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Haltzy
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# Posted: 29 Mar 2013 13:08
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Good day;
Long time viewer and first time poster..
A little background. I recently purchased some land that is going to require a large amount of prerp in order to acces the lake front location where our cottage is going to be built. Tjhis summer we will be be living off grid with RV's to claer and build a roadway and temporary camp area.
i have been weighing my options in regards to solar vs generator power. I chose both and a solar system to run everything was amazingly expensive. I started putting my solar system together, and have run into multiple snags in reagrs to wiring, system fuses and all the small parts that typiccaly are not found at your local hardware store.
Currently, i am runing 2x40W panels (12V), a blue plant 30amp charge controller with a 30amp fuse between the controller and the battery. 3 Deep Cell Lead Acid bateries in series and a 1000watt pure sine wave inverter. I will be installing a master shut off switch on the power wire to the invertor.
I am running 8gwg wire from the combiner box (Home made, no fuses) to the controller and then to the batteries, all the wiring on the batteries is 2gwg.
A couple questions - Should i have a fuse between the batteries and the invertor? It doesnt say i need one in the manual. If so i was thinking a 100amp tube fuse/holder.
Do i need to unhook the solar charing system from the batteries if i plug into shore power? is there any back feed issues from the rv charger, or will the charge controller manage that?
let me know your thoughts, i would appreciate any feedback as this is my first crack at solar. And yes i have read every thread on this site and 1000 others.
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ICC
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# Posted: 29 Mar 2013 16:55 - Edited by: ICC
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Quoting: Haltzy Should i have a fuse between the batteries and the invertor?
Absolutely!! Use a Type T, no other. A DC rated breaker is also handy to use as the switch or disconnect for the power to the inverter. Type T fuse as close to the batteries as possible; they are enclosed or sealed, no spark danger. Breaker wherever handy and away from batteries.
Quoting: Haltzy 3 Deep Cell Lead Acid batteries in series
probably parallel??? not series 
Quoting: Haltzy Do i need to unhook the solar charging system from the batteries if i plug into shore power?
Can't give a yes or a no without knowing the exact configuration. Is shore power just going to power a separate battery charger or is it also going to power the AC wiring in the cabin?
If just powering a battery charger then it is not generally necessary. Some CC may be confused by the other incoming charge power but nothing should be harmed.
If the shore power is powering the AC cabin wiring then the inverter output must be disconnected with an auto transfer switch so there can be no mistake in having both inverter and generator powering the same cabin circuits at the same time. You can do the switch manually but auto transfer makes the change over seamless. My computer doesn't even notice when our system switches to the generator input.
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ICC
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# Posted: 29 Mar 2013 17:57
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http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/Data %20Sheets/Bus_Ele_DS_1025_JJN.pdf
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Haltzy
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# Posted: 29 Mar 2013 19:48
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Thanks alot for the reply.
You are correct they will be running in parallel. My bad.
I have determined today that i am going to be building a solar generator and just running my camper off of the invertor. I will have to shut off some AC funstions but no big deal. This way, i can just switch the RV plug over to the generator if need be and will retain use of the AC functions.
I am trying to stay on a tight budget, and have already went over what i planned to spend.
Once it is all done i will post some pics.
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CabinBuilder
Admin
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# Posted: 30 Mar 2013 15:34
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I looked into exactly those fuses not long time ago (ICC' link above). For two 300A fuses and a matching fuse holder from a local supplier I got quote ~250! (~$50 each fuse + ~$90 holder + tax) 
I paid half of that for the 120Ah deep cycle battery where those would go.
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Haltzy
Member
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# Posted: 10 Apr 2013 13:41
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Hey guys,
Finally got my system all put together.
I have one question...
I am running two 30watt panles into my charge controller and am only hitting .6amps. it is kinda cloudy out, but that seems very low.
I have hooked them up seperatly, checnking all the connections and out put from each panel and one is making .2amps and one is making.3 amps. Identical panels, side by side..kinda wierd..
