Last stage question: How to make the solar equipment SAFE(?) - what do we need?

newestnewbie · January 2017

- should concern everyone, but even solar vendors fall short of selling all the safety items on top! :-(
So, here my concern:
I have this setup under construction (nice image attached):

Image: https://mygermanshepherd.org/uploads/My-solar-setup.png

and would LOVE if someone even LINKS to the *numbered items* for sale (here, or amazon, or whoever sells them). Would help everyone. Because this is where all the online "solar installation advice" articles and videos fall short. :-(

Again, would love if someone knows (really knows) what exact items are needed where the numbers are, and right away where we can buy them? Happy to use the advisor's "affilitate" links (if any)! I "learned" already that eg for breakers "100% duty cycle" is critical, so please advise for quality items not China garbage, lol.

I am not an electrician or such, so pl go easy on me, and assume everyone else too :-)

mike95490 · January 2017

At your panels, you don't want disconnect switches, you want to bring the 3 sets of wire to a Combiner Box that has 3 DC breakers in it, a sticker on the back of the panel will state what the SERIES FUSE 8A is, and you use a ckt bkr of the same rating
https://www.solar-electric.com/mnpv3.html you must add the proper breakers

12V only if this is going into an RV. Otherwise 24V system or even 48V for the large inverter

Your inverter is sized too large, it's internal losses will exceed what lightweight loads consume Do you really expect to need 230Vac

Parallel AGM batteries are a VERY poor choice. Look for 6V AGM batteries in the 400ah range
https://www.solar-electric.com/rolls-surrette-sealed-deep-cycle-s6-460agm.html

Your Charge Controller LOAD OUTPUT can seldom deliver enough power for a fridge, And your 12V fridge needs to be an efficient model, not a resistance heater/propane heater version.
You should use a 12V DC Low Voltage Disconnect for your loads to protect the battery

With limited solar, you need a generator to protect the batteries from overly deep discharge.

Photowhit · January 2017

1. Would be a breaker in a combiner box; Link
https://www.solar-electric.com/catalogsearch/result/?q=combiner+box

2. Since this is on a vehicle I wouldn't worry about an addition switch, just turn off all the panels if you like to turn off incoming current from array.

3. I'd use a Marine type breaker, you could use a switch, I would recommend a fuse here as you would only want it for protections, if the batteries are used or charged independently they will become out of balance. Link;
https://www.westmarine.com/buy/blue-sea-systems--285-series-thermal-circuit-breakers-surface-mount--P011975596?recordNum=13

4. Again the same surface mount breakers would work for me, and likely you, I doubt you will run contiguously above 1800 watts, so a 150 amp breaker should work, they generally will be slow to switch so should handle momentary loads for starting motors and such. As Mike said that's a pretty large inverter, Since you want 230 volts I suspect you are in Europe or Australia?

5. I would float the system, hard to ground some people ground the frame which is a hazard in it's self.

Most solar have all these things for land based operations, mostly search for breakers etc, RV shops would handle most of what you are looking for as RV's may have a deep cycle battery system as well as a vehicle battery.

newestnewbie · January 2017

"At your panels, you don't want disconnect switches, you want to bring the 3 sets of wire to a Combiner Box that has 3 DC breakers in it, a sticker on the back of the panel will state what the SERIES FUSE 8A is, and you use a ckt bkr of the same rating
https://www.solar-electric.com/mnpv3.html ; you must add the proper breakers

12V only if this is going into an RV. Otherwise 24V system or even 48V for the large inverter

Your inverter is sized too large, it's internal losses will exceed what lightweight loads consume Do you really expect to need 230Vac

Parallel AGM batteries are a VERY poor choice. Look for 6V AGM batteries in the 400ah range
https://www.solar-electric.com/rolls-surrette-sealed-deep-cycle-s6-460agm.html

Your Charge Controller LOAD OUTPUT can seldom deliver enough power for a fridge, And your 12V fridge needs to be an efficient model, not a resistance heater/propane heater version.
You should use a 12V DC Low Voltage Disconnect for your loads to protect the battery

With limited solar, you need a generator to protect the batteries from overly deep discharge."

