What can you do with solar?

[pianotuna]

Hi,

Please reply with what your solar system can do to enhance your RV'ing experience.

Please list the number of watts, Charge controller, inverter (if any) and amp-hours of battery bank

256 watts Unisolar in a parallel/series configuration input to charge controller 33 volts.

Blue Sky 3024 di

2500 watt Cobra MSW inverter

875 amp-hours of battery bank.

Allows me to operate the RV as if it were connected to shore power. The only high wattage item I do not run is the air conditioner.

[BFL13]

He has two 12v AGMs. My usual WAG is that at 14.4v, 90% SOC goes with 5 amps per batt and at 97% it is 2 amps per batt.

So he could be accepting 8.6 amps to around 92% SOC I suppose. Not sure when in the morning you would get to 92 in order to be "full" before noon.

[CA_Traveler]

And who says solar isn't complicated?

[HiTech]

Or panel type? My Unisolars seem to get into making power about an hour earlier than a lot of hard panels, and make good power late in the day due to both lower light requirements and not losing much output when warmed up. So the amp curve over a day is wider and flatted than some solar panels.

Jim

[BFL13]

CA Traveler wrote:
This time of year:

LA sun 6:30-5:30, max elevation 45 deg
Victoria sun 6:45-5:15, max elevation 31 deg

Plus more (probably lots more) Victoria overcast weather.

Yes, but the point (if any) is that down there in summer there is less difference than here between flat and tilted with the sun being so high at noon. That might help explain where my system isn't working right.

But you can't get noon amps at noon if the batts are full Amps would be a trickle. His definition of "full" is unknown. It does take hours to do that last 10% to 100%, so how do you fit that in before noon? So how early in the morning did he get that 8.6amps? how can the sun be high enough that early to be like at noon? You can get Isc early but you also have to be tilted high and turned toward the sun. Just being tilted South won't get the full amps until closer to mid-day. --it seems impossible.

I just don't get it and am trying to puzzle out where I am going wrong with my understanding, or if there is " more to the story" that would clarify it all.

[CA_Traveler]

This time of year:

LA sun 6:30-5:30, max elevation 45 deg
Victoria sun 6:45-5:15, max elevation 31 deg

Plus more (probably lots more) Victoria overcast weather.

[bigfootford]

JiminDenver wrote:
This weekend is suppose to be at least partially sunny, so I will run a test. I'll use the 12v fridge to take our grp 27 down to 12.1v and see how many hours it takes to get it back up to float. The last test was at 12.3v which is lower than we ever see daily even after just a few hours on the genny, so the battery really isn't fully charged to start with. Sunday I'll rerun the test with the panel flat.

12.1 with a load is not taking the battery down very far..
12.1 after the battery has rested for .5 hrs will be down close to 50% if the battery temp is in the 70's...

Jim

[BFL13]

Maybe the diff between flat and tilted is so much less down there with the sun being higher that you would get higher amps than 8.6 flat at noon similar to tilted amps, but you get peak of 8.6 mid-morning?

It would help if you would specify the scenario where and when you got the 8.6 but still were full by noon.

[JiminDenver]

This weekend is suppose to be at least partially sunny, so I will run a test. I'll use the 12v fridge to take our grp 27 down to 12.1v and see how many hours it takes to get it back up to float. The last test was at 12.3v which is lower than we ever see daily even after just a few hours on the genny, so the battery really isn't fully charged to start with. Sunday I'll rerun the test with the panel flat.

[WoodGlue]

BFL13 wrote:
OK, without any math, please clarify how you get 8.6 amps but are charged up by noon. I am still learning how solar works and I can't figure out how that can be. Thanks.

It's sunny where I live?

[BFL13]

OK, without any math, please clarify how you get 8.6 amps but are charged up by noon. I am still learning how solar works and I can't figure out how that can be. Thanks.

[WoodGlue]

JiminDenver wrote:
BFL

Looking at his list of draws on his battery, I'm not surprised really. I don't see the furnace listed so he is probably using less than we do and I can have our battery in float in 3 hrs or less seeing 8-10a at sunrise.

Thanks, I don't do math!

WoodGlue

[JiminDenver]

BFL

Looking at his list of draws on his battery, I'm not surprised really. I don't see the furnace listed so he is probably using less than we do and I can have our battery in float in 3 hrs or less seeing 8-10a at sunrise.

[BFL13]

WoodGlue wrote:
155 watt GoPower panel & controller
8.6 amps of charge power
30 amp digital solar regulator

2 Sears Platinum 12v AGM marine Deep Cycle Batteries.

Charges full before noon after an entire night of computer use, cell phone charging, 12v TV watching, led lights on, fantastic fan on.

Thanks pianotuna for this thread. It's been very informative so far to see everyones individual setup.

WoodGlue

Can you confirm/clarify from experience how my "system" compares with reality using your figures please? ( I need more proof before totally believing in my system)

155w and 8.6 amps suggests flat panels. 155/130 x 8.2 = 9.8amps if tilted and pointed to get Isc.

If at 49N in May, then flat would be 155/130 x 7.2 = 8.6 amps mid-day so that comes out right. ??

The daily AH haul you can assume from the mid-day amps is more dependent on when and where, but 8.6 in May at 49N would get you
8.6/8.2 x 70 = 73AH. So by being full at noon means your usage is 36AH?

I don't understand at all how you can be fully charged before noon though. That 8.6 amps would be a noon max in my system, but if the batts are full, the amps would be down to a trickle. In that case your peak amps would be mid-morning when the sun is lower and would be less than 8.6. What am I missing? Thanks.

[mena661]

bka0721 wrote:
I use solar for 3 things, as I full time in a Truck Camper.

VERY impressive setup!

[pianotuna]

Hi 3 tons,

I was fascinated by that tidbit. Thank you for sharing it. Words on a screen don't convey things too well sometimes.

3 tons wrote:
Sorry, PT no history lesson intended