Most reacted posts

Thank you!

Thanks, Bob, and all, for your help. It is appreciated!

Thank you for the extra clarification, and for the reminder of Victron's reasonable shunt price.(y)

Hwy 17, Thanks. That box/switch is almost perfect, just really expensive.. and I need a 4 pole.

You are correct. They are not. I mistook the white negative cable coming from the DC side as coming from the AC side. All is good. Thank you.

Time, Thank you. I hadn't thought to look on the circuit board. It states "Maximum current 150 Amps" Currently has 2-40 Amp fuses.

rodrick, Thank you.

Thanks. I put a 100 Amp load on the system while charging and got a reading of 36 Amps from the charger.

Great response! I try to consider if these “problems” I sometimes feel a need to correct, really are a problem… My basic research found this question in various forms, with the real concern voiced numerous times, that there is a range between the SCC voltage, and the SPD voltage, where there...

Thanks! It is nice to have a similar system by which to gauge. I went through my SCC settings again just now and all looked good for LFP batteries, except the rotary dial was not on 7. After changing it and looking at the other settings, all looks right, but the sun is going down. I appreciate...

My current camper 12 Volt system consists of a lead acid battery on the tongue, and a WFCO converter inside. The wire from the battery to the converter is AWG 10 and also carries current from the tow vehicle when connected. My new power source will be a 440 AH 12 Volt LFP bank inside the...

Okay, I think I have it now. First remove as many loads from the system as possible. Then the PV disconnect is switched to "off" first, then the DC disconnect is switched to "off". It doesn't hurt the PV switch to be turned off if sun is shining on the panels, but it can be hard on the DC...

Thank you.

I may not be understanding your statement? The only shared connection between the inverter system and the AC system is the ground from the AC panel to the DC distribution center, which feeds the inverter, as shown on the drawing. Thank you.

SamG340, Thank you.

I am running bare ground from my array, along with the 12 Volt PV cables to a junction box (metal, or PVC?) inside the attic, where the bare ground will tie together with an insulated ground wire, and then run in EMT to my busbar and other grounds, and then on in another metal conduit to my...

I tried it, and another for hours, but found these calculators/graphics easier for grasping the whole picture. https://andrewmarsh.com/apps/staging/sunpath3d.html https://www.sunearthtools.com/dp/tools/pos_sun.php Good I think, as you can enter your coordinates. Making me rethink this location...

I have (3) 220 Amp Hr LFP batteries. Each has a BMS of 150 Amps. Each battery terminal has an MRFB 200 Amp fuse. 4/0 Cables from the batteries will each tie to a 1000 Amp busbar, which is then protected with a 500 Amp Class T fuse before the disconnect switch. Am I correct in believing that...

Thank you. I will do more testing.

Please look over my plan and offer opinions, or point out errors. I've learned a lot from reading the Q&A's here on the forum, and appreciate how helpful everyone is!

Thanks for the thoughts, I will try to digest them. If weight distribution weren't an issue in the travel trailer, I would put all the batteries in one place and be done. The remote location keeps the balance correct, and safe for towing. 18-20' of heavy cable is hundreds... The isolator seems...

I have noticed good production on sunny days, but frequently see high numbers on overcast days, though the numbers aren't constant as they are in full sun. The cable I am running from the Victron controller to the busbar is #6 copper (stranded, about 120 count) and is 5' long. General ampacity...

Thank you.

In the attachments, I've drawn out three grounding scenarios to help me understand the ground path for a ground fault. I want to connect a bonded-neutral inverter to a transfer switch, which will allow me to choose between grid, or inverter for 4 select circuits in my main AC sub panel. In the...

Thank you. Sorry for the omission. I am running D/C. Is this style flexible metal conduit acceptable?

I believe I understand the correct/safe way to ground my system and have drawn it out. Thoughts or corrections are welcome. The system is solar panels, solar charge controller, and inverter powering a manual transfer panel, to run critical sub panel loads. Inverter is a Victron 24/1200...

Thank you.

I'll post a picture of the complete setup when done if you like. Yes, please. Pictures/drawings/layouts I've looked at here on the board have been inspirational. My projects tend to start out as functional too, but after seeing the results of just a bit more effort applied...I prefer to take on...

Thanks to both of you. Seems to me it wouldn't hurt anything (other than the power draw on the system) to have a small fan running in the component cabinet/area during daylight charging hours to keep the controller cooler, and allow better efficiency. After posting this question last night, I...

