Eco-worthy 20a MPPT controller

[JiminDenver]

Last month I purchased the Eco-Worthy 20a MPPT controller from their website for $89 plus $24 shipping. Right now it says $102.50 and free shipping. You can see them on ebay with free shipping and if good can get one for as low as $80. That will be on a slow boat too as it took forever to get here.

Eco-worthy

u tube video I found on it

I set it up crudely this morning and wouldn't you guess, instantly had cloudy skies. Dark enough that there were no shadows and the controller was at best showing 2a. The panel is my Schott 230 watt, 36v panel rated up to 7.66a imp and 8.33a isc which I've confirmed before. It is just leaned against a fence and not tilted /rotated for best results

I started out using old batteries as a test, better to fry them than my trailers grp 27. They could be pulled down fast using a 350w inverter and a few lightbulbs, otherwise even in the shade the batteries voltage jumped and the controller went into float mode. In float and absorb modes it does PWM, only bulk mode does MPPT.

When the clouds cleared or as much as can be expected with the pollution, haze and smoke from the fires, I saw the amps jump to over 12a but only for a bit. They started dropping and went down to just over 5a in bulk mode. The controller is black , sitting in the direct sun and had gotten quite hot to the touch. It has a temp sensor in it so I am assuming it caused the cut in amps because even shading the box with my hand caused the amps to rise above 7 again. I shaded it and the amps went back up.
The best I saw was 13.1a in bulk mode. The controller has a PWM-MPPT comparison and at 13.1a it said the comparison was 8.67a in PWM. This is a calculation and too high for the rating. In absorb mode (PWM), in full sun it read in the 7a+ range which is close to the rated imp.
At that point the inverter was running 160w of bulbs and the batteries voltage was still climbing.

The next test will be to see if the set up will recharge the TTs grp 27 in a day after being brought down to 50%. If it can, I will be thrilled because even with furnace use we never see a 50% drop now and the Generator can be silent once again. Not bad for $200 invested.
If it can not, I'll have to decide if the controller is good enough and can be run in parallel like cruz does or send the controller back and run both of my panels off of a Rogue.

A few other tidbits.
as i mentioned, the temp sensor is in the case. I am going to see if I can't make it remote to the batteries somehow. That is a big advantage to the Rogue among other things but for a $250 savings I'll make sacrifices. I just need a charged battery for boondocking.

[pianotuna]

Hi DS,

You would have to use a buck circuit to keep the voltage constant into an inverter with light bulbs as a load.

[HiTech]

Will an AC load through an inverter not accomplish that? Or are you looking for constant amps? I find a light bulb through an inverter to be a very steady load indeed. I have 250 watt heating lamps that work well.

Jim

[DSchmidt_2000]

bigfootford wrote:
I use this device for testing... It provides about a 13 amp load.

Thanks. I have no shortage of loads, but I'm looking for essentially a 'calibrated' load (electronic smart load), or at least a very consistent one for ANY setup (within reason). The hope is to use this as a ruler to get AH output for various different setups.

[bigfootford]

I use this device for testing... It provides about a 13 amp load.



http://www.harborfreight.com/12-volt-auto-heater-defroster-with-light-60525.html

11 bucks...

Jim

[DSchmidt_2000]

Salvo wrote:
BTW, I'm up the coast from you in Goleta. Today is a great sunny day to run solar tests. Will be looking forward for further results.

I work in Goleta, which unfortunately means my solar testing can only be done on weekends. Should be able to get some signal snooping done during the week though.

Was a beautiful weekend (and still is - love the long days).

[mena661]

Salvo wrote:

BTW, I'm up the coast from you in Goleta. Today is a great sunny day to run solar tests. Will be looking forward for further results.

Refugio? Just got back from Point Mugu SB. AWESOME weather, perfect for solar.

[Salvo]

The specified standby current is 15 mA. That's probably the night load when buck regulator is off. Specified converter efficiency is > 96%. A 300W module will dissipate 12W within the converter. So we're talking about max 1A loss in charging current when using a 300W panel. Now you're using a 45W panel. Current loss won't scale directly. Perhaps 200mA of the total 1A could be considered regulator quiescent current. The rest of the current (800mA) probably scales. That means current loss within the controller is:

I_loss = 200 mA + 800 mA * (45W/300W) = 320 mA

That's my best guess.

BTW, I'm up the coast from you in Goleta. Today is a great sunny day to run solar tests. Will be looking forward for further results.

Sal

DSchmidt_2000 wrote:


I have not measured quiescent current draw of the unit 'officially' but the clamp on meter which has 10mA resolution is showing 20mA draw during standby/snooze.

Yeah, probably not so great due to me operating it really low in its power handling capability. I do have 2 qty 45W panels though I'm only using one right now, but one of the tests I want to do is compare the charging amps with the panels in parallel vs in series going through the MPPT controller, and also vs in parallel going through a PWM controller or direct to the battery.

[HiTech]

A inverter is a constant wattage load which works fairly well.

