Battery and Solar

[dwh]

Any chance I could have Chris or his guys call you at some point? I don't know their degree of tech-savyness or the lengths they're willing to go through for a build...

I think (hope) Chris is watching this thread.

I don't work for NAWS, I'm just an old electrician who keeps tabs on this stuff and NAWS is a good shop that's been around a looooong time. LG should contact NAWS directly:

http://www.solar-electric.com/

 

[teotwaki]

Yea...the Wellsee.

http://www.027ws.com/12V/24V-10A-MPPT-Solar-Controller-WS-MPPT15.html


"Thunder Protection"
Wait...what?

"# Full charge cut:13.7V/27.4V"
14.4v is a full charge for a FLA or AGM, 14.1v is full charge for a gel...13.7v ain't enough.

All MPPT controllers are not equal. There are different algorithms and some work better than others. That's on the input side.

On the output side, the Wellsee doesn't appear to do 3-stage or 4-stage charging - just cuts on at a certain voltage and off at a certain voltage (too low of a voltage).

Informed debate is always fine but I am turned off by what appears to be ill-informed mockery, even if from "old electricians". It is quite easy to know that Wellsee/Tektrum meant lightning, not thunder protection. When literature is lacking needed details I'll take the extra step of asking questions rather than making assumptions or engaging in ridicule. If my questions to them cannot be answered then I won't buy their product. Likewise, steering the original poster to the highest priced MPPT controllers based on highest cost = high quality is not the best advice.

A charger in the Float mode will have a full charge cut off of 13.7 to 13.8 volts so no surprise from this product unless you jump to the conclusion that somehow 13.7 volts is the PWM circuit's Boost Voltage (which should be a 14.4 volt limit).

You assumed there was no 3 and 4 stage charging and I actually did write to them and ask before I bought one. The eBay ad does speak of "Microprocessor controller pulse width modulation (PWM) charging" which sounds overly complicated if you again jump to the conclusion that it simply "...cuts on at a certain voltage and off at a certain voltage...". I'll see if I still have the email as it did use staged charging suitable for AGMs.

As for this statement: "All MPPT controllers are not equal. There are different algorithms and some work better than others."

Can you share what sort of lab setup you use to measure these algorithms or are you simply repeating sales literature? For myself I often set up a test and make measurements such as this time with my Engel where I added a fan to the 2-Zone module:

Not exactly a "lab" but definitely some good measurements were obtained by measuring the deltas between the thermometers and normalizing the resulting measurements. From your statements you might have made some exacting measurements of MPPT chargers so maybe you can share your data and test setup with us? How exactly do you measure the time to convergence or if a true maximum or local maximum is achieved? What sort of DC e-Load was used to replace the battery? I'd like to apply that same approach to this inexpensive MPPT charge controller and share the results here. Otherwise I'll need to go read up more to see if I can build my own test set up. At the least a set of different value power resistors for a load and two DC amp meters would give some basic results on efficiency and possibly validate the sales literature claims.

 

[dwh]

Informed debate is always fine but I am turned off by what appears to be ill-informed mockery, even if from "old electricians".

Geez. It was just a good-natured joke. When I start mocking, you'll know it. No need to getcher panties in a bunch.

It is quite easy to know that Wellsee/Tektrum meant lightning, not thunder protection.

No kidding? Of course I knew that the Chinese flubbed the translation and actually meant lightning (or maybe they actually meant rightning), which is what spawned the joke in the first place.

But it's BS anyway, since there is not a chance in hell that there is a lightning arrestor in that unit, and even if there were it wouldn't work since it's not grounded so there is no place to divert the lighting TO.

Likewise, steering the original poster to the highest priced MPPT controllers based on highest cost = high quality is not the best advice.

You don't know what I based my recommendation on. I certainly do not equate cost = quality. Believe it or not, I've been around the block. The Morningstar gear just happens to actually BE high quality. But it's NOT the highest cost gear out there.

Since you obviously didn't get it, I'll explain...

The OP quoted a PRICE for a KIT. He quoted $945 (nine-hundred and fourty-five dollars).

WHAT I DID was to show him that he could build a system OUT OF COMPONENTS which would not only be ALL TOP QUALITY, but also cost LESS than the KIT.

I wasn't "steering" him to expensive gear, I just whipped up a quick list of quality components based upon HIS quoted budget.

