โOct-23-2017 07:34 PM
โOct-25-2017 01:29 PM
โOct-25-2017 12:25 PM
mike-s wrote:
PWM limits the voltage, and indirectly the current. Not the instantaneous current, which you seem fixated on, but the actual charge current - how fast coulombs flow into the battery.
โOct-25-2017 11:15 AM
red31 wrote:What's your point? As long as current is flowing, the battery is charging. If voltage drop prevented the battery from reaching its absorption voltage as you claimed, then no current would be flowing. But, of course, unless there's current, there's no voltage drop. And, as the battery approaches full charge, it draws less current.
panel current is either on or off, the on time tapers but not the current.
โOct-25-2017 09:55 AM
mike-s wrote:
And, why you're injecting charts applicable to an MPPT controller into a PWM discussion is a mystery.
โOct-25-2017 09:40 AM
red31 wrote:Yes, it does. Just as a cell phone which will only charge at 1.5 A won't draw more than that from a 2.4 A charger, so too is the charge current here reduced as the battery approaches full. When looking at the IV curve for a panel, the current must be considered a maximum, not a fixed value.
current doesn't taper
โOct-25-2017 09:20 AM
โOct-25-2017 09:10 AM
red31 wrote:Charge voltage is not limited below that required, since any reasonable combo of panel and wire will be able to draw the voltage at the battery up to its full absorption voltage. During bulk charging, voltage drop (both before and after a PWM controller) will result in a slight loss of efficiency, but it does not limit the ultimate charge voltage. As the battery nears a full state of charge, the current drops and so does the voltage drop.
Controller to batt voltage drop limits batt charge voltage.
Current 'taper' during abs does not solve voltage drop, the panel is ether on or off, the taper comes from more off time and not reduced current from the panel.
โOct-25-2017 05:53 AM
โOct-24-2017 07:51 PM
โOct-24-2017 07:26 PM
โOct-24-2017 12:42 PM
โOct-24-2017 09:34 AM
โOct-24-2017 09:30 AM
babock wrote:mike-s wrote:I never said that was the case.
I'm not the one who thinks that when you put 20 A into one end of a wire, less than that can come out the other end. I don't believe your EE claim.
babock wrote:
If you have a length of cable that had a 10% voltage drop at 20A you would likely get half the charge current than you would if you limited it to 1%.
โOct-24-2017 09:10 AM