James Johnson's posts

Posted by James Johnson on Sep 3, 2008 05:57 pm

#31 -  Renewable Energy > Technical Discussion: Other > Re: system grounding questions
i'm confused now for sure..fell like i'm way over my ski's with trying to figure out proper grounding...Sad

 

Posted by James Johnson on Sep 3, 2008 04:39 pm

#32 -  Renewable Energy > Technical Discussion: Other > Re: system grounding questions
I think I got the battery Neg ground figured out..

I'll pull a grounding conductor off of my shunt and run it to the ground buss bar in the combiner...the combiner and shunt are very close to each other as they whole panel is mounted on a wall in the garage. The panels themselves are mounted on the exterior wall of the garage so all the wiring is very close.

This then means I only use one "primary" ground rod...

this make sense?

thanks for all your guidance...

wish AltE had classes in the chicago area..Smiley

James
 

Posted by James Johnson on Sep 3, 2008 04:22 pm

#33 -  Renewable Energy > Technical Discussion: Other > Re: system grounding questions
ohhh boy..I'm getting dizzy reading all this..Smiley

SO..

a separate ground rod at the combiner...which is grounding the following:

negative combiner bus bar
bare copper wire from module frames
a wire connecting all "metal" enclosures

this takes care of the PV input and the "enclosures"

so totally confused about what to do with the neg off the battery that goes to my DC distribution buss bar....in the words of Bill The Cat...Ackk!

James

 

Posted by James Johnson on Sep 3, 2008 03:47 pm

#34 -  Renewable Energy > Technical Discussion: Other > Re: maximum charge rate for SLA batteries?
Thanks James,

The reason I ask is that I'm designing my system around daytime use only..so the battery is being used as a "buffer" only. IE: if my 12v DC loads exceed the current amp output of my array, then the extra needed amps are pulled from the battery. With that being said, as I increase my array to power more of my studio, I'm concerned that when the battery gets a little drained from supplying a couple of amps for an hour or two, it will suddenly get charged with the full 12amps from my charge controller. The 12v battery I have is only 32Ah, so it would be getting charged at like c/2.5 which might be too much?

maybe there is a better way to distribute DC power directly form an array, without the use of a battery? Not sure how one would go about this, and keep the voltage regulated to a constant 12v output....

Any ideas?

James
 

Posted by James Johnson on Sep 2, 2008 03:41 pm

#35 -  Renewable Energy > Technical Discussion: Other > maximum charge rate for SLA batteries?
Is there a maximum charge rate for SLA's?
 

Posted by James Johnson on Sep 1, 2008 11:19 am

#36 -  Renewable Energy > Technical Discussion: Other > Re: system grounding questions
Thanks for the links Thomas...things are becoming a bit more clear..slowly....It appears that there are way to many variations out there for grounding techniques.

So far it's totally obvious that I must ground all the metal equipment and module frames as well as the negative combined conductor at the combiner box....to a common ground rod..the most confusing part is the negative conductor at the battery...do I run a wire from the negative output off the battery to the same ground rod that is used at the combiner box?? OR Does it go to it's own ground rod and then I "bond" the 2 ground rods with buried copper wire?

NOTE: I am only using DC for power form the battery. NO inverter, No tie to AC..it is it's own little system

grounding seems to be the most confusing part of system install for sure


 

Posted by James Johnson on Sep 1, 2008 09:48 am

#37 -  Renewable Energy > Technical Discussion: Other > Re: using 12v dc appliances during the day
Got to answer my own question yesterday. Now that I have my system up and running. The laptop pulls 1.6 amps. I have 60watts of solar making 3.4amps+/- of power during the day.

I turned on the computer hooked up via DC only.(no inverter) at 10:30am and was able to run a very intensive application that kept the computer draw at max 1.5 amps continuously.

