OverTheTopCargoTrailer 7 x 16

[OverTheTopCargoTrailer]

Bruce

It's history the 63 is gone , it's now an 80.

Again 4 x 255 lg panels go into 15 amp breaker , charge controller , 80 amp dc breaker, battery.
Will do some more testing today & tomorrow mostly ....

Then will let you know about any new problems

[OverTheTopCargoTrailer]

inverter1.JPG (89.43 KiB) Viewed 2284 times

the window a/c is pulling 50 amps from the inverter

inverter2.JPG (87.25 KiB) Viewed 2284 times

the charge controller is replacing 48 amps to the batteries at 12.7 volts , 610 watts & batteries are on MPPT Float

e panel 9.JPG (125.67 KiB) Viewed 2284 times

Here is the new 80 amp dc fuse / disconnect

[OverTheTopCargoTrailer]

Hey MtnDon

Where are you , out climbing the mountain today.
Maybe at a picnic

It's pretty cool today only 70 , so I'm testing the AC by cycling it on and off ,
So far seams to work perfectly , I have enough sun for the next 90 minutes

Will report back then.

Jerry

[OverTheTopCargoTrailer]

MtnDon

So far SNAFU ........

I had it running on and off for 3 hours worked pretty well , my main conclusion is that I don't think
Charge controller is made to run full power , running over 60% gets it nice & hot but not in a good way.
In my application maybe 24 volts would work out better. I may need to reconfigure the panels.

The other thing I noticed when the meter got over 1kw .on the CC.. It wiped the data and started from Zero again.
A few times it hit 139 volts , then it said high VOC , the blower came on for 60 seconds
And then the data started from zero ? Very strange ? On the data logging it also started from zero !!
From 1-3 pm the CC was on float between AC cycles and just pulled 80 watts, t
hen after 3 pm it went into bulk and
would still pull 500 watts " remember panels are flat on the roof"

AC 5,000 btu runs ok on 1500 MSW , but maybe I'll switch over to a 1,000 PSW - it's rated 1,700 watts on start up
and should be able to handle just the AC

What's your take ?

Jerry

[bdosborn]

The other thing I noticed when the meter got over 1kw .on the CC.. It wiped the data and started from Zero again.
A few times it hit 139 volts , then it said high VOC , the blower came on for 60 seconds
And then the data started from zero ? Very strange ? On the data logging it also started from zero !!
From 1-3 pm the CC was on float between AC cycles and just pulled 80 watts, then after 3 pm it went into bulk and
would still pull 500 watts " remember panels are flat on the roof"

I looks like you're exceeding the max Voc of the controller. You'd better reconfigure your panels or you'll smoke your controller.

AC 5,000 btu runs ok on 1500 MSW , but maybe I'll switch over to a 1,000 PSW - it's rated 1,700 watts on start up
and should be able to handle just the AC

Changing to PSW will reduce your AC draw by around 20% or so but won't do anything to solve your Voc problem.
This might but it ain't cheap:

Midnite Solar Classic

Bruce

P.S. Having all 4 panels in series is a bad approach for an RV, IMHO. 8% shading on any panel reduces your entire string output by 94%. I have shadows across my panels all the time, it's extremely rare that we camp in a spot that has completely unobstructed view of the sun.

[OverTheTopCargoTrailer]

So I'm going for this

http://www.amazon.com/MISOL-Parallel-connector-Adapter-Connector/dp/B0090MTCF8/ref=sr_1_13?ie=UTF8&qid=1379259843&sr=8-13&keywords=mc4+connector



Or this


http://www.amazon.com/HQRP-T-branch-Connector-Photovoltaic-Coaster/dp/B004N725UE/ref=sr_1_2?ie=UTF8&qid=1379259843&sr=8-2&keywords=mc4+connector

I guess I could do 2 sets of panels together , but now I'm pulling 16 -18 amps vs 9 before - so what I use for a new breaker change my current 15 amp to a 20 amp ??

[bdosborn]

I've used both connectors and I like the one with the pigtails, the one piece connector snugs everything together in a big lump. Per code, you don't need a circuit breaker on the wire till you get to 3 strings paralleled. Just make sure the wire is sized for the available fault current. Per code, the wire should be sized at Isc * 1.25*1.25 (that's Isc plus 25% twice=1.56%). What size and type of wire did you run to your panels? A #10 would probably work. You can use a combiner if you want a fuse on each array, midnite solar sells DC rate circuit breakers as well.

Bruce

P.S. There is a downside to running very high Voltage arrays: the greater the difference between system Voltage and array Voltage the lower the efficiency of the charge controller.

[OverTheTopCargoTrailer]

I think the panel wires might be # 12 or 10, but on the roof I put in a # 8 for the 4 x 255 panels.
and its only a 3ft run to the charge controller.....SO DON'T worry so much...this is OverTheTop remember

We don't seam to be having a voltage drop problem HA HA HA Ha .....
if I did have voltage drop then - charge controller would be ok

Bruce says:
you don't need a circuit breaker on the wire till you get to 3 strings paralleled.
Right now I have 8-9 amps on 133 volts , with your plan I will have 16-18 amps on 66 volts.
So why the hell would I not want a 20 amp breaker before going into the charge controller ?
you have me lost somewhere , right now I have a 15 amp breaker there

No thanks to a combiner box, don't want any more BS on the roof then what I got already

i ordered this then today

P.S Bruce are you staying away from the floods I hope ???

http://www.amazon.com/HQRP-T-branch-Con ... +connector

[bdosborn]

Right now I have 8-9 amps on 133 volts , with your plan I will have 16-18 amps on 66 volts.
So why the hell would I not want a 20 amp breaker before going into the charge controller ?
you have me lost somewhere , right now I have a 15 amp breaker there

What is the Isc of your panels?