I am hoping to get a little video to post once it is 100% complete. Any feedback on the output issues would be great. The panles are Coleman Brand from Crappy Tire.
Chris
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ICC
Member
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# Posted: 10 Apr 2013 14:27
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Quoting: CabinBuilder I looked into exactly those fuses not long time ago (ICC' link above). For two 300A fuses and a matching fuse holder from a local supplier I got quote ~250! (~$50 each fuse + ~$90 holder + tax) I paid half of that for the 120Ah deep cycle battery where those would go.
look here
http://solarseller.com/class_t_dc_fuses__ul_listed__fuse__dc_power.htm
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Alaskaman
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# Posted: 10 Apr 2013 15:16 - Edited by: Alaskaman
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arn't those .2 dc amps? x 110 = 22 watts Ac If I'm reading this right?
.2A × 110V = 22W
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CabinBuilder
Admin
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# Posted: 10 Apr 2013 16:46
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Thanks for the "look here" link, ICC.
Unfortunately, they don't ship to Canada. But at least it gives me another reference on what the price should be for those items. I will look around.
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ICC
Member
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# Posted: 10 Apr 2013 17:01 - Edited by: ICC
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Quoting: Haltzy one is making .2amps and one is making.3 amps.
assuming a 12 vdc based system with 30 watt panels in bright sun i would expect 1.6 to 2.4 amps max. Bright sun; under clouds not surprised to see a trickle of current. what r u measuring the current with? If the read out is just in tenths it is also not unusual to see the readings different by such an amount as the meter is rounding up/down.
also is that measurement taken from the panel outoput before the controller or after the controller?
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ICC
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# Posted: 10 Apr 2013 17:04
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Quoting: CabinBuilder they don't ship to Canada. But at least it gives me another reference on what the price should be for those items.
too bad, their pricing is really very good on everything they sell. And class T fuses are well worth it. anyone who has ever done off road backcountry welding with a couple of batteries and jumper cables can attest to the power of two batteries short circuiting.
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sparky1
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# Posted: 10 Apr 2013 18:14
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(2) 30 (WATT) or 40 Watt panels @ 12 volt will charge battery's thru a controller--you have a very small amount of amperage @ 12 volts---less than what your car puts out-.stay using 12 volts & quit trying to run the world off of a inverter .
the small amount of SUN time & small panels Just can't do what I think your Trying to accomplish-
12 volt Batterys can only be drained to 1/2 way point.you do not get the whole Amperage your reading on the battery specs..
(2) 40 watt panels in the full sun is less than 6 amps for the small amount time-if your lucky
NO WAY will you run a microwave off a inverter and have the battery's last=
charge the batterys & quit wasting money,,, use the 12 volts to operate lights & radio's/ .
inverters are power robbing items. even when NOT being used they draw power off your battery's.
my 2 cents--- argue all you want-been using solar on my place since 2008.
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Haltzy
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# Posted: 10 Apr 2013 20:29
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Quoting: sparky1 (2) 30 (WATT) or 40 Watt panels @ 12 volt will charge battery's thru a controller--you have a very small amount of amperage @ 12 volts---less than what your car puts out-.stay using 12 volts & quit trying to run the world off of a inverter .the small amount of SUN time & small panels Just can't do what I think your Trying to accomplish-12 volt Batterys can only be drained to 1/2 way point.you do not get the whole Amperage your reading on the battery specs..(2) 40 watt panels in the full sun is less than 6 amps for the small amount time-if your luckyNO WAY will you run a microwave off a inverter and have the battery's last=charge the batterys & quit wasting money,,, use the 12 volts to operate lights & radio's/ .inverters are power robbing items. even when NOT being used they draw power off your battery's.my 2 cents--- argue all you want-been using solar on my place since 2008
Im a lttle disapointed in the reply.... I understand that a small solor system will not provide me with the power of a generator or to be able to run a microwave or AC. However, with your experience what size of panels would be best to supply an aequate charge load to 4 6V Batteries rated at 236Amp hours each?
