Pairing up the Eco-worthy 20a MPPT controller

[JiminDenver]

Thanks to BFL confirming that the Eco-Worthy controller plays well when run with another controller, I felt pretty good about combining my two matched controllers. Each had one of the Bosch 245w mono panels aimed not perfect but good enough considering that they will be flat mounted. I used a fully charged 95 ah grp 27 so that I could move the voltage easier than the 8-D.

I used the inverter and a 1875w hair dryer as a load. I tried high but the voltage dropped so fast that the inverter shut off before I could check either the controllers or the meter on the battery. After shutting off the inverter the controllers put out a combined 28-30 amps until it hit float.

After it had been in float a bit I tried the low setting on the hair dryer. This time the batteries voltage only dropped to 12.3v and both controllers were putting out 13a average. I knew they were good for more so I disconnected one of the panels and the other controller shot up near 16a. This let the battery drop in voltage and when I plugged in the other panel, both systems ran close to 16a. They stayed that way until I shut off the hair dryer and inverter and let the battery come up.

I did find that I could use the high setting for short times if I started in low and let the controllers get ramped up. They were putting out 13a each until I hit high, then they jumped up above 16a each. The voltage did drop but slower this time. With the help of the solar, the hair dryer ran a minute before the inverters alarm went off.

I did get a chance to see the Mono panels with on and off clouds. Any significant clouding and the output dropped to 2.5a for each panel even if I was running a load. I didn't pull out the 230w poly but I've seen it do 3-4a in lower light. Just shutting down the inverter would save more amps than I'm losing, it's a real pig.

So I'm pretty happy with the combined systems. I'll probably see higher amps up at altitude but only if I'm running the microwave at high noon. With this in mind, I may go with the Rogue 30a instead of the Morningstar 45a for mounting and save the money. Clipping may not be a issue often and it would only be a few amps at peak hours.

Last thing is about the absorb cycle on the Eco-worthys. Even if I set the absorb at 15v, it didn't last. The controller would come out of bulk, switch to absorb and raise the voltage to the set point. As soon as it hit that the controllers dropped to float. I will say that 32a pushes a grp 27 around pretty easy. Next test it will be the 8-D, it doesn't push so easy.

[JiminDenver]

12thgenusa wrote:

JiminDenver wrote:
It's all hype and advertising.

Yet you're planning to get a Rogue or Morningstar? 🙂

Those controllers offer features and capacities besides MPPT that the Eco-w's don't.

[BFL13]

69 Avion wrote:
I have the Eco Worthy with a 250 watt, 24v panel, and it works great.

All the calculations that some folks do, gives me a head ache.LOL I just hooked mine up and let it work. Every time I go out to use the rig, the batteries are up and I'm ready to go as far as the electric goes.

That is not allowed! Every day is a multi-meter day. You have some sort of attitude problem! 🙂

[69_Avion]

I have the Eco Worthy with a 250 watt, 24v panel, and it works great.

All the calculations that some folks do, gives me a head ache.LOL I just hooked mine up and let it work. Every time I go out to use the rig, the batteries are up and I'm ready to go as far as the electric goes.

[12thgenusa]

JiminDenver wrote:
It's all hype and advertising.

Yet you're planning to get a Rogue or Morningstar? 🙂

[JiminDenver]

BFL13 wrote:
I love how they say "power gain" for those huge percentages of MPPT over PWM. No mention of "amps to the battery gain" which is not a lot. They do mention that it is amps that count though! Gottaluvit.

Also no mention of gains for when the battery is in the usual RV range during the day with solar on--between 13 and 14.4 volts. MPPT gain is best at around 12 volts and becomes (much) less over PWM as battery voltage rises into the 13-14.4v range.

Step right up! Getchyer MPPT right here, 25% gains!!! Free box of Cracker Jacks with every purchase of our MPPT controller in the new attractive case your wife will love.

It's all hype and advertising. Mppt has its biggest advantage in a grid tied system where there is a load all of the time. In our case, it has a benefit under certain situations. Roy needs every amp he can get from a undersized system with limited sunlight, sounds like a candidate to me. Deal with cloudy conditions a lot would make you one too.

My system is over sized and normally we get more than enough sun. the only benefit I get is being able to run the ultra cheap high voltage panels I find. A Eco-w and a 24v panel makes a nice tidy package for not a lot of money if the panel fits and is big enough for your needs. At retail there could be a PWM system that cost less and still fills your needs as well.