Thanks Mike. I actually was 100% conscious when I posted, lol.
We do want switches under the panels, not a combiner box. All panels are on the wall of an "RV", and I fear that what is not hidden under the panels offers additional "interest" to some folks some day. (your links by the way are not clickable; they do open in a new tab though if users know how to request that; however then comes "We are sorry, but the page you are looking for cannot be found.").

"you must add the proper breakers" - yes, that is my question about, how funny.

No, the inverter is not sized too large, you size an inverter based on your AC needs, and these are ours, even if higher than yours please appreciate our needs.

"Parallel AGM batteries are a VERY poor choice. Look for 6V AGM batteries in the 400ah range
https://www.solar-electric.com/rolls-surrette-sealed-deep-cycle-s6-460agm.html"

Can you please explain WHY you argue that way? Because I know WHY they are a VERY good choice, but I do appreciate that you link to a 6V Rolls battery for $604, that is what everyone with 450W peak wants and needs, lol. ;-)

"Your Charge Controller LOAD OUTPUT can seldom deliver enough power for a fridge," Where did you get that from? It does deliver enough power. That's what CCs do, Mike. They deliver from the battery, NOT the solar panel.

"You should use a 12V DC Low Voltage Disconnect for your loads to protect the battery" Yes obviousyly the CC does that anyway.
OMG, not sure why you write, absolutely nothing was useful in any way. But Thanks.

newestnewbie · January 2017

Thanks Photowit, that's helpful
"1. Would be a breaker in a combiner box; Link
https://www.solar-electric.com/catalogsearch/result/?q=combiner+box"
We can use it in another location indeed.

2. is a misunderstanding, we do want a new CC as defined.

3. We do want a switch there, that's why I wrote it: For longest life batteries should be fully charged frequently (solar doesn't), and we use that switch to charge each of them individually during such "maintenance".

4. We plan to go with a hydraulic-magnetic breaker, not just thermal. And 100% duty cycle, medium we see as insufficient. Would you have a link to that as well?

5. "I doubt you will run contiguously above 1800 watts" That depends, not 24/7 no, but 20 min when we do for sure. Hence the higher amps requirement. Yes for Europe too, very flexible we are, won't say more though about how

"I would float the system, hard to ground some people ground the frame which is a hazard in it's self." Could you explain how please?

Thanks to all again :-)

Photowhit · January 2017

1; If you must have a switch for each panel at the panel, I would make one rather than pay the price for a solar isolator switch, You can search and find them, but I can see other options, but since I don't understand your need, I'll just say they are out there. If you intend to use a combiner box, recommended with 3 or more parallel panels, but want a disconnect at the panel, you might just use the MC4 connectors, or create a switch box with a NEMA enclosure (project box) and a some wire restraints, Not sure the intended use so if you give me more information I'll be glad to try to help. How often will you use this? daily or to remove the panels from the vehicle (a couple times a year)

The panels in and of themselves are not a safety hazard. 8 amps at <24 volts would require an effort to shock anyone.

2; Your question was does a switch makes sense, Are you asking for suggestions for a 40-50 amp charge controller? I would suggest Morningstars 45 amp, MPPT if you must, but likely you have 12 volt nominal panels, and will lose minimally if you use a PWM type charge controller. This is a fanless unit, fans can be annoying in a RV. Link;
https://www.solar-electric.com/trts12vochco.html

3; I've been around for a while and if you don't treat the batteries the same, as one bank, you are asking for trouble, they should be treated as one, charge them both up together, if one is low the other will be as well, loads should be applied to both and energy drawn from both evenly, use the same amount and gauge of wire through each string. If the batteries are low they both need to be charged. Battery banks can be used while they are being charge!

