classic 250 controller

[benharuna]

can standard classic 250 charge 120v battery bank. if it can how can i configure the controller. the controller work with 72v battery bank

[Halfcrazy]

No the Classic charge controllers can charge up to 72v nominal batteries and that is the limit. I know some people have used 2 separate classics to charge to half's of a 120v battery. So each classic has a 60v battery and its own identical PV array

Ryan

[benharuna]

thanks ryan
how will the connections look like we have 120v inverter

[boB]

Splitting up a 120V battery bank into 2 or more sections really merits having a wiring diagram.

We'll see if we can do this.

But basically, each Classic's pair of negative lines (Battery and PV minus) will have to stay separated from
the other Classic's  negative lines.  The Classic on the bottom of the stack of batteries will be connected to
the main battery negative bus for the entire 120V DC system.

Since the communication phone jacks in the Classics are internally tied to the negative lines of the Classic,
Follow Me would require an isolated RS232 connection.  Follow Me may really not be necessary anyway
though because the batteries are in series instead of parallel and will have their own charge timers.

You could use a Whizbang Junior on each half, too I think.

[vtmaps]

I notice this over at:  http://www.amplepower.com/products/chrg/index.html

To make 24-Volt chargers, Power Supply/Chargers are stacked in series.
<snip>
With the series connected units, improved charge performance is provided by connecting the 12-Volt junction of the two chargers to the 12-Volt junction of the 24-Volt battery bank. This reduces chances of cells failing in the battery bank. The two halves of the 24-Volt bank are charged at equal voltages, even if some of the cells in either half have unequal capacities.

Question:  If I had two arrays and two classics in parallel charging my 24 volt battery, how much better off would my batteries be if I put the Classics in series and used each one to charge a 12 volt half of my battery bank?

--vtMaps

[boB]

vtMaps,  I would say this comment is correct.  I don't think it is absolutely necessary, but it
is true that the halves of the battery bank will have better odds at being balanced.

But, you can also just watch your batteries to make sure they are OK, balance wise.

BUT, either way will not  balance individual 2 V cells.

[vtmaps]

but it
is true that the halves of the battery bank will have better odds at being balanced.

But, you can also just watch your batteries to make sure they are OK, balance wise.

So depending on the variation of the two 12 volt batteries, one controller might be floating while the other is absorbing. No need for 'follow me'. If they are in different charge stages, I wonder how the controllers will behave when a large 24 volt load is applied....

--vtMaps