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Topic: 1920 WATTS OF SOLAR POWER (Read 2613 times) previous topic - next topic

1920 WATTS OF SOLAR POWER

Installed four of six 320 Watt frameless, semi-flexible solar panels. Two more to go. Up to 1920 Watts should be available to charge the 48 Volt lithium battery. Each is held on with 15 home-made aluminum brackets and VHB tape. The total bond strength is about 1200 pounds per panel. Since the roof will now be walked from the side, I will paint white non-skid marine paint all the way up the side.

I plan on charging my Nissan Leaf when the sun if out. What have I done? Guess the warranty is void.

Re: 1920 WATTS OF SOLAR POWER

Reply #1 –
Woo hoo!!  That is some serious power.  How high did you end up mounting them off the surface of the roof?  Taken it for a test drive yet to see how they the first few panels deal with the wind?

Re: 1920 WATTS OF SOLAR POWER

Reply #2 –
Wow that's a bunch of solar! Each panel has 15 attaching points? If so I don't think they will be going anywhere.

Re: 1920 WATTS OF SOLAR POWER

Reply #3 –
Good idea. If the panels make noise or vibrate, I'll have to design an aerodynamic snubber, or reinforce the underside of the panels. That said, I figure that U270 will break the wind for the panels, which are quite rigid and rugged. The 55 pound each panels are American-made eBay specials that cost about $.63 per watt delivered. They will be wired in three two series circuits, delivering up to 120 Volts.

Re: 1920 WATTS OF SOLAR POWER

Reply #4 –
Tim,
Good going.
Looks like those panels must be pretty heavy. From your picture it looks like the roof is sagging!
Keep up the good work.

Len >:D

Re: 1920 WATTS OF SOLAR POWER

Reply #5 –
Solar power is overrated, meaning that even though they theoretically will produce 1920 Watts, in real life cloudy days, or campsites with trees, I'll be lucky to get one quarter of that. Clouds and trees would probably cause a 95% reduction, or only 96 Watts.

Re: 1920 WATTS OF SOLAR POWER

Reply #6 –
Given a 30,000 Pound vehicle and Foretravel's high-strength roof, these 55 Pound panels will be like flys on a horse's back.

Re: 1920 WATTS OF SOLAR POWER

Reply #7 –
With an 1140 watt potential, we still get about 600 watts peak (flat mount) in the middle of winter in AZ. Clouds and trees effect it from a little to a lot depending on how thick the cloud layer is or how dense the tree cover is. A tree can shade one panel but we still get good charging.

Smart to put as many as possible on the roof. They are super cheap now with the controller taking a higher percentage of the total cost.

Did you install two controllers?

Pierce

Re: 1920 WATTS OF SOLAR POWER

Reply #8 –
Hate to hijack but, do you tow the Leaf on a dolly?

Re: 1920 WATTS OF SOLAR POWER

Reply #9 –
Two replies and a comment:

1. CONTROLLERS
Only one Morningstar 45 Amp 48 Volt MPPT controller will be used, with two more controllers as backups. Long story.

Made my own solar combiner and breaker box, with breakers, surge suppressors and charge enable relay.

2. LEAF
While at home base, the Leaf will be charged. When on the road, we will flat tow a manual transmission Honda Civic Hybrid. The Leaf would have to be dollied and, due to the 70 mile range, would not fit our lifestyle, yet.

3. CHARGE MONITOR
See the photo for my home-made solar monitor box, which measures state of charge, charge current capacity, discharge current capacity, battery  charge current/voltage and solar output current/voltage.

Re: 1920 WATTS OF SOLAR POWER

Reply #10 –
Tim:
Are you sure that your "Morningstar 45 Amp 48 Volt MPPT" will safely control 1920 watts.
All the "Solar Controller" specs I have seen rate controllers with Maximum AMPS into battery bank.
I have an 80 amp Outback controller with 1470 watts which has a theoretical max amps of 90 amps.
The maximum I have ever seen is 78amps when running the microwave off the inverter with discharged batteries.
Your theoretical maximum amps into batteries will be circa 115 amps so I do not understand how a 45amp controller will suffice.

Re: 1920 WATTS OF SOLAR POWER

Reply #11 –
Having just gone through that sizing process myself I was wondering the same thing.  My initial thought was that was going to need one big controller.

Re: 1920 WATTS OF SOLAR POWER

Reply #12 –
Wyatt,

This one had me scratching my head until I remembered Tim is using a 48 volt battery. How does this quote sound to you? Quote below:

"For example, you could have a 3,000 watt solar module array that operates at 93.3 volts DC and your battery bank is 48 volts DC. MPPT charge controller are rated by the output amperage that they can handle, not the input current from the solar module array. To determine the output current that the charge controller will have to handle we use the very basic formula for power in Watts:

Power = Volts x Amps

Here we know the power is 3,000 Watts, the battery bank is 48 volts, so:

3,000 Watts = 48 volts x Amps

which gives us:

Amps = 3,000 Watts/ 48 volts

Amps = 62.5A

We still want to adjust this value by 25% to take into account any special conditions that might cause the solar module array to produce more power than it is normally rated for (e.g. due to sunlight's reflection off of snow, water, extraordinarily bright conditions, etc). So, 62.5A increased by 25% is 78.13A. In this case we'd probably choose a 80 Amp MPPT Charge Controller"

Wyatt, guess the next question is how to get the 48 volt battery to work with the 12V coach electrical system without a lot of efficiency loss?

Pierce

Re: 1920 WATTS OF SOLAR POWER

Reply #13 –
Might wanna read up on using the Morningstar MPPT controllers with array outputs higher than "normal" controller ratings. They go into MPPT mode sooner in the day, and stay later, but act like a regular controller when the array output hits the controller max. So...a Morningstar MPPT controller theoretically undersized for your array MAY actually harvest more than an oversized one.

Edit-
http://www.morningstarcorp.com/wp-content/uploads/2014/02/MPPT-Technology-Primer.pdf

The most I've seen from my 1200W array is 650W, I use a Morningstar PWM TS-60 controller.

Re: 1920 WATTS OF SOLAR POWER

Reply #14 –
Quote from: toyman –
The most I've seen from my 1200W array is 650W, I use a Morningstar PWM TS-60 controller.
This is pretty close to our 1140 watts seeing about 600W in winter. Summer with a flat mount should come within 20-25% of rating depending on your latitude. I have seen panels go over their rating with a reflector. Couple of examples on YouTube.

Still in the dark about an efficient way to convert the 48 volt battery to 12V coach voltage unless you invert 48 volts to 120VAC and then charge the coach batteries plus power the AC appliances. Looks lossy that way to me but ready to learn new tricks.

Pierce

Re: 1920 WATTS OF SOLAR POWER

Reply #16 –
That is what I used on the '81 to run lights, water pump etc. Then used 24 volt invertor to run the A/C outlets. I kept the engine 12 volt system separate.

Re: 1920 WATTS OF SOLAR POWER

Reply #17 –
Looks like one of these will cost as much or more than our total solar setup including batteries and will lose 15% efficiency plus any loss in the controller, wiring, etc. Just seems adding complexity to what can be a very simple and reliable solar system.

12V wet or AGM batteries are hard to beat.

Pierce

Re: 1920 WATTS OF SOLAR POWER

Reply #18 –
Wow ! 😳

Re: 1920 WATTS OF SOLAR POWER

Reply #19 –
X2 don't quite understand the thought on the 48v thing.