Solar panel controller

[rickst29]

Originally Posted by booster

One thing to always remember when comparing profiles and times in stages of the charging, when talking about wet cells.

The time to get to float is not any kind of indicator that the charging filled the batteries well or poorly. All it tells you is either the charger thought the batteries were full or the maximum timer ran out of time.

It all depends on the profiles, algorithms, timers, etc in the charging source. Very few of them do a very good job of getting batteries accurately charged, IMO.

The only way on the solar to compare controllers accurately, I think, would be how many watt hours of power were recovered in any particular amount of time, under the same conditions. This reading has to be taken at the controller(s) not the battery, so a monitor will not give that information unless there are no loads running at all the entire test time.

I strongly agree with everything you just said. But, if I add two more coulomb counters into my RV, my wife will take one look at it and say, "Rick, you've got to stop! It looks like a nuclear power plant control room in here!"

[booster]

Originally Posted by rickst29

I strongly agree with everything you just said. But, if I add two more coulomb counters into my RV, my wife will take one look at it and say, "Rick, you've got to stop! It looks like a nuclear power plant control room in here!"

Don't your controllers have totalizers in them?

[rickst29]

Originally Posted by themexicandoctor

The shunt - if you need better photos, please let me know - it does look like one Victron component is connected to the shunt?

If you meant were asking "what is this thing, he was brilliant but didn't explain" then here is my answer. If not, please advise me to delete this (it's largely irrelevant):

It looks a lot like a 'Coulomb Counter' meter shunt.This is almost like the shunt on my own "Coulomb Counter" meter, with one important difference: At the top middle, instead of just one wire going into the Display Unit, I have a small cable, bundling about 4 wires (they carry +12v voltage, "-" ground, sampled current amount, and maybe a separate +12V power wire for the display). But with only one wire, your Victron might be obtaining "12v Voltage", it's own power, and ground from other connections. If so, then it needs only one wire - the shunt-reduced current sample.

If it is a coulomb counter: On the left side, your two big wires go to the "-" grounding terminals of your two "house batteries. They should be the only connections to the batteries. All of the 12v "grounding wires", including charger "grounding wires" and the frame, should be hooked together before reaching the right side of the shunt. (Although I see some weirdness there, with a big bundle of small wires coming out of the flex conduit and a fairly small "main" cable going into the shunt. I would and did use Car-Audio "Power Distribution Blocks" to bundle all of my 12V grounding wires and frame into one big wire, inserting just one wire on each Distribution Block port).

The monitor counts power in, power out (Volts * sampled amps * Shunt ratio) to calculate battery capacity, and display real-time power "outbound for use" or "inbound for charging", per the direction of flow, and accumulates it over time to estimate battery capacity. If you have Lithium batteries then you MUST have one of these meters, because the battery voltage of these batteries remains very close to 12.8V over a broad range of charge states (% full).

With an LFP battery, the Voltage at 85% full looks nearly the same as the Voltage at 20% full, you can't judge the State-Of-Charge from Voltage alone.

[rickst29]

Originally Posted by booster

Don't your controllers have totalizers in them?

Nope. No Display from the PD Converter. The Solar Controller(s) display accumulated Kwh for the Solar, but my concern is total into and out from the house battery from all sources (all together). Victron does it, but my "el-cheapo" stuff doesn't.

[themexicandoctor]

Gentlemen aka The Wise Men/Council,

Next week I hope to bring my Guru out of retirement & pay for a couple of hours of re-education. And in the meantime I am going to stay out of the deep end of the pool but for a couple of ideas & questions below.

The fields of expertise I have are formidable but narrow & while I am a Practical Man, the expertise needed to feel comfortable in these electrical conversations is not native to me.

I thought, everything was dialed in & working perfectly, my concerns began when I decided to add a DC Novakool Fridge to replace a Dometic 3 Way and;

"Do I have enough power in my set up, not to tax the batteries but exercise them or would I need to add another dreaded solar panel which in truth would meaning scrapping what I installed 2 years ago & going with something like Booster designed ..."

