Sizing Off-Grid Systems And Using Gen Support

[paulcheung]

Ok yes, the panels wiring is correct. with the batteries. it gone bad already. you already have all the batteries. What we suggest is when you buying batteries, you buy the largest ah per battery and wire them in ONE series, so you don't have to parallel the batteries. I have two bank of batteries in parallel, it give me hell to balance the charge and discharge rate of each bank. can't get them equally.

You can try to wire them like the link mapmaker give you. just treat 2 batteries as one in series and try to parallel the strings the best possible way.

[Alpaca-Meadow]

wiring pannels

You CAN NOT use the single panel, because when the 24 volts battery bank under charge the voltage usually rise higher than 26 volts, it is normal it reach to 28 volts, your single panel is only 26.5 volts so it can't charge the battery bank.

As for how to wire the panels, you wire 2 in series and other 2 in another series then parallel the two series. if you not sure how to do it, please ask some one know so you won't burn up any thing.

hi thanks for the info, did you see the picture at the top of my last post showing what I think you mean, with reference to the wiring of the solar panels

regards Derek

[paulcheung]

You CAN NOT use the single panel, because when the 24 volts battery bank under charge the voltage usually rise higher than 26 volts, it is normal it reach to 28 volts, your single panel is only 26.5 volts so it can't charge the battery bank.

As for how to wire the panels, you wire 2 in series and other 2 in another series then parallel the two series. if you not sure how to do it, please ask some one know so you won't burn up any thing.

[Alpaca-Meadow]

wiring pannels

panelwiring-solar-power.jpgpanelwiring-solar-power.jpg

Your immediate problem is not the battery wiring. it is the panels wiring. you can't wiring 5 panels positive to positive, negative to negative to get high enough voltage to charge the batteries at 24 volts, you need at least 30 to 35 volts to charge the batteries properly. That charge controller only accept 100 volts DC input if I am not mistaken. You need to wire your panels 2 in a series and parallel the 2 series together. that you leave on for spare or you get one more.

Hi all I have just ordered some more MC4 connectors to re wire the solar panels as suggested above.
Can anyone do a quick sketch and upload it please so I am absolutely sure of the wiring, please

What or how do you suggest I wire the batteries please.

and a quick question

with the spare panel can I wire it into a spare 30amp none mppt controller and attach it to the batteries? and if I can do I wire it to the lead batteries or at the other end of the set?

thank you all for your help

regards Derek

if using the single panel is crazy let me know!!

on another note, if the charge controller is a 40 amp one, will it be ok to put the 4panels as suggested this will give me 32amps at 24 volts is that correct

[mapmaker]

I see that smart gauge site is showing 12 volt wiring.
the reason I wired the batteries as I did in 24 volts was because of the mppt controller only being 40amps
is there a site / image you can direct me to, to show me the correct way of wiring them please?

Two of your batteries in series is a string. In your case a 24 volt string. Pretend that your two batteries are just a single 24 volt battery. Then you have four 24 volt batteries that are in parallel. Your parallel wiring is way wrong. Look at the smartgauge site and pretend that each of those 12 volt batteries is one of your 24 volt batteries.

The smartgauge site is about how to take four strings of batteries and put them in parallel. It doesn't matter if the string is four 6 volt batteries in series (24 volt string) or three 12 volt batteries in series (36 volt string) or just one 12 volt battery as they illustrate on the smartgauge site.

Having said all that, Paul is absolutely correct:

Your immediate problem is not the battery wiring. it is the panels wiring.

--mapmaker

[paulcheung]

Your immediate problem is not the battery wiring. it is the panels wiring. you can't wiring 5 panels positive to positive, negative to negative to get high enough voltage to charge the batteries at 24 volts, you need at least 30 to 35 volts to charge the batteries properly. That charge controller only accept 100 volts DC input if I am not mistaken. You need to wire your panels 2 in a series and parallel the 2 series together. that you leave on for spare or you get one more.

