mppt charge controller - ZLPOWER ??

[conntaxman]

tried to test the sl-40

I tried to test this controller. I had 2 panels. panel A was17.10 volts@3.1 amps panel B was 17.54 volts@2.3 amps
Battery to start was 12.5 volts
I have a cheap volt ohm meter, and you can test up to 10 amps dc.
I hooked up the panels in series and it was 39.4 volts [few min later] hooked up the bat and panels to it. going into the bat first was 13.16 then little while later was 15.2
I put my meter on amps and hooked one end to the controller and the put the other lead to the battery, and my probe wire on the meter ha ha fried, and smoked. so I pulled it off quick, but too late, now i need another meter. I guess I will have to get a regular amp meter.
Only in about 10 to 15 min the battery was charged, I was only a motor cycle battery.
so I still have NO idea . ha ha ha
Let me add this, I took off the wire that was from the controller to the pos, and THEN i checked for the amps, by taking one lead and hooking it up to the controller and then the other lead to the battery. So to run the current through the meter. I think that is how you do it.

[Sunking]

The unit does do "PWM" mode, but only if the SP voltage is close to the battery voltage (eg: low solar insolation).

Toni beg your pardon but that does not jive with IR curves. Vmp knee voltage does not vary very much if at all with respect to irradiance (amount of sun light). It is the Imp current that varies proportionally to irradiance level, not the voltage.

[conntaxman]

mppt /algorithm

John,
When I get time I will check the data pins & maybe put the picoscope on the TX pin to see if it is outputting some data on the RJ connector. If it is TTL output then it will definitely require a Dallas chip or some TTL to RS232 converter.
It is strange how they have a serial port & mention that it can be used for data-logging but no information on how to use it.

Good luck in your communication. With regards to tech support, the lady has already advised that the persons in this department do not speak english so she will have to translate technical enquiries.

Sunking
When I read their manual & specifications I do not get 100% correlation, & some mild conflicting detail anyway. I have learned that specifications can be open to interpretation especially when the detail is a bit vague or not very specific.
Also the absence of a spec detail does not always mean is or is not so.
If you can wait, I will try to do some tests this weekend & then we can all get some sleep.


>>For a 40 amp 12/24 volt device the input limitations would be
>>500 watts @ 12 volt Battery
>>1000 watts @ 24 volt Battery

What you say is correct but is a "requirement" would probably be more accurate term than "limitations".

The input power required from the solar panel is a result of the output power + any losses in the converter & cables etc...
This is true for both MPP controllers & "PWM" type chargers.
Difference is an MPPT charger can increase the energy obtained from the source (SP)
by way of reducing its duty cycle (or frequency depending on the topology) to allow the SP to operate at its MPP voltage.

An MPP/MPPT charger is just a switchmode DC-DC converter with an additional control mechanism (usually microcontroller). they typically operate in the "Buck" (step down) mode & this does a current amplification & voltage division function with optimisation of maximum solar panel power(VxA). aka MPPT


>>The TL2843 is a PWM Comparator that drives the MOSFET switches. I suspect the HC908 PIC is the control for the Comparator.

TL2843 is a "current mode PWM controller", definitely not a comparator. This is the DC-DC switchmode controller.
There is a comparator IC LM339 & an opamp IC TL074 opn the control board, both these would be to process analog signals for the HC09 inputs

Toni

-----------------
Tony again tks for the look see into this.You guys are much smarter in this then I. All I could do is take someone's word on this matter, untill I can see with a volt meter or amp meter. Im going to try today to take readings of 2 panels and then hook them up in series and take another reading and then hook it up to the SL-40 and see what I get, And it looks like that Really isn't a good way to do it either.lol
But thanks to both or all that are talking about this.I still say that they made the cir. to use both pwm and mppt.
John

[tonigau]

Ok,
I've done a quick test, not a good one tho cos I'm hard pressed for time & space n don't have a decent current supply at the moment.
But a test it is & can see the results.

I do intend to do a comprehensive test & graph the results but it will likely be a while.


Some detail from reading the manual....
The 40A spec. is output current.
The unit does do "PWM" mode, but only if the SP voltage is close to the battery voltage (eg: low solar insolation).
Load current is 15A max

One thing I noticed when testing & will have to look into further is when winding up Volts on the supply the SL-40A unit cut-out well below 55V with 6V hysteresis to cut-in.


PS, Sorry John for getting a bit off topic with your post for info on the SL-40A, Maybe Sunking & me can start a new post for our game of tennis .....

Toni

[Sunking]

When I read their manual & specifications I do not get 100% correlation, & some mild conflicting detail anyway. I have learned that specifications can be open to interpretation especially when the detail is a bit vague or not very specific.
Also the absence of a spec detail does not always mean is or is not so.
If you can wait, I will try to do some tests this weekend & then we can all get some sleep.