This is what I have below & note, I rarely if ever, use Shore Power but once a month or two - then when I do within 24 hours I get the FULL Reading on my Magnum

A Go Power 170 panel with an added 80 watt, different manufacturer, probably the same voltage, wired in parallel (gave away the PWM unit)

2 X Lifeline Group 27 AGM 100ah Batteries

A Victron BMV712 Smart Meter

A Victron MTTP 30/100 Charge Controller

A Magnum MMS1012 PSW Charger/Inverter*

A Magnum ARC 50 Remote

I only went with the Magnum because at the time, Victron didn't make a small enough, 12 volt system but now they do. I chose the smaller Magnum because all I reallt needed to do was run a Blender mostly without blowing the breakers (upgraded to 30 or 50amp), or having the inverter go into fail mode & anything was more horsepower than the crudeTripplite** 612 that the Roadtrek came equipped with.plus Peter at Roadtrek suggested it as a replacement for models up to years 2010(?) because that was their answer to the squeaky wheel customers.


*question below

**someone intelligent & thoughtful always answered the phone line at Tripplite, not unlike the phenomenon of the Dometic Fridge Customer Service

Booster & I are correct in that 80% of RV Consumers have no clue what is taking place BUT are not concerned with "how to build a watch, we think that is the job of the installer, we just want to know the time, until there is an issue, usually in premature battery replacement.

Then there is 15% of us* who go on all the Forums & Reviews before we buy something, & research the dickens out of all the possibilities while at the same time analyzing** who is simply trying to sell something versus The Guru like you guys & then everyone in between.

*what is in my Truck & on the outside of it, is a reflection of my values just like when I worked overseas for 32 years, you turn up for a Mission & everything, including you the Man, is squared away. There is absolutely nothing extra added to your weapon systems that is superfluous nor is anything missing for the individual nature of the engagement planned.

**I am not a fan of the $4 bill yuppie van builders*** and their units even though on paper, they have the latest & greatest of everything but I do watch & for 5 years the Victron meters, etc seem to be the choice for these wannabes & everyone else, revamping their systems.

These Victron meters seems like the ideal system for 80% especially when viewed against the analog Magums, etc with the hours to empty, etc

***these are the checkbook mechanic types that curtail their Journeys & head home whenever their black tanks need emptying or they get a flat tire. They just love to blog about their projects & green choices even though most of them are still connected via the 30amp power cord* from the parent's house.

*the 20th Century Umbilical Cord

Show me a Millenial who can change a tire (safely), & I will find you a Pink Unicorn who crochet....

Then there are the 5% like you guys, who are willing to dismantle the Spaceshuttle down to every rivet just so you can put it back together & get that 8% extra efficiency when the atmosphere is less dense.

As it is, my system is probably running very efficiently.

I trust my guy 100%, in the past when I have asked him to explain some of the arguments here he is always very diplomatic & begins well but I get lost, I always end up saying "how close am I to the business end of the Horse ..." & if its within 11%, I am happy.

As to the solar operating without the charger being on, I include the photos.

And its only been since I installed the newer, larger 30/100 unit do I notice this info reading WHY IS THE CHARGER OFF.

Now when I looked at the photos before downloading them, I see the Solar unit is 0.00 ie; that my engine is running & when it does this, the Solar always goes to 0.00 so mayne that is the reason for the INFO MESSAGE?

The reason I only just bought up the fact I usually have the charger turned off during the day is because of what I believed was obvious; if you don't need the AC, keep the Magnum Charger off because;

1. The inverter is not needed, the MTTP has its own instructions to charge the batteries

2. The inverter wastes power by being on, taking away from ALL the juice going to recharge the battery bank

3. The only time you have the Inverter on is when you need AC Power & you are NOT connected to shore power or the generator is running

4. When you are connected to the above, there is still no need to have the inverter on because the power from the SHORE OR GENERATOR is essentially connecting your system live as though you were in a house

Are the Urban Legends I believe above, false?

Next week I hope to be back.

By the way, those shunt & bus (?) photos are the handiwork of my Guru who took a spaghetti box of wiring & removed an extra earth/battery/negative that was giving me all kinds of error messages on my BMV712.

$500/4 hours later everything was completed, he may have even done the end run fix caused by the extra 6 feet of cable when adding a second battery below versus having one of the two not getting the exact same charge

A year before I had followed the advice of the posters here, namely Booster & added a second battery to the cut out provided by Roadtrek in front of the rear tire. This was probably where the extra negative came in.

