wellsee MPPT produces flickering output

[houseofstrauss]

SETUP
I have a home built 12v solar lighting system . Has 3 panels (300W) to a wellsee MPPT controller then distributed to various LED lights. The regulator output is going straight to the LED lighting circuits via consumer on/off switches

PROBLEM
When the solar panels are producing charge during daylight hours the MPPT controller constantly flashes the red charge light about 3 times a second. This on/off cycle seems to be conveyed to the load output as a voltage spike, that appears to match the charge led's on/off switching.

For some LEDs that have a current regulator circuit board and a low forward voltage of about 3.2V, there is no problem, but other high power LEDs that have a combined forward voltage of around 10-12V, this flickering effect is very noticeable, probably because the high/ low voltage spike intersects the F/V.

ACTIONS
Tried putting large smoothing capacitor across output. (no improvement) Used CC driver befor leds. (No improvement.) Running lights directly from battery- (All works fine, no flickering.) Must be the charge controller.

QUESTION
1- Is this a normal behaviour for MPPTs during the charge cycle, or is this because I have a faulty/ poor quality MPPT?
2- Is there any way I can provide a smooth non spiking voltage to my LEDs?
3- Do you have any recommendations to improve this setup?

Thank-you for your comments.

[Mike90250]

SETUP
I have a home built 12v solar lighting system . Has 3 panels (300W) to a wellsee MPPT controller then distributed to various LED lights. The regulator output is going straight to the LED lighting circuits via consumer on/off switches

PROBLEM
When the solar panels are producing charge during daylight hours the MPPT controller constantly flashes the red charge light about 3 times a second. This on/off cycle seems to be conveyed to the load output as a voltage spike, that appears to match the charge led's on/off switching.

For some LEDs that have a current regulator circuit board and a low forward voltage of about 3.2V, there is no problem, but other high power LEDs that have a combined forward voltage of around 10-12V, this flickering effect is very noticeable, probably because the high/ low voltage spike intersects the F/V.

ACTIONS
Tried putting large smoothing capacitor across output. (no improvement) Used CC driver befor leds. (No improvement.) Running lights directly from battery- (All works fine, no flickering.) Must be the charge controller.

QUESTION
1- Is this a normal behaviour for MPPTs during the charge cycle, or is this because I have a faulty/ poor quality MPPT?
2- Is there any way I can provide a smooth non spiking voltage to my LEDs?
3- Do you have any recommendations to improve this setup?

Thank-you for your comments.

The pulse is indicative of a PWM controller maintaining float voltage. If you add some heavy loads,
does the behavior change ?
MPPT controllers modulate in the high KHz or low MHz range, way too fast for the human eye to see.
Does if flicker early in the day when the batteries are low and in BULK when the MPPT would be active ?

[sensij]

Mike's suggestion is probably the first place to look. It sounds like there is a PWM function

From here:

When Red LED(CHARGE) is on, battery is charged up strongly;
When Red LED is flickering, battery is MPPT charged up in constant voltage.

If that isn't it, is it possible that there is some voltage sag causing it to cut out?

When the battery voltage is low, the controller will automatically cutoff the load from the system. If the voltage of battery is back to normal and the load will restart working.

[houseofstrauss]

Hi Mike and Sensij, thanks for your helpful comments.

My battery is 100AH deep cycle in good condition. Even when the battery voltage peaks at 14.0V the regulator still fluctuates a charge when the sun is out. It NEVER shows green, as in fully charged. Even with no draw on the battery. I found a youtube video that's pretty useless except to show the same flicker rate as I have see here https://www.youtube.com/watch?v=hdDkSdoyQQA

As far as I can see, the controller never registers a full battery, regardless of load or time of day. ie it is always registering a 'flicker type of charge' Only time I get peace from this is when the sun goes down.

LEDs power consumption: with all lights on, they draw about 45 watts, if I pull hard on the battery to lower the voltage, the charge controller steps up the charge frequency, sometimes almost reaching constant 'ON' (red charge light) It feels like it never reaches a float state, or if it does it still pulses.

My feeling is it may be good for battery charging, but not good as an output device... any thoughts?

Thank-you.

[Mike90250]

I think your controller is a dud. Double check any settings or programming, with your manual, for the type of battery you have.

Perform the cold boot power sequence (disconnect PV & battery, connect battery first, and wait a minute or two for the controller to boot, then connect the solar panels)

Or it may be that your panels have some fault preventing them from producing full voltage. That needs to be checked, you should be providing at least 20V to the controller input for it to work properly.

[jony101]

from the youtube videos and the size of the unit and the cost, i certify it not mppt. The only way to know for sure is to open it up and see if it has a "donut' circuit inside, its a round thing with copper wire going around it, its what converts the high voltage into low voltage/high amps. All mppts have it.

