Is my battery math correct?

[kingofbanff]

I emailed FullRiver and they confirmed C4 is fine. In fact according to this chart they sent C/3 is the maximum.

[Sunking]

Yep, that is C/4

[kingofbanff]

Oops. Part of my post got cut off. In the bulk charge stage it suggests that the maximum is 25 A per 100 amp hour.

[Sunking]

Where are you picking up C/4? All I see is characteristics. I might be overlooking something.

[kingofbanff]

I found this sheet. Am I reading it correctly that the max is C/4? (

[Mike90250]

This is from Outback "The FM80 is the latest innovation in Maximum Power Point Tracking (MPPT) charge controllers from OutBack Power Systems. The FLEXmax 80’s innovative MPPT algorithm is both continuous and active, increasing your renewable energy yield up to 30%. Thanks to enhanced cooling, the FLEXmax 80 can operate at its full 80 amp maximum current rating in ambient temperatures as high as 104°F (40°C).

Included in the FLEXmax 80 are all of the features first developed by OutBack Power in the revolutionary MX60, such as support for a wide range of nominal battery voltages and the ability to step-down a high voltage solar array to recharge a low voltage battery."

My system has three of these.

OK, now there are model #'s. Those will work with PV.

[kingofbanff]

The integral controllers in the inverters, are most likely, AC chargers, from your genset. They are not Solar PV MPPT charge controllers.
Morningstar and Midnight make very good MPPT controllers, Outback also makes MPPT controllers, but I have no experience with them.

You will also need Solar PV combiners, and disconnects and you likely have overbought too many PV panels, and may be able to sell the panels to purchase the charge controllers.

This is from Outback "The FM80 is the latest innovation in Maximum Power Point Tracking (MPPT) charge controllers from OutBack Power Systems. The FLEXmax 80’s innovative MPPT algorithm is both continuous and active, increasing your renewable energy yield up to 30%. Thanks to enhanced cooling, the FLEXmax 80 can operate at its full 80 amp maximum current rating in ambient temperatures as high as 104°F (40°C).

Included in the FLEXmax 80 are all of the features first developed by OutBack Power in the revolutionary MX60, such as support for a wide range of nominal battery voltages and the ability to step-down a high voltage solar array to recharge a low voltage battery."

My system has three of these.

[Mike90250]

The plan is an Outback Flexpower Radian 8048 acting as master and a 4048 as slave. Between them they have 3 80 Amp charge controllers. Does that solve problem1?......

The integral controllers in the inverters, are most likely, AC chargers, from your genset. They are not Solar PV MPPT charge controllers.
Morningstar and Midnight make very good MPPT controllers, Outback also makes MPPT controllers, but I have no experience with them.

You will also need Solar PV combiners, and disconnects and you likely have overbought too many PV panels, and may be able to sell the panels to purchase the charge controllers.

[jflorey2]

The data sheet indicates that the initial charging current for cyclic applications is &quot;<=0.2 x C20.&quot; That's C4. As I mentioned that doesn't make sense, but C/4 does.

[kingofbanff]

C4 would be able to discharge very rapidly!
Where did you locate the C/4?

[kingofbanff]

I've been searching high and low for a charging rate for it but can't find one.

The system will be grid tied but have the ability to keep operating if the grid is down.

[jflorey2]

In your last sentence you mention AGM can handle a C/2. I think the DC224-6 is AGM...does that mean I'm ok there?

The Fullriver DC224-6 can handle C/4. (They refer to it as C4 but that's almost certainly a typo.)

[Sunking]

In your last sentence you mention AGM can handle a C/2. I think the DC224-6 is AGM...does that mean I'm ok there?

Is it AGM? If it is look in the specs and they should tell you the max charge rate. You may have dodged the bullet.

Is this a hybrid system?

[kingofbanff]

The plan is an Outback Flexpower Radian 8048 acting as master and a 4048 as slave. Between them they have 3 80 Amp charge controllers. Does that solve problem1?

In your last sentence you mention AGM can handle a C/2. I think the DC224-6 is AGM...does that mean I'm ok there?

As always, thanks!

[Sunking]

I will have 13kw of SunPower panels. My question was instead of the FullRiver dc224 which battery would you suggest?

OK you have some challenges ahead of you. I assume you will use the Full River batteries.

You really only have 1 option, 48 volts. However with 13 Kw of panels is an issue. The largest controller you can buy is 80 amps. With 80 amp output limit also limits how much panel power you can input vs battery voltage. Those limits are:

1000 watts @ 12 volt battery
2000 watts @ 24 volt battery
3000 watts @ 36 volt battery
4000 watts @ 48 volt battery

You have 13,000 watts, and at 48 volt battery 13,000 watts / 50 volts = 260 amps of charge current. That gives you two big problems.

1. It will take more than one charge controller, more like 4-65 Amp controllers. You would have to divide the panels up into 4 equal systems out puting into a common battery. That is doable as there are controllers to operate as Master-Slave. But very expensive. Want a 12 volt system? Then you need 13 very expensive 80 amp controllers. Do you have any problem with that? I would pissing all that money away. .

2. Is the Big Problem. Regardless of what voltage you configure the batteries, you have way to much panel wattage for the batteries. Anyway you do it is a charge rate of C/1.7 Lets just say C/2 for simplicity. The most you want to hit those batteries with is C/6. In other words the maximum panel wattage you should run is 4000 watts with 80 amps of charge current @ 48 volts. You would need 3 times the battery capacity to run 13,000 watts of panels. You have only made a 33% down payment so far for batteries. Is that a problem for you? Don't forget replacing all of them in 5 years.

Sorry but you have some issues to work out. There are only two battery types you have access to that can handle a C/2 charge current, AGM and Lithium. The bad news about that is it will cost as much as buying 3 times more of the same battery you have. You are screwed either way. Sorry! You other option is to get rid of the extra panels.

You need to set back and figure out just how many Kwh in a day you really need. Keep in mind anything you take off-grid is going to cost you many times more than buying power from the power company. Just in battery cost alone with replacement cost is going to run you 60-cents to $1 per Kwh. Not sure where you live, or how much you pay the utility, but where I live we pay 7-cents per Kwh. If I were to go off-grid would cost me 10 times more than I pay.