MPPT controller setup question

At 0*C, that 190 Suntech becomes a 228w panel, correct? (But then again, that's based on ambient, not panel temp. At 0*C, the panel could still get quite warm)

Hi rjsurfer,

If you look at the manufacturer's data sheet you will see a term called "temperature coefficient Pmax". For example the temperature coefficient of a Suntech 190 W (monocrystalline) solar panel is –0.48%. What this means is that for each degree over 25?C … the maximum power of the panel is reduced by 0.48%. It is not "adjustable" so far as I am aware, but rather a "fact of life".

Voltage goes down as temperature increases.

rjsurfer wrote:
Can someone explain what the temp coefficient for Voc is? I know its adjustable.

A colder panel produces higher voltage.
The coefficient will be in the panel specs.

I'd have switches on both the input and output sides. I reset my controller from equalize to regular charging profile by turning off the battery connection.

Its funny I was always wondering what the two last connections where on most controllers labeled load. For the life of me I couldn't figure out their purpose.

Now it makes some sense.

Good info on keeping the battery voltage up on the charger all the time, I know I would have made that mistake along the line somewhere. With a battery selector switch its so easy to shut the battery bank down.

Can someone explain what the temp coefficient for Voc is? I know its adjustable.

Thanks

Ron

The charging profile is not adjustable but the voltages are temperature compensated.

The charging profile is the same as my LandStar PWM controller, also made by EP Solar. With Wets the voltage climbs to 14.6v then holds there for a fixed 2 hr period, then drops to 13.8v. (then it gets dark, voltage falls, and you start over in the morning) That worked ok for the solar conditions and battery bank/panel wattage ratio we had then.

The 100Voc limit is good for allowing 12v in series if desired. Note the warning up front about never going over the Voc limit and to use the panel spec's temp coefficient for Voc to get the Voc at the lowest ambient you will be camping in. It mentions a red light and a PV over-voltage disconnect feature. IMO don't push your luck! :)

rjsurfer wrote:
I haven't received my Tracer 4210rn charge controller yet but I downloaded the manual and it seems very straight forward except for the timers.

There are two timers I have to set one is "load will be on for x # of hours since sunset" and "load will be off for x # hours before sunrise"

I'm guessing the controller turns itself on/off by itself?

How does it know the times of sunrise sunset?

Ron W.

You probably will not use load control or the related timers.

Controller knows sunrise and sun set by monitoring solar input. Default is 10 hour night and will adjust as it learns the voltage cycle. See section 4.4 page 15.

http://solarlab.se/solpanel/datablad/Tracer-4210RN.pdf

For an RV installation, all you connect is the two array input and the two battery output terminals, no loads.

So ignore all settings for controlling the loads, you won't have any. Makes it easy :)

Do put an on/off switch in one of the two wires from the array so you can turn your solar on/off as desired. Do NOT put the switch in the controller to battery side. Never leave the controller on array but not on battery. Connect to battery first and disconnect last if changing your batteries around.

The thing you want to set is your absorption voltage, perhaps 14.8 or whatever your battery specs say. Does the Tracer have an adjustable Vabs?

The load side on the controllers are if you were wanting to use it to control something like security lights. I doubt you will need to connect or use that feature.

rjsurfer wrote:
How does it know the times of sunrise sunset?

By when it senses light, and no more light...?

I don't know what those 'load' questions mean.