Jim

[DSchmidt_2000]

HiTech wrote:

It would be worth running your battery down to 11 volts or so and running similar tests.
Jim

Yeah, was thinking about how to create an ideal load. Basically create a constant voltage load. If I built two of them then I could have one panel on the MPPT controller, the other on the PWM, set them out in the sun with a Watt's up on each and at the end of the day get the AH difference between the two.

[HiTech]

JiminDenver wrote:
The you tube video early in the thread pointed out the temp sensor in the case. I've seen the controller drop the amps from 12 to below 6 when the case heated up in direct sun and bring them back up once it was placed in the shade and cooled down. Too bad i didn't have a DVM on the battery to see what happened to the volts at the same time.

I would seriously consider remoting this sensor to a battery terminal. On my PWM controller it improved the behavior, dropping back charging volts as the battery warmed up.

Any empirical data on how much voltage drop per degree the sensor buys you?

Jim

[HiTech]

DSchmidt_2000 wrote:
Did some testing today. (sorry for the data not being aligned- don't know how to post formatted text).

Setup:
45W 12V Solar Blvd panel with these specs
Maximum Power Voltage (Vmp): 18.0V
Maximum Power Current (Imp): 2.5A
Short Circuit Current (Isc): 2.73A

12V 35AH SLA battery which I depleted about 75% yesterday

Watt's-up meter in-line with the battery to measure current INTO the battery, battery voltage, and watts into battery.

DMM to measure the solar panel's voltage at the input of the MPPT controller.

I have Deans Connectors between the watts-up and the MPPT controller and between the solar panel and the MPPT controller so I can easily unplug things and make changes.

Testing: What I did was measure the current going into the battery if the MPPT controller was "in-the-loop", and then connected the solar panel directly to the battery. With the Deans connectors, I could do this switch around in seconds.

Here are the measurements in order they were taken (if no measurement listed - then I forgot to write it down)

With the MPPT "in-the-loop"
Solar V     Batt A     Batt V      Watts
16.76       3.08       12.51
17.00       3.05       12.51

Solar direct to battery
Solar V     Batt A     Batt V      Watts
            2.89       12.50V      35.5

With the MPPT "in-the-loop"
Solar V     Batt A     Batt V      Watts
17.05       3.02       12.51       37.4
16.94       3.07       12.52       37.1

Solar direct to battery
Solar V     Batt A     Batt V      Watts
            2.93       12.51       35.7

The battery voltage and watts were from the Watt's-up meter - it has uncertainty in its measurements hence the watts reported are not exactly that calculated just doing the math.

I'm a bit disappointed to not have a much greater charging amps (only ~ 0.1A greater) given the delta between the battery and the panel is about 4V. Thinking that I may just be so low in power that I'm not in a high efficiency zone for this MPPT controller.

Putting my ear to the MPPT controller, I hear a regular 'ticking' noise. Will at some point drag out my digital scope and take some measurements to see what is going on.

It would be worth running your battery down to 11 volts or so and running similar tests.

Jim

[DSchmidt_2000]

Salvo wrote:
Thanks for the testing. The 0.1A gain compared to direct charge does seem quite low; especially when battery is at 12.5V. Is the controller's operating current high that it impacts your measurements? Perhaps using a panel that's greater than 100W will provide better results.

Sounds like there's a relay in your controller. It may be measuring open circuit voltage of the panel. Time to pull out the scope.

Sal

There is no relay in there. The clicking is faint and sounds more like the oscillator driving the inductor in the buck circuit is turning off. Don't know if they're taking a measurement during that time, or it's an interrupt being handled by the PIC to do something else so they have to turn off the PWM output or what.

I have not measured quiescent current draw of the unit 'officially' but the clamp on meter which has 10mA resolution is showing 20mA draw during standby/snooze.

Yeah, probably not so great due to me operating it really low in its power handling capability. I do have 2 qty 45W panels though I'm only using one right now, but one of the tests I want to do is compare the charging amps with the panels in parallel vs in series going through the MPPT controller, and also vs in parallel going through a PWM controller or direct to the battery.

[Salvo]

Thanks for the testing. The 0.1A gain compared to direct charge does seem quite low; especially when battery is at 12.5V. Is the controller's operating current high that it impacts your measurements? Perhaps using a panel that's greater than 100W will provide better results.

Sounds like there's a relay in your controller. It may be measuring open circuit voltage of the panel. Time to pull out the scope.

Sal

DSchmidt_2000 wrote:


I'm a bit disappointed to not have a much greater charging amps (only ~ 0.1A greater) given the delta between the battery and the panel is about 4V. Thinking that I may just be so low in power that I'm not in a high efficiency zone for this MPPT controller.

Putting my ear to the MPPT controller, I hear a regular 'ticking' noise. Will at some point drag out my digital scope and take some measurements to see what is going on.

[pianotuna]

Hi Ds,

As you can see rvnet doesn't do well with tables.

If you could do one line for each measurement with a description on the line it may make it easier for folks to understand the data.

[JiminDenver]

Wow, good or bad it's great having the controller put thru its paces even if I have no idea what you are doing.