high-voltage mppt controllers?
I'd like to mount two 260-290 watt panels on my TT, rather than several smaller more expensive 100-150w panels. What controllers are popular these days, for high cell count panels (60 to 72 cells p...
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The idea of using multiple inexpensive controllers is interesting - do they network? I can see bulk charge working fine, but voltage dependent absorb / float modes, won't they sense each others voltage and flip/flop on and off? "
Can't say on all of them, but like any time there are two or more chargers on a battery, they share their amps best when each is at the same voltage. So it is best to have the same model controllers, but not necessary to get results.
They don't need to network but that might be a way used to better get them acting the same for voltage and charging profile.
I had two LandStar LS2024 20a PWM controllers on one battery bank where each controller was on a different sized 12v array. One did 12a and the other 8a and the total was 20a as seen on the Trimetric. It acted just like one controller, you couldn't tell it was two.
Another aspect for Absorption and Float is that by then, your battery acceptance rate in amps is so low that one set of panel/controller could do it all anyway, even if it happened that one controller was at lower voltage than the other so it had dropped out of play by then.
These were "series" type controllers, not "shunt" type. With shunt type you have that on/off shorting of the panel where perhaps two of them could get out of synch, don't know. Each has its own panel anyway in this idea. With the series type that did not arise. MPPT controllers AFAIK are sort of bucked up series types---somebody maybe can confirm/deny that ????
Wiring two controllers. I tried two ways, both worked. One is each controller has own wires to battery. Second way is to put a Y at the array end of a single fatter wire to the battery. Each controller is on its own array and then goes to its own leg of the Y. It all comes out the same at the battery end for total amps. (You can't tell which controller is doing what amps unless you had a clamp- on ammeter and did each leg of the Y before it becomes one wire to the battery)
Can't say on all of them, but like any time there are two or more chargers on a battery, they share their amps best when each is at the same voltage. So it is best to have the same model controllers, but not necessary to get results.
They don't need to network but that might be a way used to better get them acting the same for voltage and charging profile.
I had two LandStar LS2024 20a PWM controllers on one battery bank where each controller was on a different sized 12v array. One did 12a and the other 8a and the total was 20a as seen on the Trimetric. It acted just like one controller, you couldn't tell it was two.
Another aspect for Absorption and Float is that by then, your battery acceptance rate in amps is so low that one set of panel/controller could do it all anyway, even if it happened that one controller was at lower voltage than the other so it had dropped out of play by then.
These were "series" type controllers, not "shunt" type. With shunt type you have that on/off shorting of the panel where perhaps two of them could get out of synch, don't know. Each has its own panel anyway in this idea. With the series type that did not arise. MPPT controllers AFAIK are sort of bucked up series types---somebody maybe can confirm/deny that ????
Wiring two controllers. I tried two ways, both worked. One is each controller has own wires to battery. Second way is to put a Y at the array end of a single fatter wire to the battery. Each controller is on its own array and then goes to its own leg of the Y. It all comes out the same at the battery end for total amps. (You can't tell which controller is doing what amps unless you had a clamp- on ammeter and did each leg of the Y before it becomes one wire to the battery)