The day was full sun and I was able to run the computer non-stop till 4:30pm in the afternoon without pulling amps from the battery. The charge controller kept flipping back and forth from "charging" to "charged" state for the battery about every minute or so, keeping the battery fully charged all day. After 4:30pm I disconnected the computer and allowed the system to run normally with the battery showing "charged" on the "Trimetric" meter.

So....running 12v DC appliances during the day greatly extends run-time, as long as the load amps are less than the array amps, you never really touch the battery bank.

This reminds me of an article from Home Power Magazine, where the off-grid couple had a massive array for their daytime use and only needed a 650ah bank that they cycled only about 30% deep.

This is sort of the reverse way of designing a system, in that you see sun as "the battery" and concentrate on maximum direct "solar power" for daytime use and size the bank for just simple night-time use-age. Since I'll be using the studio only during daylight hours, this scenario works perfectly.
 

Posted by James Johnson on Aug 30, 2008 12:27 pm

#38 -  Renewable Energy > Technical Discussion: Other > system grounding questions
talk about a confusing part of setting up an off-grid system correctly..Smiley Please give me some feedback.

12v system with 3 panels (1) 20watt (2) 40watt

question #1
1 ground for the combiner/array. A ground rod that is connected to the combiner "ground" buss bar. Connected to this ground buss bar are the following:
neg from the combined neg bus bar
ground wire from panels

question #2
a 2nd ground for the battery bank as follows:
neg from battery terminal to a "ground" bus bar
ground wire from all "metal" enclosures to same "ground" buss bar. This buss bar is then attached to a 2nd ground rod

question #3
(2) grounding rods connected with buried wire.
Do the rods need to be 6'-0" or more apart


any type of help with this confusing topic would be greatly appreciated.
 

Posted by James Johnson on Aug 28, 2008 08:12 pm

#39 -  AltE > Discussion > Praise for altE community and staff
Just wanted to say what a positive experience I have had with dealing with the altE staff. Delivery of orders happens extremely fast and the online help in the Technical Forums is 2nd to none. I've started building my Solar Power system just this week with all of the parts I've purchased from altE and wanted to say "Thanks" altE!

James

P.S. I've started putting up pics of my modest system build in my gallery.

http://gallery.altenergystore.com/James-Johnson-gallery/v/7059083552/

 

Posted by James Johnson on Aug 28, 2008 07:42 am

#40 -  AltE > Discussion > Re: mount suggestions for Kyocera KC40T
good info John..thank you...I see that you are also in Illinois..I'm just at the WI border up in Antioch, so our array may end up being pretty close. I'm at 42Lat so I think I'll go with 28deg for summer and 57 for winter. Your blog is great reading.

James
 

Posted by James Johnson on Aug 27, 2008 07:35 am

#41 -  AltE > Discussion > mount suggestions for Kyocera KC40T
Anyone have suggestions for mounting (3) KC40T panels. I've gone thru the store a bit but the descriptions for sizing are slightly confusing. I'm looking at either a "roof" mount, that I'll mount on the exterior side wall of the garage OR a pole mount design. Help would be appreciated.

Thanks
James
 

Posted by James Johnson on Aug 26, 2008 04:30 pm

#42 -  Renewable Energy > RE General Discussion > Re: School Project Help
Taylor,

try this link..they sell very inexpensive alternative energy kits that might be right up your alley.

http://www.kidwind.org

James
 

Posted by James Johnson on Aug 22, 2008 03:50 pm

#43 -  Renewable Energy > Technical Discussion: Other > max series fuse for the BSP20-12?
would a 4am breaker work for this module in a combiner box? Nothing listed on my panel or in the specs.

http://store.altenergystore.com/Solar-Panels/1-to-50-Watt-Solar-Panels/Power-Up-BSP20-12-20W-12V-Solar-Panel/p1024/
 

Posted by James Johnson on Aug 21, 2008 07:43 pm

#44 -  Renewable Energy > Technical Discussion: Other > Re: Can I Parallel these 2 panels?
sweet!  thanks for the quick reply....this place rocks