Quoting: ICC assuming a 12 vdc based system with 30 watt panels in bright sun i would expect 1.6 to 2.4 amps max. Bright sun; under clouds not surprised to see a trickle of current. what r u measuring the current with? If the read out is just in tenths it is also not unusual to see the readings different by such an amount as the meter is rounding up/down.also is that measurement taken from the panel outoput before the controller or after the controller?
The reading i am taking are on the charge controller. it shows me both amps and volts. Thanks for the info. i feel as though the weather today was not a good day to fire up my first solar panel.
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ICC
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# Posted: 10 Apr 2013 23:33
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Quoting: Haltzy what size of panels would be best to supply an aequate charge load to 4 6V Batteries rated at 236Amp hours each?
how many hours of good sun a day at worst time of year (Dec - Jan. don't guess, google solar insolation map and use the data for your location. Once sun hours are known then and only then can you come up with a good estimate.
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sparky1
Member
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# Posted: 11 Apr 2013 08:36
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1. what "all"l do you plan to "run " off your Battery set up in Amps/watts.? IE; what will be the Load & length of time the load will be applied.?
2. if your only (at max) putting 80 watts into your Battery setup in the few hours sun time you have. the load your trying to use will not work. SolarBlvd,com generally Have great prices on panels I bought a lot from them (Just not installed yet)
3. 2008 I started with 45 watt panel.to a group 27 Battery,Bought a 13 watt CFL lamps & some JC Whitney Fluorescent 13 watt . this did well till you get a cloudy Day. Now I have 380 watts & 95% of my lighting is from solar. I do not us a inverter but i have one-if needed,but if used it's a power robber, so it's use is almost never.
4. you should try & find panels which will at least provide wattage use per day Thus input supply will exceed Daily output/load.
5. huge expensive Fuses are NOT needed when your only supplying 80 watts @ 12 volt to a battery Via a charging controller then to the battery's,Your Automobile doesn't. Fuses for safety (YES) over spending (NO) .
.my 2 cents,
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creeky
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# Posted: 11 Apr 2013 09:40
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You're starting where a lot of people have started! So remember everything you've put into the system stays and will be working for years to come.
I started with two sets of 60 watt panels. The "neighbor" "borrowed" one set and then I had 60 watts into 2 6v 236 amp batteries.
Here's what I learned. 1) it's best to have 1 watt of solar for every amp hour of battery. You're lucky. You've got 400 amp hours @ 12v. So you're best off with more solar panels.
2) even small amounts of shade on the panels kills the power output. I don't know if your charge controller is MPPT, but it would help if it was. Avoid even tiny amounts of shade.
I bought a modified sine wave inverter. It killed my expensive Sears portable drill batteries. I bought a pure sine inverter. you're ahead of me again.
I ran lights and the RV water pump and the radio off my system. In the morning and in the evening if I was cooking with heavy draw appliances, I unplugged my RV from the solar system and plugged it into the genny. Hey your off grid having fun. Two minutes to move a plug is not a big deal.
I also converted my RV to LED lights. 1157 auto lights, warm white. They're relatively cheap and both a nicer light and brighter than the 12v incandescent that came with the rv.
Your inverter probably is fused already? As per Sparky1. A small system can sustain some "hassle" while getting sorted out (ie. manual plugging/unplugging).
I built up a 1kw system with 1200 amp hrs @ 12v and happily run everything. Microwave, kettle, vacuum, tv, internet, led lights in the "studio" etc. I keep an eye on the batteries via the web and if they're low I run the genny for an hour. I've done that twice in the last two months.
You're on the right track. Enjoy.
Oh. And if you're Canadian I hear Montreal has some good dealers for panels. I personally order for delivery in the states and then drive down. City Electric in Ogdensburg has all kinds of the knick knacks I needed to assemble my system that just weren't available in Canada.
