Charge problems with off grid system

[Wicked3d]

Hi

and thanks for reading my post.

Firstly my system

4 * 150W 12v solar panels(parallel for 48v output)
12 * 102AH deep cycle batteries( 4 in parallel for 3*48v cells)
1 * 48v 60amp TES charge controler
1 * 3000watt Pure sine Embassy Inverter

now my problem,

Do i have enough panel to charge this system,
The first few days all went well but now i am struggling to get the system back over 48v capacity.
It stays at 45v-46.5v

I live in South Africa and have about 5 hours of direct sunlight on the panels.
Any help would really be appreciated as i don't know much about solar systems. Just the basics.
I built this myself and just need advise

Thanks in advance

[Silver_Is_Money]

I'm only a rookie, but if I'm looking at this anywhere near correctly (and this is a big "IF") it looks like if you have 4 panels wired in series and you are only seeing 46 volts, then you will need at least 5 panels in series to routinely achieve enough volts to charge a 48V bank, and also it appears that you should consider losing 4 of the batteries, and go with only 2 parallel strings of 4 in series to achieve 48V and 204 amps.

5 panels at 150 Watts = 750 Watts

750 Watts/48V = 15.625 amps charging current

15.625 amps x 8 hours = 125 amp hours (ideal battery bank that meets the ideal C/8 charge rate criteria)

For 8 batteries (I.E., 2 parallel strings of 4 in series per string) you will be at 204 AH and 48V

204 AH/15.625 Amps = ~13 hours to fully charge the bank with 5 panels (which is C/13, and this is still OK)

Disclaimer: Take all of this with a grain of salt, and wait for someone with experience to guide you down the proper path. I'm certain the real answer will require the need for some specific parameters (at least Vmp, Voc, Isc, and Imp) for your 150 Watt panels.

[Wicked3d]

Will try that and reply in 24 hours. The panels are in parallwl and at midday gives about 78v according to my tester readings. I will disconnect 1 48v cell and see if my power charges back up past 48v.

[Sunking]

4 * 150W 12v solar panels(parallel for 48v output)
12 * 102AH deep cycle batteries( 4 in parallel for 3*48v cells)
1 * 48v 60amp TES charge controler
1 * 3000watt Pure sine Embassy Inverter

now my problem,

Do i have enough panel to charge this system,
The first few days all went well but now i am struggling to get the system back over 48v capacity.
It stays at 45v-46.5v

I live in South Africa and have about 5 hours of direct sunlight on the panels.
Any help would really be appreciated as i don't know much about solar systems. Just the basics.
I built this myself and just need advise

Thanks in advance

No way any of this can be in Parallel and give you 48 volts. 4-12 volt batteries in Parallel is 12 volts period. Only possible way is in SERIES.

[Wicked3d]

Sorry for the wrong wording. English isnt my first language. I meant in series. All the system specs are in series not parallel.

[Silver_Is_Money]

I think you need to be seeing at least somewhere around 68 volts from your panels in order to charge a 48V battery bank. When you mention 46 volts are you talking about the series wired panels voltage output, or the battery banks state of charge? I believe I misunderstood you. If you are getting 78 volts from the panels then I most certainly did misunderstand.

I still believe you have too many amps of batteries for only 4 x 150 Watt panels.

4 x 150 = 600

600/48 = 12.5

12.5 x 8 = 100 amps

If your 12V batteries are 102 amps you might need to cut down to only 1 string of 4 batteries in series in order to bring them to a full charge in a reasonable time frame with only 4 panels. You would be right at the ideal of C/8 with only 4 batteries. With 8 batteries you are at C/16.

[Wicked3d]

Was refering to the battery banks syate of charge. I understood from your 1st reply that i have a ballance problem between panels and batteries. Will fix this and post results.

[Sunking]

OK is your charge controller PWM or MPPT?

