Help and Guidance with an Electrical Schematic

[77jack77]

Hello guys,

[font=Tahoma, Verdana, Arial, sans-serif]I am aware nothing in this life is free and so, in thanks for any help and advice given by the kind membership on here, I promise to make a donation to The Homes on Wheels Alliance via their website when I get my first pay from my new job which I start at the end of this month. Having been out of work for a couple of months things are a little tight right now but you have my word a donation will be made when I get my first pay check.  [/font]

[font=Tahoma, Verdana, Arial, sans-serif][size=medium][font=Tahoma, Verdana, Arial, sans-serif]I have drawn a schematic and it has helped me picture how to connect things up greatly! I am more confident in doing this now. However I'd like to get your feedback on it, to make sure I'm not missing anything that is obvious![/font][/font][/size]

This has taken quite a lot of work / time on my part because I have no real idea what I am doing and I have had to teach myself everything as I have gone along - or ask strangers on the internet. Thank God for this place! I'm enjoying it though and learning a bit too. 


You can see the [font=Tahoma, Verdana, Arial, sans-serif]schematic here:[/font] 

https://ibb.co/xCcpKtg


And how I have included switches for the lights here:

https://ibb.co/mhVzk8x





I have a few questions about the compatibility of my setup, and some more basic questions about fuses and wire diameter etc. 



1. Are my batteries, solar charge controller, solar panels, and split charge relay all compatible? Is anything too big / powerful for the other or indeed too small / weak? I have included links to these items at the bottom of this post. 


2. What amp fuse should I have between the leisure battery and the solar charge controller (point 2 on my [font=Tahoma, Verdana, Arial, sans-serif]sch[/font][font=Tahoma, Verdana, Arial, sans-serif]ematic)?[/font]


3. What [font=Tahoma, Verdana, Arial, sans-serif]amp fuse should I have between the solar panel and the solar charge controller (point 5)?[/font] 

[font=Tahoma, Verdana, Arial, sans-serif]4. What [/font][font=Tahoma, Verdana, Arial, sans-serif][font=Tahoma, Verdana, Arial, sans-serif]amp fuse should I have between the vans starter battery and the split charge relay? [/font][/font]

5. What thickness of wire / amp rating should be used for connecting the two 12v, 130ah batteries in parallel? I have heard people say 16mm - which has an amp rating of 110 amps. [font=Tahoma, Verdana, Arial, sans-serif](We may or may not struggle here with me being a Brit and this being a American site and the differences in units and measurements, but I guess the amp rating is what is important.)[/font]


[font=Tahoma, Verdana, Arial, sans-serif]Solar panel:[/font]
https://tinyurl.com/yxhbulrr
https://tinyurl.com/yxhbulrr

[font=Tahoma, Verdana, Arial, sans-serif]Solar charge controller:[/font]
https://tinyurl.com/y3tlxled

[font=Tahoma, Verdana, Arial, sans-serif]Batteries:[/font]
[font=Tahoma, Verdana, Arial, sans-serif]https://tinyurl.com/y6secnku[/font]

[font=Tahoma, Verdana, Arial, sans-serif]Split charge relay:[/font]
[font=Tahoma, Verdana, Arial, sans-serif]https://tinyurl.com/y4rza7el[/font]


My thanks in advance!

Jack. 

 

[highdesertranger]

a lot to take in in one post.

first off are you sure that the MT-50 works with that charge controller?
second what is the load side of that charge controller rate at? I would connect the fuse block directly to the batteries.
third always fuse to protect the wire. so the fuse size is dependent on the wire size which should be of sufficient size to run the load you want to run through it.
I am not familiar with metric wire sizes at all, someone else hopefully chimes in about that. I do like to use marine wire and components. no car audio or residential stuff at all.

highdesertranger

 

[77jack77]

Thanks for the reply, highdesertranger. 

I am fairly sure the MT50 works with the charge controller because they are supplied together as a package.

Th[size=medium]e load rating is 40 amps for the charge controller. It also looks like the wire should be 16mm which is equivalent to 6AWG.[/size]


When you say you would connect the fuse block to the batteries do you mean just the positive or the negative as well? If you connected the positive and the negative to the battery directly via the fuse / grounding block you wold be running the entire 12V system direct. Is this better than connecting via the charge controller?

I have largely designed [size=medium]this diagram based on this one: [/size]
https://gnomadhome.com/van-build-solar-electrical-wiring/


What size AWG would you use to wire the two 12v, 130ah batteries in parallel? 

 

[highdesertranger]

for the batteries,

what is the largest load you ever plan on putting on the batteries? gauge your wire according to that and remember it's always better to oversize than to undersize.

for the fuse block,

what are the load terminals on the controller rated at?
most are rated at 10 amps some are 20. that is quite limiting.
some sensitive electronics tell you to wire straight to the battery and don't go through a charge controller.
when I bought my first charge controller I was told to wire straight to the battery and don't use the load terminals by the seller.
some load terminals only have power when the sun is up although I think these are few and far between now-a-days.

so you might want to check out those points. also when hooking up charge wires or load wire to a battery bank always connect the positive to one battery and the negative to the other battery.

on your schematic you want to take the chassis off the battery on the right and put it on the battery on the left. make sure you always do everything that way.

highdesertranger

 

[Cajunwolf]

As mentioned, it's a bit much to take in all at once. At a glance, I see a couple of things that might be questionable, but let me look closer. Since highdesertranger already asked, I'll wait for your full load specs. All I need your total max load in watts/day, and I think I might have an economical suggestion that takes all of the guesswork out of it.

