20 volt 18000 electrolytic capacitor

[rockhouse]

looking for a 20 volt 18000 electrolytic capacitor seems like they are like hens teeth
any suggestions
thanks for any info

 

[robertlucas1970]

looking for a 20 volt 18000 electrolytic capacitor seems like they are like hens teeth
any suggestions
thanks for any info

Do you not have room to fit a 35v or 50v as see a few of those on ebay.

 

[Paul]

Pardon our interruption...

 

[AlanJ]

ebay. get a 25v one or higher voltage as long as it’s rated higher voltage it will work fine.

i’ve only got 15,000 uf 25v ones, and a huge 30,000uf 25v one

 

[Fubar]

Maybe this? https://uk.farnell.com/epcos/b41231a5189m000/cap-18000uf-25v-alu-elec-snap/dp/3525294

 

[DanLewell]

Out of interest, does it matter if capacitance is higher as well, or do you need the right value for that, just voltage that can be higher?

 

[Paul]

Out of interest, does it matter if capacitance is higher as well, or do you need the right value for that, just voltage that can be higher?

Capacitance should be the same, the voltage should be the same or higher.... the higher the voltage rating usually the bigger the cap... (also linked to capacitance as well!)...

 

[rockhouse]

many thanks for the info

 

[rockhouse]

Pardon our interruption...

ouch

 

[Paul]

ouch

Also one thing to watch for... if NOS they might even need reforming depending on how old they are...!

Failing that, you could stick a couple of circa 8k in parallel at 25v.... https://uk.rs-online.com/web/c/pass...itor&applied-dimensions=4292048923,4294466465

 

[rockhouse]

Maybe this? https://uk.farnell.com/epcos/b41231a5189m000/cap-18000uf-25v-alu-elec-snap/dp/3525294

went with your suggestion many thanks

 

[rockhouse]

Also one thing to watch for... if NOS they might even need reforming depending on how old they are...!

Failing that, you could stick a couple of circa 8k in parallel at 25v.... https://uk.rs-online.com/web/c/pass...itor&applied-dimensions=4292048923,4294466465

thanks for the suggestions but went with fubars suggestion

 

[rockhouse]

thanks for all the help appreciated

 

[Andy_B]

Also one thing to watch for... if NOS they might even need reforming depending on how old they are...!

Failing that, you could stick a couple of circa 8k in parallel at 25v.... https://uk.rs-online.com/web/c/pass...itor&applied-dimensions=4292048923,4294466465

Paul, what is reforming?

 

[Paul]

Paul, what is reforming?

I'll quote this as i'm no expert

The electrolytic capacitor is a critical part of both old and modern electronic equipment which must be used correctly in order to get the longest and safest operational life and this is particularly important with high voltage versions of these components. Electrolytic capacitors rely on an electro-chemical process to provide the insulator between the two metal plates and this process can degrade over a period of years if the capacitor has not had power applied. The result is that the working voltage of any electrolytic capacitors in equipment gradually falls with time. If full power is applied to long unused equipment then the electrolytic capacitors can pass excessive amounts of current that could cause a catastrophic failure to the entire equipment and a potential fire hazard to the equipment and surrounding property.

The correct course of action is to ensure that each electrolytic capacitor’s insulation layer is ‘reformed’ by the application of a current and voltage limited DC supply to each individual capacitor. Current limiting ensures that the heat generated within the capacitor is kept at a sufficiently low level that damage does not occur. My preferred method is to carefully disconnect each electrolytic capacitor and apply a voltage, equal to the working voltage of the respective capacitor, via a suitable current limiting resistor to that capacitor.