!! If the load wires are connected through the solar controller ( load connection), that setting takes precedence much, much earlier. For this to operate, those wires must be connected, otherwise the solar controller is unable to sense the low voltage and operate disconnection of load/s.

I have the LVD on my MPPT solar controller set at 11.80 volts (30% remaining capacity) and LVR at 12.2 volts (60% capacity available). The LVD setting is just before things are dropping into oblivion and the "no go area" to protect my battery. If the voltage was to drop into this zone because of very heavy short term demand with load and disconnection occurred, I can always reduce load/s, and the reconnection will be made automatically as voltage recovers, even without charging.

I have just finished working on Daughter's van and NO SMOKE!! The line +ve comes off the Battery Output in the Setec distribution panel at fuse panel, and goes to the battery disconnect switch. I disconnected the wire from the other side of this battery switch and ran a direct line to the Pos Load connection on solar controller. The wire from the Neg connector on the controller returns to join the wire disconnected from back of battery switch, to place the load/s in series with the controller. The Neg line (return after handling the various loads) remains connected to the battery -ve to complete the circuit.
Hope you can understand this okay. With a Drifter panel, all this may be of little use or interest, but perhaps there are others who may find this valuable in avoiding expensive damage to battery. I look forward to you comments. Cheers.
 

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Boots in Action

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Unfortunately, Jayco never connects those Solar controller load output terminals to anything because they all go to Setec. Also, controller only has max 30A load. I'm pretty sure no other caravan manufacturer uses these units to give the full load status. You'll have to buy a unit and fit it at the battery terminals to get the full consumption.
Hi @Eddii , have a read of my latest posting and have a think about your Setec letting battery voltage drop to 10.00 plus/minus 0.2 volt before alarm or disconnecting load. There are reasons for having LVD on solar panels, but most of the cheaper ones are too low eg Topray is 10.7 plus/minus 0.4 v. Tread your own path.
 

Boots in Action

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Great explanation @mikerezny :) I noticed that if you have an external solar panels plugged directly to the house batteries and solar produced from house controller they seem to be “fighting” each other. I have 150w/Topray PWM in house setup plus 200w/xxxPWM controller folding panels charging 2 x 100ah ritar gel batteries and the don’t seem to be efficiently working together, they both jack up the voltage which puts both controllers in float mode and slows the chargers down. I’ll be replacing the Topray today with Victron energy smart controller MPPT and move that controller to the folding panels so I can really see much more status via mobile app and also see how much the folding panels are charging as well . Then I’ll do more experiments like introducing the folding panels to see how much the house controller pulls back.
Hi again @Eddii , this situation has been covered in depth some time before. Perhaps you may have missed it. Go back on this post for Solar and have a read of post # 928. Whilst there has been some disagreement by some members, it still remains a good topic to discuss. @mikerezny has said before that to keep it simple and get the max out of what you have, purchase a good MPPT controller (my LD MPPT controller cost less than $150.00, does not need a separate panel or computer as ALL settings can be made on controller). Then, instead of having two controllers "fighting" each other, connect another line from outside of van to same solar input terminals as roof solar to MPPT controller (house control) with Anderson plug on outside. Bypass the controllers on back of portable panels, there is a posting on this too) and connect the portable panels by cable with Anderson plug to external plug on van. The solar on the roof and any portable panels deployed (if any) are then connected in parallel and controlled by the very efficient MPPT controller. In bypassing the controllers on back of portable panels, you do not lose the ability to use them is the normal way to charge car battery etc as they still have their own controller available.
 

Boots in Action

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Hi Boots
Just fitting a TopRaySolar and was wondering what needs to go into the LOAD side. Do I just run another twin from the battery to the "Load" terminals and leave the existing wires/circuits coming straight from the battery?
Hello @Glen Bundesen , no doubt you have been following the latest on the TOPRAY controller, its virtues and faults. I have just completed another post on why I think (my OWN ideas!!) that the load wires should be connected to the solar controller. Have a read and make your own decisions. Note that even if connected to the load terminals, Low Voltage Disconnect for the TopRay is a very low 10.7 volts (give or take 0.4 volt) and if you have a Setec distribution control, its fixed LVD setting is an abysmal 10.00 volts plus or minus 0.2 volts. Crazy - far too low to protect battery from permanent damage - even a great AGM! Tread your own path. But better to have a higher LVD than a lower one. I am doing a wiring diagram for another member to help with you connections if needed. We do not want any smoke and flame, do we??
 
