4 405w panels vs 12 100w panels...

HRTKD

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I agree with not using that circuit breaker on the input side of the solar charge controller. A DIN rail mounted breaker rated for 250v DC and an amperage closer to the actual is appropriate.
 

Tbleppy

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I think you are using a LiFePO4 battery (which I think can deliver 10,000 to 20,000A into a short), so I don't think this breaker is good connected directly to the battery. If there is suitably rated over-current protection (e.g. a class T fuse) on the battery and this breaker is downstream, then maybe OK.
i checked out this fuse:
that you gave me. The product image reads 42v, but the specs say 48v
CB185-100_C (500x500_72dpi).jpg

so this is a good one for the 50amp fuse?

i have 4 inline fuses at 12a each for each parallel string.
y's connect them down.
After that it needs to connect to a 50a circuit breaker which serves as protection and a shut.off switch.
Then connect to solar charge controller: 40a renogy 100VDC max, max battery voltage 32V, rated load current 20a.
from there 8 awg connects to battery posts.
i have attached a diagram of my plan. Can you please verify the specs of the 50a circuit breakers, 1 before charge controller, 1 after charge controller, that I should be looking for...other than 50amp...what are the other requirements for this fuse/circuit breaker to work properly.
can you do the same for the class t fuse 150a? What other requirements need to be fulfilled in the fuse im looking for for it to work properly.
IMG_20210317_163720.jpg

i would really appreciate the additional fuse info or a link to one(s) that meet all the parameters im looking for. This is the last thing i should need.

i did not include a bus bar because it can be added later. Right now i only have 1 DC appliance and my charge controller allows for 1 direct load.

i applied an extension cord at the end of inverter to apply AC loads. Plan to hardwire in the future with an AC breaker box with circuits.

Please point out anything erroneous. Thanks!
 

Tbleppy

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These breakers say 150VDC, non-polarized, 10,000A interrupting.
Note they are panel mount (two screws from the front) with studs on back for ring terminals.


can you verify this is the correct class t 150a fuse please?
 

Tbleppy

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These breakers say 150VDC, non-polarized, 10,000A interrupting.
Note they are panel mount (two screws from the front) with studs on back for ring terminals.

i got the class t fuse! I was able to find the blue sea one. I am all set with that.

heres what i plan to get for the breakers:
2 of MidNite Solar MNEDC50 > 50 AMP 150 VDC PNL Breaker ($17.75ea)

1 of Midnite Solar MNEDC-Quad > Quad Enclosure ($55.00 ea)

1 of Midnite Solar MNGBB > Ground Bus Bar ($11.00ea)

This is adequate right? I added a ground bus bar on. Will that work for this set up? Would that need to be enclosed too? Do you think this is a wise decision or is it lacking? I am hoping this will complete my system. Can you confirm if it looks alright please? Thank you!
 

Hedges

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$43, great price for class T fuse with holder! 150A looks like good size for 2000W 24V inverter.

Those should work.
The 50A breaker for PV just serves as a disconnect because current will never be that high.

Ground bar - depends on what you are grounding. Breaker enclosure says grounding lugs sold separately. That might connect one ground wire from panel frames and one back to system.

In schematic, you have four batteries 2s2p. Inverter wired to one pair, then other pair paralleled.
Instead, connect inverter diagonally, to negative of one series pair and positive of other series pair. That makes it balanced so current supplied equally.

Connect charge controller diagonally as well, with breaker connecting after the fuse not directly to battery. (Fuse has better short circuit interrupt rating than breaker)

Does inverter have an on/off switch?
Some people like to have a precharge resistor to there isn't a high current into capacitors when first connected. I don't know when that matters and when it doesn't. Some use a rotary 2-position battery switch, first position connects resistor, second makes full connection.
 

Tbleppy

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$43, great price for class T fuse with holder! 150A looks like good size for 2000W 24V inverter.

Those should work.
The 50A breaker for PV just serves as a disconnect because current will never be that high.

