Review request for my DIY solar setup.

[tripcode]

Hi guys

I really dont mean to spam this board, I have already received great support from one of the more senior members of this forum and I am super happy about that. I personally thanked him in my messages for his assistance. But for the sake of quality control, I would like to ask for another quick review of my setup, after making the necessary amendments (outcome of previous review basically).

Here is my setup, with a sketch and the necessary calculations. I tried to focus my wiring (this is where I would like your input the most) on the circuit lenght and the total amperage/voltage drop. But basically keeping the costs in focus as well, i.e. I didnt want to just stupidly oversize the cables because I was too lazy to do the math. The risk however, chosing this path is, that if I have made a mistake in my calculations / setup sketch / diagram. I might be in trouble later on... therefore, I highly appreciate any critique.

https://imgur.com/a/j8WuLhv

My setup consists of:
2x250W Mono Panels (in parallel): https://www.ebay.com.au/itm/12V-250W-Solar-Panel-Monocrystalline-with-Anderson-Plug-MC4-Connector/333652927223?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
DCDC with integrated MPPT charge controller: https://au.renogy.com/renogy-50a-dc-dc-on-board-battery-charger-with-mppt/
2x105Ah Platinum Power (AGM lead acid batts, also in parallel): https://imgur.com/U0nXzkR
1000/2000W inverter: https://www.ebay.com.au/itm/Large-Shell-Pure-Sine-Wave-Power-Inverter-1000W-2000W-12V-240V-USA-Transistor/231544077381?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
Cables (for everything except inverter): https://www.altronics.com.au/p/w4200-1666-0.12-110a-red-power-cable/
Cables (everything inverter related, i.e. the full circuit from batt to inverter and back): https://www.altronics.com.au/p/w4206a-287-0.30-160a-red-power-cable/

Thanks again, I am planning on finishing the wiring of the electronics this week and then mount and connect everything by the end of the week, so I would still have the chance to correct something if necessary.

 

[erik.calco]

You win a kudos for being the first person to draw a diagram with a spreadsheet. We had a thread on drawing tools awhile back, and now this wiki page, and no one came up with the spreadsheet idea. I love originality.

 

[tripcode]

You win a kudos for being the first person to draw a diagram with a spreadsheet. We had a thread on drawing tools awhile back, and now this wiki page, and no one came up with the spreadsheet idea. I love originality.

Lol thanks I was just being lazy and efficient, I recently used google drawings for my drone project, also to draw a wiring diagram. Its nice too, but meh - this did the job as well..

Any comments on the setup, do you see any flaws ? ^^

 

[erik.calco]

You have the basics. Looks like a mobile setup that could endure freezing temps.

Why are you using the chassis as a negative instead of just a bus bar? I don't really understand what all you have connected to it. I see a hot going to it, including fused MC4s? But, in general, in DC, you might have a bus bar for the battery's positive or negative if needed, and a separate bus bar for PV positive or negative if combining in parallel and not using a branch connector.

Decide where you need bus bars and show them clearly for others to read. Otherwise, the components should connect to each other, perhaps with a fuse or breaker in the line, rather than to the chassis. There were discussions on grounding PV negative to a chassis. Most don't do it. You still ground the chassis of things like the combiner box. But, that doesn't get connected to the negative bus bar. I have a MidNite Solar combiner box, and the PV negative bus bar is raised so as to not contact the chassis. There is a chassis ground bus bar in there to connect panels to (their frames, not MC4 connections), and to then ground. I don't know how proper grounding works in mobile solar systems, but there is something on it in FAQ IIRC. And yeah, I realize that the actual electric of an auto is often grounded to the frame with the DC negative of the battery. There are discussions on that, too. But, we don't carry that over into the rest of our DC circuits like PV. You can obviously use that for the battery side if you are charging a vehicle battery.

Where is your load? Are you just charging a vehicle battery when not driving with solar and running load off it?

I, personally, haven't gotten into vehicle solar systems. Will has a lot of opinions on alternators. But, you are using a controller designed for an alternator. So, he might be OK with that. IDK. Others need to chime in.

 

[tripcode]

You have the basics. Looks like a mobile setup that could endure freezing temps.

Why are you using the chassis as a negative instead of just a bus bar? I don't really understand what all you have connected to it. I see a hot going to it, including fused MC4s? But, in general, in DC, you might have a bus bar for the battery's positive or negative if needed, and a separate bus bar for PV positive or negative if combining in parallel and not using a branch connector.

Decide where you need bus bars and show them clearly for others to read. Otherwise, the components should connect to each other, perhaps with a fuse or breaker in the line, rather than to the chassis. There were discussions on grounding PV negative to a chassis. Most don't do it. You still ground the chassis of things like the combiner box. But, that doesn't get connected to the negative bus bar. I have a MidNite Solar combiner box, and the PV negative bus bar is raised so as to not contact the chassis. There is a chassis ground bus bar in there to connect panels to (their frames, not MC4 connections), and to then ground. I don't know how proper grounding works in mobile solar systems, but there is something on it in FAQ IIRC. And yeah, I realize that the actual electric of an auto is often grounded to the frame with the DC negative of the battery. There are discussions on that, too. But, we don't carry that over into the rest of our DC circuits like PV. You can obviously use that for the battery side if you are charging a vehicle battery.

Where is your load? Are you just charging a vehicle battery when not driving with solar and running load off it?

I, personally, haven't gotten into vehicle solar systems. Will has a lot of opinions on alternators. But, you are using a controller designed for an alternator. So, he might be OK with that. IDK. Others need to chime in.

Ok, the diagram might be a bit confusing, I guess using a spreadsheet has its limitations haha... (or not even the spreadsheet, but my lazy ass didnt bother making a more elaborate diagram). But basically, the solar panel wires are supposed to go through the roof, connecting to the solar panels. The MC4 inline fues are on the positive end of each panels wire. before reaching the branch connector basically. I am not using ground wire on the PV, I dont even have one? I have two wires coming out of the solar panels, one with a female and one with a male connector.

It is common in cars to use the chassi as the GND wire, as it is a big piece of metal and conducts really well. Thus, saving additonal wiring costs on higher gauges, battery wires are not cheap.

I will update the diagram with the fine details, you have a point.

>>Where is your load? Are you just charging a vehicle battery when not driving with solar and running load off it?
I have an inverter, and a couple of 12V appliances that I am intending on connecting with the use of a fusebox. A portable fridge, LED lights and some USB charge connectors. The inverter will serve primarily to charge my computer and maybe attach some other appliances for periodic usage, such as a blender or a coffee machine. Obviously within the power limitation ratings.

Yeah I learnt a lot about alternators and also their place in a solar charge controller equpped system. I am even considering disabling the alterantor and only enabling it on a very cloudy day, as the solar wont generate enough amps on those days.