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Boots in Action

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Interesting fine there @Boots in Action, I shall check my Setec then. Thanks. I’m a bit confused with your wiring though, can you please put out a rough diagram if possible. I’m not quite sure how it works in series.
Yes @Eddii , a bit disturbing when one does the research. Even I did not know until Daughter's van battery failed and did not sound any alarm until power disconnected with only two LED lights on and a small DVD player - less than 2 amp draw total!! But then they were only checking voltage during the day with NO Load and the voltage on their TopRay was showing 12.56 volts. Put a light load on it, and it dropped to below 11.6 volts in seconds and continued to drop to 10.6 volts and still had not disconnected!!! I will get rough drawing to you asap. With a good MPPT controller, YOU can set the levels YOU want, as mostly they are "user adjustable".
 

mikerezny

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Hi @Boots in Action,
I am unsure about connecting the van load to the load terminals of a solar controller.
My main question is that if this is done then how does one charge the battery from 240V via the Setec unit? How does one charge the battery from the tug via the AUX input (assuming one does not want to go down the path of a DC-DC charger)?

My next question concerns the solar controllers ability to handle the total current drawn from the battery to supply the van.
Contrived example: if one buys a 10A solar controller to assist in keeping the battery charged, but the van load occasionally requires 20A to say power an inverter for a few minutes. It seems that in choosing a solar controller, one would have to take into account the solar panel size as well as the maximum anticipated load.

I understand the importance of having an adjustable LVD, but there is also a more frequent possibility that inverters of 1000W or more will be wired directly to the battery via very heavy gauge wire and there is no possibility of expecting the Setec or a solar controller to protect the battery in this case.

Whilst LVD is a great backup in case something is inadvertently switched on, in my opinion, it should not be used instead of gaining a thorough understanding of the 12V systems installed in vans which includes knowing SOC every morning and ensuring, whenever possible, that full recovery is achieved by the end of each day. Once that is achieved, it should be most unlikely that LVD will ever be activated and whether it is set at 10V or whatever, will not be all that important.

With the quite complex 12V systems installed in tugs and vans and the myriad of possible ways of connecting the various components together to suit the wide-ranging requirements of users, it is clear that there are, at this point in time, no foolproof, perfect systems. Every solution has its pros and cons and requires a lot of thought to understand our individual requirements, expected performance, and the evaluation of possible solutions, quite often with some degrees of compromise.

On a more optimistic note. Although this thread does oscillate back and forth over many of the issues in this area, it is and I hope always will be a great source of information and assistance allowing everyone to get a better understanding of this quite complex subject. There is usually no single solution, but in discussing various solutions to each problem given by people with varying requirements and experiences, we all gain valuable insights.

Now, off to the fridge to get a cider.....and set up my stool so I can admire my new shiny cost-free AL-KO corner steadies and contemplate what extra I can load into the van since the new jacks weigh, in total, 1.2kg less than the old longer ones.

Enjoy what is left of the weekend, wherever you are.

cheers
Mike
 
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Boots in Action

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Hi,
the issue is that the solar controller and the Setec have both been designed to be the MASTER controller. In my opinion, it makes much more sense to keep the Setec as the master controller. You then get a multi-stage 240V battery charger, a 240V to 12V power supply, ability to charge via the AUX input from the tug alternator, fuse distribution system, low voltage disconnect, and on the Setec III, the ability to completely isolate the battery from all loads.

You then add a roof mounted solar panel/controller to the system by connecting the battery terminals of the solar controller directly to the battery via an inline fuse. Keep the wiring from the controller to the battery as short as possible. You do not connect anything to the load terminals of the solar controller. In this way the solar controller is NOT the master controller and becomes the SECONDARY controller.

In more sophisticated controllers, you will be able to measure battery voltage, instantaneous current coming from the panels to the battery, and accumulated charge and possibly many other things.

Battery state of charge can (SOC) only be measured with no load on the battery, and some time after any charge has been put into the battery. I have found the best time to measure SOC when off grid is first thing in the morning. If you have a Setec III, then also switch the battery off to ensure there really is no load. You will need to print off a table or chart for your particular battery type which shows no load voltage against % SOC. AGM, GELs, and normal Lead Acid batteries differ in this regard.