[Winston]

Originally Posted by booster

Here is a profile from the Magnum ARC50 remote that controls the charging profile and it itself is getting it's data from the battery shunt.

We have the ARC50, but it's been 3+ years since we programmed it. Re-reading the manual [Page 28] . . . we apparently are not using either the "time" or "current" triggers, instead, have turned the time feature to "OFF".

Magnum suggests that turning this feature off could result in holding the batteries at too high a voltage, too long. That would be true if we programmed ours to a 'high voltage'. Our 13.4 volt 'continuous' setting is approximately the resting voltage of our pack at 90% SoC . . . a voltage we assume where our battery can safely remain 'forever'. :~)

[themexicandoctor]

Here is the WHY IS THE CHARGER NOT ON messages, again its probably when the RV is on, ie; the Alternator of the truck being driven is switching off the solar input.

[themexicandoctor]

I will ask this question in deference to Booster ( the Lifeline contact/friend I called suggested the charged voltage should be kept at 13.2 but he isnt a tech although all the Lifeline literature suggests 13.2)

Booster suggested, knowing my Lifeline AGM setup, that I should change the CHARGED VOLTAGE SETTING on the Battery Meter to 13.6, versus the 13.2.

And that in his estimation, even the 13.6 is too low.

What are your opinions?

[themexicandoctor]

I am getting an average 6-8 hour overnight draw of 27ah with the new fridge installed.

[themexicandoctor]

Correction; the only reason I bought up the subject of the Magnum charger being off most of the time, is because starting around post 10 of this thread, everyone started referencing the Magnum Charger being on, etc.

The only time my Magnum is on is on the rare occasion I am connected to shore power or the generator is running & then its only employed as a PASS THROUGH SYSTEM?

Is this a correct assumption?

Or when I choose to use the AC to run the TV, Blender, whatever.

[Winston]

Originally Posted by themexicandoctor

As to the solar operating without the charger being on . . .

The reason I only just bought up the fact I usually have the charger turned off during the day is because of what I believed was obvious; if you don't need the AC, keep the Magnum Charger off because;

1. The inverter is not needed, the MTTP has its own instructions to charge the batteries

2. The inverter wastes power by being on, taking away from ALL the juice going to recharge the battery bank

3. The only time you have the Inverter on is when you need AC Power & you are NOT connected to shore power or the generator is running

4. When you are connected to the above, there is still no need to have the inverter on because the power from the SHORE OR GENERATOR is essentially connecting your system live as though you were in a house

Are the Urban Legends I believe above, false?

We also have the Magnum ARC50, but connected to a Magnum 2812. Assuming our Magnum inverter/chargers operate the same with the ARC50, you can independently turn on/off the inverter and charger.

If you like the "Urban Legend" that leaving your inverter "on" wastes energy, turn it off. We have chosen a different path desiring that our RV 'replicate our house' - - our 120 volt outlets are always energized, whether we're using any appliance requiring that voltage or not. When we plug something in, the outlets are hot and ready-to-go. Yes, it wastes power . . . but this 'keep alive' "wasted" power was accounted for in our design.

But we don't understand your concern over the charger portion of the Magnum - - whether it's on or off. Ours is always on, but rarely on. Which is to say we've told the Magnum charger to "be on" anytime we're connected to shore power. Recently that's practically never. So, although 'ready' to be on when on shore power, our Magnum charger is really off most of the time. But this 'on/off' switching is automatic.

As we agree with Rick that, generally, you can run both your shore power charger and solar controller (charger) at the same time, why not have the Magnum configured to automatically turn-on when on shore power? In our case, we've programmed our Magnum for a Constant Voltage of 13.4 volts - - equivalent to a 90% SoC of our lithium batteries. If the batteries are above 13.4 volts when we plug into shore power, the Magnum just sits there and does nothing. If below 13.4 volts, it commences charging until the 13.4 volt level is reached at which point it just sits there BUT importantly, it supplies all the current to any load that's connected to the system. Why turn-off the charger and use batteries . . . in short, why cycle your batteries . . . when you're sitting there with shore power connected?