James
 

Posted by James Johnson on Aug 21, 2008 07:17 pm

#45 -  Renewable Energy > Technical Discussion: Other > Can I Parallel these 2 panels?
running a 12v system

I just bought 1 of these
http://store.altenergystore.com/Solar-Panels/1-to-50-Watt-Solar-Panels/Kyocera-KC40T-40W-12V-Solar-Panel-with-J-Box/p722/

and have one of these as well
http://store.altenergystore.com/Solar-Panels/1-to-50-Watt-Solar-Panels/Power-Up-BSP20-12-20W-12V-Solar-Panel/p1024/

I should be able to run these in parallel using a combiner box easily since their Voc & Ioc are so very close? Yes? No?

James
 

Posted by James Johnson on Aug 20, 2008 05:35 pm

#46 -  Renewable Energy > Technical Discussion: Other > Re: Do new solar panels "settle" in?
Just tested my new Kyocera KC40T panel in the sun all day yesterday to see that it meets the specs as shown on it's label.

The Isc rating is 2.65amps...however, I got reading with a digital volt meter of over 3.21amps at times and sustained amps of around 2.7 to 2.8 amps..will the panel settle in to its rated 2.65Isc after a bit? My concern is that I have sized my system to use 3 of these panels in parallel going to an ASC 12/12-a charge controller.

By the way the specifications in the altE store for the KC40T need to be updated.

James

James

The current "peaks" you've observed may be the result of what some people call "Edge of Cloud" events.  It is called that because momentary performance peaks have been observed as the sun emerges from a cloud. I believe that these current peaks are the result of sunlight suddenly hitting panels that have had a chance to cool down while the sun was behind the cloud.  If you look at the spec-sheet for your panel, it shows that improved performance with cooler temperatures.  Others may have different explanations, but this is MHO.

I have 5 (85-watt) kyocera panels in parallel, and I should see current readings of no more than 25.1 amps.  I've seen peaks in excess of 29 amps last winter, but not more than 26 amps during on any recent hot summer day. 

So, to answer your question, I believe that you'll continue to see those current peaks, especially in cool weather. 

John
 

This is great news...It's like getting a 45 watt panel for the price of a 40watt..Smiley I've been monitoring the panel for a few days now and it's consistently around 2.8 amps..very cool. And this is during the summer..so I would think that I might get even more amps in the winter months up here in northern IL.

James
 

Posted by James Johnson on Aug 18, 2008 04:20 pm

#47 -  Renewable Energy > Technical Discussion: Other > Re: panel wiring review please
Thanks for attempting to look at it James..Smiley I used one of the schematics from the "Cabin" packages when designing it, as well as a few ideas from Home Power. I should post a better image of it, as I would really like to get a 2nd opinion on it be fore I purchase more panels, breakers and such. Could I possibly e-mail you the .jpg?

Thanks  James
 

Posted by James Johnson on Aug 17, 2008 11:05 am

#48 -  Renewable Energy > Technical Discussion: Other > Do new solar panels "settle" in?
Just tested my new Kyocera KC40T panel in the sun all day yesterday to see that it meets the specs as shown on it's label.

The Isc rating is 2.65amps...however, I got reading with a digital volt meter of over 3.21amps at times and sustained amps of around 2.7 to 2.8 amps..will the panel settle in to its rated 2.65Isc after a bit? My concern is that I have sized my system to use 3 of these panels in parallel going to an ASC 12/12-a charge controller.

By the way the specifications in the altE store for the KC40T need to be updated.

James

James
 

Posted by James Johnson on Aug 17, 2008 09:17 am

#49 -  Renewable Energy > Technical Discussion: Other > Re: panel wiring review please
having some strangeness with the gallery. 1 minute the image is there, the next it's gone..I keep having to re-list it in my gallery. Anywho...anyone have a chance to look at my diagram?


