mppt or pwm An opinion from Victron
Hi all, Victron, which makes high quality equipment, has charge controllers. At the end of an overview they give their description of the differences between PWM and MPPT. They do not support it wi...
Forum Discussion
Hi,
I would surprized to see a panel temperature much higher than 45 C (113 f) in low light conditions. Their definition of low light is 1/5 of STC test conditions or an irradiance of 200 compared to 1000.
If you read the entire white paper you will find they say that between 45c and 75c that pwm and mppt perform more or less the same. Below and above those numbers MPPT has an edge. Since BFL13 has measured 51 C at an ambient of 25 c I'd not be surprized at all to see panel temperatures above 75 C when it is 40 C ambient.
My interpretation of the reason for high temperatures is that pwm panel voltage may be below the 14.8 volts needed to complete the charging on a lead acid jar. That can not happen with MPPT because voltage drop is not going to be from 34 down to 14.8 EVER (maybe on Venus?).
They are also of the opinion that with 12 volt batteries pwm for small wattage systems is probably the way to go. But with larger wattage (and amperage is of course higher) then MPPT comes into its own.
They make both pwm and mppt controllers, so they have no reason for a bias to one type or the other. I don't think they are hiding anything.
I would surprized to see a panel temperature much higher than 45 C (113 f) in low light conditions. Their definition of low light is 1/5 of STC test conditions or an irradiance of 200 compared to 1000.
If you read the entire white paper you will find they say that between 45c and 75c that pwm and mppt perform more or less the same. Below and above those numbers MPPT has an edge. Since BFL13 has measured 51 C at an ambient of 25 c I'd not be surprized at all to see panel temperatures above 75 C when it is 40 C ambient.
My interpretation of the reason for high temperatures is that pwm panel voltage may be below the 14.8 volts needed to complete the charging on a lead acid jar. That can not happen with MPPT because voltage drop is not going to be from 34 down to 14.8 EVER (maybe on Venus?).
They are also of the opinion that with 12 volt batteries pwm for small wattage systems is probably the way to go. But with larger wattage (and amperage is of course higher) then MPPT comes into its own.
They make both pwm and mppt controllers, so they have no reason for a bias to one type or the other. I don't think they are hiding anything.
red31 wrote:
IV and power curves :B
Comment: They use a 45C temp for their low light conclusion :h
The white paper supports free standing portables for those so inclined :C
