Tilting Solar panels makes a big difference!

[DAS26miles]

I had 2 100 watt Renogy solar panels on my roof and they seem to only have an output of 3.4 amps each. I added a third panel and now the max is around 10 amps this time of the year for the 3 panels. I also have a Renogy Solar100 watt portable suitcase which has a max output of 5.5 amps. I laid it flat and it only added 3.7 amps but when I tilted it for max sun it rose up to 5.5 amps. I hope during the summer my max on the flat panels gets up to over 5 amps each.

[Almot]

Sorry Mr Wiz, I've got lost between your two rigs :).
I remember that 600W array now.

If solar is meant to support almost permanently, with generator occasionally only, solar size should be planned for average-low harvest on the credit side of energy balance sheet, and average-high use on the debit side. Whatever somebody's average use is.

[MrWizard]

like i said, this is the Bounder, not the Safari
this fridge is a Dometic side*side LP RV fridge
so far it is working very well
IF it should die in the future, then AT THAT TIME, a change will be in order

the safari DP has the Over 600 watts of solar and the electric fridge

the Bounder has NO Solar
thus the new 200w portable system due to arrive on tuesday

[Almot]

SoundGuy wrote:

'Though I'm sure unintentional you're supporting my argument that for some a 100 watt system can serve their needs just fine.

...And I also mentioned the situation when ZERO solar could serve somebody's particular needs as well.

The key word - in my post about 100W - was "live". Not necessarily fulltime, but reliably. If somebody's needs are 15AH, he can live on 100W that will get him on West Coast Lat 49 (for example) 35AH daily average, flat, in July. 30AH average in June. It doesn't matter (much) what is the maximum on a good day, it matters what it will harvest average (battery should be big enough to get you through the days below average, but this is another question).
Can be days and weeks when 100W at Lat 49 will harvest less than 15AH. More with tilting, but when flat output is 12AH, tilt would only increase it to 15AH. Living on 15AH? Sure, even on 0AH - when I was younger and there was no solar, I said it - my bad :)... Vast majority of members here would probably correct me that this was a surviving, not living.

For a fulltimer like Mr Wiz, with residential fridge, 100W or 200W is nothing, a stop-gap between generator runs while waiting to fix the big system on the roof. His (400W?) is still not big enough, considering his needs and days with "marine layer" on the coast.

[MrWizard]

This is a stop gap, do something now, save some fuel and generator wear
One place in particular, I'm broadside to the sun for the important 10am to 4pm solar hours, so placing this, on the side of the RV, facing the sun should accomplish what i need, for a helper, for now
Then i will do the roof install later this year

[BFL13]

MrWizard wrote:
i run the generator for breakfast and morning charge routine
i figure 200w will maintain charge status and power my laptop,
so the batteries are still charged come evening
just run genny for supper

Tilting is important, but the real money is in being able to twirl the tilted panels during the day to be more aimed at the sun. This is really easy to do. As you go about your business back and forth during the day, passing by the solar set, you just give it a little twirl.

It varies a lot, but the figures I got from my 130w panel in May at 49N when I tested for daily AH haul:
Flat- 56AH
Tilted pointing South all day- 70AH
Tilted and Twirled three times a day- 90AH

You can scale up from 130 to 200 to get the figures for 200.

(Those figures were for solar on batteries with a load on them to keep their voltage from rising so the test would be consistent. For actual battery charging, you would get a lower daily haul. More AH in the morning and less in the afternoon if it is sunny all day)

You can get a few more AH by twirling it more often. I twirled back to SE in the evening so it would be already aimed for the next morning, then South for mid-day, then SW mid afternoon.

I eventually made a contraption to hold the panel(s) but some guys just prop it against a folding chair. You can stake one end and use a bungee or whatever and rotate from the stake. You can use a swivel chair with the panel in the chair. Anything that works. It is really worth it as you can see from the above figures.

It is especially useful when it is say, overcast in the morning and it clears by lunchtime. Being aimed in the afternoon gets you full advantage of what sun there is that day.

[SoundGuy]

SoundGuy wrote:
... there are some here on the forum who for their particular needs manage just fine with a single G31 battery and 100 watts of solar.

Almot wrote:
100W solar will harvest ~30AH on a good day.

I often use under 35AH a day.

'Though I'm sure unintentional you're supporting my argument that for some a 100 watt system can serve their needs just fine. I hate being repetitive but what I said stands - "for their particular needs", the point being everyone has different expectations from a solar system. Is 200 watts more useful than 100 watts? - of course, but it's a matter of whether the larger system is worth the cost and additional size & weight. Only the OP can answer that for himself. 😉

[Tom_M1]

DAS26miles wrote:
My controller is the the 30amp Renogy Adventurer. I may upgrade to a MTTP depending on how much more amps I can get out of the existing panels.