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Haltzy
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# Posted: 11 Apr 2013 11:30
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Thanks for all the good information and the confidence booster to keep on learning and developing my off-grid systems.
What is MPPT in regards to the CC? Here is what i am using.
http://www.sunforceproducts.com/prodinfo/manuals/12V30ASlarchargeManual.pdf
From what i have read, i will definatly be upgrading my panels or maybe ading a wind turbine to make up for the cloudy days, and since im in the praries, there is never a lack of wind. Please note it is just a thought and i have not done any research or pricing on wind vs soloar so any feeback would be great.
Can i just plug in a wind turbine to my existing solar combiners/CC or is it completly different?
Chris
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sparky1
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# Posted: 11 Apr 2013 19:22
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Wind & solar Should NOT be combined ,
Blocking doides would be required so not to burn up the one NOT putting out power.Most solar Panels allready have them-I add a second-.
If you have a constant wind-that might be a better provider.BUT they are noisey..Yes they need their own controller.
my 2 cents.
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ICC
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# Posted: 11 Apr 2013 20:40
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Quoting: sparky1 Wind & solar Should NOT be combined
i strongly disagree with that.
each uses their own separate controller, power goes from wind/sun to controller to batteries. the wind system must have a dump load which is not needed in pv systems. pv can use mppt and wind does not need that
you CAN run both a wind system and a pv system into the same batteries at the same time. the worst that will happen if it's sunny and windy at the same time is the two controllers might get confused because of having different set points for absorb and float. the controllers keep them separated electrically, no need for any additional parts. if that wasn't true our system would have bloen up years ago.
wind generators need height above trees and buildings as well as reasonably steady winds. 30 feet above obstructions is best.
Quoting: Haltzy What is MPPT in regards to the CC?
go read this stuff here
http://www.windsun.com/ChargeControls/MPPT.htm
Quoting: sparky1 Blocking doides would be required so not to burn up the one NOT putting out power
not my understanding. IF you had pv panels connected to a battery WITHOUT a charge controller than a blocking diode would be needed to prevent current flowing from the battery to the panels when it got dark. most people have a charge controller and even the cheapest dumbest CC have diodes built into them.
there are other diodes called bypass diodes that are built into panels that are needed to prevent high resistance problems when one panel of several connected in series or a portion of a single panel is partially shaded.
lets not fuel internet myths with partially correct info please
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Haltzy
Member
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# Posted: 14 Apr 2013 01:27
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Thanks for all the good info.
One more questions...
Am I further ahead to wire the solar panels together in parallel or should i run a wire from each panel to my combiner box to tie them together?
I currently have about 6' of 14 gauge wire from each panel to the main bus bar, from there im about 2' to the CC and then 2' to the battery.
Thoughts?
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ICC
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# Posted: 14 Apr 2013 10:52
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as long as the leads all go to a combiner with breakers sized properly for each input set you are covered. personally I place the combiner right by the pv panels to enable the mc4 cables to be all that is needed to connect to the comb box. then the larger wires to run to the CC.
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Sda1c
Member
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# Posted: 15 Apr 2013 11:12 - Edited by: Sda1c
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I know this is a bit off topic but for the light power consumer and the ease of installation i would suggest looking at the Duracell600
http://www.duracellpower.com/backup-power/power-packs/powerpack-600.aspx
This is the newest version I believe and they just keep getting better. I use two 30 watt panels with the built in charge controller and wire directly to the battery pack. Set it in the sun or run wires to your panel and your done. I know it wont run a microwave but it will run a small shop vac and it will run led lights with no supplemental charge for who know how long. They say 50 hours but I have not charged the one I use for lights in about 2 months. Not the be all end all but convenient, portable and adequate to say the least.
I looked at the charge controller and battery banks and all that but for the cost and hassle it beats the heck out of a full battery room. Especially if your intention is not more than two 40 watt panels. it won't keep up with a 1200 watt solar array that is obvious but it is no slouch. And its a car jumper if you need one for the 4 wheelers that have sat since last season.
p.s. I have no affiliation to Duracell. Just a very happy customer.