The import point is that you can have your Magnum charger 'armed' to charge and supply power when its connected to shore power while simultaneously leaving the inverter off. You can 'have your cake and eat it too'. You can live green, live by the Urban Legend and waste no power.

PS: Concerning your Legend #4, the inverter is never on when you have an alternative source of 120 volts connected, whether shore power or generator. Thus, although our inverter is programmed to 'always be on' . . . it isn't on when shore power takes over. That's all part of the Magnum programming and automatic 'switching' between inverter and shore power.

[themexicandoctor]

I may have your Charger ON/OFF description misunderstood. Parked harvesting the sun.

Not hooked up to power here but these 3 photos might help.

In the first photo, the Solar is going through, being read, by the Magnum but the Magnum inverter is turned off.

In the second photo I have pressed the Inverter on button, now if I was wanting to run an ac source it would power up.

In the third photo, I have a close up image of a couple of light/controls starting from the bottom;

INVERTER on/off

CHARGER on/off.

[themexicandoctor]

Is my unit essentially in the On but Off Charger/Charged Ready position as you describe?

[GeorgeRa]

Originally Posted by Winston

.....................
If you like the "Urban Legend" that leaving your inverter "on" wastes energy, turn it off. We have chosen a different path desiring that our RV 'replicate our house' - - our 120 volt outlets are always energized, whether we're using any appliance requiring that voltage or not. When we plug something in, the outlets are hot and ready-to-go. Yes, it wastes power . . . but this 'keep alive' "wasted" power was accounted for in our design.
.................

For your design the inverter drain could be insignificant, but for many it is not an urban legend. In my case leaving inverter, Magnum 1000 on would result to 19W unnecessary constant drain, 38 Ah/day. I wouldn’t use the 5W search mode due to loud clicking.

[themexicandoctor]

Quoting Winston; But we don't understand your concern over the charger portion of the Magnum - - whether it's on or off. Ours is always on, but rarely on. Which is to say we've told the Magnum charger to "be on" anytime we're connected to shore power. Recently that's practically never. So, although 'ready' to be on when on shore power, our Magnum charger is really off most of the time. But this 'on/off' switching is automatic.

Because I believe, my system is already set up the right way. Because I rarely use AC Power, I don't thibk I have my House/RV set up as you do ie: your house /RV replicates the always on, your 120 volts are always ON.

As it is, I have the Magnum affixed upside down, under the bed, outside the orginal box that housed all the wiring & the TrippLite. I also had a computer fan installed on the trap door that is in the under bed/dinette wall that dissects the two areas (under the bed & in the dinette), so as to extract heat from the Magnum during really hot days.

Tripplite like Dometic were very quick to point the finger at the Roadtrek installation claiming that both technologies (the inverter & the fridge) were poorly vented & therefore overheated when in reality, the Tripplite was a dog & the Dometic RM2354* 3Way, were completely inadequate for the normal rv use, in climates in excess of 80%.

*it has now been revealed to me by other members & Dometic, the RM2354 was a failure. I was informed of this only after I refused to buy a 4th RM2354 & went with the DC Fridge instead. The previous owner, replaced his also - 15 years, 3xRM2354 units.

[themexicandoctor]

I state that I believe my systems are set up the right way however, I persevere here because for many years I laboured under the Urban Legends all newbies do.

I have an Open Mind even though the Space Shuttle is good enough for me.

I do believe I have a Yellow Belt in Battery* Dynamics when related to undercharging, overcharging, etc.

Its when all the layers are added, in terms of various charging methods, etc that its difficult & I refuse to put me head in the sand & cross my fingers.

[themexicandoctor]

Quote by Winston; the import point is that you can have your Magnum charger 'armed' to charge and supply power when its connected to shore power while simultaneously leaving the inverter off. You can 'have your cake and eat it too'.

I am under the impression, my Charger is already armed to charge & supply power when connected to shore power while simultaneously leaving my inverter off - I was under the belief that when external power hits my inverter there is a switching mechanism that when using a weapon analogy is set up to go from "Barrack safety to a charged weapon" upon the activation of that switch.

[themexicandoctor]

Would love your opinion guys, did I misunderstand & yet have my rig set up right?

[booster]

Originally Posted by themexicandoctor

Would love your opinion guys, did I misunderstand & yet have my rig set up right?