Thank you. Point taken. What I am unclear about is the wire ratings. As I tried to convey in the previous message, there seems to be two different rating ranges, depending on the type of wire, and the seller of the wire. The standard ampacity charts, and then the welding/battery cable charts...

I have a “farm panel” electrical setup where main power from the utility feeds the meter and a main breaker set on a pole in the yard. The house and barn are fed separately from this main panel. The house and barn each have a sub panel, with a main breaker. The ground and neutral are bonded in...

As seen in the attached drawing, my RV has two separate battery banks. Battery bank #2 is connected to bus bars that feed the inverter with very hefty 4/0- 18 inch long cables. The SCC and 120 chargers are also connected to the bus bars. The bus bars also feed a 6 AWG cable that runs to a...

Thank you for the recommendation. Are you using one of these units? I read the manual and it looks like the max setting for battery priority voltage before it switches back to grid is 25.6 volts? If that is the case, it would draw down my battery bank to 20% capacity before auto switching to...

Sounds like you have a good plan! Thanks for sharing it. Rob

Thanks, lots to digest, but it helps.

I am connecting 4- 12 volt LFP batteries to provide 24 volts. Is my placement of MRBF fuses correct to protect each battery in case the BMS of any one of the group fails? I do also have as shown in the drawing, a Class T fuse directly after the bus bar.

I have a new 24 volt off grid system with batteries. All has been good for a couple of months, with the system producing 3-5 kwh per day, and recharging the batteries. Victron 250/85 is set at 28.40 volts max (position 7) It typically maxes out at 28.56 volts, but a couple days ago it hit 30.21...

Hedges, Thank you. I listed the panel info in my drawing, but I appreciate the reminder that it should also be in my post text. It has been added. Great panel price in the link you provided! Angling the panels is a good idea. I planed on an adjustable angle panel mount, but up and down, not...

Non grid tie system I have a PV disconnect switch just before the PV wires enter the MPPT. I also have a battery disconnect just after the main fuse coming from the battery bank which isolates my batteries from the distribution center. It is safe to turn off power to my distribution center...

Thank you Reed. The busbars are a holdover from my original plan to use the 4- 12 Volt batteries paralleled. I needed the extra spaces before. I have updated the drawing now I have chosen to wire as 24 Volts. Can you elaborate? I am not following...

Thank you. I have a 2000 watt inverter, and 85 Amps of 12 Volt DC circuits. 3019.2 Watts/251.6 Amps max load in worst case scenario. But if one battery shorts out, then the other two try to take the (potentially much larger than 150 Amp) load, no?

Thank you for all the detail. I'm going to buy the smart shunt with the accessory display. Tell me more about why you want to monitor the inverter. Will yours be running all the time? In my system, the inverter will not see much use.

Equalization is disabled. The fuse that blew was 60 Amps. I replaced it with same. On the day the voltage hit 30.12 Volts, the panels produced 2254 Watts. The panels, at rated Watts, total 2235. Thank you.

I measured Volts, and Amps at each end of the coiled 21' cable, and got those results. There may be other factors at play that I don't understand? Voltage drop over the 21' run (42' total loop) was 0.46 Volts, It was higher near the charger, and lower near the batteries by 0.46 Volts The Amp...

Hi, They are intended for 24 Volt systems. Voc on the panels is 45.4 volts.

Okay, got it now :fp2 I was somewhere else yesterday... 2 panels create more than enough to charge a 48 volt battery-I would just need to replace my 24 volt SCC and inverter with a 48 volt SCC, and inverter. Thanks.

This is the PV disconnect I plan to use. I am using a Victron controller, so will read through the manual to see the suggested shut down procedure. Thank you for the discussion and ideas.

A picture would help a lot. There's a couple ways to do this. Usually the PV is transitioned to EMT conduit on the roof (some people prefer PVC), going into a junction box. And then a length of EMT is bent to go around the eaves, or flashing used to go straight down through the roof (easier with...

Thanks for the discussion, it is helpful. I could have given more details in my original post, but didn’t believe them to be relevant. I will correct that now; The weight balance issue I am working with is not tongue weight but rather too much weight behind the axles. The travel trailer has...

Thank you for the math. A bigger fuse is in order, and I am pleased with the panels output!

Thank you. The motor data tag has manufacturer/mobility chair company info, but no Amp or voltage. The chair has a master 50 Amp breaker.

