BB. wrote: »
Vmp~30 volt panels will not (properly/efficienty) charge a 24 volt battery bank...
A 24 volt battery bank needs >~29 volts to charge--And the Vmp in hot weather can fall by 10-20% (~30 volts * 0.8 = 24 volt Vmp). While the panels can charge (morning/evening & discharge battery bank, etc.)--It does not leave much room for wiring and controller voltage drops.
With 30 volt Vmp panels, an MPPT charge controller with 2-3 30vmp panels in series for a "high voltage" array--that is a good solution.
You can still use your 12 volt/true 24 volt array (Vmp>35 volts) with a (less expensive) PWM charge controller--And move your MPPT controller to the new non-standard battery Vmp voltage array.
Move the combiner box over to the array too--And you will have plenty of room for expansion.
No correct answers--Just options that can work fine. Do a couple paper designs for your ultimate system and see what would work best for you.
Cariboocoot wrote: »
The "true 24 Volt" panels are rapidly disappearing in favour of the 30 Vmp GT style. Usually they would be more than 150 Watts and less than 200 Watts, although not always. This is the only one NAWS has listed now: http://www.solar-electric.com/eoplly-ep125m-72-190w-monocrystalline-solar-panel.html
mark68 wrote: »
I dont have a specific panel chose yet but like that I could get 250 or even 300 watt panels in 24 volt vs 150 watt is as good as I have found in 12volt ...