Correct Tony and that is why I suspect the product is a complete fraud. For example they claim 99.5% efficiency which is impossible

>>For a 40 amp 12/24 volt device the input limitations would be
>>500 watts @ 12 volt Battery
>>1000 watts @ 24 volt Battery

What you say is correct but is a "requirement" would probably be more accurate term than "limitations".

The input power required from the solar panel is a result of the output power + any losses in the converter & cables etc...
This is true for both MPP controllers & "PWM" type chargers.
Difference is an MPPT charger can increase the energy obtained from the source (SP)
by way of reducing its duty cycle (or frequency depending on the topology) to allow the SP to operate at its MPP voltage.

Ok this is where I disagree with your assessments to some respect. I have to separate the two types because they work completely differently. All MPPT controllers have a maximum wattage input vs battery voltage, and maximum Voc. If you look at any quality MPPT controller one of the first things and most important specs is the maximum Voc voltage. Typically th elow current models Voc limits is around 100 volts, while the higher current models have a 150 Voc and soon to be 600 Voc. To the consumer or lay person this might not mean much to them, but the advantage is running very low currents on the input side to minimize wire size, cost, and losses. So for example using a 80 amp controller on a 12 volt battery, if you run say 120 Vmp on 1000 watt panels input current on the controller is around 8.3 amps with roughly 80 amps out to the 12 volt battery

The big advantage of MPPT other than the tracking ability which is huge, is the overall efficiency because the panels are operated at Vmp at all input levels and overall efficiency including wiring and converter losses is up around 95%.

PWM is a completely different animal. The panels do not operate at Vmp, rather something lower like around 1 volt higher than the battery voltage at 100% duty cycle. At best if the panels are precision matched, the best efficiency you can obtain is 70% with 50% being typical. The problem with any serial type controller is Input Current = Output current. PWM controllers do not specify maximum wattage. They only specify maximum voltage (Voc) and current input (Imp of the panel).

So with this SL-40 the max Voc is 55 volts, and input current is 40 amps. So if we had a 12 volt system, and we used say a panel with a Vmp of 40 volts (roughly 55 Voc), and a Imp of say 40 amps would give us a panel wattage of 40 x 40 = 1600 watts. Problem is the Vmp would be pulled down to around 15 volts at the input to give us say 13 volts @ 40 amps out to the battery. So we have a 1600 watt panel, but at best we can only deliver at best around 520 watts to the battery. Roughly 33% efficient under worse case scenario.

So how can you tell what is really going on. Just a simple test. Connect say a 100 watt panel say made for 24 volt system and a discharged 100 AH 12 volt battery. Measure the input voltage and current and you will have your answer if it is MPPT or PWM. I bet you see the input voltage get pulled down to around 15 volts rather than 34 to 36 volts and input and output current around 2.7 amps knocking you 100 watt panel down to 35 to 40 watts.

An MPP/MPPT charger is just a switchmode DC-DC converter with an additional control mechanism (usually microcontroller). they typically operate in the "Buck" (step down) mode & this does a current amplification & voltage division function with optimisation of maximum solar panel power(VxA). aka MPPT

Yep I know I have designed a few switch mode power supplies, and work a lot with PWM motor controllers.

[tonigau]

----------------
tonigau,,, did you know that you also can parallel these to 80A, 120A
and so on.
John
let me know when you get yours, and I'll do the same

I bought a few & will try to hook both up to the same load, Parallel operation should work with most simple chargers because they operate CC (Constant Current) mode initially untill the battery is charged then go into CV mode (float).
Note: Can not parallel the input, connect separate panel(s) to each charge controller.

----------------
tonigau ....did you order them after reading about them when I put up the spec.
John

I found this supplier on alibaba, it took me a while to purchase because of difficulty confirming product details so I just bit the bit & got some samples.


toni

[tonigau]

John,
When I get time I will check the data pins & maybe put the picoscope on the TX pin to see if it is outputting some data on the RJ connector. If it is TTL output then it will definitely require a Dallas chip or some TTL to RS232 converter.
It is strange how they have a serial port & mention that it can be used for data-logging but no information on how to use it.

Good luck in your communication. With regards to tech support, the lady has already advised that the persons in this department do not speak english so she will have to translate technical enquiries.

Sunking
When I read their manual & specifications I do not get 100% correlation, & some mild conflicting detail anyway. I have learned that specifications can be open to interpretation especially when the detail is a bit vague or not very specific.
Also the absence of a spec detail does not always mean is or is not so.
If you can wait, I will try to do some tests this weekend & then we can all get some sleep.