On the surface your panel wattage to battery ratio size is OK. However your system cannot support a 3000 watt inverter. At 12 volts it would take a 2500 AH battery with a 3000 watt panel system. At very best you should not be running more than a 500 to 800 watt inverter.

Assuming you have it wired correctly you are just using way more power than the system is capable of generating. Disconnect the inverter and give your batteries a a few days to recharge.

FWIW generally speaking for a battery system, Inverter wattage should not be larger than panel wattage if using FLA batteries and up to 2x if using AGM or LFP. FLA batteries can only supply about C/8 discharge current where C = the battery rated AH capacity. In total you have 12 volts @ 408 AH which means no more than 50 amps discharge current. 50 amps x 12 volts = 600 watts.

[SunEagle]

Hi

and thanks for reading my post.

Firstly my system

4 * 150W 12v solar panels(parallel for 48v output)
12 * 102AH deep cycle batteries( 4 in parallel for 3*48v cells)
1 * 48v 60amp TES charge controler
1 * 3000watt Pure sine Embassy Inverter

now my problem,

Do i have enough panel to charge this system,
The first few days all went well but now i am struggling to get the system back over 48v capacity.
It stays at 45v-46.5v

I live in South Africa and have about 5 hours of direct sunlight on the panels.
Any help would really be appreciated as i don't know much about solar systems. Just the basics.
I built this myself and just need advise

Thanks in advance

Ok so the 150w panels are wired in series and the 12 x 12volt 102Ah batteries are wired (4 in series with 3 sets wired in parallel). That gets you a 600 watt panel system and a 48volt 306Ah battery system.

I couldn't find the specifications for a TES 48volt 60 amp charge controller so I will assume it is MPPT type. With a MPPT type charger and 600 watts of panels you will only get you about 12.5amps to charge that 48volt 306ah battery system which gives you a C/24 charging ratio which is too little. You need about 1200 watts of panels to get about 25amps for that 306Ah system.

Also another question is how many watt hours are you using per day. If you are using more than what you can put back into the battery with the solar panels you will never charge your batteries back up to 100%.

[Silver_Is_Money]

What is your load? If the load is high you will need to add panels rather than reduce batteries.

[SunEagle]

OK is your charge controller PWM or MPPT?

On the surface your panel wattage to battery ratio size is OK. However your system cannot support a 3000 watt inverter. At 12 volts it would take a 2500 AH battery with a 3000 watt panel system. At very best you should not be running more than a 500 to 800 watt inverter.

Assuming you have it wired correctly you are just using way more power than the system is capable of generating. Disconnect the inverter and give your batteries a a few days to recharge.

FWIW generally speaking for a battery system, Inverter wattage should not be larger than panel wattage if using FLA batteries and up to 2x if using AGM or LFP. FLA batteries can only supply about C/8 discharge current where C = the battery rated AH capacity. In total you have 12 volts @ 408 AH which means no more than 50 amps discharge current. 50 amps x 12 volts = 600 watts.

I think he confused you (or maybe me) with the number of batteries and how he has them wired.

He has 12 batteries rated 12volts at 102Ah ea. He then has 4 of them in series to get 48volts and then 3 sets of those in paraller to get 306Ah at 48volt system.

Yes the 3000 watt inverter is too big for those batteries but no way will those 600 watts of panel charge a 48volt 306Ah system.

[Wicked3d]

The inverter is not even connected but i still cant get the charge over 46.5v on my current battery bank. I will reduse the bank size and see if the charge goes up and over 48v.

[Sunking]

The inverter is not even connected but i still cant get the charge over 46.5v on my current battery bank. I will reduse the bank size and see if the charge goes up and over 48v.

Then you have a major problem with either equipment or wiring configuration. You have more than enough panel wattage to fully charge those batteries with no load connected.

[Wicked3d]

Charging went well today. Charging 2-48v cells got to 48.3v. Hope it goes higher tommorrow

[Sunking]

You are not done till you see 52 volts.