That is the big question that many, many, people have, and probably always will when they start actually wondering if they are getting all they paid for with their systems.


The big deal comes in how you define "right".


If "right" is inferred to mean that the system is giving top end accuracy results, all the time, with no user input or monitoring then the and answer to the question if the system is setup "right" would be "no, because it isn't possible with this system's components" for nearly all current systems out there, except some of the very high end fully integrated systems.


If "right" is inferred to mean that the system has been setup with the variable parts of it tweaked to give close to the best results possible for that system when being used in the use pattern of the user, then the answer is that is it unlikely to "right", but could be tweaked be better. The big disclaimer is that just because you get the system as good as it can be for the user patterns, it doesn't necessarily is it doing a good, fair, or poor job as it could be any of them.


Because nearly all the systems aren't capable of automatically adjusting to different use patterns and other variables the systems are very difficult to be able to pick a set of "best case" settings of parameters for them. A setting that gives good results on one recharge might be poor on another recharge of different depth. Plus it gets orders of magnitude harder to do if you aren't right there looking at the system operate and asking the user all the "how do you use the system and RV in everyday life" questions.



An example of the types of decisions about compromises would be the absorption time allowed for solar controllers, which comes up a lot on systems because they are very susceptible to undercharging (most common) and overcharging (less common but more damaging). Some controllers run a full charge every time they activate, so you might be repeatedly putting full absorption voltage on your batteries all day when it is sitting in the sun but not being used (maybe even on shore power). A long absorption time could be 6-8 hours of overcharging, every day, which will be very hard on the batteries. If you shorten up the absorption time, to 1 hour to prevent that kind of overcharging, you wind up without enough time at absorption to recover enough power to cover your use when the unit is being used and wind up chronically undercharged. It is these kinds of choices that determine "right" but even the best choice may give poor results in use in many cases. Other controllers may have different, but also conflicting issues that require compromises.



The manufacturer's of the equipment try to address some of this with complex algorithms, which may or may not help as they can't address a lot of the variables in the real world, and may limit the amount of tweaking you can do to make the system perform better.



We also fall into the trap of transferring other's settings to our application on occasion. It is very easy to do as there are always a lot of opinions as to how things should be done. Just because a group of settings work well for Tom, Dick, or Harry doesn't mean they will work well for anyone else unless they have identical equipment and use it identical ways.



Bottom line is that "right" is so extremely variable and even at it's best can give anywhere from poor to good results, it is very hard to define, I think. It is very hard to tell someone that their system will not be able to produce good results, even with fine tuning, as the components just aren't capable of doing it. Getting a little improvement on a poorly functioning system makes it better by a bit, but it certainly can still be a poorly functioning system.

[Winston]

Originally Posted by themexicandoctor

I am under the impression, my Charger is already armed to charge & supply power when connected to shore power while simultaneously leaving my inverter off - I was under the belief that when external power hits my inverter there is a switching mechanism that . . .

Mdoc, we have lost ‘the flow’ of this thread so perhaps a slight refocus will clarify whether there are any outstanding issues. As we recall, you replaced an old frig with a new compressor model and it is working fine and your system is supplying more than enough power to operate it. You also expressed concern that your system might not be operating at maximum/proper efficiency. Although we are uncertain what has led you to this concern, nothing you’ve said suggests to us that your system isn’t wired properly and efficiently. Whether your charger “is armed” or whether you keep your inverter “on” are not really wiring errors, rather choices we each make on how we want our system to operate. Concerning your photos and the question whether you’re “already armed to charge” . . . the only way to tell is to plug in shore power and see if your Magnum “Chg” light, lights. And if it doesn’t illuminate - - and you want to be armed - - all you need do is press the Magnum “Chg” on/off button and you’ll be armed.

And, George, we weren’t questioning the truth of the Urban Legend that says ‘inverters waste energy when left on’, only that we accept this waste (more like 40 watts in our case) as the cost that must be paid to achieve the desired “like home” operational mode. MDoc, turning-off your inverter is the norm in the RV world particularly where, like yourself, you rarely use 120 VAC. Indeed, we suspect that we (and possibly Davydd) may be the only RV’ers who squander and waste energy by leaving our inverters on 24/7.

Let us know if we’re missing something.