Taking the SOC of the battery, you can then determine how many Ah must be generated during the day to fully restore the SOC to 100%. You need to add a bit more for efficiency losses (i.e the battery dissipates heat when it is charged and discharged). I would suggest adding about 10%. With time you will generally get a feel for how much power you are consuming per day.

After this you can get more complex by adding portable solar panels, a DC-DC charger to get higher charge rates to the van battery from the tug.

If contemplating putting charge into the van battery from a portable generator, I would strongly suggest not using the Setec but getting a more heavy duty multi-stage charger that will deliver more current. The reason is to charge the batteries faster, use less fuel, and annoy fellow yor campers much less.

As an example, assume a 100Ah battery and a Setec ST20 has a MAX charge rate of 10A. So, the maximum power going into the battery from the generator will be approximately 140W. (14V x 10A). Drwaing only 140W is tot really an efficient use of a 2kW generator! At 10A and a battery that is down to 50%SOC, it will take way longer than 5 hours to pump the 50Ah needed to fully charge a 100Ah battery. The reason it will be way longer is that the last part of the charging cycle to get the battery back to 100% will be done in float mode which will be charging at currents much less than 10A.

Now, a Ritar 100Ah battery has a maximum charging current of 20A. So, getting a good 20A multi-stage charger will pump twice as much into the battery from the generator. It will charge the battery up twice as quickly and use much less fuel. 20A x 14V is now a more respectable 280W load on your 2kW generator.

If you have multiple batteries, get an even bigger charger. i.e a 40A charger for 2 x 100Ah batteries.

If you have a solar controller that does not output battery voltage, instantaneous charge, and accumulated charge, invest $15 or so on buying one of these on eBay. Note that these will only measure current on ONE direction. So they are good for measuring solar panel output but not good for measuring charge into and discharge out of a battery.

cheers
Mike
View attachment 60685
Hi Mike @mikerezny , I am in agreement with your first paragraph, except for the Master Controller. All functions still operate as you stated even if the Load wiring goes through the solar controller. The last two sentences of the second are not correct in my opinion. Firstly, solar input is connected across the battery terminals and has nothing to do with the Setec controller. The Setec controller is mainly for distribution of power to different areas including various other charging options. It does not control voltage or current from solar, as this is the solar controller's task. The Setec does have other functions amongst which is LVD and LVR and 240 volt charging at various stages of battery use. However, if all loads go through the solar controller, it has first dibs at monitoring/controlling the state of battery voltage ie LVD and LVR . So instead of being a slave to the Setec in voltage awareness, it provides an early warning system BEFORE the Setec can do so. In view of the specs on the Setec manual of 10.00 volt LVD setting, I would not want to leave it to the Setec to decide my battery 's future.
The rest of your post is the "usual good stuff".

Getting cold up here at night. Bring some warm clothes when you come.
 
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Boots in Action

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Hi @Boots in Action,
I am unsure about connecting the van load to the load terminals of a solar controller.
My main question is that if this is done then how does one charge the battery from 240V via the Setec unit? How does one charge the battery from the tug via the AUX input (assuming one does not want to go down the path of a DC-DC charger)?

My next question concerns the solar controllers ability to handle the total current drawn from the battery to supply the van.
Contrived example: if one buys a 10A solar controller to assist in keeping the battery charged, but the van load occasionally requires 20A to say power an inverter for a few minutes. It seems that in choosing a solar controller, one would have to take into account the solar panel size as well as the maximum anticipated load.

I understand the importance of having an adjustable LVD, but there is also a more frequent possibility that inverters of 1000W or more will be wired directly to the battery via very heavy gauge wire and there is no possibility of expecting the Setec or a solar controller to protect the battery in this case.

Whilst LVD is a great backup in case something is inadvertently switched on, in my opinion, it should not be used instead of gaining a thorough understanding of the 12V systems installed in vans which includes knowing SOC every morning and ensuring, whenever possible, that full recovery is achieved by the end of each day. Once that is achieved, it should be most unlikely that LVD will ever be activated and whether it is set at 10V or whatever, will not be all that important.

