Eco-Worthy 12v solar panels, Now drifting to... mono vs poly

jrnymn7 wrote:
Here's something weird. That pm3 I just bought, I bought it on Ebay from boatandrv, but it was sent from Florida, from Errin.

Interesting. Now we get to look again at what exactly it says on the label on the lid, compared with what it does.

Boatandrv makes their "PM3s" sound a lot like PM4s having the fourth stage zap of "equalize" during float every so often, and with PF correction. You are hoping it does not have that 15 minute thing, which some later PM3s might have got just before they went to "PM4s"

No doubt we will be able to hear the howls from there if it turns out all funny :) Do report when you know! :)

Here's something weird. That pm3 I just bought, I bought it on Ebay from boatandrv, but it was sent from Florida, from Errin.

dang!!!

jrnymn7 wrote:
It appears there is no difference what time of day it is. The two curves are the same.

Not if you are selling controllers! Early, you have 3 instead of 2 which is 50% better for MPPT. Never mind Noon, when it is 8.5 instead of 8 so only 6% better with MPPT.

Your ad for the Super-Dooper MPPT will say "You can expect 'up to' 50% more amps with this controller than the 'ordinary kind sold by those other people' gets. "

i

jrnymn7 wrote:
"Whatever controller you get, make sure it has adjustable high set point. IMO ignore temp comp except for long term storage battery Float. While camping you can play with the Vabs if especially hot or cold out."

Yeah, I was thinking I could make any temp adjustments manually, throughout the year, just like with my charger.

If I understand correctly, that Eco-W 20a mppt has a set point adjustment of 13-15.5v... except they call it "Constant voltage (Over charge) voltage".

And I'm guessing "max discharge current" only applies to a direct load off the controller, not from the bank?

The Eco -W has two voltage adjustments. the Vabs goes to 15.5 but the Float only goes to 14.5. As soon as battery voltage reaches the set Vabs it drops to float. No time at Absorb. So the trick to stay at your say, 14.8 Vabs a couple hours would be to sset Float the same as Vabs at 14.8. but you can't set it above 14.5.

It turned out that my 6s did great on that 14.8 then 14.5 rest of day and kept up baseline SG when full. No equalizing needed.

The T-1275s didn't do well at that. They want longer at 14.8 or else maybe even higher.

Meanwhile the Solar30 has the one setting for Vabs to 15v highest, and once batts get there it stays there till dark. Vabs is the float.
what I liked was the thing was not calibrated that well, so it went 0.5v higher than set. So if I wanted 14.8 I set 14.3. No problem. Even better, if I set 15 it would do 15.5 and equalize! :) Niner says his goes above setting too the same way. Once yiu know the index error you can allow for it. Be a bummer if it went below setting though.

I never had my Eco-W do 19.9 and 20.0 amps so I can't say if it would clip the amps at 20 if it got more in. Some MPPT controllers do clip the amps at rating so they will not overheat.

PWM 12v controllers will pass through more amps than rated and overheat, so you are supposed to have some margin there in case the panel is doing better than its rating. 20% margin is recommended, so if your array can do 20a at STC, then allow 20% =5a and use a 25a controller.

It appears there is no difference what time of day it is. The two curves are the same.

A lot of the so called improvements we discuss are less than the hype makes them out to be. Had I been able to run those $50 panels with a PWM controller, I would have never bought the Eco-W.

The difference between hot and cold for my panels is more like a half of a amp.

Even if the MPPT does better early and late in the day compared with mid-day, before getting all excited, consider how much better that might be in AH.

Here is Salvo's graph (with my 130w tracking graph on it too) Notice that he gets way more amps with MPPT early and later in the day.

Yes, three instead of two! Wow! so in three hours you will get---wait for it!---3 more AH!!!! Oooowee, where can I buy one of those $600 MPPT jobs instead of a $15 RJ Special?

BFL13 wrote:


My 130w was about 20.3Voc in the sun in the summer (rated 21.9) That 42-45 limit on the Eco-W is very awkward!

Ambient temperature does have a effect on the panel but it isn't going to stay cold long. On a normal cold day the panel is slowly exposed as the sun rises. It will be putting out lower levels of power and Voc until fully exposed to the sun. Those lower levels still produce heat so by the time the panel could get above its Voc, it is already too warm to do so.

My 220w mono did jump above it's rating a lot when suddenly exposed to bright sun in freezing temps. Even then the really high numbers didn't last long once the panel had a chance to start working and then warming up.

So maybe on a cold cloudy day and the sun suddenly pops out.....

"Whatever controller you get, make sure it has adjustable high set point. IMO ignore temp comp except for long term storage battery Float. While camping you can play with the Vabs if especially hot or cold out."

Yeah, I was thinking I could make any temp adjustments manually, throughout the year, just like with my charger.

If I understand correctly, that Eco-W 20a mppt has a set point adjustment of 13-15.5v... except they call it "Constant voltage (Over charge) voltage".

And I'm guessing "max discharge current" only applies to a direct load off the controller, not from the bank?