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creeky
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# Posted: 15 Apr 2013 19:23
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Haltzy, I can't speak to the wind turbine question. I live in eastern C and it's a poor wind zone. Ah the prairies though!
Personally I have 4 48v 250w 5 amp panels in my system. I combine 2 250 watt panels (which use 8 gauge cables) into one 6 gauge (500 watts at 48v or 48v at 10 amps) cable and run that to the combiner box. Then I run 2 gauge (48v at 20 amps) to the CC. Remember the higher the voltage and the lower the amps the thinner and cheaper the wire. So run your low amp circuit the longest distance (panels to combiner, or in my case: combined panels to combiner box) and your high amps the shorter distance (in my case: 20 amps from the combiner box/circuit breaker to CC). I'm oversized on my wiring, but have put in a bit bigger wire in anticipation of increasing the system size.
Sorry, your CC doesn't appear to be mppt. the advantage of mppt is that it allows you to use or run your panels at a higher voltage and it will down convert (rectify?) to a lower battery voltage but with higher amps. A non mppt cc will also lower the voltage but not increase the amps. (sad face) {watts=voltsxamps}
So in my case where I'm 48v at 20 amps or 1000 watts after the combiner box/circuit breaker my mppt charge controller converts that power to 12volts (my battery bank) at 80 amps (well, I have a 60 amp controller but you get the idea. and yes. i am throwing away some power when my system is at peak production. when it's cloudy/hazy/rainy of course more panel = more power).
This is one of the key mppt advantages. Many folks run very high voltage (96 volt) arrays and then let the mppt controller convert the voltage to amps when charging a lower voltage battery pack.
For many reasons: high voltage/low amps means thinner/cheaper wire with lower line losses over distance of course; but also inverters and many direct connect dc appliances are available or much cheaper at 12 volts or 24 volts. ie. at 48 volts you may have a lot of trouble finding a fan and a 96v fan ... forget about it. a 12 inverter will be less expensive than a 24v which is much less than a 48v inverter... although, fortunately, this is changing.
mppt also extracts more power from your panels in the morning and evening and handles shading better. it's magic. what can i say.
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Haltzy
Member
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# Posted: 17 Apr 2013 14:44
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Wow 2 guage to your CC? mine would not even be able to take that wire size (Lug Size).
Thanks for all the good info. I am looking at upgrading my panels here shortly so will ensure that 14 gauge is ok from the panel to the combiner box.
I do not have them fused at any point before the CC. My combiner ternmials are basicall bus bars, brass strips with multiple screws and one big one for my 10 guage coming off. Is this wrong?
If i continue to build this system knowing what i know now. i will definatly make sure my next CC is an MPPT.
Thanks
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ICC
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# Posted: 17 Apr 2013 17:01 - Edited by: ICC
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Quoting: Haltzy I am looking at upgrading my panels here shortly so will ensure that 14 gauge is ok from the panel to the combiner box.
the best way to approach wire size, imo, is to use a voltage drop calculator like the one at this link. be sure to select DC and a single set of conductors. enter your data in the fields, click calculate. the answer gives you actual drop in volts as well as a percentage. in low voltage systems it is best to keep the drop as low as possible, no more than 2% is best. Mine works out to about 1% at maximum power with #2 wire over several hundred feet.
from what i've seen most mc4 panel connector wires are 10 gauge. smaller wire may be okay for systems with lower amperage. this is where panels in series have the advantage over panels in parallel. the CC must be able to handle the voltage including cold weather spikes though.