With the quite complex 12V systems installed in tugs and vans and the myriad of possible ways of connecting the various components together to suit the wide-ranging requirements of users, it is clear that there are, at this point in time, no foolproof, perfect systems. Every solution has its pros and cons and requires a lot of thought to understand our individual requirements, expected performance, and the evaluation of possible solutions, quite often with some degrees of compromise.

On a more optimistic note. Although this thread does oscillate back and forth over many of the issues in this area, it is and I hope always will be a great source of information and assistance allowing everyone to get a better understanding of this quite complex subject. There is usually no single solution, but in discussing various solutions to each problem given by people with varying requirements and experiences, we all gain valuable insights.

Now, off to the fridge to get a cider.....and set up my stool so I can admire my new shiny cost-free AL-KO corner steadies and contemplate what extra I can load into the van since the new jacks weigh, in total, 1.2kg less than the old longer ones.

Enjoy what is left of the weekend, wherever you are.

cheers
Mike
Hi @mikerezny , you make some good points there. But some of them are easily answered.
para 1. I do not think the Setec would see the battery charging as a "LOAD" as current/voltage would be directed across battery terminals and not through the various fuse outlets for various loads. If using/obtaining power from tug,, fridge power is normally NOT connected through battery in van. For maintaining a reasonable voltage to van battery (and that is all it would be doing - 14.4 vehicle voltage minus .7 volt through power diode less any other losses) is the reason for not being able to CHARGE van battery - just reaches float voltage , so in reality NOT charging up a lower voltage in battery! and would not be seen as a load. Other items running in van WOULD be seen as a load, but would not affect charging I believe. Not tested by me and subject to correction by advanced "Tech Heads"!
Para 2. Good point if low power Solar Controller. However, most solar controller instructions advise to connect "high power devices" directly across the battery terminals, so that that high current draw would not be seen as a load and only a sharp voltage drop would be seen on controller. Incidently, my Setec controller has 8 fused outlets @ 10 amps each. BUT, the total output from these outlets is limited to 25 amps by fuse and over current protection.
Para 3. Agreed, but see previous post regarding auto reconnect if very large current drain drop causes large voltage drop.
Para 4. One has to work on the lowest common denominator as a lot of people with very limited knowledge (my daughter was until now!!) need to have some sort of fall back - even if it is too late!! The SOC is important, but some sort of light load after checking voltage will determine whether just a "surface charge" or whether the battery has no guts and cannot carry any sort of load. Talk to you more about this and the not so smart "smart charger" when faced with this dilemma.
Para 5 . Agreed entirely. It is far more complex and diverse than most realize.
Para 6. With your help, this will continue I hope.

I hope this answers some or most of your points, but I am sure we will have further discussions on this subject. Thanks for raising some of those issues.
 
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Boots in Action

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HI @Boots in Action,
hmm. You have me thinking about this. I think we are in dire need of a good schematic diagram to focus this discussion. Will you volunteer?

cheers
Mike
Yes Mike @mikerezny , I will see what I can do. But I do not have a wiring diagram for the internal workings of the Setec, only what is in the manual. But probably it will do!! So far I have got away with all this without the smoke and flame demons appearing including with direct charging with my "smart charger" and also with the Setec on 240 volt power. But NOT with solar power at the same time, which would not happen anyway.

For you to think about - what happens at caravan parks when a van is connected to 240 volt power and there are solar panels on roof and a solar controller is in operation??? Because the Setec maxes out at 14.00 volts and most solar controllers (even the cheap ones too) usually put out 14.4 volts or more, the recommended charge for Gel battery is 14.2 to 14.4 volts (as on the side of the Ritar Gel), and my AGM wants 14.4 to 14.7 volts, I believe the solar controller would take precedence in charging. What are your educated "Tech Head' ideas on that???? The mind boggles and does my head in too!!!
 

mikerezny

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Hi @Boots in Action,
In drawing the diagrams, you shouldn't need to consider the guts of the Setec. Initially the Setec and solar controller should just be 'black' boxes with all the terminals shown and labelled.
There needs to be two diagrams: 'standard' and your 'proposed'. The main ingredient is the interconnecting wiring.

Ah yes, the on-grid problem. Once again two controllers, both capable of being the master. My simple solution: disable one of them! My preference would be to disconnect the solar panels and just let the Setec get on with it. Mainly because everything will be working correctly with / without sun and both during the day and night.