I.e., if he's planning to spend a grand on his solar system, he might as well get the best setup he can with that money. If you combine the extra 40w from the larger panel, plus the 15% or so bump from the MPPT, he's looking at around 30%-40% greater watts harvested with the component setup.

A charger in the Float mode will have a full charge cut off of 13.7 to 13.8 volts so no surprise from this product unless you jump to the conclusion that somehow 13.7 volts is the PWM circuit's Boost Voltage (which should be a 14.4 volt limit).

No.

Most 3-stage chargers will do the BULK stage up to 14.4v (when set to FLA or AGM...14.1v when set to GEL), then drop into ABSORB stage at 13.8v for a set time, and then drop into FLOAT stage at 13.2v.

And again, no.

PWM doesn't boost. NO charge controller that I'm aware of boosts. Some of the DC-DC chargers DO boost, for instance 12v-24v chargers, but not solar charger controllers.

MPPT controllers DOWN convert voltage which is BUCK not boost. Normal PWM controllers simply connect the solar straight through to the battery and don't alter the voltage at all (they neither buck nor boost).

As for multi-stage charging - that can be designed in to any type of charger; PWM, MPPT, constant current, constant voltage. It's a completely separate function from modulating the pulse width.


Is it possible that the Wellsee guys designed a controller with MPPT on the input side and PWM on the output side? Sure, but it'd be the MPPT that does the buck, not the PWM - and neither one will boost.

You assumed there was no 3 and 4 stage charging

Yes, I assumed that. The -reason- why I assumed that is because there is no mention anywhere of different voltage set points, as would be used for multi-stage charging. The only mention of voltage is that 13.7v battery charging cutoff voltage (if it really is a multi-stage charger, it would run the bulk stage up to 14.4v), and the 10.5v (?) cutoff point for the load terminals. I can't think of any multi-stage chargers that -don't- mention their voltage set points in their spec sheets.

And 4-stage charging is normally just 3-stage + equalization. EQ is an occasional, timed overcharge, usually to 15v. The purpose of EQ is to stir up the electrolyte by bubbling it, and to try and knock a bit of sulfation off the plates, thus (hopefully) making all the cells more or less "equal".

AGMs and GELs normally recommend to NOT EQ. (How can you stir the liquid, when it's not liquid?) A few can accept an EQ, but it has to be done in a specific way, which almost no regular multi-stage chargers can do.

and I actually did write to them and ask before I bought one. The eBay ad does speak of "Microprocessor controller pulse width modulation (PWM) charging" which sounds overly complicated if you again jump to the conclusion that it simply "...cuts on at a certain voltage and off at a certain voltage...". I'll see if I still have the email as it did use staged charging suitable for AGMs.

PWM has nothing to do with multi-stage charging. PWM stands for "Pulse Width Modulation". All non-MPPT controllers connect the PV voltage straight through to the battery. PWM controllers do that exact same thing - but in pulses. Good quality PWM controllers can switch the power to battery on/off (pulse) hundreds of times per second. Lowbuck PWMs do it slower.

(And Specialty Concepts -deliberately- does it slower as the battery voltage rises:

http://www.specialtyconcepts.com/issues.html#D )

The "micropocessor" in a PWM controller simply switches off the current to the battery, checks the battery voltage and decides whether or not to switch the current back on.

As for this statement: "All MPPT controllers are not equal. There are different algorithms and some work better than others."

Can you share what sort of lab setup you use to measure these algorithms or are you simply repeating sales literature?

Actually, neither. I'm repeating what has been said many times - with the math to back it up - by solar engineers who frequent the Northern Arizona Wind & Sun forums. These include the founders of Outback and Midnite Solar, as well as the founder of Rogue, an R&D engineer who does work under contract for companies such as Xantrex, and quite a few other electronic engineers who specialize in solar systems.

Feel free to spend a few years reading what they have to say - as I have:

http://www.wind-sun.com/ForumVB/

(A few weeks ago, I declined an offer to become a moderator on that forum, because I could not be sure I would have time to do it properly. But it's a standing offer if I should find that I do have the time after all.)

I'd like to apply that same approach to this inexpensive MPPT charge controller and share the results here.

