Solar test...

[John in Santa Cruz]

ok, doing a battery/solar test, this will take a week+

I have 412AH of Lithium (5260WH) and a 360W solar panel on a MPPT 100/30. The N2175 DC Compressor fridge is on and set quite cold (close to 0F freezer, 34F fridge). The Maxxfan is run much of the day and into the evening, usually on 30%. LED lights are getting light use. The furnace is switched on at around 62 or 63F when its getting colder than that late at night, as I'm sleeping in the trailer every night during this test. My phone is getting USB C charged at night, usually about midnight til around 10am.

When I'm done with this, I plan on posting some graphs from the Victron shunt and solar, showing the week or so of discharge and whatever it takes to fully recharge without shore power.

The last week or so, the solar has been outputting 650-730 WH a day, recharging the batt.

tonight at 8:20pm, I shut my solar controller off.

2024-08-19 8:20pm battery @ 96%

oops, solar decided to recharge battery this morning, i used the wrong 'off' setting, i guess. ok, restarting test.

2024-08-20 8:00pm battery @ 97% (its been a couple years since I reset the charge state, me thinks I should do that when I've fully recharged)
2024-08-21 8:00pm battery @ 84%
2024-08-22 8:00pm battery @ 74%
2024-08-23 8:00pm battery @ 63%
2024-08-24 8:00pm battery @ 52%
2024-08-25 8:00pm battery @ 40%


edit: I will be editing this post each day until the battery is deeply discharged, then cranking on the solar to see how fast it recharges.

Saturday update: its looking like Monday/Tuesday will be the best days this coming week for the solar recharge, both days the sun breaks through morning clouds around 10am. so after tomorrow evening, the battery should be at 40% or so, thats deep enough for me.

 

[John in Santa Cruz]

annnnd, I turned the solar charging back on to see how fast it can charge. I was going to go a few more days, but after tuesday, we're getting a bunch of cloudy/foggy weather.

Total discharge was over 5.5 days was -299AH.

2024-08-26 10:30am, battery minimum overnight was 35%.
2024-08-26 8:00pm, battery @ 50%, days sunshine is over.
2024-08-27 8:00pm, battery at 63%
2024-08-28 8:00pm batt at 77%
2024-08-29 8:00pm batt at 89%
2024-08-30 midday batt at 96%



about 1:30pm on the 26th (peak sun), I checked my solar, was getting 16A battery output which seems low, so I got on my ladder, wow, panel was FEELTHY, so I washed it down and hosed it off, and now its outputting 21A. It may improve as it dries off, the wet surface is shinier than the bare panel. k, half hour later, panel is 90% dry, no real change in current, but the drying water left water rings on the panel (we have hard water here).

note on 08-27.... Houston, we have a problem. I realized where my trailer is parked, with the tongue facing west, the sun doesn't clear the trees and fully expose the panel til 11am, and after about 4pm the shadow of the A/C unit starts obscuring my panel. Net result, I'm only getting 1.4-1.5KWH a day, I know my panel can generate more than 2KWH if the tongue is north and there's no shade. As it is, after 2 full days of charging, I've gotten from 35% to 63%, suggesting around 3 more days to be fully charged, after 5.5 days of 'typical' camping usage with solar off.

note on the 29th, we just might end up fully charged tomorrow night. Still generating around 1.40-1.48 kWH/day. So 5.5 days of usage, 4 days of suboptimal solar charging plus one more, and we're back where we started, and if 5.5 days of usage ran me down to 35%, then my 7 days of dry camping without sun should hold true, but maybe not with as much margin as I thought I had.

if anyone cares, I'll post a bunch of graphs from the victron history once this is done..