Ok, I have been having a senior's moment and got some bits mixed up in my previous posts.
With your idea, the Setec WILL charge the battery when on 240V, no problems. Perhaps disconnect the solar panels to stop the solar controller fighting the Setec. The tug WILL still charge the battery via the AUX input on the Setec.

In thinking about the Setec one has to consider that it is two (or more) devices in one: It can operate without a battery and is thus a 12V power supply.
But with a battery it is ALSO a multi-stage battery charger. So the Setec doesn't care whether a battery is connected or not, and the load doesn't really ever know whether a battery is connected or not, unless the battery, 12V on the AUX input from the tug, and 240V are ALL not present. Then there is no 12V for the van.

If the load is shifted from Setec terminals to the solar controller load terminals, one will need to supply an alternate fuse block to replace the one in the Setec.

I don't know how the Setec and the solar controller will handle all the possible connection scenarios. I am not suggesting it won't. I am only stating only that "I" don't know.
With and without 240V;
No or stuffed or flat battery but 240V available;
No 240V, no sun, no or stuffed or flat battery, but tug battery and alternator available.

One issue I foresee is that the Setec never sees a 'load', since connection is only made to the Setec battery terminals.
A Setec ST25 is capable of delivering 25A to a load but will only deliver a maximum of 10A to a battery. BUT it will deliver less when it 'thinks' the battery is up to float voltage. If there is no, or flat or a stuffed battery, AND there is a load on the terminals, I have no idea how the Setec will react.
Basically, when on grid, the Setec will now only deliver a maximum of 10A to the load instead of 25A.

If you have a MKIII you will loose the battery isolate function. This is a simple switch that turns an internal Setec relay on and off. In your suggestion, one would have to get the solar controller to switch the load off or provide an external heavy duty switch or relay.

cheers
Mike
 
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Boots in Action

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Hi @Boots in Action,
In drawing the diagrams, you shouldn't need to consider the guts of the Setec. Initially the Setec and solar controller should just be 'black' boxes with all the terminals shown and labelled.
There needs to be two diagrams: 'standard' and your 'proposed'. The main ingredient is the interconnecting wiring.

Ah yes, the on-grid problem. Once again two controllers, both capable of being the master. My simple solution: disable one of them! My preference would be to disconnect the solar panels and just let the Setec get on with it. Mainly because everything will be working correctly with / without sun and both during the day and night.

Ok, I have been having a senior's moment and got some bits mixed up in my previous posts.
With your idea, the Setec WILL charge the battery when on 240V, no problems. Perhaps disconnect the solar panels to stop the solar controller fighting the Setec. The tug WILL still charge the battery via the AUX input on the Setec.

In thinking about the Setec one has to consider that it is two (or more) devices in one: It can operate without a battery and is thus a 12V power supply.
But with a battery it is ALSO a multi-stage battery charger. So the Setec doesn't care whether a battery is connected or not, and the load doesn't really ever know whether a battery is connected or not, unless the battery, 12V on the AUX input from the tug, and 240V are ALL not present. Then there is no 12V for the van.

If the load is shifted from Setec terminals to the solar controller load terminals, one will need to supply an alternate fuse block to replace the one in the Setec.

I don't know how the Setec and the solar controller will handle all the possible connection scenarios. I am not suggesting it won't. I am only stating only that "I" don't know.
With and without 240V;
No or stuffed or flat battery but 240V available;
No 240V, no sun, no or stuffed or flat battery, but tug battery and alternator available.

One issue I foresee is that the Setec never sees a 'load', since connection is only made to the Setec battery terminals.
A Setec ST25 is capable of delivering 25A to a load but will only deliver a maximum of 10A to a battery. BUT it will deliver less when it 'thinks' the battery is up to float voltage. If there is no, or flat or a stuffed battery, AND there is a load on the terminals, I have no idea how the Setec will react.
Basically, when on grid, the Setec will now only deliver a maximum of 10A to the load instead of 25A.

If you have a MKIII you will loose the battery isolate function. This is a simple switch that turns an internal Setec relay on and off. In your suggestion, one would have to get the solar controller to switch the load off or provide an external heavy duty switch or relay.

cheers
Mike
Hi @mikerezny , too much for me to think about tonight. I will have to sit down and go through YOUR thoughts individually to provide some sort of acceptable reply. I am not sure that the system would work without a battery, as I think the transformer would need to "see" some sort of "load" to even out the power demands if as a huge capacitor that the battery would be. I do know that on a previous post that when a member tried to use a reasonable?? load and the battery was really "stuffed" (and obviously a very high resistance to charging from the Setec), power from the battery failed to operate the load even though 240 volt supply was available to charge battery. More later when I can think things through.
 