Ground bar - depends on what you are grounding. Breaker enclosure says grounding lugs sold separately. That might connect one ground wire from panel frames and one back to system.

In schematic, you have four batteries 2s2p. Inverter wired to one pair, then other pair paralleled.
Instead, connect inverter diagonally, to negative of one series pair and positive of other series pair. That makes it balanced so current supplied equally.

Connect charge controller diagonally as well, with breaker connecting after the fuse not directly to battery. (Fuse has better short circuit interrupt rating than breaker)

Does inverter have an on/off switch?
Some people like to have a precharge resistor to there isn't a high current into capacitors when first connected. I don't know when that matters and when it doesn't. Some use a rotary 2-position battery switch, first position connects resistor, second makes full connection.
there is a 50a breaker for pv before the charge controller. After the charge controller i should have a 50a fuse, then another 50a breaker before connecting to the battery. Is that correct?

I like the midnite solar 50a breakers you showed me. My problem is the box enclosure. I found the quad, baby box and big baby as small enclosures available. If i will have an enclosure, i would like to have a ground bar in there. I am rethinking the busbar and considering including it now while its easy to add. Do you know what enclosure i could use with the 50a breakers? The quad looks to.handle the mnedc breaker which is what i believe you had recommended. The baby and big baby handle mnepv breakers. Quad and baby box have no room for any bars. Big baby does. So my question is instead of 50a mnedc breaker, could i use 50a mnepv breaker? This way i would get the big baby box.

My heart is not set on that box. If you know of a good box, can you recommend one please? Also can you recommend the 50amp fuse i should be looking for? Thank you!
 

Hedges

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It looks like mnepv breakers mount on DIN rail.
They also are "polarized", which means they can interrupt current going one way but not very well going the other. They have a magnet to deflect the arc into chutes to separate and cool.

prefer non-polarized breakers. I think polarized are OK for something where a load is powered from a source, and there is no way for current to backfeed.

"After the charge controller i should have a 50a fuse, then another 50a breaker before connecting to the battery. Is that correct?"

I didn't mean a 50A fuse. If you put a 150A class T fuse on the battery (for inverter), I suggest using a 50A breaker between charge controller and the 150A fuse. Because it is class T, it is able to interrupt the high current that would flow if a dead short occurred from positive wire back to negative. The other breakers and fuses usually available can't interrupt as much.

I think that box for panel-mount breakers said grounding lug was an accessory. So it probably has a screw hole to connect something. The ground bars usually use multiple screws or dimples to hold them straight, but you could probably drill a hole and use a self-tapping screw. The grounding bars I've used (in Square-D breaker panels) came with screws.
 

Tbleppy

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ground bars usually use multiple screws or dimples to hold them straight, but you could probably drill a hole and use a self-tapping screw. The grounding bars I've used (in Square-D breaker panels) came with screws.
do you recomend those square d panels? I was looking at them and it looks like a really good deal. read that their reputation is bottom of the line among electricians and knon for burn outs. Other than that i was interested in their panel.
 

Hedges

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I use all Square-D QO panels. The 125A and larger have copper bus (100A and smaller are aluminum.)

The other Square-D model, "Homeline" have aluminum bus and several other brands of breakers will fit.

Apparently there have been other brands made to fit QO as well. Square D objected, saying they weren't part of the tested system, and have been known to fail.


Have any links to objections people have with Square D products?
 

Tbleppy

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I use all Square-D QO panels. The 125A and larger have copper bus (100A and smaller are aluminum.)

The other Square-D model, "Homeline" have aluminum bus and several other brands of breakers will fit.

Apparently there have been other brands made to fit QO as well. Square D objected, saying they weren't part of the tested system, and have been known to fail.


Have any links to objections people have with Square D products?
Now that I look for it, I cant find it. Regarding the square d comment. It was just an amazon reviewer. Nothing more than that.