You will not gain much on a 12 volt panel configuration. MPPT's big advantage is using panels that are higher volts. This can be accomplished by using a panel that is 24 volts or higher or connecting panels in series. If panels are connected in series, they must have similar current ratings. If connected in parallel, they must have similar voltage ratings. The portable unit mentioned previously has panels that can not be easily reconfigured.

If you want a better PWM controller you might want to consider the Grape GS-PWM-40BT. It's 40 amps and has Bluetooth. Home Depot is selling it for $59.98.
40 Amp PWM Solar Charge Controller with Bluetooth

[MrWizard]

i run the generator for breakfast and morning charge routine
i figure 200w will maintain charge status and power my laptop,
so the batteries are still charged come evening
just run genny for supper

[Almot]

SoundGuy wrote:
there are some here on the forum who for their particular needs manage just fine with a single G31 battery and 100 watts of solar.

I wrote earlier in some other thread that could manage my particular needs with zero solar, when traveling in a kayak :).

100W solar will harvest ~30AH on a good day. It requires a certain lifestyle, certain appliances (like no DC thermostat in fridge), and a bit of self-discipline, to live on 100W, especially since not all the days are good. If 100W is your ONLY energy source, - it's tough.

I often use under 35AH a day. But my 500W flat array will get me those 35AH 99% of time, including days with low overcast and some rain. And when I need to use laptop more than usual, or charge power tools, or do something inside or outside after dark with plenty of light - 500W will take care of this. Battery bank size is important for solar living too.

[SoundGuy]

Almot wrote:
There is not much harvest from 100W portable, you can't live on this source alone.
There is more harvest from 200W portable, but this is more panels to handle and it's still tough living on 200W even when tilted - doable but not always.

Yet there are some here on the forum who for their particular needs manage just fine with a single G31 battery and 100 watts of solar. :W

[Almot]

Like BFL said - it's all about scenario. Latitude, climate, energy needs.

There is not much shade in SoCal, Az and Northern Mexico. Put 600W flat on the roof and you're good to go, no tilting or messing with portables. If it wasn't for controller box inside on the wall, I would forget that I even have a solar - it just works.

There is not much sun in BC and PNW. Put 1,000W on the roof and tilt it all you want, the harvest won't even cover small grey LCD clock on your radio when it rains.

There is not much harvest from 100W portable, you can't live on this source alone.
There is more harvest from 200W portable, but this is more panels to handle and it's still tough living on 200W even when tilted - doable but not always.

And so on.

[MrWizard]

I have No solar on the "N.T.US" Bounder
full time, using lots of generator gas
Fiances and situation not right at this moment for doing 400w on the roof
don't have and extra $1000 laying around right now (panels, hardware, wiring, controller)

so i just ordered the the 200w folding solar kit
i have easy access to the converter and extra battery in the bay on the curbside/passenger side, so easy connection to the 12v house system

so maybe this will help reduce my fuel costs, and save some money to go for the roof system
great price for 200w of portable solar and the pkg folds up nice and small,
should be no problem storing behind sofa

maybe i can get the roof system come late spring

[red31]

DAS26miles wrote:
The 200 watt portable probably can't be tapped into my system as the voltage is only 18 volts and my Renogy system is 20 volts.

Solar panels have a wide range of operation, with PWM controller they operate @ battery voltage. Probably can, certainly can be paralleled with the others.

[SoundGuy]

DAS26miles wrote:
My controller is the the 30amp Renogy Adventurer. I may upgrade to a MTTP depending on how much more amps I can get out of the existing panels.

MPPT - Maximum Power Point Tracking. 😉

[DAS26miles]

Tom_M wrote:

DAS26miles wrote:
I have disconnected the controller on the Renogy suitcase and use the existing wiring and Anderson connector. I added an Anderson connection mounted near my batteries and controller for the roof mounted panels. Now easily able to attach portable directly into wiring before controller with disconnect switch.

The Dokio 200 watt mentioned consists of four 50 watt panels connected in parallel. This has a Voc of 22.5 volts which is typical of a 12 volt panel. If your existing panel is 12 volt you can parallel this panel with yours if your existing controller can handle the added current. Or you could use this panel and controller and connect directly to your batteries using the included battery clamps.

My controller is the the 30amp Renogy Adventurer. I may upgrade to a MTTP depending on how much more amps I can get out of the existing panels.