# WTH Helpers can do calculus but not arithmetic?!?

Ok, so part of the problem is that your points aren’t in order

Ok, so this list of data should work…

a b
0.0095 0
0.49 410
0.63 530
2.67 2230
3.05 2620
3.29 2850
3.81 3380
4.23 3770
4.61 4120
4.9 4420
5.07 4610
5.11 4670
5.19 4780
5.25 4850
5.28 4970
5.31 5050
5.38 5210
5.42 5230
5.43 5220
5.43 5250
5.45 5300
5.48 5390
5.49 5330
5.49 5400
5.5 5420
5.52 5560
5.58 5630
5.65 5720
5.73 6050
6.094 8200

with 6th order

Thanks, I will give that a try.

Here’s the whole thing

``````compensation:
estimated_pv_panel_power:
source: sensor.small_solar_panel_voltage
unique_id: estimated_pv_panel_power
precision: 0
unit_of_measurement: W
degree: 6
data_points:
- [0.0095, 0  ]
- [0.49, 410  ]
- [0.63, 530  ]
- [2.67, 2230 ]
- [3.05, 2620 ]
- [3.29, 2850 ]
- [3.81, 3380 ]
- [4.23, 3770 ]
- [4.61, 4120 ]
- [4.9, 4420  ]
- [5.07, 4610 ]
- [5.11, 4670 ]
- [5.19, 4780 ]
- [5.25, 4850 ]
- [5.28, 4970 ]
- [5.31, 5050 ]
- [5.38, 5210 ]
- [5.42, 5230 ]
- [5.43, 5220 ]
- [5.43, 5250 ]
- [5.45, 5300 ]
- [5.48, 5390 ]
- [5.49, 5330 ]
- [5.49, 5400 ]
- [5.5, 5420  ]
- [5.52, 5560 ]
- [5.58, 5630 ]
- [5.65, 5720 ]
- [5.73, 6050 ]
- [6.094, 8200]
``````

How did you select which data points to use, and the order?

I just sorted the points, deleted the ones that were way off from what you wanted, then chose a polynomial order that fit close to what you wanted. I used Excel.

It looks to be behaving. The output isn’t going wild. I will have to check tomorrow when there is sun light to see how well the estimator output tracks the actual PV array output.