 

Posted by James Johnson on Aug 16, 2008 11:35 am

#50 -  Renewable Energy > Technical Discussion: Other > panel wiring review please
I'm on my way with a small system now. I just got my 1st Kyocera KC40T panel and other items and am going to order a 2nd panel probably tomorrow. I know I should have an electrician look at this schematic, but I'd like to have a sense of how the system should be wired for my own piece of mind. I've designed the panel based on a minimal budget with the hopes of eventually getting to a pair of controllers and 6 total KC40T panels. I know it's not a big system by any means, but it should get my studio completely off the grid.

I would really appreciate some feedback on the schematic I'm proposing to use for my power panel. A couple of things I'm still a little foggy on.

does my system ground look right?
do i need a breaker between the controller and battery, even though I can "technically" disconnect the combined array at the baby box?

as always, thanks so much for the help. Everything I learned up till now has been through this community and I'm definitely still learning.

NEW EXTERNAL link to the .jpg of my panel wiring diagram:

http://picasaweb.google.com/circlingcranestudio/NewSolarSystemConstruction



 

Posted by James Johnson on Jul 30, 2008 05:31 pm

#51 -  AltE > Discussion > Re: 2amp breakers for BabyBox?
sweet! thanks guys....

James
 

Posted by James Johnson on Jul 30, 2008 03:36 pm

#52 -  AltE > Discussion > 2amp breakers for BabyBox?
I can't seem to find 2amp breakers for this box in the storefront.

http://store.altenergystore.com/Enclosures-Electrical-and-Safety/Electrical-Enclosures/DisconnectLoad-Enclosures/AC-andor-DC/Midnite-Solar-BabyBox-4-Slot-AC-or-DC-Breaker-Panel/p4480/

I'm going to combine 2 of these panels

http://store.altenergystore.com/Solar-Panels/1-to-50-Watt-Solar-Panels/Power-Up-BSP20-12-20W-12V-Solar-Panel/p1024/

and need to know if a 2amp is even available AND if a 2amp breaker will accept the #18awg wire coming from the panels?

thanks

James
 

Posted by James Johnson on Jul 20, 2008 05:45 pm

#53 -  Renewable Energy > Technical Discussion: Other > Re: power directly off of Panels?
James,
I would just like to add that using power directly from the solar panels to power a load is much more efficient than storing and retrieving it with batteries.  Personally, I would start with one 80 to 100ah battery...

John D - you hit the nail on the head here..my idea is to be as efficient as possible hence the DC powered studio..good ot know I'm on the right track. As for battery size..again I think you nailed it..I'll get an 100ah battery and see how the system does..more than likely I'll get a battery monitor as well that handles multiple shunts, so I can monitor the pv array coming in and the battery power coming out..

John B - you're explanation below seems to spell it out perfectly for me..which is what I thought all along...


"...So if you have a pv panel capable of delivering 7 amps (84 watts for easy math) at 12v, and say your fully-charged battery requires 1 amp to maintain the float, then your 40 watt load would be drawing its 3.3 amps directly from the charge controller. The charge controller would also be delivering 1 amp to maintain the float voltage, so it will effectively be "de-rating" your 84w panel down to about 50w.

Now if you add a second 40w load, the charge controller would turn the panel power back up to 72w and service both loads while still maintaining the 1 amp battery float current. Add a third 40w load and suddenly you are drawing more current than the pv panel can deliver so you start taking current out of the battery....."

If the battery only needs 1amp to maintain float and the array is generating much more than the 1amp..the excess power will then be available for my DC use until I run over the array's  amp output, which will then switch over to battery power. Needless to say, I'm sure this will fluctuate a quite a bit during daylight hours as the sun dances in and out of the clouds. So the Gobal Solar Panels might very well be the best choice for optimum "averageing" amp performance during the day...thanks again everyone..I'll post some photos as the system goes together..

James
 

Posted by James Johnson on Jul 16, 2008 05:25 pm

#54 -  Renewable Energy > Technical Discussion: Other > Re: power directly off of Panels?

