Will adding more solar panels charge my batteries to full?

[surfergirl]

Hi all, Needing some advice. I currently run 6x405watt panels (approx 2.4kw) with 4x12v 270ah AGM batteries and 5kva inverter. I get 6 hours of full sun in the non summer months but even during summer, my battery volts never go above 54.8v. As soon as the full sun disappears from my panels, I'm running at 50.8v by 6pm
The supplier said I should be reaching 58,5v by lunch time but maybe because my batteries are 4 yrs old, they aren't operating at full capacity?
I have an extra set of solar panels totalling 1.5kw and wondering if I add these to my existing kit then maybe my batteries will fully charge?
When I run my generator and smart battery charger, the battery charger reads 58.5v but at the end of charging when I unplug it, the battery bank reads 51.1v
On average, I use 1.5v overnight so not a big user-am in a tiny house. Also, am in the southern hemisphere.
Thanks in advance

 

[DIYPV]

What’s your total daily consumption through the inverter? If you set your solar priority to your loads then only excess solar will be utilized to charge your batteries.

Yes, adding more panels should get your batteries to full charge. I would try figure out your daily loads, and add to battery capacity to determine solar panels needed.

 

[Rednecktek]

What type and age are the batteries?

 

[rodrick]

If your batteries are 4 years old and you haven’t been charged fully on a regular basis you may have damaged them some that is one of the reasons lithium is so much better it doesn’t care if you don’t always get topped off

 

[surfergirl]

What type and age are the batteries?

They're AGM Nomad 270ah 12v x 4 to make up a 48v battery bank. They're 4 years old

 

[surfergirl]

If your batteries are 4 years old and you haven’t been charged fully on a regular basis you may have damaged them some that is one of the reasons lithium is so much better it doesn’t care if you don’t always get topped off

The old saying. Batteries don't die, they're murdered....

 

[sunshine_eggo]

Hi all, Needing some advice. I currently run 6x405watt panels (approx 2.4kw) with 4x12v 270ah AGM batteries and 5kva inverter. I get 6 hours of full sun in the non summer months but even during summer, my battery volts never go above 54.8v.

Do you mean 6 solar hours, or 6 hours of sunlight on the panels? Huge difference.

As soon as the full sun disappears from my panels, I'm running at 50.8v by 6pm

That's not completely horrible. Presumably under load, that's 12.7V for each 12V, which is a high state of charge.

The supplier said I should be reaching 58,5v by lunch time

This depends on how you use power, if the panels are optimally tilted and getting sun from sunrise.

but maybe because my batteries are 4 yrs old, they aren't operating at full capacity?

Generally, as batteries fail, they either get harder to charge or hit full faster.

I have an extra set of solar panels totalling 1.5kw and wondering if I add these to my existing kit then maybe my batteries will fully charge?

Maybe. Do you have the MPPT capacity to add it?

When I run my generator and smart battery charger, the battery charger reads 58.5v but at the end of charging when I unplug it, the battery bank reads 51.1v

Again, not at all uncommon for voltage to plummet if there's a load present.

On average, I use 1.5v overnight so not a big user-am in a tiny house. Also, am in the southern hemisphere.
Thanks in advance

At noon, what is battery voltage, and what is the current going into the battery?

Additionally, when battery bank is at peak voltage, are all 4 12V at the same voltage?

 

[surfergirl]

Do you mean 6 solar hours, or 6 hours of sunlight on the panels? Huge difference.

Yes 6 hours of full sunlight on the panels

That's not completely horrible. Presumably under load, that's 12.7V for each 12V, which is a high state of charge.

Yes on a SOC chart it's okay but my batteries never get above the required 58.5v by lunch time. The load is very light. Fridge rated at 282kwh/year and a laptop/phone charging. Of course the inverter used power. I have a pump for my rain tank with a pressure tank so the pump isn't going on/off every time I turn the tap on.

This depends on how you use power, if the panels are optimally tilted and getting sun from sunrise.

Three panels are at 29 degrees and 3 panels at 38 degrees. I had to lower the front 3 to prevent shading on the back three in the early morning hours but haven't noticed any difference in the battery volts at 6pm

Generally, as batteries fail, they either get harder to charge or hit full faster.



Maybe. Do you have the MPPT capacity to add it? Yes, the charger is 80 amps so I can take up to 3.8kw



Again, not at all uncommon for voltage to plummet if there's a load present.



At noon, what is battery voltage, and what is the current going into the battery? 54.8 and on a sunny day 600-800 watts incoming

Additionally, when battery bank is at peak voltage, are all 4 12V at the same voltage? Yes, one is slightly higher 12.7 with the other three at 12.6 so not a huge difference. Thanks for your help. Been a steep learning curve for me. Trying not the reinvent the wheel so this forum is wonderful for me

 

[sunshine_eggo]

Yes 6 hours of full sunlight on the panels

Okay, that's not very much. I guess it's winter for you folks in the southern hemisphere. You may only have the potential for 4.8-7.2kWh/day of solar harvest.

Yes on a SOC chart it's okay but my batteries never get above the required 58.5v by lunch time.

What installers say is never to be trusted or expected - only confirmed or refuted.

The load is very light. Fridge rated at 282kwh/year and a laptop/phone charging. Of course the inverter used power. I have a pump for my rain tank with a pressure tank so the pump isn't going on/off every time I turn the tap on.

