CapXon UJ series aluminum electrolytic capacitors

9.2 Selection improvement

Replace with CapXon UJ series UJ681M450P500A (680 µ F/450 V/35 × 50 mm), with a rated ripple current of 2580 mA @ 105 ℃, much higher than the original product's 1900 mA. Moreover, the useful life of UJ series is 5000 hours @ 105 ℃. According to the doubling of life for every 10 ℃ decrease in temperature, the theoretical life at 78 ℃ exceeds 5000 × 2 ^ ((105-78)/10) ≈ 5000 × 2 ^ 2.7 ≈ 5000 × 6.5 ≈ 32500 hours, and the actual use can reach more than 5 years.

9.3 Transformation Results

After replacement, the surface temperature of the capacitor on the charging pile decreased by 3 ℃ at the same ambient temperature (due to lower ESR reducing self heating), the ripple voltage decreased from 12 Vpp to 8 Vpp, and the overall efficiency increased by 0.2%. It has been running for 3 years now and there have been no capacitor failures.