Small Cabin

Small Cabin Forum
 - Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Off-Grid Living / Upgrading our solar
. 1 . 2 . >>
Author Message
jawarren77
Member
# Posted: 14 May 2021 12:14
Reply 


We have a 2 bedroom cabin in the Olympic Mountains of Washington. We currently have propane for heat, 6500w Honda generator to run our well pump and emergency power, and (4) Keyocera 130w solar panels. They are all tied into (4) L16 Full River 6v batteries, Magnum MagnaSine invertor and an Outback controller. Our solar panel rack was custom made out of aluminum angle to only fit these 4 panels. we just purchased (5) Grape Solar 100w panels and are looking for ways to mount them without putting alot of holes into our new roof (replaced a couple years ago due to a tree landing on it).

Brettny
Member
# Posted: 14 May 2021 12:42
Reply 


If you want them on the roof theres almost no way around putting more holes in the roof.
How old is the system?

jawarren77
Member
# Posted: 14 May 2021 16:48
Reply 


The existing panels are at least 10 years old. I have access to some 8020 extrusion, was thinking using that for the rack and some SnapNrack L foot kits for the roof penetrations.

scott100
Member
# Posted: 14 May 2021 21:07
Reply 


I had a lot of trouble finding solar racks when I did ours for a reasonable price. I was thinking of going with 8020 for rails. I ended up ordering Prosolar standard support rails and clamps and Fastjack e series standoffs and low profile flashings from these guys:

https://www.solarflexion.com/category-s/193.htm

It turned out that the full length rails would have to be shipped freight at a huge expense. They cut them in half for me and so they could be shipped UPS for a lot cheaper. I just had to buy some more couplings. Good company to deal with.

Steve_S
Member
# Posted: 15 May 2021 06:41
Reply 


PLEASE PAUSE !

Stop and think for a slight moment. 24V/250W panels for $50 USD are a few hours drive from you !
$200 = 1000W of panel.

Check out SanTan Solar (Gilbert Arizona)
https://store.santansolar.com/product-category/solar-panels/

A Video covering these, testing etc:
https://youtu.be/0yDVXJmsowU

Hope it helps, Good Luck

Brettny
Member
# Posted: 15 May 2021 10:01
Reply 


Are your batteries also 10yrs old?

Nobadays
Member
# Posted: 15 May 2021 10:02
Reply 


Quoting: Steve_S
24V/250W panels for $50 USD are a few hours drive from you !


Ehhh... Steve... try a two day drive each way...well theoretically only a 24 hour drive straight thru. Not very practical.

Not knocking Santansolar heck their 250watt panels power our cabin and shop.

Brettny
Member
# Posted: 15 May 2021 10:32
Reply 


I'm going to second checking the "used market" over going new. I found 230w pannels locally that where new old stock for $75 each. Never installed and never plugged in. I also wasn't looking super hard for them and am not in a very solar productive region.

jawarren77
Member
# Posted: 17 May 2021 10:55
Reply 


It's a family cabin and other members have already purchased the 100w panels because they wanted new. I am just trying to make it work. I tried to get them to purchase the 250w, then we would only need 2 or replace the old 130w with 4-250w.

gcrank1
Member
# Posted: 17 May 2021 13:15
Reply 


Not so good when people who dont 'understand' buy stuff and tell 'us' to just use it....
Im sure you can make it work in some fashion, even if not ideal.
Ive made test-racks from 2x wood to get stuff up and functioning, easier/cheaper to make mistakes in wood even at todays prices.

jawarren77
Member
# Posted: 17 May 2021 14:27
Reply 


Quoting: Brettny

Are your batteries also 10yrs old?



no, the L16 AGMs are new, the L16 lead acid went bad.

jawarren77
Member
# Posted: 17 May 2021 14:28
Reply 


Quoting: gcrank1
Not so good when people who dont 'understand' buy stuff and tell 'us' to just use it....


I agree, too many cooks in the kitchen.

jawarren77
Member
# Posted: 19 May 2021 16:50
Reply 


Alright, one more stupid newbie question...
Our (4) 6v batteries are wired to increase our AmpHour and stay 12v (Series/Parallel). How should our panels be wired to keep it at 12v and increase our solar charging capability?

Steve_S
Member
# Posted: 19 May 2021 17:22
Reply 


Typically, a proper solar charge controller will take higher voltage and amperage to deliver what is required to charge the battery system.