Great idea! I suggest that you head over to the NAWS forum and ask the guys who actually design and build some of the top MPPT charge controllers. They're a helpful bunch who will no doubt be willing to advise you on test procedures. But be warned - those guys WILL double-check your math. They thrive on it.

 

[Titanpat57]

well at least I understood "Geez"....

 

[teotwaki]

I'll play along and right back atcha'. I hope that the OP reads up more on MPPT for himself and learns from all of this.

Geez. It was just a good-natured joke. When I start mocking, you'll know it. No need to getcher panties in a bunch.

People that level accusations about bunched panties are the ones who exhibit the first signs of bunching theirs. :ylsmoke:

No kidding? Of course I knew that the Chinese flubbed the translation and actually meant lightning (or maybe they actually meant rightning), which is what spawned the joke in the first place.

Joking at other folks' expense is not a joke. But lately the Expo Forum seems to thrive on ill-mannered mockery so you fit in well.

But it's BS anyway, since there is not a chance in hell that there is a lightning arrestor in that unit, and even if there were it wouldn't work since it's not grounded so there is no place to divert the lighting TO.

So you've never bought one but you know so much about them? You could go spend years reading about MOV devices and transient suppression. I suggest that you do so well before further pronouncements on circuit design.

You don't know what I based my recommendation on. I certainly do not equate cost = quality. Believe it or not, I've been around the block. The Morningstar gear just happens to actually BE high quality. But it's NOT the highest cost gear out there.

Just 4 times as expensive.

If you had actually read the Morningstar manual, that little box has no external attachment to "divert the lightning to" yet in their very own manual it says:

High Voltage Transients
Solar, battery, and load power connections are protected against high voltage transients. In lightning prone areas, additional external suppression is recommended.

So you'd pay 4 times as much and still get no terminal to divert the lightning to? Maybe the Morningstar unit is better at diverting thunder too.

Since you obviously didn't get it, I'll explain...

The OP quoted a PRICE for a KIT. He quoted $945 (nine-hundred and fourty-five dollars).

WHAT I DID was to show him that he could build a system OUT OF COMPONENTS which would not only be ALL TOP QUALITY, but also cost LESS than the KIT.

I wasn't "steering" him to expensive gear, I just whipped up a quick list of quality components based upon HIS quoted budget.

Wow. Your CAPS LOCK key must be smokin' hot. Anyhow, your quick list was so quick that you only cited very expensive components and made no effort to shop beyond what NAWS offers? That is understandable that you go with what you buy from NAWS. There are other products available that don't cost as much if you just look.

I.e., if he's planning to spend a grand on his solar system, he might as well get the best setup he can with that money. If you combine the extra 40w from the larger panel, plus the 15% or so bump from the MPPT, he's looking at around 30%-40% greater watts harvested with the component setup.

So you are reaffirming your belief that "best" does equal "more expensive" as I said earlier. All I said is that he can have an MPPT setup for less money and that sparked your tirade.

Most 3-stage chargers will do the BULK stage up to 14.4v (when set to FLA or AGM...14.1v when set to GEL), then drop into ABSORB stage at 13.8v for a set time, and then drop into FLOAT stage at 13.2v.

And this has to do what with your hasty assumptions about the specs of the cheaper unit?? So you do design the charge controller circuits for a living? This is just so inconsistent.... maybe you meant to say "old electrical design engineer" and not just old electrician? You're obviously intelligent but the message I'm getting is that you use solar products and you try to understand them but that the actual circuit design is beyond your life experience.

PWM doesn't boost. NO charge controller that I'm aware of boosts. Some of the DC-DC chargers DO boost, for instance 12v-24v chargers, but not solar charger controllers.

Better do your research on circuit design. Unless the MPPT is an old linear design (which lose tracking in heavy clouds) it will be based on PWM. But you can't seem to understand that nuance. An "old school" PWM controller is not designed to consider the Vmp of the solar array and it does not have the extra circuitry to perform the measurements or the software to implement an MPPT algorithm. A digital MPPT controller absolutely uses PWM as well as the other features just mentioned.

MPPT controllers DOWN convert voltage which is BUCK not boost. Normal PWM controllers simply connect the solar straight through to the battery and don't alter the voltage at all (they neither buck nor boost).

See the above answer as I am seeing a pattern here. Simply repeating scattered readings of sales literature does not qualify for understanding circuit design.