I want to confirm the inside fuses please. I drew the inside control center. Please note the solar panels along with y connections and inline fusing are not included in the drawing but are all there.
IMG_20210318_231529.jpg

I have 2 50a breakers mnedc50 enclosed in the quad enclosure. 1 breaker is before the charge controller (for pv shut off), 1 is after charge controller and before batteries. Then after batteries and before inverter is one 150a class t fuse and holder.

please verify this is correct as to what you meant. If not, would you be able to provide a drawing that is accurate as to what you mean? Im more of a visual learner so that would be helpful.

if my drawing is accurate, please let me know. Ill be good to go after that! Thanks!
 

Tbleppy

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I got it! I got the 2 50amp breakers mnedc50 and the quad enclosure for it! I think I am good now. Should i get a grounding busbar? I think the answer is yes. I guess I will need quite a bit of bare copper wire for the ground. I would use green copper wire outside and bare copper wire inside? Connct all equipment with one single uninterrupted path to ground.

Quick question about the ground. A copper rod 8ft under ground though there are other methods. Anyone know about the methods? I am sure that there was a metal rod, looked like rebar, sticking up out of the cement flooring and framework. The builder had said this is for electrical. Is this the ground for the house? Do I need a rod outside buried or do I use this which is currently enclosed with drywall but that is easily enough removed and repaired? Anyone know about this type of thing? Thank you for all your help! This has been so awesome having this advice and resources! Thanks for all the time you take to help and teach.
 

Hedges

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Now that I look for it, I cant find it. Regarding the square d comment. It was just an amazon reviewer. Nothing more than that.

I want to confirm the inside fuses please. I drew the inside control center. Please note the solar panels along with y connections and inline fusing are not included in the drawing but are all there.
View attachment 41611

I have 2 50a breakers mnedc50 enclosed in the quad enclosure. 1 breaker is before the charge controller (for pv shut off), 1 is after charge controller and before batteries. Then after batteries and before inverter is one 150a class t fuse and holder.

please verify this is correct as to what you meant. If not, would you be able to provide a drawing that is accurate as to what you mean? Im more of a visual learner so that would be helpful.

if my drawing is accurate, please let me know. Ill be good to go after that! Thanks!

The charge controller is connected to 24V, from positive to negative of four, 12V batteries connected 2s2p.
The inverter is connected from 12V midpoint to 12V midpoint, so gets zero volts.

Once you have moved inverter and 150A fuse to the 24V positive/negative connections of battery, I suggest moving the wire that connects 50A breaker, presently connected directly to battery positive, and connect it to 150A fuse instead. If there is a > 50A overload, breaker trips. If there is a dead short of 20,000A, the fuse blows (in case breaker just sits there burning.)
 

Tbleppy

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The charge controller is connected to 24V, from positive to negative of four, 12V batteries connected 2s2p.
The inverter is connected from 12V midpoint to 12V midpoint, so gets zero volts.

Once you have moved inverter and 150A fuse to the 24V positive/negative connections of battery, I suggest moving the wire that connects 50A breaker, presently connected directly to battery positive, and connect it to 150A fuse instead. If there is a > 50A overload, breaker trips. If there is a dead short of 20,000A, the fuse blows (in case breaker just sits there burning.)
Is this what you mean?IMG_20210319_235632.jpg
 

Hedges

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Is this what you mean?

Not quite.
Inverter now sees 24V, but doesn't go through the fuse.

Just move inverter negative to negative of the bottom battery (will be 3 wires at that connection), and move inverter positive to 150A fuse (where charge controller "batt" terminal connects).

Also, negative wire doesn't go to 150A fuse (just bypasses it), and I think the 50A breakers are single pole so negative wires also don't go to those (just bypass them)
 

Tbleppy

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Not quite.
Inverter now sees 24V, but doesn't go through the fuse.

Just move inverter negative to negative of the bottom battery (will be 3 wires at that connection), and move inverter positive to 150A fuse (where charge controller "batt" terminal connects).