Boots in Action

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HI @Boots in Action,
hmm. You have me thinking about this. I think we are in dire need of a good schematic diagram to focus this discussion. Will you volunteer?

cheers
Mike
Hi Mike @mikerezny, @Eddii and @Glen Bundesen and @Bellbirdweb , I have completed the wiring diagram and will send it tomorrow for you to digest for yourselves. Connected my own van and daughter's with load through Solar Controller Load terminals and no normal features are lost or made inoperative. And NO FLAMES, OR SMOKE and no mirrors either!! More info tomorrow. Cheers
 

Boots in Action

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Hi Mike @mikerezny, @Eddii and @Glen Bundesen and @Bellbirdweb , I have completed the wiring diagram and will send it tomorrow for you to digest for yourselves. Connected my own van and daughter's with load through Solar Controller Load terminals and no normal features are lost or made inoperative. And NO FLAMES, OR SMOKE and no mirrors either!! More info tomorrow. Cheers
Hello @mikerezny , @Eddii , @Glen Bundesen , @Bellbirdweb , @G Daddy and any other interested "Tech Heads". As promised, I have finally been able to persuade the BOSS to do these diagrams to help you all understand what I am driving at, and despite several arguments and threats of mayhem and divorce, the diagrams are now available on the computer!! Now these are schematic line drawings only and do NOT show all parts of the circuits - just the connections in question.

Let us look at Diagram 1 first. This appears to be the normal setup for Jayco vans where a cheaper solar controller is provided (Topray???) and there is no provision for logging amp hours in or out. It also means that as @Eddii said that Jayco or other manufacturers only connect the solar Input and Battery connections to the controller and NO connections are made to the "Load" terminals as "all loads goes through the Setec". If my understanding is correct, it means that the fixed settings for LVD and LVR in the Setec control have the final say. Every thing functions fully as per the Setec manual.

Now let's have a look at Diagram 2. You will see that the only change is that the battery output (to the loads) from the Setec is routed via the "Load" terminals on the Solar controller just after the battery switch and before the 25A fuse, (could be other way around?) but still allows the circuit to be unaltered beyond that point. The battery switch is still able to disconnect load from battery and the necessary fuses are still in circuit and all other operations (charging etc) are unaffected. THE BIG change is that the Solar Controller now has a chance to sense voltages under load conditions and therefore can control LVD and LVR according to its own specifications. This would operate BEFORE the Setec which although still in the same circuit has different (and possibly/probably??) lower settings before operating.

I have also attached a copy of another instruction for connecting a Solar Controller. Note the diagram and the advice that high /heavy use appliances should not be connected to the Load terminals of the controller and MUST be connected directly across the battery terminals. And of course, one should NOT try to draw more current through the Solar Controller Load terminals that the rated output. This should not be a problem as the in line fuse should stop this from happening if correctly rated fuse is there.

Now let's see what would happen in the event that the solar controller senses the battery voltage is too low to carry the load connected. It disconnects ALL the loads beyond/after the controller , BUT does NOT disconnect any loads still connected across the battery (Inverters etc). The Setec will still allow current to be drawn from the battery AND the ability to charge at the higher rate is still available. If the load still being carried continues to cause the battery voltage to drop, the Setec LVD will eventually operate as normal. At 10 volts, that is far too late for my liking, as I believe battery would be "stuffed" at that point!!

IMPORTANT NOTE: this type of connection is for Solar Controllers within the van, and although possible to make similar connections to a portable panel, it would be a messy arrangement. But very suitable for connecting to battery/ies being charged by solar and having load placed on them. Just check out the LVD and LVR settings on controller - fixed or adjustable - to see that they suit your own requirements. Also, this may not be applicable to those with sophisticated systems such as "Drifter" panels??

So to sum up, by having battery output sensed by the solar controller earlier than the Setec, there is more protection for the battery, but there is still the "fail safe" back up of the Setec.

