mppt vs pwm
Hi, A nice little video comparing mppt vs pwm with the batteries in bulk mode. mppt vs pwm
Forum Discussion
If the battery wanted more it is there. the fact the battery is not taking it all means it would not help to create more headroom for making amps, unless you want to run more loads. The buck converter is still there, so just because you are in PWM does not limit you to panel Isc like with a PWM controller (no buck converter) Also, in Float the panel voltage is higher than Vmp.
The Isc at 14.8 is not still 8.2 You have to look at the IV curves for that model/brand panel to see what the Isc would be at various panel voltages. Should be 7.x amps and ready to drop off the cliff at 15v.
BTW 8.2 Isc rating is the same as for the 130w poly. 140/130 x 8.2 = 8.8 amps. The voltage must be a little higher with that panel so you get a lower Isc.
The MPPT controller goes back into Bulk when battery voltage drops to whatever, say 13.2v If the load demand in Float goes above what the battery is taking, you get more amps up to what the solar can do at the time. That will not lower battery voltage. You get the same thing with PWM and 12v for some "free solar" to do things. Good time to recharge the laptop for instance.
Once the load demand goes over what the solar can do, battery voltage will decline. "It depends" how long it takes for that to get down to 13.2 and kick the MPPT back on. So I don't think it has anything to do with the buck converter in/outs.
Salvo, that is a good diagram! The micro-controller does two things: MPPT and battery charge control. I was calling that micro-controller the "MPPT part" ahead of the buck converter and was asking if it did two jobs. Things are becoming more clear.
The Isc at 14.8 is not still 8.2 You have to look at the IV curves for that model/brand panel to see what the Isc would be at various panel voltages. Should be 7.x amps and ready to drop off the cliff at 15v.
BTW 8.2 Isc rating is the same as for the 130w poly. 140/130 x 8.2 = 8.8 amps. The voltage must be a little higher with that panel so you get a lower Isc.
The MPPT controller goes back into Bulk when battery voltage drops to whatever, say 13.2v If the load demand in Float goes above what the battery is taking, you get more amps up to what the solar can do at the time. That will not lower battery voltage. You get the same thing with PWM and 12v for some "free solar" to do things. Good time to recharge the laptop for instance.
Once the load demand goes over what the solar can do, battery voltage will decline. "It depends" how long it takes for that to get down to 13.2 and kick the MPPT back on. So I don't think it has anything to do with the buck converter in/outs.
Salvo, that is a good diagram! The micro-controller does two things: MPPT and battery charge control. I was calling that micro-controller the "MPPT part" ahead of the buck converter and was asking if it did two jobs. Things are becoming more clear.
