jrnymn7 wrote:
Just to clarify, with the eco-worthy, one can go 12v panels in series, for 24v in, and still get 12v out, right? (NOT just 24 to 24, and 12 to 12)
Yes. It has a buck converter plus an MPPT component. There is some question whether its 42 or 45Voc intake limit will allow two 12v (22Voc each added) in series. That is what Jim was referring to whether the guy in the video has truly done that successfully and whether we could get away with it too.
Don't forget that higher panel temperature will screw up the MPPT on 12s too, the way its buck converter makes amps from watts. PWM just passes the Isc along so it doesn't take a hit with higher panel temperature. (OTOH it doesn't make any more amps with really low battery voltage either if you want that feature if you run big loads all day)
I would not risk my Eco-W on two 12s in series, but it would be fine with two 12s in parallel. (edited!) The Tracer has 100Voc limit so that would work with two 12s in series but you have a fixed charging profile--it is a pretty good profile though.
My thinking is if I had two 12s I would swap over to the PWM Solar30 for when using them in parallel and save the MPPT (a Tracer maybe, not the Eco-W) for when they are in series. I would swap over to PWM once it got warm enough in the season that I could see my peak amps from MPPT was down to less than what PWM would get me and then I would swap back in the Fall when MPPT would do better than the PWM again.
The guy in the video was confused about the Eco-W "demo" in an earlier show. The "PWM amps" figure bottom left, is actually the same amps as the Panel Isc. This makes it easy to tell if you are getting as much or more Isc as total rated Isc as an indication you are getting full STC insolation and so you should be seeing peak amps now too.
If you are getting full Isc but less than what peak amps ought to be, panel high temperature may be the culprit. That is what I found when I was getting only 13.5 amps peak when 230w should have been getting 14.5 PWM and the same MPPT set-up was getting 15.5 earlier in the season when it was cooler. I have an IR gun thermometer and was able to see it was panel temperature to blame.
I have not risked putting the Solar30 on my 230w panel. I didn't like how the PWM RJ Special acted on that, although it did not fry. I have read that it should work but only pass along panel Isc as usual so it would work, except the Isc is only half what it would be with a 12v panel at least you would get something. somebody else can risk his PWM controller on that. Note that you don't see the Voc intake limit in the specs for those. they don't have a buck converter in them so maybe that is why no Voc limit is specified, no idea. Anyway I am saving my Solar30 in case I ever get a 12v panel again.
