When was the 50 watt solar panel upgraded to 100 W

[Protagonist]

Originally Posted by Tampatomgirl

I would like to install solar panels on my 34'. Can anyone tell me how many it would require to be fully operational with two rooftop A/Cs?

Not possible at all. Even if you had all of the solar capacity in the world, you wouldn't be running the A/Cs from the solar panels, you'd be running them from the batteries through the inverter. And your A/Cs aren't wired to run from the inverter in the first place. Those circuits are shore-power-only.

[LB_3]

Originally Posted by Tampatomgirl

I would like to install solar panels on my 34'. Can anyone tell me how many it would require to be fully operational with two rooftop A/Cs? I'm not interested in pro installation. I can do it myself. Just having trouble figuring out all the calculations on the websites. Can't be that complicated. I have roughly 225 sq ft of interior space & all the usual appliances. Any help would be appreciated 🌺

As others have said, it can't really be done. It would require between 50 and 100 panels and your roof probably maxes out with 15 panels.

A generator is the only option for off grid air conditioning.

[lewster]

Uh......guys...................

IT CAN BE DONE and IS BEING DONE as everyone reads this!!!

With new lithium battery technology, you can EASILY operate ONE roof A/C from the battery bank thru a suitably sized inverter. I have an Interstate client on the road now with an 800 amp/hour lithium, Magnum MSH3012-M inverter/charger and 400 watts of solar that can run his roof A/C for around 5+ hours while stationary during daylight hours. (A larger solar array and controller will extend this operational time by contributing more charging amps into the battery bank during daylight hours).

While running down the road, the engine alternator provides a 50-60amp boost into the batteries that will extend the A/C run time to 7-8 hours. The batteries are then easily recharged at a rate of 125 amps by the generator/inverter at any time.

I haven't had the opportunity to try this yet, but with a similar arrangement and properly sized generator, this would probably start and run 2 roof A/C units as well, but not for the duration listed above.

The only problem is the cost.

[Protagonist]

Originally Posted by lewster

IT CAN BE DONE and IS BEING DONE as everyone reads this!!!

Thanks for the clarification/correction. My response was based on an interpretation of Tampatomgirl's post that didn't include changing out the batteries for LiFePO4 but rather just adding solar panels to the existing electrical system. The fact that she said, "I'm not interested in pro installation. I can do it myself," is what led to my interpretation.

[Mcrid]

I'm on day 3 with no hook ups. The 300 watts and good weather (sun) is recharging completely during the day. I'm dropping to 55% DOD over the evening. Frig is running 24 hours and fan during the afternoon. Nothing else. So I will be adding two additional batteries to store more reserve and allow more convenience items to be on. Pleased with the outcome so far.

This would be so easy for AS to plop an addition 200 Watts and I think most folks would be very satisfied. I will be replacing the 15 thermal breaker as I think it has popped at least a couple of times so I'm not able to take full advantage of the solar power available at peak charging. I've not seen 17 amps yet, but 16 regularly between 11:30 and 1.

When the below freezing charging issue is solved for Li I'm all in.

[lewster]

Originally Posted by Protagonist

Thanks for the clarification/correction. My response was based on an interpretation of Tampatomgirl's post that didn't include changing out the batteries for LiFePO4 but rather just adding solar panels to the existing electrical system. The fact that she said, "I'm not interested in pro installation. I can do it myself," is what led to my interpretation.

Protag,

You are absolutely correct based on the OP's basic stipulation. And you are correct again as this type of all-encompassing trailer re-wire is definitely not for the inexperienced nor the basic DIY-er.

There are several folks on here who have done similar upgrades to their rigs, but all seem to be coming from a related tech field with transferable skill sets. 😁




Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[73shark]

Originally Posted by lewster

Protag,

You are absolutely correct based on the OP's basic stipulation. And you are correct again as this type of all-encompassing trailer re-wire is definitely not for the inexperienced nor the basic DIY-er.

There are several folks on here who have done similar upgrades to their rigs, but all seem to be coming from a related tech field with transferable skill sets. 😁




Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

As Clint Eastwood famously said,"A man has got to know his limitations."

[InterBlog]

Originally Posted by AnnArborBob

Here are two pictures of our current installation. We will be getting two additional panels in another week or so. They are Grape Solar panels provided by AM Solar. (BTW, these were installed by LEWSTER.)

As has been mentioned on other threads, for the benefit of thread readers who may be just beginning their solar research, your panels appear to have raise-lower ability. That is potentially very useful, but in the first photo you show, shadows appear to be cast on the background panels. According to solar guru Handy Bob, huge losses can result from little shadows, to the point where (depending on configuration) it might be better to have a smaller number of shadowless monocrystalline panels vs. an array with more panels but which is subject to more frequent shadowing. That kind of thing ought to be evaluated on a case-by-case basis.

We followed Lewster's general principles and also Handy Bob's advice when DIY-designing our 3-panel system, which looks like this (below). Because we had a very small available roof space and a very nice OEM Airstream roof rack already in place, we vaulted our panels above our air conditioner by affixing them to the roof rack (the custom panel frame is hinged so the a/c can be accessed when needed).

