PWM controller question
I'm looking at the following panels, which are too big for indoor storage, but I think I have a viable plan for side mounting them http://2solar.ca/product/12v-140-watt-pv-solar-panel/ And I'm l...
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I have that same el cheapo model PWM controller, and I did some logging with it. It has the cr*ppiest charge algorithm I have ever seen for PWM charging. It chokes down the voltage and the amperage on 3 out of the every 4 or 5 cycles per second to your batteries. By dropping the voltage so much, and the amps, your batteries take for ever to get even closed to topped off.
The Solar 30 is a much better unit. Recently, for S&Giggles, I bought this 20 amp PWM unit on Amazon. The display seems to me to be more useful, but I want also to have a useful PWM algorithm that actually doesn't drop the V and Amps as much as the el Cheapo you are considering. It's coming on a slow boat from china, but I will have it hooked up to a 150w 8.8A at 18.0V solar panel.
When looking for panels for PWM controllers, you are probably better off with a panel that makes only 17.0V at max power, and instead is putting out more amps. This is because the PWM controller pretty much controls the V out to your batteries, and that is where the loss is with PWM, so if you have less voltage loss from V max to your bulk charge voltage setting, say 14.8V or 15.0V, you yield more amps, since it's V x Amps that makes watts. To make the same watts, drop the V output and the A output from the panel is increased. So always look for the highest Isc rating on any panel you are hooking up to a PWM controller. 17.0V is plenty.
20Amp PWM charge controller for solar.
I would not hesitate to buy the Solar 30. In fact, with that little bit of surplus voltage it has over stated on the gauge, in my case 15.0 comes out at 15.3 at the battery, you just might be able to go with a little bit thinner wire from the charge controller to the batteries, to engineer in some voltage loss through that last run of cables from controller to battery!!!! In other words, pick a smaller gauge of wire that will give you 0.3V loss for the length of run of copper wire from Solar 30 to batteries... you get to buy cheaper wire too for the last run or wiring!
The Solar 30 is a much better unit. Recently, for S&Giggles, I bought this 20 amp PWM unit on Amazon. The display seems to me to be more useful, but I want also to have a useful PWM algorithm that actually doesn't drop the V and Amps as much as the el Cheapo you are considering. It's coming on a slow boat from china, but I will have it hooked up to a 150w 8.8A at 18.0V solar panel.
When looking for panels for PWM controllers, you are probably better off with a panel that makes only 17.0V at max power, and instead is putting out more amps. This is because the PWM controller pretty much controls the V out to your batteries, and that is where the loss is with PWM, so if you have less voltage loss from V max to your bulk charge voltage setting, say 14.8V or 15.0V, you yield more amps, since it's V x Amps that makes watts. To make the same watts, drop the V output and the A output from the panel is increased. So always look for the highest Isc rating on any panel you are hooking up to a PWM controller. 17.0V is plenty.
20Amp PWM charge controller for solar.
I would not hesitate to buy the Solar 30. In fact, with that little bit of surplus voltage it has over stated on the gauge, in my case 15.0 comes out at 15.3 at the battery, you just might be able to go with a little bit thinner wire from the charge controller to the batteries, to engineer in some voltage loss through that last run of cables from controller to battery!!!! In other words, pick a smaller gauge of wire that will give you 0.3V loss for the length of run of copper wire from Solar 30 to batteries... you get to buy cheaper wire too for the last run or wiring!