As for multi-stage charging - that can be designed in to any type of charger; PWM, MPPT, constant current, constant voltage. It's a completely separate function from modulating the pulse width.

And you are almost admitting that the Wellsee unit just may have it. OK. backpeddling is acceptable.

Is it possible that the Wellsee guys designed a controller with MPPT on the input side and PWM on the output side? Sure, but it'd be the MPPT that does the buck, not the PWM - and neither one will boost.

So previously you had pronounced that there was no way it could do more than simply have high and low set points. Now you are considering that you were a bit hasty?

Yes, I assumed that. The -reason- why I assumed that is because there is no mention anywhere of different voltage set points, as would be used for multi-stage charging. The only mention of voltage is that 13.7v battery charging cutoff voltage (if it really is a multi-stage charger, it would run the bulk stage up to 14.4v), and the 10.5v (?) cutoff point for the load terminals. I can't think of any multi-stage chargers that -don't- mention their voltage set points in their spec sheets.

So you will mock their English but dismiss the unit because you could not read the original spec sheet in Chinese if it was sent to you? The joker would become the joke, good naturedly mocking so to speak.

And 4-stage charging is normally just 3-stage + equalization. EQ is an occasional, timed overcharge, usually to 15v. The purpose of EQ is to stir up the electrolyte by bubbling it, and to try and knock a bit of sulfation off the plates, thus (hopefully) making all the cells more or less "equal".

Okay, repeating literature again, but that does nothing to address your claim that the Wellsee/Tektrum unit did not have 3 or 4 stage. You offered no proof but you explain charging again.

AGMs and GELs normally recommend to NOT EQ. (How can you stir the liquid, when it's not liquid?) A few can accept an EQ, but it has to be done in a specific way, which almost no regular multi-stage chargers can do.

Okay, repeating literature again, but that does nothing to address your claim that the Wellsee/Tektrum unit did not have 3 or 4 stage. You offered no proof but you explain charging yet again.

PWM has nothing to do with multi-stage charging. PWM stands for "Pulse Width Modulation". All non-MPPT controllers connect the PV voltage straight through to the battery. PWM controllers do that exact same thing - but in pulses. Good quality PWM controllers can switch the power to battery on/off (pulse) hundreds of times per second. Lowbuck PWMs do it slower.

Okay, repeating literature again, but that does nothing to address your claim that the Wellsee/Tektrum unit did not have 3 or 4 stage or even PWM. You offered no proof but you explain charging terms all over again.

The "micropocessor" in a PWM controller simply switches off the current to the battery, checks the battery voltage and decides whether or not to switch the current back on.

Okay, repeating literature again, but that does nothing to address your claim that the Wellsee/Tektrum unit did not have 3 or 4 stage. You offered no proof but you explain charging again and again, even though you don't grasp that a microprocessor can incorporate charging routines, PWM and MPPT algorithms in the same program. With a few extra sensor points and new s/w a PWM unit becomes MPPT and 4 times as expensive overnight. Do you even realize that an MPPT controller is operating in PWM mode at a higher frequency with smoother application of charging current?

Actually, neither. I'm repeating what has been said many times - with the math to back it up - by solar engineers who frequent the Northern Arizona Wind & Sun forums. These include the founders of Outback and Midnite Solar, as well as the founder of Rogue, an R&D engineer who does work under contract for companies such as Xantrex, and quite a few other electronic engineers who specialize in solar systems.

Okay, finally admitting to repeating literature again, but that does nothing to address your claim that the Wellsee/Tektrum unit did not have 3 or 4 stage. You offered no proof but you explain charging again and offer no math that I have seen. Did you even realize that based on math you can make a case that a traditional PWM controller can be the right choice based on the system design needs? Maybe I missed that multi-quote-quote-quote....

Here is a quote for you:

Systems in which array power output is significantly larger than the power draw of the system loads would indicate that the batteries will spend most of their time at full or near full charge. Such a system may not benefit from the increased harvesting capability of an MPPT regulator.

Feel free to spend a few years reading what they have to say - as I have:

I'm not sure that those years have been fruitful for you as evidenced by not knowing how MPPT circuits are designed, that they actually incorporate PWM. It is not a magically new charging method. It is a clever way to approximate the internal resistance of the battery and the solar panel and match them up for better efficiency. Think of it as an evolutionary step for PWM circuits but not an entirely new species.