>>For a 40 amp 12/24 volt device the input limitations would be
>>500 watts @ 12 volt Battery
>>1000 watts @ 24 volt Battery

What you say is correct but is a "requirement" would probably be more accurate term than "limitations".

The input power required from the solar panel is a result of the output power + any losses in the converter & cables etc...
This is true for both MPP controllers & "PWM" type chargers.
Difference is an MPPT charger can increase the energy obtained from the source (SP)
by way of reducing its duty cycle (or frequency depending on the topology) to allow the SP to operate at its MPP voltage.

An MPP/MPPT charger is just a switchmode DC-DC converter with an additional control mechanism (usually microcontroller). they typically operate in the "Buck" (step down) mode & this does a current amplification & voltage division function with optimisation of maximum solar panel power(VxA). aka MPPT


>>The TL2843 is a PWM Comparator that drives the MOSFET switches. I suspect the HC908 PIC is the control for the Comparator.

TL2843 is a "current mode PWM controller", definitely not a comparator. This is the DC-DC switchmode controller.
There is a comparator IC LM339 & an opamp IC TL074 opn the control board, both these would be to process analog signals for the HC09 inputs

Toni

[conntaxman]

SL-40 mppt controller

Tony, thanks for the reply.all what you said sounded good,I'm not that smart into electronics as you. So your saying that we cant JUST hook up that ,,,looks like phone jack to a lab top or desk top, that we will need another part?
I also didn't have time to hook up like 2 -65 watt x 21 volts to see if it charges at 12 volts and more amp's, then the single panel.
Im going to emil them tonight, or hook up skyp and talk to the sale people / girl and ask if I could be put in touch with a person in the other deptment were they figure all this stuff out and give them this link so they could read what you/we are tring to find out.
TKS
John

[Sunking]

Tony thanks for the observations. Here is my problem with the unit. If it were a MPPT controller, there would be a maximum wattage input specification vs battery voltage. For a 40 amp 12/24 volt device the input limitations would be

500 watts @ 12 volt Battery
1000 watts @ 24 volt Battery

That is not the case as you have observed. The input spec reads like a series PWM or linear regulator with a max input Voc of 55 volts and input current of 40 amps. As with any series voltage regulator INPUT CURRENT = OUTPUT CURRENT roughly minus losses.

All the ingredients are there to do MPPT, freescale HC908 MCU, TL2843 SMPS controller, Large inductor, 3 banks of MOSFETs, analog amplifiers & comparators.

The TL2843 is a PWM Comparator that drives the MOSFET switches. I suspect the HC908 PIC is the control for the Comparator

Tony as I think you know the real test is to monitor input and output currents. If they are roughly the same it is not MPPT, rather just plain ole inefficient PWM.

[tonigau]

Hello John,
I've been away playing with a 330KV substation, now that I am back in the real world I can do some playing with 33V.

I received my SL40's a couple of days ago, the build quality looks reasonable considering the cost.
I have only briefly looked at the board & may have some error in analysis for now & will correct as find or someone will correct me.
All the ingredients are there to do MPPT, freescale HC908 MCU, TL2843 SMPS controller, Large inductor, 3 banks of MOSFETs, analog amplifiers & comparators.
The 3 large Electrolytic caps on panel input , smaller Electrolytic next to is these is output cap 4700uF.
If it was a "PWM" charger it would not need the large inductor on the input.

The smaller inductor(green core) to the upper right is the common mode noise filter.
There are 2 current sense resistors(that I can see) 0.001ohm
The 2 fuses soldered into the board are 30A in parallel, These would be only for worst case fault.
There is transient over-voltage protection devices(82V MOV ) on the input & output, It is recommended to include primary transient protection in your wiring.

I think ZL power needs to improve its communication in their sales dept as I struggle to get meaningful information when asking questions as you have noticed.
Looking at what they say seems like rubbish but I would er on the side of they don't understand what they are saying (in english anyway)

I need to yet obtain detail of the BTS & the communications port.
From looking at the board it would appear the serial port is not RS232 voltage levels, so a converter is required to connect up a PC for the data-logging.

I read specifications for this type of product with scepticism until test results & observed confirmation.
To do a quick calc say 28V battery, recharging at 40A = 1120W & say 5% waste heat = 56W, the heatsink I estimate would be about 40degC rise.
I think if someone has spent k's$ on a KW of solar panels wouldn't skimp on getting a cheap charge controller.
I intend to use mine on 500W 36V(MPP) panels I think this SL40A should be well suited for now. It looks easy enough to repair.
A specification of 40A does not mean it can charge at 40A continuously, I prefer to operate equipment well below maximum to ensure reliability & longest life.
In the railway industry where I work, 40A supply does mean 40A because there is a generous margin built-in & it costs too.