[Alpaca-Meadow]

wiring batteries

Thank you Mapmaker.
I see that smart gauge site is showing 12 volt wiring.
the reason I wired the batteries as I did in 24 volts was because of the mppt controller only being 40amps
is there a site / image you can direct me to, to show me the correct way of wiring them please?

Thanks again for your kind response

Derek

[mapmaker]

this is how I have wired the batteries x 8 of course

That wiring is a disaster. Look at the diagrams on Smartgauge.

http://www.smartgauge.co.uk/batt_con.html

One problem with the smartgauge site is they show you how to do parallel batteries, but they don't tell you how bad an idea it is to have parallel batteries at all.

--mapmaker

[Alpaca-Meadow]

batteries

battery2.jpg
this is how I have wired the batteries x 8 of course
the controller is EPsolar 40A Tracer4210RN MPPT Solar Battery Charge Controller

Its been a while since my days of wiring please remind me parallel and series
thanks you all for you help, the chickens will be most grateful

Derek

[mapmaker]

What is the spec of these panels? I suspect the voltage may be too low to properly charge these batteries at 24 volts wired in parallels, how far is the panels to the charge controller?

Good catch on those panels, Paul. I saw he had 5 panels and an MPPT controller and just assumed....

--mapmaker

[paulcheung]

Yeap, These panels are 26.52 volts Vmp, Can't charge the 24 volts battery bank wired in parallel, You either have to wire in 2 in series with 2 parallel totals four or get one more panels wire 2 or 3 in series to charge your battery bank properly depend on the charge controller.

[Alpaca-Meadow]

solar panels

HI The panels I purchased are Ideal Thermasol TSPV 205 PE – Solar PV Collectors 205W

they are wired negative to negative and positive to positive the furthest panel is about 12 meters away from batteries and they are all joined together so the last panel is only 7 meters away from battery.

not sure of the spec but will look on back of one of the panels

regards Derek

[paulcheung]

What is the spec of these panels? I suspect the voltage may be too low to properly charge these batteries at 24 volts wired in parallels, how far is the panels to the charge controller?

[Alpaca-Meadow]

batteries

HI Mapmaker and thank you for your time and answer, it took me ages to find the reply! lol
anyway am here now,
the batteries are 12 volt caravan batteries all brought new and at the same time, the ones with the green lights on them to show charge.
they are wired series / parallel combination bringing the voltage up to 24 volts
does this throw a different light on it (excuse the pun)

[mapmaker]

HI All this is my first thread, I am not sure if I should be posting here as I could not find a way of posting back in the main screen.

Welcome to the forum Derek,

Hopefully the moderators will move this to its own thread.

I'm guessing that your batteries are 12 volt batteries. It that is correct you have 440 ah at 24 volts and the batteries are in 4 parallel strings of 2 batteries (in series) per string.

Therefore you have 10,560 watthours of storage and you should try not to use more than 2500 of them before recharging.

Your brooder is 75 watts. I will guess that between the end of one charging day and the beginning of the next day is about 18 hours. 18 hours X 75 watts = 1350 watthours. Of course your inverter is not 100% efficient, so figure you need to draw 1500 watthours overnight.

During the day, your array will typically provide about 25 amps of charge current to your batteries. That's a bit on the low side, considering the panels must charge the batteries while still powering the load.

Chances are you are doing a slow deficit charge. It takes a long time to get a battery up to 100.0% SOC (state of charge). If you only get to 99.9% every day, the 99.9% becomes your new 100% because of sulfation. After awhile you have 99.9% of 99.9% of 99.9%, etc.

I think there are some other issues with your system. The most serious is that (I think) you have 4 parallel strings of batteries. That is a formula for disaster... the batteries do not charge evenly because the current to the 4 strings does not divide evenly.. As the battery strings diverge, you have one string doing all the work while the others die of sulfation. The hard working string(s) die sooner from overwork, and because you daily load is being powered by a smaller battery which then gets over discharged.

Also, what type of batteries are these? They may not be suited for deep cycle service.

--mapmaker