A few weeks ago, I declined an offer to become a moderator on that forum, because I could not be sure I would have time to do it properly. But it's a standing offer if I should find that I do have the time after all.

So along with being an expert at sales literature and never having actually tested an MPPT unit you can add "Almost Moderator" to the list? I was more comfortable with "old electrician" in your other post.

Great idea! I suggest that you head over to the NAWS forum and ask the guys who actually design and build some of the top MPPT charge controllers. They're a helpful bunch who will no doubt be willing to advise you on test procedures. But be warned - those guys WILL double-check your math. They thrive on it.

It looks like a very nice forum and I'm sure that as an old electrician you can offer all sorts of advice about installing solar products according to local code and all sorts of real-life opinions as to the products that you have bolted down and wired up.. I have no fear of being questioned as it is a form of the Socratic method. In other words, critical thinking does not include dismissing a product based on the English language skills of the manufacturer.

It is obvious that you used a lot of words to say that you have opinions about MPPT but have never actually tested a Wellsee unit in any scientific manner. I've already said that I have not fully tested one but am willing to try before I jump to too many conclusions. If you were more willing to reassess your earlier errors and and focus on those and not literature lectures we could both help out the OP.

 

[dwh]

Oooo kay.

It's obvious that you have faith in the Wellsee and are greatly offended that I don't share that opinion. You took it personally.

You immediately crossed the line into personal attack, and now you're going even further - as well as making several attempts at putting words in my mouth.

There's no fighting that sort of unreasonable attitude; it just ends up in a flame war. I don't do flame wars.



We're done.

 

[zukrider]

wow. you both should be ashamed of yourselves for getting that far. but in retrospect, it was very informative. i just learned a heap of stuff about solar! im an electrician as well, but i have never branched out of commercial 120-480. i think i may now!

i would love to see the two of you calm down, and continue to add great info.

cheers

 

[evldave]

i would love to see the two of you calm down, and continue to add great info.

x2

 

[teotwaki]

well at least I understood "Geez"....

I agree..... :elkgrin:

 

[teotwaki]

wow. you both should be ashamed of yourselves for getting that far. but in retrospect, it was very informative. i just learned a heap of stuff about solar! im an electrician as well, but i have never branched out of commercial 120-480. i think i may now!

i would love to see the two of you calm down, and continue to add great info.

cheers

There really is a lot to learn, especially with MPPT. I'm only a dabbler in comparison to all that has gone on with the circuit development in the last couple of years. Providing numerous accurate counterpoints to bad information provides focus and encourages me to pursue further research and understanding. In all of the Global Warming debates with PaulJ and others we gave each other fits but no one ever ran away saying "I'm done". In other words, if you're gonna throw sand in the sandbox, please wear goggles. If you're going to show someone a better way to build sandcastles you don't need the goggles. :ylsmoke:

 

[teotwaki]

Oooo kay.

It's obvious that you have faith in the Wellsee and are greatly offended that I don't share that opinion. You took it personally.

You immediately crossed the line into personal attack, and now you're going even further - as well as making several attempts at putting words in my mouth.

There's no fighting that sort of unreasonable attitude; it just ends up in a flame war. I don't do flame wars.


We're done.

It's obvious that you hate the Wellsee and are greatly offended that I don't share that opinion. You took it personally.

You immediately crossed the line into personal attack, and now you're going even further - as well as making several attempts at putting words in my mouth.

There's no fighting that sort of unreasonable attitude; it just ends up in a flame war if you have already made up your mind and stop listening.

 

[dwh]

i just learned a heap of stuff about solar! im an electrician as well, but i have never branched out of commercial 120-480. i think i may now!

Already being an electrician it won't take you long to get up to speed on solar.

One thing that's a PITA is that below 50v the NEC doesn't care what color wire you use. Most automotive stuff uses black for negative. I've seen quite a bit of automotive wiring where white was positive because black was in use for negative/ground.

Above 50v you hit the NEC and have to start using white for negative and green for ground. There are quite a lot of solar systems out there that use red for positive and black for negative and ground, and then there are systems that are over 50v and all of a sudden black isn't negative or ground anymore.

And to make it even more fun, there's also a lot of <50v where the installer -did- follow the NEC color codes even though he wasn't required to.