For a 12V system your math is easy. Just divide your watt-hours by 12 to get that will be taken in amp-hours from the battery. In your case, 240/12 is 20AH.

One small caveat is that the efficiency of a lead-acid battery can be anywhere from 50 to 80 percent. So in order to recharge a lead-acid battery that you have taken 20AH from, you may have to put back the equivalent of anywhere from 25AH to 40AH from your charging source.

As for the PV panels, I would recommend (without having used them myself!) a couple of CIGS modules such as this one that will work well in low light conditions, and is attractively priced at $5 per watt.
http://store.altenergystore.com/Solar-Panels/51-to-99-Watt-Solar-Panels/Global-Solar-60W-12V-Framed-Solar-Panel/p5574/
[/quote]

Wasn't even aware of battery inefficiencies, so thanks for that knowledge.

So if I base my calcs on cycling the battery only 20% deep AND want 2 days of autonomy at 20ah per day. Then I would need a 200ah battery based on my usage of 20ah a day.

To be on the very safe side, I would then need to make sure to put back 40ah a day, just to be safe.

AGAIN, my question is, what is really happening when I am the computer system is using 3.33ah of DC off the battery, when at the same time, the battery would be receiving 7.0ah of solar. Is ALL of the 7.0amps from the panels going into the battery? OR is my battery usage somewhat offset, by the solar panels, thus requiring a smaller battery?

thanks so much for your help...just about there..

James
 

Posted by James Johnson on Jul 15, 2008 04:32 pm

#55 -  Renewable Energy > Technical Discussion: Other > Re: power directly off of Panels?
Thanks all for the great info and feedback. What I'm tryng to figure out is how "small" of a battery I can get by with while not discharging it more than 80%. This is the last thing I need to figure out before I start purchasing parts and start building. I have my mini system figured out with the following  components:

PV array = (3) PowerUp BSP 20. I currently have (1) and am adding (2) more to the system

BSP 20 specifications
Maximum Power (Pmax) 20W
Voltage at Pmax (Vmp) 17.3V
Current at Pmax (Imp) 1.20A
Short-circuit current (Isc) 1.30A
Open-circuit voltage (Voc) 21.7V

Combiner Box
Midnite Solar MNPV6 Combiner Box

Breaker Box
Square D QO24L70RB Square D QO Load Center

Charge Controller
Xantrex C35 35A, 12/24V PWM Charge Controller

I'll be working in the studio for approx 6 hrs a day during daylight hours only. Hence my question about how much I really need in terms of battery storage.

The computer system I am powering with DC directly off the battery will consume approx 40w an hour DC (40wx6=240w) per day.

I really only need 1 of 2 days of autonomy for so, if you could figure out how much storage I need that would be great! I'd prefer to have only (1) battery and not mess wiring a battery bank.

Now all this talk has got me thinking...maybe I should purchase just (1) larger panel (say an 80w) panel? and then I can sell my existing 20w panel. This would probably end up being more cost effective in terms of cost per watt and mounting just 1 panel would be much easier than managing a string of panels?

So, I guess I need to still nail down the battery and Panel size...

James

 

Posted by James Johnson on Jul 14, 2008 08:41 pm

#56 -  Renewable Energy > Technical Discussion: Other > power directly off of Panels?
when using a 12v dc appliance directly off the battery bank, during the day while the sun is out, are you pulling power directly from the solar panel OR are you pulling power from the battery?

the reason I ask is that I'm trying to figure out just how much ah of battery I need for my system.

I'll be using 40w of 12v power for 6 hours a day during sunlight hours. The panel array will be 60w. So will the battery be acting in effect as a "voltage regulator" during the day and only be storing the extra 20w an hour?

thoughts?

