Polaris DI (FICHT) 4010198 Capacitor Substitution

[bfarnam]

Thought I would share this:

I don't see a lot of failed capacitors but they can and do fail in a variety of ways. Another member on the board suspected that he had a bad one and yet another member stated that the terminals loosened and arced pretty good.

The OEM Part Number 4010198 is no longer available.

However, this is a currently produced part: United Chemi-Con Part Number E36D630HPN393MC92M (39,000uF, 63v, 8.7mOhm ESR, 11.62A Ripple Current) is the OEM capacitor but is usually not stocked by Mouser or Digikey.

This is part of their U36D series capacitors.

There are a variety of substitutions available with equivalent or compatible specifications besides just the voltage or capacitance. It is important to note, you can increase the voltage or increase the capacitance slightly as these are used just as "power" storage for the surges in the system from the firing of the injectors. However, other parameters must be more closely matched. Additionally, you want to stay at the OEM diameter of 2 inches and the same type of terminals if you want to easily swap it out.

I recommend the United Chemi-Con Part Number E32D630HPN393MC92M (39,000uF, 63v, 9.1mOhm ESR, 20.62A Ripple Current) which is the the same as the OEM except that it has a higher temperature rating (+105c vs +85c). This is available on Mouser for $20.



EDIT:
Another recommended substitution that is stocked:
United Chemi-Con PN E36D800LPN393MCA5M 39000uF, 80v, 6.3mOhm ESR, 16.65A Ripple Currently available on Mouser or Digikey for approx $22

EDIT:
Added U36D Datasheet

[martincom]

Thank you for sharing Bret!

I've seen a few posts about the connecting screws working loose, but I've yet to hear of that capacitor actually failing. I suppose, it is inevitable as age is a failure factor with electrolytics and a number of these have past the 20 year mark.

Another spec I considered when sourcing replacement electrolytics within the EMM was operating hours. Was there any significant difference between the two you suggested?

[bfarnam]

Both United Chemi-Con have a rated lifetime of 2,000 hrs at the rated temperature and rated ripple current. However, Capacitors are very temperature temperamental and I would never have specified a 85c cap in a marine environment - in the hot sun I am sure the cap just bakes in there . . . LOL

[martincom]

Yup and if memory serves me correctly, that is exactly the temp rating of those that fail within the EMM.