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Small Cabin Forum / Off-Grid Living / Solar System CC Problem
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ArtifactJack
Member
# Posted: 19 Jul 2021 09:41
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My 30 amp PWM charge controller 30A circuit breaker is tripping going to the battery bank. Before it trips the amperage indicated on the CC from the panels is going all the way up to 20A, and I have never seen the amps from the panels to the batteries go over 6-7 amps, the batteries are fully charged and good. Any insight would be appreciated before I buy a new MPPT controller.

gcrank1
Member
# Posted: 19 Jul 2021 11:17
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What specifically is your '30a CB'?
Is a 30a Fuse/CB what the scc manufacturer recommends for size?

curious
Member
# Posted: 19 Jul 2021 11:32 - Edited by: curious
Reply 


How old are the batteries? Am I right to assume they are lead=acid flooded batteries?

If nothing in your system has been changed from panels to batteries, then there is no good reason for the amperage to the batteries to jump way high out of what has been their normal charging rate.

What and how many panels are there. Is it even possible for the panels you have to produce enough current to pop the breaker?

My bet is that the breaker may have gone faulty.

The batteries could even be old and bad and developed a problem, a lowered resistance that allows a large enough inrush of current that pops the breaker. BUT with that being a PWM CC that is highly unlikely unless the panels are actually capable of delivering 30+ amps.

How have you determined that...
the batteries are fully charged and good.
. Do the batteries hold up to a big load, like operating a microwave if you have one. Have you looked at the fluid, used a hydrometer?

ArtifactJack
Member
# Posted: 19 Jul 2021 11:38
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Yes it is a inline CB.....and I have never had a problem with the system since I installed it 2 years ago. The solar panels are maxing out at 19V also....I have four 100 watt panels. Its a HQST CC....

curious
Member
# Posted: 19 Jul 2021 11:49 - Edited by: curious
Reply 


100 watts / 19 volts = about 5-1/4 amps. If the panels are parallel connected the theoretical max amps would be about 21 amps or a bit more.

What is the Isc current rating of the panels? THat multiplied x4 (if parallel connected) will indicate the max amps of the 4 panels combined. 4X the Imp rating = the max amps under normal bright sun conditions.

The more details of the hardware being used the easier it is to make guesses as what to look at.

It does seem to me that the breaker is at fault with what we know so far.

ArtifactJack
Member
# Posted: 19 Jul 2021 12:49
Reply 


Thanks for all the advice/input.....I'm going to change the CB first and see what happens. I'll let you know how it turns out.

gcrank1
Member
# Posted: 21 Jul 2021 19:09 - Edited by: gcrank1
Reply 


Being careful you can check the operation of your system sans the CB to find out what you might need to buy. Works for me, if you dont like the idea dont do it.
Iirc there was recently a thread specifically about CB's over at
diysolarforum.com
Summary (again, iirc):Many used are cheap 'imported junk'. What you want is marine grade as sold by Blue Sea. At least see what type of CB's they have so you know what to look for elsewhere (they are pricey. But then, safety has a cost).
Fuses are better than CB's for the DC sides of solar elec systems.

curious
Member
# Posted: 21 Jul 2021 19:38
Reply 


Why do you say a fuse is better than a breaker designed for DC? A good one, not a piece of junk, but that goes for all kinds of parts.

gcrank1
Member
# Posted: 21 Jul 2021 21:06 - Edited by: gcrank1
Reply 


You should look it up on diysolar, as I said, 'iirc' so Im second hand info.
As I recall, fuses are pretty much a 'good' or 'bad' and react quickly at close to the rating; blow and thats it. CB's are a mechanical device and with dc the arching internally can trip, arch, and maintain a connection. My impression is that arching is similar to why we shouldnt use ac switches and fixtures for dc wiring. And that is a major reason I went with inverting at the bat-bank, get a long ac run with just 12ga. wire (90+') to the cabin and can use inexpensive and available 120vac switches, fixtures, etc.

Brettny
Member
# Posted: 22 Jul 2021 05:24
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The fact that your seeing 20a out of the pannels and never have before could just mean your batteries are full. You will get some voltage sag when you load a pannel. Also your seeing 20a on the CC then the breaker trips would mean the 30a circuit breaker could be more like a 20a.

