TriStar TS-45 (PWM) Questions on numbers I'm getting..

Re: TriStar TS-45 (PWM) Questions on numbers I'm getting..

Al, you're obsessing. That's not good.

Panels do not put out anything like consistent or fixed power. It will vary all over depending on insolation, atmospheric conditions, temperature, and load requirements. The STC panel rating, the one on the specs that says "145 Watts", is obtained under ideal conditions in a laboratory. It is really nothing more than a relative number for comparing to other panels.

Your 20.7 Volt reading is Voc; open circuit, nothing connected. It is meaningless except in terms of not exceeding a controller's input maximum. Panels source current, not Voltage. In one instance you have 7.6 Amps, in another 7.0. That's fine. If the load doesn't demand more or the insolation isn't perfect you won't see more. The Voltage will be <Vmp in according to losses through wiring and mainly what the battery pulls it down to.

A brief review of charge stages:
Bulk: maximum current from panels. Voltage rises to Absorb set point, current tapers off.
Absorb: fixed Voltage at battery over time, current tapers off.
Float: fixed Voltage lower than Absorb point, current remains relatively steady in accordance with load demands.

If you keep on like this you're going to drive yourself crazy. The panels are fine; don't worry about them.

Re: TriStar TS-45 (PWM) Questions on numbers I'm getting..

ywhic wrote: »

So when it says PWM on the meter that means Absorption stage correct?? (my book says PWM Absorption)

"PWM" stands for Pulse Width Modulation. It is the type of charge controller and the way it functions; by turning on and off at different rates/intervals (very rapidly) to regulate the charge. In this case to keep the Voltage on the battery side at the Absorb set point.

Then why when it hits 99% PWM it then goes to BULK??

Operational fluke; it tries to pulse, can't hit the proper Voltage even at 99%, then goes into Bulk mode (100% ON) because it figures it needs it.

I thought it was BULK then Absorption?? I did notice this changes with sun/shade/clouds..

It is. However controllers can get confused about what stage they are supposed to be in and may take some time to sort itself out. Especially if someone turns the panels on and off while it's trying to charge.

I did hook an automotive 12v bulb today to the unit and it still held up for 2 1/2 hours of run time..

How much of a bulb? Did you see Windsun's comment? You really need to load it if you want to see the full potential.

I was fine till a person on another forum made me think about it again.. (oh and I hate having ADHD)..

Don't worry about that either. Confusion reigns!

Also.. I noted 20.7 when disconnected from the charge controller.. then once I kicked the breaker back on the voltage dropped to be 13.9 (which was the system/battey voltage at that moment).. does that mean the the controller was in fact regulating the INCOMING panel based on what the battery needed (it seemed that way)..??

Technically the controller doesn't regulate the panel Voltage; the load against the panels does. When in "ON" mode, a PWM controller is basically a straight-through connection between panels and battery. The panel Voltage gets pulled down to wherever the batteries are at. The current goes up to whatever the demand is. Panels are a current source and willingly let the Voltage go all over the place: you can have full current at anywhere from near zero Volts to Vmp. Voc will only be there at absolutely no load; the opposite of Isc which can only be read at dead short.

During Absorb or Float you can read a steady Voltage on the output side of the controller, and an apparent steady (but higher) Voltage on the input side. If you could slow down time and watch it closely you'd see Voltage & current fluctuations on both sides; the current going off and on and the Voltage on the battery side elevating slightly when "on", the Voltage on the panel side jumping up and down between Voc and about Vmp.

It is a hard thing to wrap your head around.