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2024.02.24 panel and controller comparisons:



I've been planning on doing this for awhile now, but we finally got some sunny and reasonably warm weather this
weekend so I headed outside around noon to do some testing. My main goal was to compare performances of all
my solar controllers as well as compare my three types of 100w solar panels. I didn't get any pictures this
time, but I did get a lot of useful information.

- my FLA battery may have a problem it discharges rapidly to well under 12 volts, easily falling to 11.6 before
  I disconnected the load. then it quickly charges back up to 14+ volts.

- I think I can use an electronic load in CV mode, set it at CV=13.0, and connect to a battery as reference load

- renogy, 4lb, and dokio panels have nearly identical performance

- PWM controllers (both the $3 and the CPY) perform okay but tend to drag the panels down very close to the
  battery voltage. they dont waste much power themselves though, they just don't attempt to operate the panels
  at their Vmpp

- my CMG controller runs proper buck regulation, whines a little while in use, and operates with about the same
  panel efficiency as the tracer. But it tracks very slowly, taking several minutes to arrive at Vmpp. Panel
  voltage changes by around a tenth of a volt every few seconds.

- the tracer has an idle power draw of about 300mW. It also has a very fast tracking speed and appears to be
  able to lock onto Vmpp in a matter of seconds. It clearly makes very coarse adjustments early on. I also
  witnessed a consistent problem, the tracer stops power generation if the panels are completely disconnected
  and then reconnected. I had to also disconnect the battery to "reboot" the tracer to get it to resume operation.

- when Vp goes up around 18v due to low draw, the Renogy panel seemed to still produce a fairly large amount of
  current, whereas the 4lb and Dokio panels produced substantially less current and power. (while connected in
  parallel with the Renogy) They may be wired differently in the entrance box on the panel.

- the 12v trucker heater performed very well to keep the battery voltage in check, though it had to be operated
  intermittently. It only took it about 30 seconds to bring the battery down from 13.6v to 11.8v. Part of this
  may be due to needing to replace the CCA with CU in the battery box.

- the Elejoy solar tester looks to work well, though for some reason it defaults to "manual MPPT" instead of
  "auto MPPT" when plugged in. The top line on the display (Pmax) is difficult to read in the sun due to the
  bezel shadow, and the backlight doesn't help much.

- the Mk1 two panel combiner box's meter glitched out again. it reset after it had been unplugged for awhile.
  This has happened before, and I may end up replacing the meter board in it if it keeps acting up.

- I may want to make a large plastic box with 2 or even three 20A meters in it to test several loads in parallel
  easily. The largest pinfox box I have used so far could only (barely) fit two meters in sideways.

- I could have used more short CU jumpers during testing. Also the shortest CU jumpers I have are 6ft.

- I was able to produce over 80 watts from the 4lb and Dokio panels while angling them, and this is in February,
  so I may have to re-evaluate what I consider Pmax for those panels. (I've been going by 76w)

- the CMG charger did not hesitate to charge the battery to over 14 volts, and I think I saw the Tracer doing
  the same, to a lesser extent. (lower current)

- the leafless tree across the street was producing a very noticeable drop in power, as power came up quite a
  bit when the sun got past the tree. The sun was at about a 35 degree angle at 1pm when it had cleared the
  trees. I expected the sun to reach a much higher angle than that, even at this time of the year. (37 degrees
  is the max at this latitude in late Feb)

- I had to borrow the $3 controller out of the Escape for testing. I should connect powerpole pigtails to at
  least one of those $3 controllers.

- I considered replacing the Escape's controller with one of my two CMG, but I don't want to be overcharging the
  battery.

- placing the 4lb and Dokio panels in series may not have produced quite the expected double the output. I
  initially was getting 56w each from them but only getting around 92 with them in series. Battery charger may
  have affected this though.

- the $3 controller survived being connected to three panels in parallel, which was generating over 8 amps total.
  they are rated 20 amps, but that sounds dubious, given the price of the controller.




last updated 02/25/2024 at 15:35:49 by make_www_index.command version 2024.02.01.A