Incidentally, this sort of connection was made when I had my first solar controller connected (Powertech) and as it logs amp hours into system as well as lights to indicate battery voltage above and below LVD setting, I guess that the "load" connections were applicable then. It also had user adjustable settings for bulk and float voltages and the same for LVD and LVR.

Criticisms,advice and comments are most welcome. But my connections have been without problems in any area and NO FLAMES or SMOKE demons appeared. Always willing to learn!! Cheers

Circuit diagrams deleted as absolutely WRONG and MISLEADING!! New diagrams to be redrawn. If read beforehand, please disregard all circuit diagrams!! Apologies from an over enthusiastic "Tech Head".
 

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Eddii

Active Member
Jun 28, 2017
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Burua Central QLD 4680
Hi @Boots in Action, thanks for your detailed explanation and diagram;). I wasn't aware that this configuration works. It seems like you have used the controller output as some type of "shunt" which will see all your power consumption. Was your controller configurable or did it mention that you could wire it this way?
My head hurts a bit trying to decipher this diagram :bi_polo: :biggrin-new: One part of my brain says it shouldn't work and the other part saying well it works:clap2: but howww?;)
It's like shorting the controller output because there's no potential difference across the terminals.
Must be an internal setting in the controller somehow..
 

Boots in Action

Well-Known Member
Mar 13, 2017
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Ferny Grove, Queensland
Hi @Boots in Action, thanks for your detailed explanation and diagram;). I wasn't aware that this configuration works. It seems like you have used the controller output as some type of "shunt" which will see all your power consumption. Was your controller configurable or did it mention that you could wire it this way?
My head hurts a bit trying to decipher this diagram :bi_polo::biggrin-new: One part of my brain says it shouldn't work and the other part saying well it works:clap2: but howww?;)
It's like shorting the controller output because there's no potential difference across the terminals.
Must be an internal setting in the controller somehow..
Hi @Eddii, I did not know that you were a "Tech Head" because you have been fairly quiet on some of these issues raised previously. No wonder you could not understand my previous post as it seems I was discussing something you had not previously considered and my explanation appeared "double dutch" to you. Sorry about that, but @mikerezny forced my hand in providing a "rough" circuit diagram!!
I do not think there is anything magic about the setup. All solar controllers (good ones anyway) claim to have some sort of LVD and LVR and obviously this has to be "sensed" somewhere in the circuit. Could not be in the Solar Input circuit, and the Battery charging circuit is mainly about regulating charging voltage and current. So if you are going to have some voltage sensing in the unit, is that different to voltage control on the input circuit??? But then it must be able to sense a lower voltage setting AND disconnect load but not any input that may be trickling in . Not only that, it must be able to sense a re-connection voltage state , and re-connect the load again, sometimes automatically, sometimes it has to be manually. I am not pretending to be an expert on this at all, just raising issues that some "smart"Tech Head" on this forum might be able to answer.
The original Powertech 20A PWM controller I had was connected by a van "Sparkie" who obviously knew that as the controller had to be able to record and display current into battery AND log up to 3 days Ah generation separately, besides have have lights for : 1 - battery voltage is lower than 12.6v, 2 - battery voltage has reached low voltage dis-connect, 3 - battery voltage is higher than 12.6 volts, 4 - battery voltage has reached BULK charging setting (fully charged before going to float), 5 - battery voltage is lower than LVD and load has been disconnected. All this whilst charging and various loads may or may not be applied at the same time. Computer chips can do this can't they?? But they have to wired for this to happen.
That Powertech did not total load output for that day or the previous two days, only Ah input into the system. Bulk voltage, Float voltage, low voltage dis-connect and low voltage re-connect were all adjustable parameters for the user.
However, when I installed my LD MPPT solar controller, it DOES have all these display functions (and many otherrs too) including input and output in amp hours on an accumulating scale display, besides the number of LVDs and LVRs during that period. Has not happened to me but I have accidentally hit the wrong button while checking display readout and this disconnect was recorded and displayed. So I guessed that those sensors had to be in the Load circuit?? I just connected up the leads to the MPPT controller as before and EVERYTHING works perfectly. Ain't technology great???? If you can get your head around all that and let me know how it all operates, please let me know.
 