Thank you all, the information provided is very helpful! So if I buy a smart shunt/BMV712; for around $130, it comes with the ability to monitor battery temperature via the add on sensor at around $31 And if I buy the smart sense at around $40, it will measure voltage and battery temperature...

I have a 40 Amp LFP charger, the 120 Volt plug in variety. I'm experimenting with how much voltage drop I will get in a given length of wire. With my batteries partially discharged, the charger is putting out a maximum of 28 Amps at 14.20 volts, measured at the charger output (within 1 foot of...

I agree that not worrying about cost is sometimes the wiser choice. For now, for me, cost is weighing heavily on my decisions. I'm new to solar, am trying to get my feet wet and learn. An AIO would be advantageous for some, and maybe even me, but I already have a charger for my camping trailer...

Thank you Joe.

Thank you. I will further discharge the batteries before trying again.

Thank you. So keeping them separated at all times is the answer. Any thoughts on how to charge both banks from one source without combining them?

Thank you for the detailed info. I've come here to learn, and am fast learning how little I know... I am in an area that does not require permits or inspection, but want to build the system to be safe. It is a small 1200 Watt system with the panels on the gable end of a pole barn/garage, and...

I am looking at Ebay auctions checking "sold" prices for controllers. I am not interested in purchasing anything used, but several sold, used controllers popped up. Most every used model looked like it had been very warm, with discoloration of the paint/finish on the controller. (Photo as an...

Thanks. I am not talented with the CAD program I am using... The panels will be mounted on a wood frame that tilts them, from the bottom, to 31.5 degrees. The top of the panels will be even with the fascia. This location points south, and gets great sun 4 hours a day, and lesser amounts in the...

I've been considering a 3000 watt inverter, not because I need that capacity, but to stay more in the middle of the range so as not to overtax the inverter. Is that a wise strategy? There is no "third" ground wire. I will have a #6 bare ground connected to all solar panel frames, and connect it...

I am refining my PV wiring plan and need direction regarding the PV disconnect switch. In my area, I am under 2008 NEC. No permits, no inspections, and as I understand it, no requirement for a rapid shutdown system. I will have 2 separate array systems, 4 cables, plus ground running in 1.25"...

My off grid system produces a max of 142 volts. It is being fed into a Victron 250/85. The closest SPD is 300 volts. All indications are that if I feed more than 250 volts to the SCC, such as by over paneling, I will destroy it. If that is the case, then will the SCC be destroyed by surge...

Thank you Joe. I do have a shunt/monitor, it isn't visible in the photo as it is inside the camper. Good tip though! In addition to having "better" batteries than the lead acid that was on the tongue, I am trying to shave off unneeded weight. The battery on the tongue is very heavy. Do you have...

Sounds like I was misinformed, and should have placed a question mark behind my statements. I do have a good disconnect switch, but was under the impression that it wasn’t supposed to be turned off under load. I understand how to remove loads using the battery disconnect switch, but believed...

Inspecting my RV wiring found the incoming 30 amp AC service having the ground wire connected to the ground bar. There is then a bare ground that connects the ground bar to the steel RV frame. The neutral wire is connected to an un-bonded neutral bar, and the hot connected to the breaker, all...

Critical distinction...I missed that. Thanks again to all. I am on the right path now :)

I have an electric mobility chair that has two lead acid 75 AH batteries providing 24 volts to the system. Works fine, but want to be able to add an easily removable 24 volt LFP on an external bracket, connected via a switch or plug in port (one battery bank or the other, not both at once) to...

PV girl, Thanks. That looks like a feasible solution.

That makes sense, thank you.

Reed, Thank you for your thoughts. I have attached a drawing that may help. I do not intend to use the converter to charge my new LFP battery bank. I have a stand alone charger. I will be using the WFCO simply as an AC-DC breaker/fuse panel.

Hi, I am building an off grid system for a cabin. It has two 220 Amp hour Time USB 12 Volt batteries Wired in parallel via bus bars, which power a 12 volt fridge, lights, cigar and USB outlets, as well as a 2000 Watt inverter. The inverter runs a small microwave for a max of 10 minutes a day...

I currently have a Victron SCC and Renogy shunt in my system. I plan to add another Victron SCC and panels to increase capacity. Will the two Victron SCC's work together with the Renogy shunt, or do I need to replace it with a Victron smart shunt?

Joe, Thanks for your reply. Your are correct with your understanding. I do have a new charger. I will have to think of a way to create a failsafe for the breakaway as I do have a system disconnect switch. Maybe a very small LFP on the tongue. My lack of understanding is with the amperage...

