creeky
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# Posted: 1 Nov 2015 17:12
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If I could clarify a few things.
Groingo you are right amps is what a charge controller works with.
Voltage is important in that you must keep your panels lower than the limit (usually 100 or 150v). if you go over voltage you will fry your CC.
The CC takes the voltage and amps, and, in the case of an MPPT CC, turns it into the required voltage your battery pack needs to charge efficiently. Increasing Amps* as available. A PWM CC simply loses the extra amps* only providing the necessary voltage.
*if there is any extra power available from the panels of course.
So what voltage does my battery require in order to charge?
Your 12v Lead acid (LA) battery pack is most likely to charge at around 14.5v at 25C/75F. Some are a bit lower, some a bit higher. Lithium you would probably limit at 14.1-14.4.
600w / 14.5v = 40 amps. A typical 60 amp controller will handle 800w. Mine both have 1kw on them.
Now the more important stuff.
What kind of CC is it? Any modern good quality MPPT CC will happily "overpanel." And it's an excellent idea now that solar panel costs have dropped so much. During peak solar production you will see a message "current limiting." That would be your controller limiting the current to keep within the max amperage. It does not damage a good CC. But nor will it go over the amperage max.
Now is a good time to remember, 80-90% of your solar collecting day will not be prime time. Cloud, mist, morning, evening etc all reduce the amount of power your panels can create. (I have a neat story but I'll save it for another time).
Quoting: groingo do I add a second charge controller?
A second controller is an excellent idea. Here is a brief overview from morningstar how to parallel a second controller with 2 arrays.
In your case Groingo tho, you would probably be best served with a bigger controller. Sell the old one.
But to parallel controllers just plug them in. If you want to get fancy and buy a special doohickey so that you get a master / slave relationship. each to their own. there is no reason to though. you may see a slight imbalance without it. but in the big scheme of things. no worries.
hope this helps.
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