ArtifactJack
Member
# Posted: 22 Jul 2021 10:37
Reply 


I changed the fuse/CB and it fixed the problem. Thanks for all the great advice and replies. I am using the audio type fuse/CB that has a reset. I added a 100W panel plus another 100A AGM battery to the system this spring, so maybe its to much for a 30A fuse. I had a spare 30A so I am going to order a 40A and keep it for the spare. They may be underrated or just cheap China junk. Right now the sun is probably at its peak in my area(Ohio), so that may have something to do with the panels maxing out. I also use the same type CB(150A) for the positive battery going to the inverter, so lets see how long it lasts. My biggest power load is the mini fridge, it runs off the panels this time of year as the batteries stay fully charged during the day when its running. I only stay there 2-3 days a week, but its nice not to buy ice now to keep my food and drinks cold. Thanks again for the advice, I hate troubleshooting by throwing parts at something to get it right. Don't have cell service or internet at the cabin, so if something breaks its 10 miles to town just to get solar advice, or order any parts online. I have a 150 acre farm, and added the solar power 3 years ago to the cabin, that has been there for 20 years. Its a luxury to have electric no matter where you live.....have a great day everybody.
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IMG_20201129_095916_.jpg


gcrank1
Member
# Posted: 22 Jul 2021 18:19
Reply 


The array is more likely to spike in the cold, counter-intuitive, that.
Iirc fuses/cb's need to be up-sized by 125% from the combined panels rating for the cold spike then x 125% again for elec code? I would rather try to stay at that rather than oversizing beyond to compensate for a poor quality cb.
Wonder if there is an affordable cb tester to find where they trip? Thing is, they can be bad by tripping too soon or too late causing a melt-down and/or fire, we dont know which it will be.
I think I remember reading that those audio-type are typically imported bad stuff. Not sure....comes to mind though.

ArtifactJack
Member
# Posted: 22 Jul 2021 20:37
Reply 


gcrank......they are advertising the CBs for marine and solar dc systems besides audio use. I just got another one in the mail today that is 50 amps. The only need for a fuse/cb between the cc/batteries would be in case the CC went bad, and started over charging the batteries. But I could be wrong. Never had any problems with my solar system except with the dc solar side.....thinkin buying a quality/new mppt charge controller would be a safer upgrade. Yeah we don't want to burn the cabin down, unless its the woodstove.....

Brettny
Member
# Posted: 23 Jul 2021 05:43
Reply 


What mppt controller where you looking at?

ArtifactJack
Member
# Posted: 23 Jul 2021 07:33
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Brett....looking for a 40-50 amp controller in case I add a couple more 100w solar panels. Right now I have 400w of panels at 20amps, so I will need at the least a 40 amp charger, and they start getting pricey over 30 amps. They also seem to jump from 30A controllers to 60A with not a lot of choices in the 40-50A range. I only have two 100A AGM batteries right now, so I may end up buying another battery or two. And then I start looking at turning the system from 12V to 24V. My current system has pretty much paid for itself over the past 3 years compared to what my electric bill would be grid tied. And if I added the cost of physically hooking to the electric pole, I am way ahead of the game...

Nobadays
Member
# Posted: 23 Jul 2021 08:56
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We just set up a solar system at my neighbors cabin and we went with Victron SCC/Inverter Charger. Really nice equipment, Bluetooth to adjust and monitor it. Pretty slick! I see on Amazon that a Victron 100/50 is ~$325. A cheaper but pretty good quality for Chinese SCC is the EPEVER which runs about $100 cheaper... ~$225. I use the 40 amp EPEVER in my shop on a 24v system with 1000 watts of solar, has performed fine for over a year now.

Brettny
Member
# Posted: 23 Jul 2021 11:48
Reply 


I also have a epever 40a CC. It's the BN series that dosnt have a on unit display, it can take 150v input which is why I own it. But mine only has 460w of pannels connected to it.