The lowest cost mppt I seen is the ecoworthy 20 amp at 102 dollars, its what I bought and it has the donut circuit plus it does produce the high amps a true mppt does. And it does charge my 145 ah battery from my 240 watt panel every day. With your 300 watts of panels your 100 amp battery should be fully charged by noon even with you running some lights. 300 watts should produce at least 16 amps with mppt, that will charge most batteries in a decent time plus have spare amps to run your lights.

The fake mppt do not work as mppt and are also not very good pwm from the numerous test videos i seen on youtube. Some of them did have power spikes as you describe which showed up on oscilloscopes. I would stay away from them.

I also owned a 20 dollar wincong 20 amp pwm charger (which also fully charge my battery) besides the ecoworthy, when I had items connected to the load out of the controller, the power fluctuated with the clouds, I think that is normal. For me its noticeable when using fans, where I can hear the rpm go up and down, but never notice any flickering with my lights. In my case I just connect everything directly to the battery which always provides a stable source of power.

I think the only problem with your controller is that the company used cheap parts in it, even if you try to send it back they would send you another one with the same performance.

if you get another controller just make sure it can handle the voltage of your panels connected in series, some of the cheaper ones can only handle a maximum of 50 volts.

[houseofstrauss]

from the youtube videos and the size of the unit and the cost, i certify it not mppt. The only way to know for sure is to open it up and see if it has a "donut' circuit inside, its a round thing with copper wire going around it, its what converts the high voltage into low voltage/high amps. All mppts have it.

The lowest cost mppt I seen is the ecoworthy 20 amp at 102 dollars, its what I bought and it has the donut circuit plus it does produce the high amps a true mppt does. And it does charge my 145 ah battery from my 240 watt panel every day. With your 300 watts of panels your 100 amp battery should be fully charged by noon even with you running some lights. 300 watts should produce at least 16 amps with mppt, that will charge most batteries in a decent time plus have spare amps to run your lights.

The fake mppt do not work as mppt and are also not very good pwm from the numerous test videos i seen on youtube. Some of them did have power spikes as you describe which showed up on oscilloscopes. I would stay away from them.

I also owned a 20 dollar wincong 20 amp pwm charger (which also fully charge my battery) besides the ecoworthy, when I had items connected to the load out of the controller, the power fluctuated with the clouds, I think that is normal. For me its noticeable when using fans, where I can hear the rpm go up and down, but never notice any flickering with my lights. In my case I just connect everything directly to the battery which always provides a stable source of power.

I think the only problem with your controller is that the company used cheap parts in it, even if you try to send it back they would send you another one with the same performance.

if you get another controller just make sure it can handle the voltage of your panels connected in series, some of the cheaper ones can only handle a maximum of 50 volts.

Hi jony, thanks for your comment. I've seen this question about the toroidal transformer before on another youtube, so I'll def' check this out. Other youtubers also rate the wellsee as a pretty poor piece of kit. I bought it 2 years ago and It's time to upgrade to a better product. BTW, I'm in the UK and NOWAY will I ever get full output from my PVs, except maybe that one sweet spot when the sun is dead inline.

LEDs are very reactive to voltage/current so any sort of electrical ripple is seen. And yes, I originally had the feed off the battery, not from the MPPT output. I hoped the battery capacitance would sink the ripple, but it doesn't, at least not enough. Again I think the MPPT charge voltage is fluctuating just above the battery top voltage and fractionally exceeding the LED Forward drive voltage. Hence the flicker effect.

Bottom line, I think I need to kiss this unit goodbye, does anyone have any other top recommendations for replacing this 15A unit. ? I will look into the ECOWORTHY though.

THanks all for your generous comments. The power of community eh!

[Mike90250]

.....
Bottom line, I think I need to kiss this unit goodbye, does anyone have any other top recommendations for replacing this 15A unit. ? I will look into the ECOWORTHY though.

THanks all for your generous comments. The power of community eh!

Not sure what your PV voltage is, if you need MPPT, (PV over 21Vmp) but the Morningstar line has some good PWM, and a small MPPT
Morningstar SunSaver 15 Amp MPPT Solar Charge Controller

http://www.solar-electric.com/inverters-controllers-accessories/chco/mochco/admpchco/mosumpsochco.html

and their PWM controllers

http://www.solar-electric.com/inverters-controllers-accessories/chco/mochco/stpwmchco.html

Also, I believe STECA has a small MPPT. I know nothing of Ecoworthy, which would make me pass it by.

[boostinsteve]

The Wellsee charge controller is not MPPT, and is very low quality. I would throw that away and spend some money on something that is actually worth something. The manufacturer is very devious in trying to hide the fact it isn't. No one I have heard of has had good experiences with this charge controller. I would get a new one.

[houseofstrauss]

Thanks for your comment boostinsteve, that seems to draw to a conclusion, I think. Thanks all for your helpful comments. Here's to an off-grid new year!