Bruce

[OverTheTopCargoTrailer]

Technical Data
Electrical Properties at Standard Test Conditions
Max Power
255
Nominal power [Wp] † Pmpp
≥ 255
Voltage at nominal power [V] Vmpp
30
Current at nominal power [A] Impp
8.50
Open-circuit voltage [V] Voc
37.2
Short-circuit current [A] Isc
8.85
Module Efficiency [%] η
15.8
STC (1,000 W/m2, AM 1.5 cell temperature 25ºC)

Data at Normal Operating Cell Temperature (NOCT)
Nominal power [Wp] Pmpp
187.03
Voltage at nominal power [V] Vmpp
27.26
Open-circuit voltage [V] Voc
34.46
Current at nominal power [A] Impp
6.86
Short Circuit Current (Isc)
7.14
Efficiency reduction (from 1000W/m2
< 4.5%
NOCT (800 W/m2, wind speed 1 m/s, ambient temperature 20ºC)

Data at Low Irradiation
At a low irradiation intensity of 200 W/m2 (AM 1.5 and cell temperature 25ºC) 97% of the STC module efficiency (1000 W/m2) will be achieved.

Temperature Coefficients
Power [%/ºK]
-0.44
Open-circuit voltage [%/ºK]
-0.32
Short circuit current [%/ºK]
+0.04

Characteristic Data
Solar cells per module
60
Cell type
Monocrystalline
Cell dimensions
6” x 6 " (156 mm x 156 mm), full square
Junction box
IP 65 with 3 bypass diodes
Length of cables
2 x 1000 mm 2 x 39.37 in
Connector Type
IP 65 with 3 bypass diodes

Dimensions and Weight
Dimensions
64.25” (1,632 mm) x 38.2” (986 mm) x 1.65 (42 mm)
Weight
Approx. 41.89 lbs (18.4 kg)

[bdosborn]

8.85A *1.56=13.8A so a 15 amp breaker is still good with two panels in series instead of four. The current doesn't change when you put panels in series, you just need two circuit breakers sizes at 15 amps instead of two. Your wire is good through-out. Code doesn't *require* a breaker, it's not a bad idea though if it makes you feel safer.

Bruce
P.S. No floods for us but our grass sure looks great.

[OverTheTopCargoTrailer]

a panel wire.PNG (56.93 KiB) Viewed 2152 times

Bruce

Your MAKING ME NUTS !!!! breaker ( # 1 diagram above ) used to be 15 amp - now I'm thinking 25- 30 amp,
when you cut the volts by 50% - you DOUBLE the amps !!


Breaker (#4 - diagram above ) was 63 amps dc prior now its 80 amps dc,
not sure why you keep saying I don't need any breaker for # 1 or then you say I need 2 x 15 amp ?

I only have 2 wires coming from the roof , 1 negative & 1 positive

Where the hell am I gonna put 2 breakers X 15 amp

First I had 4 panels connected plus - minus ( one plus & 1 minus) coming down
9 amps x 133 volts

Now I have 2 sets of panels plus & minus ( then those are combined on the roof )
With those 2 into 1 connectors
18 amps x 66 volts

FOCUS !!!!!!

By your calculation 18 amps x 1.56% - would put me closer to a 30 amp dc breaker
They don't make a 25 amp breaker.


http://www.ecodirect.com/ProductDetails.asp?ProductCode=Midnite-Solar-MNEPV20&gclid=CJuD95rGzrkCFUXhQgodRjAAyw

[OverTheTopCargoTrailer]

Bruce

P.S. Having all 4 panels in series is a bad approach for an RV, IMHO. 8% shading on any panel reduces your entire string output by 94%. I have shadows across my panels all the time, it's extremely rare that we camp in a spot that has completely unobstructed view of the sun.

I got some bad news, maybe panels are getting better, right now 30% of my panels are shaded and it's still
Putting out the 160 watts - I was using in full sun. I'm really surprised at that myself.
I'm only running a fan , the tv & the float for the battery , I'll keep you posted as I get more shade.

Jerry

[MtnDon]

Now I have 2 sets of panels plus & minus ( then those are combined on the roof )
With those 2 into 1 connectors
18 amps x 66 volts .............
............ 18 amps x 1.56% - would put me closer to a 30 amp dc breaker
They don't make a 25 amp breaker.

That's what I make it. A 20 might trip, the 30 would still protect. The main purpose for the breaker(s) on the incoming though, are for a convenient way to disconnect the array from the CC.

..... maybe panels are getting better, right now 30% of my panels are shaded and it's still...

I have never noticed a huge drop off because of a little shading on a portion of the series connected array. Not an expert on this but I thought the purpose of the bypass diodes that are incorporated in todays panels, is to pass the current from cells in full sun through the shaded cells with little loss. ???

One nice advantage of the series connected array is that the MPPT CC can really make hay with the lowered cell outputs that occur later (or earler) in the day when the sun angles are all wrong.

[MtnDon]

I thought I posted this before the previous messages but don't see it???

Here's a photo I took of the CC wires... forgot I had moved the ground connector to make it easier.





I was in the mountains Jerry. Doing some road repair work to keep ahead of the rain destruction. I've won for now. But then I did not have the Boulder, CO amounts of water to deal with. Plus I'm on the ridge top so water runs away from us. Along with dirt, small stones, etc.