Dont buy those no name ebay MPPT controllers. Generaly there $40 and cheaper, there also not MPPT.

gcrank1
Member
# Posted: 23 Jul 2021 12:04 - Edited by: gcrank1
Reply 


Im running mppt because at 24v from the array I can use smaller ga. wire and/or go farther; the line losses at 12v can really reduce how far away from each other your components are. When I looked at the wire ga. charts I was surprised to learn that many roof-top or pole mounted arrays seemed to have too small a ga. wire for the distance for the voltage used.
Same from the scc to the bat-bank, though I have those two close together so Im still at 12v. If I have to buy a new inverter, it will be psw only and 24v so I can then series the bats.
Knowing what I do now Id start out with a min of a 24v system (except for maybe a little basic van, small rv, tiny cabin set up).

ArtifactJack
Member
# Posted: 23 Jul 2021 12:10
Reply 


Nobadays> I was looking at the EPEVER brand. They seem to have the best rating for the dollar. I was thinking about going to a mppt controller a couple of months ago before this CB problem, wanting to collect more solar power over the winter months.

ArtifactJack
Member
# Posted: 23 Jul 2021 13:33
Reply 


Now with that said....my last hurdle at the farm is water, thinking about sinking a shallow well with a solar water pump. A friend of mine had one about 12 feet deep....

Brettny
Member
# Posted: 23 Jul 2021 15:37
Reply 


For such a minimal use item (water pump) why not just get a 120v pump and put the extra money into more batteries or pannels? Arnt those solar pumps prety expensive?

gcrank1
Member
# Posted: 23 Jul 2021 17:28
Reply 


Hand pump from Lehman's?

ICC
Member
# Posted: 23 Jul 2021 18:01
Reply 


Who wants to hand pump when you can flip a switch?

ArtifactJack
Member
# Posted: 23 Jul 2021 19:16 - Edited by: ArtifactJack
Reply 


I hear what you guys are saying...the water line tap is $1400 bucks. Then a monthly bill of around $25 dollars. That's a pretty expensive shower, while I can clean up in town a couple of days a week. Not frugal but realistic.....food, water, and shelter is getting expensive when you have to make payments.

Brettny
Member
# Posted: 23 Jul 2021 19:48
Reply 


How much rain do you get a year between your first and last frost dates? Is there a stream or spring on the property?

For $1400 +$25month I wouldnt connect our property to a water main but a stream is something that was required when we where looking just for this purpose. We found 1 decent and 1 un developed spring on our property after the fact. Although a shallow well would never work in our clay/rock unless once you get below 6ft it turns to sand/gravel. You really need a high water table to do a shallow well and that's prety hard to come by.

gcrank1
Member
# Posted: 23 Jul 2021 20:22
Reply 


I dont mind using a hand pump because we do not use water like it is hooked up to a main. It would be fine if I had water shallow enough to be able to utilize a hand pump.
As it is, our rain barrel provides all and more, much more, than we need for utility. No problem keeping clean and refreshed. Until rural electrification in this country that is how people lived, and how much of the rest of the world still does live.
This fits fine with my concept of 'off grid, dry cabin'.

Steve_S
Member
# Posted: 24 Jul 2021 06:56
Reply 


EPEver makes good respectable Tier-2 grade equipment and are a good value. They have also really stepped up with improvements and they did not push up the prices because of it.

AVOID Renogy ANYTHING ! not saying more on that.

Circuit Breakers do DC are the way to go, none of this AC/DC compatible shenanigan, they will be problematic. Stick to Known Good ONLY, this is NOT the thing to skimp on by any means !

Fuses !
Ohh what a horrid little mess. so KISS Applied.
Buy ONLY good quality fuses never ever cheap imports with no branding. Eaton Corp (Top Notch) many "Brands" that make Breakers & Fuses. Brands owned by Eaton below: *Bussman, Cooper, Babco and many more...

https://en.wikipedia.org/wiki/Eaton_Corporation#Brands

ArtifactJack
Member
# Posted: 24 Jul 2021 21:06
Reply 


Yeah I stay away from the companies selling solar packages like Renogy....you know there are quite a few middlemen, when they sell their crap at Lowes. My solar system cost me 2/3 of what they wanted for it as a package, all you have to do is buy the solar components separately...

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