 

[77jack77]

Thanks a lot both. Your help and advice is appreciated!  :thumbsup:

The load rating for the solar charge controller (model Tracer4210AN) is 40 amps, according to the image I inserted into my last post. Is that what you mean by load terminal rating, highdesertranger?


Cajunwolf, I still get confused as to why people ask for Watts when battery capacity is rated in Amps / AmpHours. I'm not being critical of anyone here, it is my understanding that is not up to scratch! It's all immensely confusing to me. I am pleased people are patient. :huh:  :s

Usage Calculations 
My usage will likely be very low at first, because I plan to build and add things slowly over time. 

Electrical items to be used now:
LED lights - 9 x 3.5W say 8 hours a day 3.5w x 9 light = 31.5 w. 31.5w x 8 hours = 157.5 wh
iPhone charger (USB socket) - say two charges, even if I only ever charge once = 5 hours x 5 watts = 25 wh
Lenovo laptop 65W - 5 hours per day = 65w x 5 hours = 325 wh

Total: 507.5 wh usage per day.


Batter WattHour Calculations

The system I have designed uses two 12v, 130ah batteries. Therefore the whatt hour capacity is (12x130)x2 = 3,120 wh. However you can only use 50% before damaging batteries so it is effectively half this number at 1560 wh

This is quite good because if we take the wh capacity of 1560 and divide that by the daily usage of 507.5 there is enough capacity for 3 days of use before the batteries are depleted to 50%. The issue may come when I possibly start adding things in the future, such as a electric vent or a fridge. At which point I may need to add more batteries and solar panels? 



I am not entirely confident in my own math here, but hopefully what I have done is right???? 


Thanks so much again to you both!! I look forward to reading both of your thoughts. 

 

[Cajunwolf]

No, you're good. I always use watts. Volts time amps equal watts. To me, you've got it right since you've got three days figured in for battery before having to recharge, which is the proper way to size your needs. If you have future needs, just get an additional battery doubling the watt-hours you have available. You did an excellent job! Kudo's  :thumbsup:

 

[highdesertranger]

ok read page 22 of your manual. the battery charge rating is 40Amps. the rating of the load terminals is 20Amps. big difference. I would hook the fuse panel up to the batteries. highdesertranger

 

[Cajunwolf]

It's rated at 40 amps, and that would be the maximum the charger could handle if his load is below that no problem. As to fuses, highdesertranger, you and I are together on that one. In marine applications, we fuse both legs of every wire. A fuse is cheap compared to an expensive piece of electrical equipment if things go South.

Oh, forgot, a fire on a boat hundreds of nautical miles from the nearest shore is a scary thing indeed!

 

[77jack77]

highdesertranger,

Am I looking in the wrong place when I look at this figure here, which I have circled in red? 



I have looked at the manual I have (Here: https://www.epsolarpv.com/upload/cert/file/1811/Tracer-AN-SMS-EL-V1.0.pdf) and page 22 seems to be about connecting the controller to your phone or laptop. See picture below.



I have looked through the manual, searching the term "load", and can find no other reference to any load terminal capacity. I would be most grateful to you if you could show me a link or take a snapshot of where you are reading that the capacity is 20 amps. Obviously this is something that I wish to get right and it is concerning to me that we three (myself, yourself and Cajunwolf) aren't all agreeing on the same figure. 

Thanks again for taking the time to try and help me! It's a kind thing to do. 

---

I guess there is no reason why I couldn't hook up the fuse panel direct to the battery regardless? If that is better? The only reason why I didn't is because the diagram I have based my system on used the load terminals on the solar controller. They are there, so it seems silly not to use them. That is unless the amp rating is indeed too low. 

Are there any pros and cons of hooking up to the battery direct and to the terminals on the controller? For example, would there be an amp limit when hooking up to the battery?

Why would they bother to include load terminals if you hook up directly to the battery anyway?

---

Thanks again to you both for your continued help. I'd be very lost without it! 

 

[highdesertranger]

hahahaha I thought you were talking about this Tracer,

https://www.renogy.com/template/files/Manuals/20A-30A-40A-MPPT-Solar-Charge-Controller-Manual.pdf

it's odd because they both have the same name and the remote meter is the same. they are probably built by the same company.

does anybody know the answer to this?

back to the load terminals I scanned through that whole manual and I could find an exact answer as to what the load terminals are rated at. that "discharge current" that you circled I am not sure what that is. easy enough though call the phone number and talk to tech support. let us know what thy say.

highdesertranger

 

[tx2sturgis]

Why would they bother to include load terminals if you hook up directly to the battery anyway?

Because there are some constant loads you might forget to turn off (like a fridge) that need to be OFF if the battery is heading south.

But if you need your solar controller to 'baby sit' ALL of your loads, the only good way to do that is to have the load terminals control a relay, and that relay will apply power to the fuse panel. Or a large inverter.


But, most inverters have an LVD (low voltage disconnect) anyway.

 

[Cajunwolf]

The way I read it is that the EPEVER Tracer solar charge controller comes in three(4?) flavors, and one uses the spec for the particular model. If it's a 1210A 2210A it's 20A, 3210A 30A, and 4210A 40A. Kind of confusing if you ask me, but it's made in China, go figure.