DC rated breakers are better than fuses as breakers can also be used as a simple disconnect. they also last for more than one overcurrent event/ yes, they are a very good idea. without a fuse or a breaker any short circuit could cause havoc. at the least, imo, you should have a breaker coming off that buss bar where the heavier gauge wire leads to the CC.
before jumping ahead with more panels i'd suggest reassessing all your components to be sure they are compatible (will handle the amperage and surge volts for example). it's hard enough to have to buy new equipment a second time let alone a third.
and yes, panels in series with an mppt controller has many advantages as creeky pointed out. they do cost more but end up being well worth it , imo.
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Haltzy
Member
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# Posted: 18 Apr 2013 09:03
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That is an awesome calculator, thanks alot.
Once i finalize my panel sizes i will purchase an inline fuse. How big should i go? If i was creating max 20amps at 12.5 volts, would a 30 amp fuse be sufficient?
From what i can see, my CC should be able to take 24V, as it states in the manual max 25V. i am going to do some more research to confirm this, and hopfully i can run two sets of panels in Series to bring up my voltage.
Chris
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creeky
Member
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# Posted: 18 Apr 2013 10:23
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you'll need a better cc to run your panels in series.
maybe someone has a good mppt controller they can suggest?
I use a morningstar mppt 60. it plugs into my router and I can monitor all kinds of data. for instance, my 48v solar panels rated to a max of 57v actually put out 64.19 volts during the coldest part of the winter.
Remember that 12, 24, 48v are nominal references. a 12v battery pack is actually 12.7 fully charged. In charging it may go as high as 16v to equalize depending on temperature. take this into account when looking at inverters and cc. I turn my inverter off when equalizing if the batteries are cold because my cc will raise the voltage over 16v and trigger an over voltage alarm on my inverter.
so your 25v max cc cannot effectively charge a "24v" battery system nor can it handle the current your "12v" panels will create if run in series. While charging your panels will be more like 14.4v, in series that would be 29v and they could go higher if cold.
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ICC
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# Posted: 18 Apr 2013 15:02 - Edited by: ICC
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Haltzy, look at the spec sheet for your panels. there are a bunch of terms and numbers; they all mean something you need to know when planning a pv array.
the important numbers from mine, for example:
Voc = 36.1 (open circuit voltage)
Vmp = 28.5 (maximum power voltage)
Isc = 8.13 (short circuit current) (amps)
Imp = 7.3 (maximum power current)
note these numbers are at standard test conditions, (STC) of 25 C or 77 F. as the temp goes up the max voltage output goes down and vuce versa.
when connecting in series add the Voc and make a correction for cold temperatures. It is generally suggested to use a multiplier of 1.25 when making a general correction for cold temps. When connecting parallel add the Isc, the amps just like you would with batteries. Neither the max volts or amps or watts can exceed the ratings of the CC.
example: my system has 6 panels; two sets of three panels in series with the series strings connected in parallel. using the specs above three panels in series has a Voc of 36.1 x 3 = 108.3 vdc. apply a cold weather correction; 108.3 x 1.25 = 135.375 vdc theoretical maximum. However in the real world the system has recorded spikes as high as 141 vdc during the winter which is very close to the CC limit of 150 volts. There is a handy tool on Outback's website, called a string sizing tool. It is meant for those using Outback equipment but trying it you can see the difference temp makes, both highs and lows. Btw, that tool says my system should have a max cold weather Voc of 138, pretty close to what I have recorded. it did get colder than the -30 used for the calc though.
Amp output is not affected by the cold but higher altitudes can increase the amp output of the panels because of less atmosphere screening.
Keep in mind series connections almost always means you need an mppt controller, depending on panels and other variables.
Look at Blue Sky for mid price range mppt controllers. (not blue planet – Blue Sky) I've not used them, I have used an Outback FM60 to this point, but have a Midnight Solar Classic 250 that will replace it by June. (the pv array is being reconfigured and about tripled in size). i have set up the Xantrex XW series, they're great as well, all those are top line. . Xantrex used to have a string sizing tool and outback and Midnight have forums aimed at their users. AZ Wind-Sun also has a good general pv and wind info forum.
do some more research before buying anything new, imo
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