I hope to do some tests this weekend, my variable power supply is broke so I will have to unpack some solar panels & setup but I think there is some rain coming...





Toni

[conntaxman]

amp/watts/volts

I know a few will jump all over this one from me. lol but here it goes.with solar panels that are rated 36 cells and each cell puts out 1.8 watts and 3.5 amps. How many panels will make 40 amps ph. oh and im going to say the sun Never changes in this location, but a sunny day , ave. output of sun hummmm alot. lol

[conntaxman]

Hi John,
From reading user manual & other information These charge controllers definitely appear to be genuine MPPT. I ordered some & am waiting for delivery. Confirm the temperature sensor is included as it is stated as an option in the manual, it would operate without the sensor. (just to be sure)
There is an isolated RS232 port on the side of these for data logging. But I am having some trouble getting any detail on the com port & data structure.


>>"Simple it is false advertising. You cannot have a PWM MPPT CC"

I suspect the manufacturer is meaning that they use PWM to control the battery charging after the MPPT stage of their converter. The 3 large electrolytic caps I would assume to be the output bus from the MPPT, then PWM to charge the battery.

I intend to do some testing when I get my SL-40A's so I will let know the results & confirm other detail.

Toni

..................

Toni
I just got my Mppt controller and by reading the book FAST it dose do the mppt stuff, and It looks like it will handle up to 40 amp input from the panels.
Could we hook up a lab top to one of the Looks like phone connections on the side? I thought i read some were it said we could .
You should have gotten yours by now also.
I still have to make a rack to hold my panels and everything. But I'll try someway to hook it up.
Hope to hear from you on this. I'll also will be asking some questions on all the settings for the batteries. lol.
I didn't think that this unit would be so large. Didn't look inside yet.
John

[Sunking]

...........
Hello Tony. I just got my email back form Zlpower about the controller. Here it is and it tell's about the "input of Watts"
The max watt is 55V for the one we sent to you.And we can make it to 65V by changing another software.But coulst would be usd96 for the controller.

And by watt,there is no limit,you can put any watt to it but make sure the voltage.

How is the garden now?Which step you are in?When will it be ready?

You need to wake up and smell the coffee burning. This proves it is a PWM controller and does not have anything to do with MPPT.

They are flat out lying to you, there is a wattage input limit of 55 volts @ 40 amps = 2200 watts maximum input. If you use a 12 volt battery system means 2200 watts in, and 480 watts out, 78% loss of power. With a 24 volt battery 2200 watts in 960 watts out or 56% loss of power.

The product is a flat out fraud. Only good thing I can say about it is if you use a 2200 watt solar panel array with a 12 volt battery it will make a good space heater or a hot plate to burn your morning coffee for you to smell and wake up to...

[conntaxman]

mppt /algorithm

Hi John,
From reading user manual & other information These charge controllers definitely appear to be genuine MPPT. I ordered some & am waiting for delivery. Confirm the temperature sensor is included as it is stated as an option in the manual, it would operate without the sensor. (just to be sure)
There is an isolated RS232 port on the side of these for data logging. But I am having some trouble getting any detail on the com port & data structure.


>>"Simple it is false advertising. You cannot have a PWM MPPT CC"

I suspect the manufacturer is meaning that they use PWM to control the battery charging after the MPPT stage of their converter. The 3 large electrolytic caps I would assume to be the output bus from the MPPT, then PWM to charge the battery.

I intend to do some testing when I get my SL-40A's so I will let know the results & confirm other detail.

Toni

...........
Hello Tony. I just got my email back form Zlpower about the controller. Here it is and it tell's about the "input of Watts"
The max watt is 55V for the one we sent to you.And we can make it to 65V by changing another software.But coulst would be usd96 for the controller.

And by watt,there is no limit,you can put any watt to it but make sure the voltage.

How is the garden now?Which step you are in?When will it be ready?

BEST REGARDS
Yours,
Phylis
Shenzhen ZLPOWER Electronics Co.,Ltd.

[conntaxman]

mppt /algorithm

I am not one of those people. I said being from CHINA makes it very suspect. They do not have a very good track record. China is about where Japan was right after WWII with very poor quality. It took Japan around 25 years to catch up and pass the USA and most other countries.

But answer my question, what voltage and wattage does this so called MPPT/PWM CC have? I do not see it listed in the specs. The answer will tell you if it is MPPT or not. I suspect it is a PWM controller based on the specs I see so far.

Just about every 12/24 PWM charge controller on the market has a maximum Voc of 55 volts. Guess what this controller Max Voc is? 55V. MPPT max is usually 150 Voc.

You might also want to read this thread

..............
The input voltage is over 50 volts