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A bit theoretical, but has practical implications: What's more energy efficient: Pushing PV power to the grid, or storing in battery and using it ? Let's say our PV array produces 5kwh a day. For the sake of the discussion let's also assume that we are on a fixed grid tariff, and grid-tie is...

Great! I'm happy it worked out for you.

No pre-charge problem if you use my method, by switching via the inverter on/off switch. Also, as the relay I recommended has an LVD and return voltage setting, you could set LVD to pretty low to take into consideration voltage drop during load. Then set return voltage to above resting voltage.

Yeah, I had some more things going on in that picture. Let's focus on this: Basically, you need 6 lines: 1. Voltage sensing lines (pos/neg) going to your battery pos/neg, or straight to the inverter DC inputs. 2. 2 lines to the rocker switch terminals. These are the lines that are switched...

I have a similar breaker and 10awg PV wire. Although the strands are pretty thick, I preferred to use ferrules. No problems so far.

What inverter do you have? Does it have a remote switch/panel ? If so, it's not that hard. I recently did this with a voltage sensing relay and an FCHAO 24v 1800w inverter. I opened up the remote panel, which has a simple ON/OFF switch. Soldered two wires, one to each if the switch terminals...

Why do you think so? Because of the weight of the panels? Anyways, I was necessarily recommending the use of these, I just wanted to understand if this the OP's intention.

Do you mean something like this? https://www.aliexpress.com/item/1005006208628561.html

First, I think it's rated at 30 amps, not 20. Second, if you are worried about voltage spike backfeeding into your 12v system, you could add a diode on the input. It could be a standard Schottky diode, or an ideal diode (MOSFET based) but with less power losses. I had it connected to my 12v...

I have this little beast: https://www.aliexpress.com/item/1005002315724901.html Also used by Andy from Off-Grid-Garage on YT. It can boost up to 60v. Although it's a cheap Chinese device, it's pretty capable and reliable if you don't push it to it's limits. I hope this helps.

What is your setting #2 set to ? If it's set to UPS, it might be intolerant of noisy/unstable AC voltage. Make sure it's on APL.

The Xiaoxiang app is only for JBD BMSs, not JK.

Bingo... Sorry I didn't have the time to draw up a diagram in the first place. It would have saved all of us the confusion, trying to understand each other...

No, look at it again. First they show it opens at 4x the amperage, but no fire, cause it's wired correctly. Then they do the same test but wired in reverse: immediate fire!

OK, so about #2 ‐ It depends what you want to do. If you are doing serious maintenance (like rewiring) then yes, you will want to turn off inverter output to the MTS. But in most cases the MTS is enough. Most inverters have an ON/OFF switch for AC output. But AFAIK this will not prevent the...

I use the MTS on the OUTPUT (to loads panels). I'm not understanding your intentions... Can you scribble a diagram of your setup?

Great. I use mine solely as a manual transfer switch. I do not count on it to be a breaker in case of overload. So I have proper breakers before and after. You should get a model that will handle your max loads amperage though...

Yes

This is when wired incorrectly. Most DC breakers for PV use are polarized, meaning that the direction of power flow matters. So you need to connect them properly (notice the +/- signs, and INPUT / LOAD markings).

I use this as a selection switch for the output (to loads): https://www.aliexpress.com/item/1005002992599504.html Basically it's a 2 pole manual transfer switch, which allows only on input to be selected at a time. One of the inputs is the grid, the other is the inverter's output. That way if I...

I wonder if this helps prevent degradation in Lifepo4 too...

Finally got to connecting everything: Time-delay relay, Tyco Contactor, and a voltage sensing relay for low voltage cutoff. The low voltage cutoff is not mandatory, but it's a feature I added, because I wasn't happy with the LVD of the inverter (at about 20v, which is pretty low for Lifepo4)...

My solution using the time-delay relay solves this too. Basically, whenever BMS discharge is enabled, and main DC breaker is ON, there is a path to the inverter via resistor, and after 5-10 seconds the time delay relay switches the contactor ON. If the BMS cuts out, or the main DC breaker is...

Can't you achieve the same goal by pushing the data to HomeAssistant via MQTT ? I know it's also possible to change inverter parameters via the MQTT interface.

Let me guess what happend: Your Lifepo4 ground was connected to chassis ground, just like your starter battery, right? I blew up a CC converter because of this. Only to find out that the negative MUST go through the converter, because there is a shunt resistor on the negative side, which gives...

I don't think you need a boost converter. You should check to see what voltage your alternator outputs. Also, these boost converters will not stop charging your Lifepo4, so basically it will float charge the battery with the voltage you set. This is not healthy for Lifepo4 batteries and will...

You paid alot for those Victron SCCs, make good use of them: If you have "smart" BMSs with some kind of communication, you should be able to hook up communication to the SCCs. This will allow the BMS to throttle down charging current, when a certain SOC is reached, for example. Look up DVCC and...

I have a small 1.3kwp array, so not much choices... Maximum PV voltage (VOC) is around 85v, inverter max is 145v. I prefer these lower voltage inverters for safety, as some of the higher voltage ones have a known issue of having AC on the PV lines. Quite a few posts on the forum about this...

I thought it wasn't a thing until Lifepo4 batteries came around, having low internal resistance and a high discharge capability. Of course Lifepo4 and BMS go together.

Yes, you should have an MCB BEFORE the SPD. That's because the SPD will by design short the line to ground, should a high enough voltage spike occur. The SPD itself could melt, same for the wires. An MCB will protect from this, should the SPD short or heat up.

I think the inverter does care - won't that high inrush damage the capacitors, or at least shorten thier lifespan?

Thanks. I've seen documentation regarding battery voltage calibration on some inverters, but nothing on PV amperage. I guess I'll have to live with it then...

Hello. I recently got to connecting my PV to my MUST 3kw 24v AIO (PH18-Plus). I have noticed that it's under-reporting PV amps, sometimes as much as 1.5 amps. Overall PV wattage reported also seems to have about 100w missing. How I checked this: 1. Using SolarAssistant, looking at PV amps...

Since when does Ford use LFP ?

Pass-through means when loads are powered from the grid, not the battery. Depending on your inverter settings, it can be in this mode for various reasons.