For example, the EPEver BN Series MPPT Solar Controllers can handle:
Rated charge current 20A 30A 40A for models
Rated charge power
for 20A = 260W/12V / 520W/24V
for 30A = 390W/12V / 780W/24V
for 40A = 520W/12V / 1040W/24V

With a Max PV Input Voltage of 150V(at minimum operating environment temperature)
138V(at 25℃ environment temperature).

Link to Product: https://www.epsolarpv.com/product/61.html

Brettny
Member
# Posted: 19 May 2021 19:45 - Edited by: Brettny
Reply 


Series vs parallel wireing on solar pannels depends on the wire length, size and charge controller. It also depends on what type of sun the pannels are going to see. I have found that filtered sun through trees it's best to parallel them.

The easiest thing to do right now may be to series them to near the max PV input on the charge controller and see how it goes. MC4 branch connectors are prety cheap and be bought later if you want to try something else.

Since you have so many pannels now have you thought about mounting them in a different location and buying another charge controller? This way you could set one up for early season and one up for late season.

For my system I only see 3hrs of direct sun and the rest of the day its complete shade. I have two 230w pannels in parallel and currently cant fit any more on the roof. Really the heart of any weekend cabin is the batteries. When you leave after 3days there you have 4 days to charge the batteries with no useage. Useage really has to do alot with how big of a system needs to be. We have 6 205AH 6v golf cart batteries and run a mini fridge with top freezer along with lights, charge phones and shop vac before we leave. We stay well above the 12.2v that is 50% capacity.

gcrank1
Member
# Posted: 20 May 2021 09:09
Reply 


Watch out for the max input VOC to the charge control.
Ive read various + factors but 1.2 x the added together VOC's seems fairly common to avoid the cold temp spike that blows Scc's. I prefer to edge up on max'es and have the elbow room.
Thinking about the shading thing and multi-direction arrays the past few days myself. For Instance:
If one array of 2s is pointing S-SE and the other 2s is pointing S, both paralleled together to input to the CC, what happens when the S-SE one becomes shaded/out of the direct sun?

razmichael
Member
# Posted: 20 May 2021 10:05 - Edited by: razmichael
Reply 


Standard in larger arrays to break things up and use multiple CCs and also can be a good plan (as Brettny mentioned) for smaller systems with some type of multiple sets of panels (different locations, voltages etc). I added two much larger panels last summer to my setup with a new CC MPPT charge controller (along with a new battery bank). I kept the old battery bank as a back up and use a dual battery bank CC with the old panels to keep the old batteries charged and then add to the charge to the new bank when available. You need to do some custom configurations so things like equalization does not happen too often but the two CCs will "see" each other as the battery voltage and adjust as needed. Given how much cheaper CCs have become it can be a very simple way to add multiple arrays.

gcrank1
Member
# Posted: 20 May 2021 10:53
Reply 


So, to be clear, in my scenario with 2s/2p arrays facing somewhat different directions (I have little solar exposure after 2pm, dst and am thinking the 8-11am s-se one would get me a head start) I need a scc for each? Need, or just best practice?
If I can parallel the 2 arrays though my one existing scc without cutting my charging from all 4 (2s'2p) facing S (ie, make an overall increase in watt-hrs chg) without spending more) I'll go to the trouble.
Apologies to the OP, but as you see, opening a thread on solar here (anywhere?) may generate (pun intended) more questions than you ever expected.
Kinda like sitting around a campfire an having a free flowing discussion amongst friends

jawarren77
Member
# Posted: 20 May 2021 10:55 - Edited by: jawarren77
Reply 


Thanks for all the input, sound like I need to take a closer look at our Charge Controller/Inverter. I know its an MPPT Magnasine Magnum. Charge Controller is an Outback MX60 (60amp).

Steve_S
Member
# Posted: 20 May 2021 12:02
Reply 


OutBack MX60 Specifications (Replaced by FlexMax 60)
Nominal Battery Voltages

12, 24, 32, 36, 48, 54 or 60 VDC
(Single model - selectable via field programming)
Output Current
60 amps maximum with adjustable current limit for smaller systems
Maximum Solar Array Size
12 VDC systems 800 Watts / 24 VDC systems 1600 Watts / 48 VDC systems 3200 Watts
PV Open Circuit Voltage (VOC)
150 VDC absolute maximum coldest conditions / 140 VDC start-up and operating maximum

For this SCC and a 12V Battery system, it can take up to 800 Watts of Panel and no more than 140VDC input from the panels.