So it still comes down to the panels. What can you afford out of what's available that fits on your roof and fills your needs. Now that you know what panels you have, you can pick the controller best suited to run them. This is when you consider if the extra cost of MPPT is worth it, not at the beginning.

[12thgenusa]

red31 wrote:
I guess I thought it was the MPPT that picked the voltage (power), if it is off, why not pick 40v @ zero amps? There's not much power @ 40v (24v panel) so I assume the MPPT is still on and picking some power level way over that of the IV power curve @ float and not all the available power is being used.

When MPPT is off as you put it, the panel voltage is allowed to be whatever it chooses. Right now mine is in float at 39.8 volts and .2 amps. The panels are idle with virtually no power being produced. The controller is waiting for a demand and then it will power up.

[12thgenusa]

red31 wrote:
12thgenusa help with stinking thinking.

Why do ya need a DC to DC if no MPPT?
For those that use nominal 24-volt panels it is imperative unless you want to lose half the power.
I thought MPPT fooled the panel to put out more power than the battery load voltage so that if MPPT is off, the panel would only put out battery voltage (walk the power curve as batt volts rise).
No. It decouples the panel voltage from battery voltage so the panel can operate at the voltage that produces the most power. No trickery required.
If MPPT is off is there other logic to fool the panel to put out more volts (power) than battery volts?

[red31]

I guess I thought it was the MPPT that picked the voltage (power), if it is off, why not pick 40v @ zero amps? There's not much power @ 40v (24v panel) so I assume the MPPT is still on and picking some power level way over that of the IV power curve @ float and not all the available power is being used.

[BFL13]

This was all with a 24v panel.

The Isc of the 24v panel is about half what the Isc is of the same wattage 12v panel, you need to "buck" that amperage to what you would get with no buck using 12v panels.

Perhaps my 230w panel that does about 15.5a in MPPT (which is on only in Bulk) where 230w of PWM would do 14.5amps, will only do 14.5 amps in Absorb or Float when the controller is "in PWM."

That is still way over panel Isc of 8.3a. IE, it still bucks the amps to make up for being 24v instead of 12v.

Voltage regulation to limit battery voltage at say 14.x volts is common to both PWM and MPPT controllers.

The "controlled" voltage levels are not to be confused with going from 36v panel ("24v") to "12v" battery or 22v ("12v") panel to "12v" battery which is all this DC to DC business.

[red31]

y'all have suggested MPPT is off (float) but the power is in excess of the power curve at float voltage (>Isc). If MPPT is off, what do you call the tracking of excess power? At some point the controller limits voltage but ain't the MPPT still tracking and the 'logic' is limiting charge voltage.

[BFL13]

I love how they say "power gain" for those huge percentages of MPPT over PWM. No mention of "amps to the battery gain" which is not a lot. They do mention that it is amps that count though! Gottaluvit.

Also no mention of gains for when the battery is in the usual RV range during the day with solar on--between 13 and 14.4 volts. MPPT gain is best at around 12 volts and becomes (much) less over PWM as battery voltage rises into the 13-14.4v range.

Step right up! Getchyer MPPT right here, 25% gains!!! Free box of Cracker Jacks with every purchase of our MPPT controller in the new attractive case your wife will love.

[JiminDenver]

Red

here is the Northern Arizona wind and sun's site explanation of MPPT

click

In layman's terms they put it like this.

Maximum Power Point Tracking is electronic tracking - usually digital. The charge controller looks at the output of the panels, and compares it to the battery voltage. It then figures out what is the best power that the panel can put out to charge the battery. It takes this and converts it to best voltage to get maximum AMPS into the battery. (Remember, it is Amps into the battery that counts). Most modern MPPT's are around 93-97% efficient in the conversion. You typically get a 20 to 45% power gain in winter and 10-15% in summer. Actual gain can vary widely depending weather, temperature, battery state of charge, and other factors.

A lot easier to get through than Wiki's page here.

click

[red31]

12thgenusa help with stinking thinking.

Why do ya need a DC to DC if no MPPT?
I thought MPPT fooled the panel to put out more power than the battery load voltage so that if MPPT is off, the panel would only put out battery voltage (walk the power curve as batt volts rise). If MPPT is off is there other logic to fool the panel to put out more volts (power) than battery volts?

[12thgenusa]

JiminDenver wrote:
MPPT just controls what volts and amps are needed to best charge the battery the fastest.

No. It sets the panel voltage to maximize panel power (watts).