As far as we know, to date we're the only Interstate owners who have taken this kind of approach. Our system works wonderfully, with no shadows being cast at any time, and we've noticed no handling degradation in the vehicle with the panels up that high. The frame and panels weigh less than 100 pounds and the front of the frame is tilted down slightly to deflect air flow when the vehicle is in motion.

[lewster]

Sorry, but many don't consider 'Angry Bob' to be a guru!!!!

He is certainly opinionated!!!!


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[lewster]

Originally Posted by 73shark

As Clint Eastwood famously said,"A man has got to know his limitations."

One of my fav. quotes of all time!!!!


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[InterBlog]

Angry Bob does not suffer fools gladly, but I've heard his advocated basics echoed by other reputable sources, including segments in "This Old House" and it's "Ask" spin-off TV series. Especially on the issue of shadowing. *IF* Bob is correct in his shadowing loss calculations in the example that he provides, i.e., if a 3-panel assemblage can lose 30% due to minor shadowing, then that's effectively the same as losing the contribution of one of those three panels. That owner would do just as well functionally (and would save money) by re-configuring such that he installs two un-shadowed panels instead of three panels in which two are partially-shadowed.

[lewster]

For the record, I did that installation and your comment on shadowing, while correct is NOT APPLICABLE to the photo you are referring to. I place panels with a primary concern to avoid any shadowing.

The 'shadow' that you think you are seeing is actually the cover of the raised Fantactic Fan. There is NO SHADOWING on that outer rear panel.

PV modules will effectively lose most of their output if even a small section is shaded, as all of the cells that make up that module are connected in series.

Depending on the section of a panel that gets shaded, you could lose a bit of the output or the entire panel's output.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

[Marks71]

Originally Posted by toskeysam

To UKDUDE...the shunt controller will not take a battery to full charge. It reaches a set point and shuts down, whereas the PWM and MPPT controllers will not stop charging until the battery is full....as long as there is sun available. I am sure the LEWSTER can provide a more accurate and detailed response...he is the master in this subject.

Question re: PWM vs MPPT:

• I have a base system w/ 100w panel and 30w PWM
• am considering adding either 1 or 2 add'l 100w panels
• can the existing 30w PWM handle the 3 panels? would you swap it out for am MPPT? what are the trade-offs?

Thanks for any input

[Mcrid]

Originally Posted by Marks71

Question re: PWM vs MPPT:

• can the existing 30w PWM handle the 3 panels? would you swap it out for am MPPT? what are the trade-offs?

Thanks for any input

This post will help ya. http://www.airforums.com/forums/f240...ml#post1806655

All my research concludes no real benefit switching to a MPPT controller at our voltage and Solar Wattage size.

[Marks71]

Originally Posted by Mcrider

I'm on day 3 with no hook ups. The 300 watts and good weather (sun) is recharging completely during the day. I'm dropping to 55% DOD over the evening. Frig is running 24 hours and fan during the afternoon. Nothing else. So I will be adding two additional batteries to store more reserve and allow more convenience items to be on. Pleased with the outcome so far.

This would be so easy for AS to plop an addition 200 Watts and I think most folks would be very satisfied. I will be replacing the 15 thermal breaker as I think it has popped at least a couple of times so I'm not able to take full advantage of the solar power available at peak charging. I've not seen 17 amps yet, but 16 regularly between 11:30 and 1.

When the below freezing charging issue is solved for Li I'm all in.

Curious about your amps. I have a 200w system and my monitor regularly shows 19-20 amps. Unless the monitor is faulty?

[Mcrid]

Originally Posted by Marks71

Curious about your amps. I have a 200w system and my monitor regularly shows 19-20 amps. Unless the monitor is faulty?

The specs on your panels will indicate what their maximum current will be. I doubt 200 Watts would ever see that current. At least sustained. My 300 watts will tip over 20 amps on a rare occasion, but not long enough to cause a thermal breaker issue.

[Marks71]

Originally Posted by Mcrider

The specs on your panels will indicate what their maximum current will be. I doubt 200 Watts would ever see that current. At least sustained. My 300 watts will tip over 20 amps on a rare occasion, but not long enough to cause a thermal breaker issue.

It really does show that current for much / most of the day. Could the monitor be set wrong or something? I know I have a good controller and good wiring.

[73shark]

200W/12V=16.7amps max Might check monitor calibration if possible.

[lewster]

First, solar modules do not have a 12 VDC output. It should be more like 19-21 VDC going into your charge controller.

I just finished a new 400 watt system that was showing a 23 amp output into the controller and 26.5 amps into the batteries at solar noon with a Blue Sky 3024iL controller.

I seriously doubt you will ever see 30 amps from 200 watts of solar regardless of the conditions.

[Mcrid]

Originally Posted by Marks71

It really does show that current for much / most of the day. Could the monitor be set wrong or something? I know I have a good controller and good wiring.

Flex 100 Solar panel Specs
Max Voltage 17.5V
Max Current 5.71A
Short Circuit Current 6.28A

So something is not right.