@gcrank1
There are folks who have homes aligned North-South and they install solar panels on both E & W sides and use only one controller. The caution is to ensure that one side is not still generating high voltage & amperage so that cumulatively you exceed max input allowable. As you know, even in dim light panels produce something, so you would have to be quite cautious & "certain".

Alternately, many of the new AIO Systems have multiple MPPT Solar Inputs which allow for multiple racks to be used as well as more costly advanced SCC's.

gcrank1
Member
# Posted: 20 May 2021 12:14
Reply 


Thanx, Steve.

Brettny
Member
# Posted: 20 May 2021 21:08
Reply 


So your about 220w over what the charge controller can handle technically. Although you will prob never see 800w input even with a 1020w of pannels.
What's the max voltage of each pannel? This will tell you how many to can run in series.

jawarren77
Member
# Posted: 21 May 2021 10:49
Reply 


the 130w panels are 24v and the 100w panels are 12v. The most we see on the (4) 130w panels is 300w.

Brettny
Member
# Posted: 21 May 2021 11:40
Reply 


Dont hook those to the same CC. Hooking different wattage pannels to the same CC basically will turn your 130w pannels into 100w pannels.

Seeing only half of the output that the array is rated for is prety poor. Can you aim them better? There is an online calculator that can tell you what angle and what direction to best mount them for your zip code.
http://www.solarelectricityhandbook.com/solar-angle-calculator.html

jawarren77
Member
# Posted: 21 May 2021 15:23 - Edited by: jawarren77
Reply 


Quoting: Brettny
Dont hook those to the same CC. Hooking different wattage pannels to the same CC basically will turn your 130w pannels into 100w pannels.



Thanks for the info!

Hope this Google Map Link works... Map

The existing panels are mounted on the right side of the cabin (in the shade), I am planning on mounting the new panels on the left, near the ridge to catch more sun. According the the angle calculator, our panels should be at 66 degrees.

Brettny
Member
# Posted: 21 May 2021 21:15 - Edited by: Brettny
Reply 


Dont post the location of your cabin. The whole world now knows. Open google earth and take a screen shot if you want us to see the roof.

Also so many things like trees and hills come into play when aiming pannels. For me I had to aim them into the hole in the tree canopy...but that did end up being south west.

scott100
Member
# Posted: 22 May 2021 18:27 - Edited by: scott100
Reply 


Quoting: Brettny
Dont hook those to the same CC. Hooking different wattage pannels to the same CC basically will turn your 130w pannels into 100w pannels.


Not necessarily true. While it's not advisable to hook panels of different wattages together, it depends on the configuration and operating voltages and currents of the panels. If in series, you are current limited by the smaller current panel. If all the the panels have roughly the same operating current, you won't lose much. If in parallel, you're voltage limited by the smallest voltage panel. If they're all close, no big deal.

In his case, if he wired his 12 v panels in series for 24 v, and their rated operating voltage in series was pretty close to the existing 24 v panels, he would be ok, more or less, to run them paralleled with the others. Maybe not advisable or ideal, but it would work.

jawarren77
Member
# Posted: 24 May 2021 12:08
Reply 


Quoting: Brettny
Dont post the location of your cabin. The whole world now knows.


Yeah, I know. I don't have a photo hosting site to link a photo to.

I took a chance that people here are respectful enough and with its semi-remote location, would safe.

gcrank1
Member
# Posted: 24 May 2021 20:01
Reply 


Well, yes, those of us that are respectful....are.
Then there are those miscreants that visit, etc. that arent.

Brettny
Member
# Posted: 25 May 2021 05:59
Reply 


You dont need a pic hosting site to post a picture here. Take a screen shot with your phone or PC then use the "upload file" link near the post message button. You dont need to be a member here to view threads so any one can see it.

. 1 . 2 . >>
Your reply
Bold Style  Italic Style  Underlined Style  Thumbnail Image Link  Large Image Link  URL Link           :) ;) :-( :confused: More smilies...

» Username  » Password 
Only registered users can post here. Please enter your login/password details before posting a message, or register here first.