4. Here is a 200 amp, they make marine at least as high as 300 amp (that I've seen) I have no idea if these are hydraulic-magnetic, you could likely find out pretty quick. 2000 watts is a huge load, These high loads creat wiring issues for low voltage systems. 190-200 amps would require 4/0 or better to the inverter and a short wire run to prevent losses. You've said you understand the wiring.

https://www.delcity.net/store/EATON-Marine-Breakers-!--Hi!Amp/p_795454.h_795462.r_IF1003?mkwid=sIDeGB8L5&crid=38094426869&mp_kw=&mp_mt=&gclid=CjwKEAiAkuLDBRCRguCgvITww0YSJAAHrpf-GGcj6ob6ZY-Kpa4XfH9j5iGyf7q6nf8_0RaZyOsc7BoCjTXw_wcB

5. "grounding " is also called 'earthing' in some places, the idea is to dissipate a short that might occur. If grounded to earth a short between you and the system would be shared by the earth. In a vehicle, a vehicle a ground made to the frame is isolated from the earth nicely by the tires, and the metal will make a nice connection to you, if shorting out something...

dennis461 · January 2017

Ooops,
Forget what I said about fuse holders.

BB. · January 2017

Double check this:

The din mounted fuse holders are a tilt out version.
Pull the plastic holder, the fuse tilts down and breaks the connection.
You can use as a switch.

Do not use touch safe fuse holders as switches (pop the fuse out under load)--They can arc and self desctruct/catch fire:

http://www.midnitesolar.com/pdfs/MidNite PV Combiners explained w diagrams.pdf (page 3)

By the way, don’t ever open a touch safe fuse holder under load!!! The following pictures are the result
of a 250 volt array that had only 5 amps flowing through it when the fuse holder was opened. This fuse
holder is UL listed to 1000VDC and 30 amps. It does say “Do not open under load”. It’s a good thing we
build our combiners out of metal. The arc and fire lasted for about two full minutes until it burned out.
The upcoming 250VDC MidNite Classic controller presents some problems. There will be consumers
installing this high voltage controller. We highly recommend professional installation. The pictures
above show a very real issue. MidNite has addressed this potential problem by creating high voltage
circuit breakers

-Bill

mike95490 · January 2017

Panel disconnects vs Breakers in a Combiner box
First, with more than 2 panels in parallel, you MUST use a combiner box to prevent a panel fire in case of a fault,
The combiner box generally has a mount provision for DC breakers or fuses, Most fuse holders cannot be used as a disconnect and the system must be powered down (very inconvenient) to look at a fuse, (touch safe is not the same as disconnecting)
(the picture at midnight clearly shows DO NOT OPEN UNDER LOAD printed on the side of the holder)
http://www.midnitesolar.com/images/products/photos/MNTS_Lg.jpg

Box   http://www.midnitesolar.com/productPhoto.php?product_ID=78&productCatName=Combiners&productCat_ID=9&sortOrder=4&act=p

Breakers (chose the rating that matches the value on the panel sticker as series fuse)
http://www.midnitesolar.com/productPhoto.php?product_ID=183&productCatName=E-Panel - Samlex&productCat_ID=9&sortOrder=1&act=p   These come in 1A steps

Charge Controllers   Control charge to batteries, If you need Load Control, some small hobby controllers have load control, but is usually quite limited in ampacity, This is usually handled by PROPER system design and operator awareness, or using a Low Voltage Disconnect (LVD). Google low voltage disconnect
The small Brat has load control up to 10A
20A charger with 10A load control, 30A charger without load control
http://www.midnitesolar.com/productPhoto.php?product_ID=615&productCatName=Charge Controllers - Brat&productCat_ID=49&sortOrder=1&act=p
30A Kid has 30A load terminal http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=43&productCatName=Charge Controllers - KID
The big 90A charger has no load control, same with Conex 80A, Morningstar 60A, no load control

( I hope these links work )
Midnight also has a wide selection of breakers, not sure which are the hydraulic-magnetic models
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=16&productCatName=Breakers
models C, F, Q, QY came up as mag-hyd breakers.

I'm doing this all over again with fresh links, because you need to know this, already someone has suggested using fuses as disconnects and that NEVER works on DC.    If things have been working, even with misapplication, consider yourself lucky and carry on.

Batteries - In parallel, it's very hard to get proper current sharing between banks:
http://www.smartgauge.co.uk/batt_con.html   covers the math and shows some examples
Series wiring of lower voltages is a much better path to long life.
AGM (sealed) batteries have very low internal resistance and are less likely to "share in parallel" correctly.

Last stage question: How to make the solar equipment SAFE(?) - what do we need?

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