James
 

Posted by James Johnson on Jul 10, 2008 04:09 pm

#57 -  Renewable Energy > Technical Discussion: Other > Re: battery temperature & distance questions
Thanks for chiming in Jon. Did you just set aside an area in the garage or did you build a battery box?

No worries about freezing the batteries?

do you run sealed lead acid or just plain lead acid?

so many questions..sorry..glad to hear from another northern climate person...

James
 

Posted by James Johnson on Jul 9, 2008 05:05 pm

#58 -  Renewable Energy > Technical Discussion: Other > battery temperature & distance questions
I live in the upper midwest at Illinois / Wisconsin border. we have some rough winters on occasion with heavy snowfall.

where can I find info on insulating a battery bank that will be set in my unheated garage? Other than ventilation what types of things (related to temperature) do I need to take into account when setting up the battery bank?

how far away can the bank be from the studio if I choose to run the inverter in the garage and send the AC power via wire to the studio?

Where does one find wire sizing for AC wire?

any help would be much appreciated. This is the last thing I need to figure out before I start building my small system.

James

 

Posted by James Johnson on Jun 29, 2008 07:41 am

#59 -  Renewable Energy > Technical Discussion: Other > Re: please review my system design
Thanks much for looking at my system specs Thomas. By EGC I assume you mean tying in all the equipment to a continuous wire and then sending that wire to a grounding rod right?

James
 

Posted by James Johnson on Jun 28, 2008 11:50 am

#60 -  Renewable Energy > Technical Discussion: Other > please review my system design
I'm ready to buy a couple more panels and a new combiner box, breaker box, charge controller and breakers. Here's what I have designed and would like a 2nd pair of eyes to look at my calcs to see if I'm in good shape.

PV array = (3) PowerUp BSP 20. I currently have (1) and am adding (2) more to the system

BSP 20 specifications
Maximum Power (Pmax) 20W
Voltage at Pmax (Vmp) 17.3V
Current at Pmax (Imp) 1.20A
Short-circuit current (Isc) 1.30A
Open-circuit voltage (Voc) 21.7V

Combiner Box
Midnite Solar MNPV6 Combiner Box

Breaker Box
Square D QO24L70RB Square D QO Load Center

Charge Controller
Xantrex C35 35A, 12/24V PWM Charge Controller

These panels come with 15.5’ of #18 AWG cable pre-attached, so I will be using it to go to the combiner box box. It seems sized correctly for the Isc of 1.3 x 156% = 2.028amps per panel. OR do I need something other than #18awg? I cannot find #18awg in the NEC wire table for 12v systems. I don’t plan on using the entire 15’-6” of cable and will probably end up cutting it down to about 10’-0” in length to get to the combiner box.

I am going to wire them individully into a Midnite Solar MNPV6 Combiner Box and then send the “paralled” combined output to the charge controller. This will give me 60watts at 12vdc nominal. Each panal will go to a 10amp breaker? Again, I cannot find #18awg in the NEC wire table, so I’m assuming that #18awg cannot carry more than 10amps?

The combined wire I will use from the Midnite Solar MNPV6 Combiner Box will be rated for the total Isc of 1.3amps x 3 x 156% = 6.084amps. the wire run length from the combiner box to the breaker panel before the charge controller will be approx  10’-0”. So I will use #8awg for the run from the combiner box to the breaker box. I will use a 40amp breaker in the breaker box before the charge controller.

The last run of wire is from the breaker box to the charge controller. I’ll upgrade my charge controller from a Sunwise Sunguard to Xantrex C35 35A, 12/24V PWM Charge Controller. The wire from the breaker box to the charge controller will only need to go about 6’-0” at the most so I will again use #8awg from the breaker box to the charge contoller. Allowing for expansion in the future.

My plan is to eventually add a couple more BSP20 panels, so I end up with 5 panels. The #8awg should handle the upgrade to (5) panels in the future as well as the rest of the system.

Thoughts?  Comments? Suggestions? Please...

Thanks so much for all the great info I have learned so far through this forum.

James
 

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