battery not charging properly

[the picker]

Well i am thinking maybe later. But if you think i will never need to add more panels to charge those 4 batteries then it is probably not needed. But been mislead many times since i started with this solar idea and has been a expensive learning curve. Please take in consideration i live in eastern Canada with not alot of good sunny days.

 

[FilterGuy]

Please take in consideration i live in eastern Canada with not alot of good sunny days.

Definitely read the resource I linked to in my last post.

 

[the picker]

Perfect, but if one ads more panels then the controller is rated for , what does the controller do with the extra?

 

[FilterGuy]

But if you think i will never need to add more panels to charge those 4 batteries then it is probably not needed.

We have been discussing how to get the most out of the 4 panels you have, but have not touched on whether it is enough..... that is going to depend on your energy usage and we do not know what that is.

For lead-acid, you really need to fully charge the batteries each day or they will wear out really quickly. That means you need to replace what you use each day.

 

[FilterGuy]

Perfect, but if one ads more panels then the controller is rated for , what does the controller do with the extra?

When the battery is full, the controller stops the current from the panels.... with no current flowing through the panels, no energy is being generated by the panels, so there is no extra.

 

[the picker]

Makes sense.

 

[the picker]

Always thought the controller used the extra. Also put a different option out there. Would 24v work better?

 

[FilterGuy]

Would 24v work better?

* The original post said 2400W inverter. This is at the very top end of what I would ever do on a 12V system.
* You would probably have to replace the inverter if you go with 24V, so I would probably not change unless you decide you want a larger inverter.
* I like 24V for small/medium systems, but this touches on a debate that is kinda raging right now on a different thread:

What happened to the 24v DIY system web page?

Where did the web pages go for the 24v 1kW off grid system? I was using that as a basis for my system.

diysolarforum.com

 

[the picker]

If i went 24v my amps will be cut in half, so could i keep just the controller i have and not need any more.

 

[Wibla]

Yes - though I would look at the difference in Vmp on those panels. As long as the difference is only a few volts, it won't affect the total power output by much.

Just to be sure - you turn that inverter off when it's not in use, right?

 

[the picker]

Why turn inverter off? So do i need to split panels and get another controller?

 

[Wibla]

Why turn inverter off?

They use some power to generate the sine wave output even if nothing is actually using that power.

Some quick googling tells me that some of the smaller Giandel inverters are rated at 1A idle current. That's 24 Ah per day or 288 Wh per day.

So do i need to split panels and get another controller?

If you stay on 12V? yes.

 

[the picker]

Seems like a lot ,288 per day. What would you do 12 or 24 volt, either way i have to buy something

 

[FilterGuy]

Going to 24 volt does not solve the dissimilar panel problem with the existing configuration. If you go with 24 volt (new inverter) you will still need a 2nd controller.

 

[acdoctor]

This is from Rolles Surrett:
ABSORPTION CHARGE TIME - FLOODED
Where: T = 0.42 x C /I T = ABSORPTION CHARGE TIME
C = 20 hr RATED CAPACITY (total AH capacity of battery bank)
I = Charging Current (Amps) (*see Note: CHARGING CURRENT below) 0.42 = (factors in assumed current loss during Absorption charge phase)
EXAMPLE:
2 strings of 6 Volt 6 CS 25P models
C = 20 hr AH rate = 853 AH x (2 strings) = 1706 AH
I = 10% (recommended) of 1706 AH = 170 Amps
T = 0.42 x 1706/170 = 4.2 hrs
However, if actual measured current is less (~160 Amps), or maximum charger output is limited to 160 Amps, 160 is used. (Ex. 2 x 80 Amp controllers)
T = 0.42 x 1706/160 = 4.48 hrs

ABSORPTION TIME FOR YOUR BATTERY BANK AT RECOMMENDED CURRENT.
C=20 hr (890AH)
I = 10% (89)A
T= 0.42 x 890/89 = 4.2 hrs.
Don’t forget this is after you come out of Bulk Charging
If you are like the rest of us sun hours are short now.

ABSORPTION TIME FOR THE TWO 400 WATT PANELS
T= 0.42 x 890/50 = 7.476 hrs.
If you have not you need to study up on your battery
Rolles has literature and videos available.

 

[Wibla]

Seems like a lot ,288 per day.

It is. Standby draw like that can easily degrade your batteries if you have multiple bad solar days in a row. I'd make it a priority to get that shut off ASAP.

What would you do 12 or 24 volt, either way i have to buy something

I'd probably go 24V, but I wouldn't buy another controller before checking out the panels first, see why below:

A rule of the thumb for connecting up dissimilar solar panels is that same Vmp = parallell, while same Imp = series. Check the nameplates for the panels and try running two 320W+400W series strings in parallell if the Imp is close enough (within 0.5A). To see any real benefit from this you will have to go 24V.

 

[the picker]

So if i went 24v , what type of inverter charger would you buy. I am thinking i should get a charger inverter in one.

 

[Wibla]

What kind of budget do you have?

 

[acdoctor]

Are thinking AOI inverter with solar charge controller and line voltage charger? Or are you thinking inverter with line voltage changer? Do you have a generator and what is it?

 

[the picker]

Not sure but i have a 4000 watt generator. Budget not good after all the expensive miss leads along the way.