Thank you for that clarification!

I appreciate your concerns and will weigh them carefully. Will you define "annoying" in this scenario, both the bonding and servicing? The fame mount allows easy access from underneath to all cables but the ground, and that can be remedied by bonding the panels on the bottom instead of the top...

Sorry if I am beating a dead horse here...but I want to be sure, and safe. The inverter loads are isolated from the main AC ground in that they are not tied "directly" together, but because of the bonded ground/neutral in the inverter, and the inverter case being connected to the AC ground...

Thanks guys, I pondered over a 48 volt system, but went with 24 for this project. Wouldn't I need 58.4 Volts to charge a 48 Volt battery? I may not understand what you are saying...? I should consider connecting the solar panels in series to create a higher input voltage to the SCC? I have...

I discharged the 560 Amp hour battery bank to 50%. Voltage from the charger reads 14.18, so about the same as the 14.20 when it was almost fully charged. At one point during this new charging I got 41.21 Amps going in, but just for a few minutes. The average reading over a 1 hour period is 26...

Or maybe I'm making it more complicated than it needs to be... Maybe use a steel junction box, and mount the plastic disconnect in it?

I was trying to use the inverter I already have. I am also looking for a different inverter but am restricted by the fact that I have a 12 volt system and am trying to stay at or below $1200 for an inverter isn't making the chore easy. I have a 2000 watt now, but should go up to a 3000 watt...

Thank you for the clear answer. Now I can take my time to find a good deal on a new shunt, but won't stress out if I don't have one right away.

Thank you again for the additional info. I will continue to study and absorb all these ideas. (y)

pvgirl, Thank you. I need to do some further calculations; I could add two more panels to the 3 hour site at less cost in effort and material than the install at the 5 hour site, though early calculations showed only an 83 Amp hour gain. Cutting down a few trees would solve the problem ;)

I am starting my system with a Victron 250/85. As I understand it, I need to use the Victron smart shunt in order to monitor the system via Bluetooth on my phone, or using a Victron SmartSolar MPPT Control Display that mounts in the face of the controller. Do I need any other “devices” to...

I may not have worded it clearly, sorry. As is, the main bank runs the inverter and 12 volt RV system. The remote bank can also run the rv 12 volt system. The selector switch allows me to use the remote bank for daily/normal use (lights, tv, water heater, fridge, etc). When morning coffee or...

Clear as mud, huh?:oops: They are LiFePO4

With two individual controllers and panels strings, the bluetooth will show each system separately? So I do not need the Victron shunt to monitor the controller(s) any shunt with a display would work to monitor in/out power of the batteries? but if I want to monitor everything as a whole...

One of the reasons I am considering this plan is because of the more or less even sun hitting them through the peak hours. I can just as well mount them on the roof at the end of the gable in the photo, but then the two strings are facing two different directions, and I have only 1 string...

I have a 12 volt system for my camper. 440 Amp hrs of LFP battery, and 800 Watts of panels. I Installed a 120 volt charger as well, and have charged to 100% several times in the last couple months, and discharged down to 150 Amp hours as the lowest discharge, and several other levels, but...

Indeed it is! Thanks :)

After trying to design a practical system using 12 volt components, I have seen the light. I have a 12 volt RV system that works very well for what I expect from it, and had hoped that by making my off grid garage project a little bigger, 12 volts would work there too. It would, if I wasn’t...

Thanks! Great ideas :) I ended up with 2 Power in's, instead of separate busbars. It was cheaper, and will look better, I think. The battery protect is something I hadn't thought of, and seems like a good safety for the money! Negative 25 is the coldest here. It does look like I need to go up...

Thank you all. After further reading and watching videos, I have a better understanding of the advice you have offered, and of the constraints of my system-as planned. In short, my cheap internally bonded inverter is not suitable for use with a transfer switch because there cannot be more than...

I am running 8 AWG cable from my array on an exterior wall, down into a plastic disconnect on the exterior wall with waterproof fittings, then back up through a gland into an unfinished attic, and then as I drop into the finished space downstairs, it will be run in PVC conduit. Does the entire...

Thank you. The nearest size to the potential 126 Amp draw is a 150 Amp fuse, which will protect the 4/0 wire, while not blowing the fuse if one battery goes bad? The 4/0 cable coming off the busbar, protected by the class T fuse, is rated at 378-440 Amps, depending on temperature. Max load on...