130w ecoworthy flex solar over voltage with renogy dcdc mppt

[turtle2121]

I have a strange problem. I have an Ecoworthy 130w Solar Panel on which the specs say open voltage/ max load voltage are 23.5/20,5. Yet I'm getting 26.5 out of the panel into my renogy dcdc mppt, causing it to go into over-voltage protection as it allows max 25V.

Any idea what would be causing this? Could a defect raise the voltage?

Thanks as always for this great forum.

 

[T6Jay]

I would be taking a photo of the voltmeter, and asking the supplier for a refund, or a replacement panel that meets their own specifications.

 

[yossarian]

This review They work but not the rated power.. suggests the reviewer got 26V and about 80W out of the same panel.

 

[Raul a/3]

The reviewer says 80v for the four panels in series, that’s 20v per panel.

On the op case I believe is the controller not the panel. The higher the voltage over the spec, the better. Indicates a healthy panel. I doubt the panel is pushing 26v, more likely a fault with the controller. Besides, a 25v ceiling for a controller, it’s pretty poor , sounds like a very poor cheap design.

 

[yossarian]

A little further on in the linked review:

 

[T6Jay]

The reviewer says 80v for the four panels in series, that’s 20v per panel.

On the op case I believe is the controller not the panel. The higher the voltage over the spec, the better. Indicates a healthy panel. I doubt the panel is pushing 26v, more likely a fault with the controller. Besides, a 25v ceiling for a controller, it’s pretty poor , sounds like a very poor cheap design.

The op has measured the open circuit voltage at 26.5V, so if the test was done properly, it's no fault of the controller, and in this case, more is not better.

The Renogy DCC50S/DCC30S (if this is what the OP has) is a really popular product, with the known limitation for PV max OCV, the CTEK DC/DC/MPPT devices have a similar limitation, it's no problem if you know about it and plan accordingly, this is why it's important for manufacturers to adhere to their own specifications.

Ask the supplier to sort it out!

 

[turtle2121]

Thanks all for the advice. Controller is a DCC30S, pretty happy with it apart from the app.

Checked the panel again under a bit of cloud today 25.5 open and 1.25 short circuit amps, I would have expected more like 4 as the max is 6.7. Have written to Ecoworthy. Unfortunately it's sika-ed to the van.

I've connected a BM2 to the solar input on the controller to get some graphing.

 

[T6Jay]

Thanks all for the advice. Checked again under a bit of cloud today 25.5 open and 1.25 unloaded amps, Should be more like 3-4. Have written to Ecoworthy. Unfortunately it's sika-ed to the van.

130w would be with bright sun directly overhead, if its sikad to the van that cant be the case in September under a bit of cloud. Are your expectations too high?

Nevertheless the voc is your biggest problem. If the supplier cant help, you can fit a diode (or two) to drop the voc.

 

[turtle2121]

I corrected my bad terminology as you were posting @T6Jay !

This is my first solar panel. I've had it on for a couple of weeks and haven't seen more than 30w out of it, but that could be the renogy locking out at the higher voltages.

Thanks as well for the diode tip. Sounds like a plan.

 

[Raul a/3]

What do you mean by ‘unloaded amps’? Sounds like a oxymoron.

Also, 130w would be with bright sun directly overhead, if its sikad to the van that cant be the case in September under a bit of cloud. Are your expectations too high?

Nevertheless the voc is your biggest problem. If the supplier cant help, you can fit a diode (or two) to drop the voc.

Open circuit voltage with no load, not amps. The amps was measured short circuit. Pretty well explained.

 

[Raul a/3]

Thanks all for the advice. Controller is a DCC30S, pretty happy with it apart from the app.

Checked the panel again under a bit of cloud today 25.5 open and 1.25 short circuit amps, I would have expected more like 4 as the max is 6.7. Have written to Ecoworthy. Unfortunately it's sika-ed to the van.

I've connected a BM2 to the solar input on the controller to get some graphing.

Do you take a voltage reading with a multimeter, or you rely on the controller to tell the voltage. A mppt with 25voc it’s not much of help.

 

[T6Jay]

Open circuit voltage with no load, not amps. The amps was measured short circuit. Pretty well explained.

The op had edited his post, and now I have too, to clear up any confusion.

 

[Raul a/3]

Makes sense.

 

[turtle2121]

Hi All, thought I'd update on this now we have good weather and a few people have messaged me asking if I managed to fix it.

I added a 20A10 diode in front of the Renogy DCC30S and it seems to be working well. The drop is around 1V. Getting just over 100w out of the panel today in full sun, which I'm happy with. The diode gets very hot, which I guess is expected, even with 6A passing through. Once the renogy accepts charge from the panel the voltage drops to 17V. So it's only when there is no load that the panel voltage is over 25V.

Some circuit which would lower the voltage only when over 25V and then allow the full power though on load would be ideal.

 

[yossarian]

Your diode is dissipating about 4.2W. it's a simple solution, you could try a Schottky to save 2W or so. Doesn't seem much point. Even less so to start messing with a zener.

 

[T6Jay]

Your diode is dissipating about 4.2W. it's a simple solution, you could try a Schottky to save 2W or so. Doesn't seem much point. Even less so to start messing with a zener.

sound advice. A heat sink of some kind could cool things down

 

[turtle2121]

Your diode is dissipating about 4.2W. it's a simple solution, you could try a Schottky to save 2W or so. Doesn't seem much point. Even less so to start messing with a zener.

It's amazing how much heat that 4.2w gives off!

 

[yossarian]

If the heat is a problem you could try a wirewound connected across the panel output. They come in heat sinking packages eg this 250 ohm one

That one should dissipate 2.5W or so; well within it's rating.