Eddii

Active Member
Jun 28, 2017
129
137
43
40
Burua Central QLD 4680
Thanks for your explanation @Boots in Action I like technology but not an expert at all. I always like to learn new things, keeps my brain ticking hehehe. I’m aware of most controllers functionality and advance settings especially the more expensive type. I just couldn’t get my head around the part where you wired incoming 12v to the positive side of controller load output and negative side to inline fuse which then feeds the loads in the van. I thought you’re suppose to wire the negative side to - terminals of battery?
What you have successfully achieved there was placed the controller in series ( as per your explanation) which means if I measure the voltage across the load output terminals I’d get 0v because there’s no potential difference or voltage drop across.
The setting ( if there was any) that I mentioned was how you have achieved to wire it(series) instead of conventional way.
Normally negative terminals are commoned in the circuit board to the negative side of battery.
I’m not saying it’s wrong but I would like to know the how. Cause for me, you have discovered something I wasn’t aware of and I think it’s awesome and I want to learn it.
Thanks again ;)
 

Boots in Action

Well-Known Member
Mar 13, 2017
650
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93
Ferny Grove, Queensland
Hi again @Eddii , of course you ARE RIGHT. I probably have the correct wiring in the van, BUT my circuit diagram is WRONG!! Referring to diagram # 2, delete reference to the pos wire from the Setec Control to battery switch as power for loads comes from the Solar Controller Battery Terminals and voltage is "sensed" at the solar controller. Somewhere in there, the battery isolation switch manages to disconnect the load/s, and the Setec LVD and LVR would have to be across the pos and neg lines between the battery and Setec controller. Ah well, back to the drawing board for a new circuit diagram to match what I actually have in connections. And the reason I knew that if pos to the controller was earthed to neg, THAT would create a dead short and there would be lots of sparks, smoke and flames!! So do not believe every thing you see as not always what you think if led astray by a nutter Tech Head!!!. Will see if I can get the BOSS to do me another circuit that MATCHES what I have actually done. I will also check all operations for disconnection of loads to confirm again what I believe is happening.
 

Boots in Action

Well-Known Member
Mar 13, 2017
650
628
93
Ferny Grove, Queensland
Hi again @Eddii , of course you ARE RIGHT. I probably have the correct wiring in the van, BUT my circuit diagram is WRONG!! Referring to diagram # 2, delete reference to the pos wire from the Setec Control to battery switch as power for loads comes from the Solar Controller Battery Terminals and voltage is "sensed" at the solar controller. Somewhere in there, the battery isolation switch manages to disconnect the load/s, and the Setec LVD and LVR would have to be across the pos and neg lines between the battery and Setec controller. Ah well, back to the drawing board for a new circuit diagram to match what I actually have in connections. And the reason I knew that if pos to the controller was earthed to neg, THAT would create a dead short and there would be lots of sparks, smoke and flames!! So do not believe every thing you see as not always what you think if led astray by a nutter Tech Head!!!. Will see if I can get the BOSS to do me another circuit that MATCHES what I have actually done. I will also check all operations for disconnection of loads to confirm again what I believe is happening.
Hello @Eddii and @mikerezny , after making a fool of myself TRYING to draw an electrical circuit incorporating what I have successfully connected in my van and my Daughter's, I used what little brain power I had left and looked up on my computer more info on how a solar controller actually works. Unfortunately it does not show an electrical circuit, but it DOES confirm what I have been unable to properly explain about the value of having the LOAD connected through the solar controller. In fact, the site states that to be able to know/record/display amps in AND out of controller (plus other info on charge settings LVDs and LVRs settings etc), you need to connect the Load through the controller. The following site helps explain this and there may be others too. So sorry to all on this site for getting off to a misleading start, but this site vindicates what I have said about having a better control of safe battery voltage operation of van battery by using settings on a good solar controller. The settings in the Setec if LOAD terminals on controller are NOT connected do not stack up against good controllers IMHO. I shall leave it up to you on how/what you think, but I am confident that my controller is going to look after my van battery better by connecting the load to the terminals than not doing so. You do have to have a controller that has user settings, but even if you have one of the cheaper controllers, connecting the load through the solar controller will /may give you better settings than the Setec when you look at the specs of same.

https://itechworld.com.au/blogs/learn/how-does-a-solar-regulator-work

I am still trying to work out a circuit on how this is incorporated into my set up so that the settings on my controller are involved in the battery operation without losing any of the other features in the SETEC controller!!
 
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