That's what I do, I just follow the NEC color codes regardless if the voltage is under 50 or not. I have a feeling that's going to end up being what most installers do. It's just easier that way, plus inspectors expect to see NEC color codes on everything they look at, so it'll make them happy too.

i would love to see the two of you calm down, and continue to add great info.

I'm calm.

 

[teotwaki]

I need help picking out my battery(ies) and solar.

I can get Optimas through the company plan at a great price and like either the Yellowtop D27F(140 amp reserve) or Bluetop D31M (155 amp reserve).

Will be powering a fridge (likely the ARB 50), LED lights, fantastic fan on occasion, maybe a small electric blanket for short bursts.

One or two batteries?

I'd also like to try and keep it/them topped with solar on longer stays. I like Martyn/Mario's flexible solar panel but a hard-mounted panel would be much easier. This 145 watt panel looks pretty good.

Any suggestions?

So, back on topic. I understand the temptation to buy a kit and so on but some basic homework will help a lot with the decisions and probably save you a lot of money on unneccessary solar bling. MPPT is really a neat approach but it primarily benefits us in colder climates or when a battery's voltage is very low and a solar panel is getting excellent sunshine, and some other specific situations. As I mentioned before, an "old school" $60 dollar charge controller may be just fine.

My Engel 45 fridge is quite happy with just one blue top battery. When I was in Death Valley just one 54 Watt panel and a dead simple on-off solar charge controller kept the battery very well charged. Probably less than $400 bucks in cost for the panel, battery and controller if you shopped around.

Before you can pick the number of batteries or the size of the panel you need to estimate the amperage draw over the course of the 24 period. Also, will you have uninterrupted sunshine or will you have clouds very often? Along the freeways you'll see the emergency phones with a solar panel on top of the pole. In desert regions that solar panel looks mighty small compared to one in a coastal region.

How about if you list the devices you will use and their voltage and amperage specifications. Also list how often you might use the things besides the fridge.

 

[Hilldweller]

Most of our camping is in wooded areas and 2-5 days. We might do 1 or two longer trips a year right now (hoping to do more...).
It will never get ideal sunlight except for roadtrips. That's why I was looking at jumbo panels.

We're not trailer novices ---- right now I've got a Conqueror with one Diehard Platinum marine battery. In the warm months is will last 3 days until it's getting close to 40% and I feel I need to charge it. If I'm in the boonies, I use a Honda genny.

The idea for solar is to avoid the genny use entirely. On a cross-country trip there's the inevitable stay at a Dennis-the-Menace RV park for a real shower, 110v power, washing machines, etc. But I'd like to avoid these Satanic places as much as possible.

this trailer is in the for sale area; somebody buy it already...

 

[teotwaki]

Most of our camping is in wooded areas and 2-5 days. We might do 1 or two longer trips a year right now (hoping to do more...).
It will never get ideal sunlight except for roadtrips. That's why I was looking at jumbo panels.

We're not trailer novices ---- right now I've got a Conqueror with one Diehard Platinum marine battery. In the warm months is will last 3 days until it's getting close to 40% and I feel I need to charge it. If I'm in the boonies, I use a Honda genny.

The idea for solar is to avoid the genny use entirely. On a cross-country trip there's the inevitable stay at a Dennis-the-Menace RV park for a real shower, 110v power, washing machines, etc. But I'd like to avoid these Satanic places as much as possible.

When I was in Death Valley I did not have to start the truck to charge the batteries at all. In the trailer I have dual Optima Blue tops, a nice metered SunForce (PWM old school) charge controller and a Kyocera 65 watt panel. I mainly used the batteries to power a few hours of use on the HF radio, guessing an equivalent to 20 AMP hours of use (?). With the panel charging the batteries all day I never ran the batteries low.

Okay, I see why you were thinking of the higher wattage panel. I have not put my finger on it yet, but the flexible panels seem to have an advantage in that they are not in as much need of pointing accurately at the sun as a rigid panel. It may be that the larger surface area is affected less by small shadows and such. I got mine off of eBay but I think I found the source company. I got my like-new 65 watt unit for less than half. They are either mil surplus or manufacturer's seconds.



Do you have any amp numbers on your 12 volt items? Or are you saying that for most of them in use you can go 3 days in warm months (no electric blanket use?)? Does your trailer have a fridge in it now?