More Solar for "Us"
Ok, I went off.the deep end? Bought 3 used 37watt uni-solar panels and a blue sky 2000e controller for the hefty price of $400, They were being listed as 75w panels, they are not The tested open...
Forum Discussion
BFL13 wrote:
If the controller drops to Float voltage before you want it to, it is very frustrating trying to get it back to Bulk, since the batts have to get down to 13.2 (eg) which can take a long time.
Yes, it would have to go through Absorb again.
No, it won't take a long time if controller is smart enough to shorten the Abs stage accordingly to the current and/or voltage at the beginning of this "new" Abs stage. Those cost more than Grape though.
BFL13 wrote:
If you can program Float to be near the same higher voltage as Bulk, then you are good all day.
Why keeping batteries all day at elevated voltages is good?
BFL13 wrote:
If the controller is set to do two hours at Vabs after getting there, and it gets there before lunch, then you have a problem depending on the situation.
Vabs plus 2 hours = +95% SOC, this is early in the day yet. Scenario that most users would consider ideal. Then it would float without (hopefully) having to cycle through Vabs again due to high demand or low sun, and even if it would cycle again, a lower end controller would then do what Mr Wiz does (increasing total Vabs time), and a higher end models would quickly transit to Float and stay there. I don't see any possible problem here.
BFL13 wrote:
The MPPT controller has a buck converter in it to "make amps", which it still does even when not in Bulk (tracking active). A PWM controller does not have the buck converter and "makes amps" a different way. Apples and oranges.
PWM doesn't increase the amps, it gives as many amps as there are available at that time of the day. It cuts the voltage off to setpoint, instead. (I was wrong earlier saying that "any" controller would do this - PWM won't increase Amps output, it simply gives all it has as long as battery accepts it).
MPPT "makes" amps out of this cut-off voltage and uses those amps to maintain whatever stage the controller is on. I don't think this matters (much), or if it does, then you guys have not enough solar.
My apologies for multi-quoting. Profound essay deserves detailed comments, no? :)