Also, negative wire doesn't go to 150A fuse (just bypasses it), and I think the 50A breakers are single pole so negative wires also don't go to those (just bypass them)
Is either of these correct? Picture 1 or picture 2?IMG_20210320_131356.jpg
 

Hedges

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Not quite.
Starting with picture 2, move the inverter positive wire from direct to battery positive (where it is now) to other side of 150A fuse.

That way, 150A fuse protects wire connecting inverter. 150A fuse also protects wire going to 50A breaker and charge controller.
 

Tbleppy

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Not quite.
Starting with picture 2, move the inverter positive wire from direct to battery positive (where it is now) to other side of 150A fuse.

That way, 150A fuse protects wire connecting inverter. 150A fuse also protects wire going to 50A breaker and charge controller.
I think.I understand what you mean. Im waiting for the fuse to arrive so I can work it out.

My batteries had stated they need to be charged fully individually and then placed in parallel 24 hours, then configured as needed. I have a lithium battery charger but would have to use my generator for the charge...which I can do. Its a 20amp charger and I think that will take a long time. The batteries say 300-600watts per battery will take 4-5hours to fully charge.

I set up 3 panels in parallel, hooked the battery up to charge controller. The battery was reading at 10.8. I know thats really low but I dont think they are damaged until it reads 8 something. Anywho, it was getting dark and so I left the battery, charge controller there hooked together. Panels were ready to be hooked up but werent yet. It all spent the night out there. My husband went ahead and completed the hook up for me the next day. When I went and checked on it, it was not reading 10.8. It was blinking 0.1. It had a warning light blinking and I was really confused as to what happened. My husband doesnt remember what it said before he hooked up the panels. Im worried maybe the cold air during the night did damage to it. Will the charge controller being hooked up all night to it cause damage?

I want to disconnect the panels from it so I can view it again the way I was before and see if it still reads the 10.8 like it was. Can I just throw a blanket over the panels and then disconnect it? I know not to disconnect under load. There is no load. Will I be ok doing this? No circuit breaker switch is installed because this was a temporary set up to charge the batteries individually.
 

HRTKD

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Sure, cover up the panels. Cardboard, blanket, whatever.

Solar charge controllers consume battery power. So the controller would have drawn some amps from the battery. It should have been a small amount though.
 

Forbisher

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How cold was it overnight and during the day?

LFP should not be Charged at 32°F or lower But can be discharged in Much colder temps and just being in cold temps does not hurt them.

10V is totally empty for LFP and should trigger the BMS low voltage disconnect.
What voltage were your 100Ah Ampere time batteries when you received them?
Have you been discharging and using the batteries?
I think.I understand what you mean. Im waiting for the fuse to arrive so I can work it out.

My batteries had stated they need to be charged fully individually and then placed in parallel 24 hours, then configured as needed. I have a lithium battery charger but would have to use my generator for the charge...which I can do. Its a 20amp charger and I think that will take a long time. The batteries say 300-600watts per battery will take 4-5hours to fully charge.

I set up 3 panels in parallel, hooked the battery up to charge controller. The battery was reading at 10.8. I know thats really low but I dont think they are damaged until it reads 8 something. Anywho, it was getting dark and so I left the battery, charge controller there hooked together. Panels were ready to be hooked up but werent yet. It all spent the night out there. My husband went ahead and completed the hook up for me the next day. When I went and checked on it, it was not reading 10.8. It was blinking 0.1. It had a warning light blinking and I was really confused as to what happened. My husband doesnt remember what it said before he hooked up the panels. Im worried maybe the cold air during the night did damage to it. Will the charge controller being hooked up all night to it cause damage?

I want to disconnect the panels from it so I can view it again the way I was before and see if it still reads the 10.8 like it was. Can I just throw a blanket over the panels and then disconnect it? I know not to disconnect under load. There is no load. Will I be ok doing this? No circuit breaker switch is installed because this was a temporary set up to charge the batteries individually.
 
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