Do you have a battery monitor that shows the state of charge of the battery based on the net flow of current in or out of the battery and also reports the flowing current?

Three panels are at 29 degrees and 3 panels at 38 degrees. I had to lower the front 3 to prevent shading on the back three in the early morning hours but haven't noticed any difference in the battery volts at 6pm

Again, what are the 12V batteries' voltage at peak voltage? At 54.8V, what is each 12V?

Note that the average of 54.8V is 13.7V, and that's a common float voltage for AGM, so your MPPT may not be configured properly.

What MPPT?

What is the bulk/absorption/boost setting (3 terms for the same voltage)?
What is your float voltage setting?

At noon (or peak solar conditions), using a voltmeter, take these two measurements: 1) voltage measured at the MPPT battery terminals and 2) voltage at the battery terminals. What are they? What is the MPPT reported voltage and charge current at the time of the voltage readings?

Are any components or connections between the MPPT and battery warmer than other parts?

 

[OzSolar]

The old saying. Batteries don't die, they're murdered....

Love it! Yep, 30 some odd years dabbling in off grid solar installations on the side of my regular business (licensed electrician/general contractor then went back to college and finished my engineering degree ) and I've never seen a battery bank die from cycles.

 

[surfergirl]

Okay, that's not very much. I guess it's winter for you folks in the southern hemisphere. You may only have the potential for 4.8-7.2kWh/day of solar harvest.
Yes winter here, just began June 1st


What installers say is never to be trusted or expected - only confirmed or refuted.

Understood

Do you have a battery monitor that shows the state of charge of the battery based on the net flow of current in or out of the battery and also reports the flowing current?

On my list to buy!!

Again, what are the 12V batteries' voltage at peak voltage?

At 54.8V, what is each 12V? Today was 54.6v and each battery tested at 13.6v at noon.

Note that the average of 54.8V is 13.7V, and that's a common float voltage for AGM, so your MPPT may not be configured properly.

What MPPT? I have a MUST inverter Model PV18-5kva MPK with built in mppt - 60amp charger with max charging current of 120amp. The supplier said to set it to 120amp on the inverter. Attaching spec sheet

What is the bulk/absorption/boost setting (3 terms for the same voltage)? Bulk is set to 58.4v
What is your float voltage setting? set to 54.8v

At noon (or peak solar conditions), using a voltmeter, take these two measurements: 1) voltage measured at the MPPT battery terminals and 2) voltage at the battery terminals. What are they? What is the MPPT reported voltage and charge current at the time of the voltage readings?

Voltage at battery terminal as above 54.6 and not sure how to measure voltage at the mppt battery terminals? Inverter read PV input 114v and PV input 400w at noon- does that help?

Are any components or connections between the MPPT and battery warmer than other parts? Not that I can tell but I'm 'just a girl' lol

 

[sunshine_eggo]

Please try to hit enter when replying to my text. This will put your text on a new line and exclude it from my quote. If I reply to you, and you have added portions to my quoted text, it will not include it.

Understood

On my list to buy!!

Good.

At 54.8V, what is each 12V? Today was 54.6v and each battery tested at 13.6v at noon.

Good.

Is there any chance that you're missing the batteries hitting peak voltage? Do you actually check in every 15-30 minutes to note the voltage? If you let a couple hours go by without checking, you may miss it.

If your utilization is very low, it may cycle through bulk/absorption/float very quickly.

Voltage at battery terminal as above 54.6 and not sure how to measure voltage at the mppt battery terminals?

I assumed we were dealing with a separate MPPT. In this case, you would measure at the battery terminals and where the battery connects to the inverter.

Inverter read PV input 114v and PV input 400w at noon- does that help?

How much of that 400W was going to the battery vs. being used in loads?

"just a girl"? Cut that shit out. Everybody secretly knows that women are running the show and have duped men into thinking they're in charge.

Your system is capable of 60A PV charging and 60A AC charging (generator or grid).

The specs say a maximum of 3000W, so you won't be able to fully utilize the additional PV you have in reserve, but it will still help.

It's really hard to say what's going on at this point. I'd make a point of checking the voltage and watching it like a hawk on your next clear day. Make sure it's not sneaking through the charge phases.

 

[pollenface]

Seeing 54.8v at noon would likely by FLOAT which is great

Check voltage at 9-10am it will be in BULK/ABSORB and read a higher voltage.

Disconnecting all load from the batteries in the afternoon and observing the resting voltage before sunrise the following day will allow you to see true resting voltages. I think 50.8v is acceptable with small loads attached.

It is possible that the batteries are not doing equal work. If you haven't had a balancer over those 4yrs I would suggest getting one, maybe swap the batteries around, put the outside batteries on the inside and have a look on ebay/amazon for a HA02/PowMr 48v balancer for piece of mind.

 

[SamDeleted]

"just a girl"? Cut that shit out. Everybody secretly knows that women are running the show and have duped men into thinking they're in charge.

Oh yea women are just as valuable as men, and they're get at getting things done... Like coming on here and saying 'I'm just a girl' so all the men rally round and help!



Not saying it's a bad thing, in fact I support it...What else are us men supposed to do other than be wrapped round a women's little finger

, but there are certain ways & means women use to get their own way lol