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electrical:solar:pwm_tweaking [2019/07/17 08:20] frater_secessus [set Vabs and Vfloat relatively high] |
electrical:solar:pwm_tweaking [2023/11/19 16:16] frater_secessus [PWM's achilles heel] |
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- | ===== the controller's achilles heel ===== | + | ===== PWM's achilles heel ===== |
- | During charging with a PWM controller **the solar panel will be running at the voltage of the battery bank**. | + | During charging with a PWM controller **the solar panel will be running at the voltage of the battery bank**.((or close enough for the purposes of this discussion. |
This affects charging in all three [[electrical: | This affects charging in all three [[electrical: | ||
- | {{ http:// | + | {{ http:// |
17.8v x 5.6A = 99.68w <-- rating under laboratory conditions \\ | 17.8v x 5.6A = 99.68w <-- rating under laboratory conditions \\ | ||
- | 17.8v x 5.6A = 94.70w <-- MPPT running at 95% efficiency \\ | + | 17.8v x 5.6A = 94.70w <-- MPPT running at 95% efficiency |
+ | |||
+ | PWM harvest | ||
14.8v x 5.6A = 82.88w <-- power at a high Absorption voltage, as with flooded lead acid \\ | 14.8v x 5.6A = 82.88w <-- power at a high Absorption voltage, as with flooded lead acid \\ | ||
14.4v x 5.6A = 80.64w <-- power at a lower Absorption voltage \\ | 14.4v x 5.6A = 80.64w <-- power at a lower Absorption voltage \\ | ||
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12.7v x 5.6A = 70.61W <-- power at 100% state of charge (SoC) \\ | 12.7v x 5.6A = 70.61W <-- power at 100% state of charge (SoC) \\ | ||
12.4v x 5.6A = 69.44W <-- power at 75% state of charge; bulk charging \\ | 12.4v x 5.6A = 69.44W <-- power at 75% state of charge; bulk charging \\ | ||
- | 12.1v x 5.6A = 67.76W <-- power at 50% state of charge; | + | 12.1v x 5.6A = 67.76W <-- power at 50% state of charge; |
+ | 10.0v x 5.6A = 56.00W <-- battery bank accidentally run flat | ||
This last number shows how far off PWM output can fall when battery voltage (Vbatt) is at its lowest.((The last number is also the source of the "30% boost!!!" | This last number shows how far off PWM output can fall when battery voltage (Vbatt) is at its lowest.((The last number is also the source of the "30% boost!!!" | ||
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Note: consult the battery manufacturer' | Note: consult the battery manufacturer' | ||
+ | DO invest in the $10 temperature probe option. | ||
==== battery: maintain a higher state of charge ==== | ==== battery: maintain a higher state of charge ==== | ||