Heat 1, MPPT 0
Previously we noted that heat is hard on MPPT due to the panel's loss of voltage with increasing heat. Doesn't bother PWM though, you still get Isc or more. This Spring, I took some measurements p...
Forum Discussion
I tried a couple things today- at 1030 and then at 1230.
Conditions today at noon the same so same readings. However, I did move the panel right up to the trailer and swapped out the long hot wire for a short cool set that had been in storage out of the sun
This did not change any of the readings, so the wire idea is eliminated. Also shows my regular panel-controller run with long but fat wire is not costing me anything in amps compared with the short run.
Earlier in the day it was cooler and I did get some numbers that show a little better, but not a lot.
Panel Isc was just over its rating so insolation good, sun high enough etc.
Ambient 22C back of panel 44C ( yesterday noon was with 24/48)
Panel wattage was a little higher at 184 vice 181
Got 14.03a at 13.1v, 14.53a at 12.7v, and 15.57a at 11.9v
So the under panel temp was 44C same as in the Spring with ambient then 16C so that leaves the difference in ambient temp as the prime (only?) suspect.
Panel voltage and amps were the same with same panel temp, but the wattage was lower with the higher ambient temp and amps thus lower for any same battery voltage.
So that all happens in the controller which is in a cool shaded spot in the cargo bay but is at ambient temp. Hmmmm. Now I suppose I should put a bag of ice against the controller !!!
EDIT: ok first the temp on the board the controller is mounted to is 23C , same as ambient. The controller was 31.5C --they do warm up when running; I can't say if that is a normal amount.
I put some things from the freezer against the controller with it first showing with the load added on 13.0v 12.4a 161w in Float, but then with the load running it changed to Bulk 13.0v 14.31a, 184w
After a time with the freezing bags against the controller, the controller was down to 25C but no change in watts at 184w. I couldn't keep it going long enough to get the controller down to whatever it might have been above ambient when ambient was 16C.
So I don't have any more ideas. I see the "controller snobbery" has come up a few times over the Eco-Worthy not being True Blue etc and the implication is that this whole thing could never happen to them with their expensive "proper" controllers.
To that I say, run your own tests and post the results and let's see!
Snobbery is not test data folks.
It would be worth knowing if some controllers are better than others for how many amps are lost in hot weather, ASSuming it is indeed there and not in the panel which was the first thought (maybe still correct but doesn't seem like it now)
Conditions today at noon the same so same readings. However, I did move the panel right up to the trailer and swapped out the long hot wire for a short cool set that had been in storage out of the sun
This did not change any of the readings, so the wire idea is eliminated. Also shows my regular panel-controller run with long but fat wire is not costing me anything in amps compared with the short run.
Earlier in the day it was cooler and I did get some numbers that show a little better, but not a lot.
Panel Isc was just over its rating so insolation good, sun high enough etc.
Ambient 22C back of panel 44C ( yesterday noon was with 24/48)
Panel wattage was a little higher at 184 vice 181
Got 14.03a at 13.1v, 14.53a at 12.7v, and 15.57a at 11.9v
So the under panel temp was 44C same as in the Spring with ambient then 16C so that leaves the difference in ambient temp as the prime (only?) suspect.
Panel voltage and amps were the same with same panel temp, but the wattage was lower with the higher ambient temp and amps thus lower for any same battery voltage.
So that all happens in the controller which is in a cool shaded spot in the cargo bay but is at ambient temp. Hmmmm. Now I suppose I should put a bag of ice against the controller !!!
EDIT: ok first the temp on the board the controller is mounted to is 23C , same as ambient. The controller was 31.5C --they do warm up when running; I can't say if that is a normal amount.
I put some things from the freezer against the controller with it first showing with the load added on 13.0v 12.4a 161w in Float, but then with the load running it changed to Bulk 13.0v 14.31a, 184w
After a time with the freezing bags against the controller, the controller was down to 25C but no change in watts at 184w. I couldn't keep it going long enough to get the controller down to whatever it might have been above ambient when ambient was 16C.
So I don't have any more ideas. I see the "controller snobbery" has come up a few times over the Eco-Worthy not being True Blue etc and the implication is that this whole thing could never happen to them with their expensive "proper" controllers.
To that I say, run your own tests and post the results and let's see!
Snobbery is not test data folks.
It would be worth knowing if some controllers are better than others for how many amps are lost in hot weather, ASSuming it is indeed there and not in the panel which was the first thought (maybe still correct but doesn't seem like it now)
