Newbie Question: Sourcing Capacitors

Electronics
#1

I need to make this repair to an Aerogarden

https://youtu.be/9UU7ohY7acg

So I will need 3 “25v 1500uf radial lead electrolytic capacitors”

I know how to solder wires but my electronics knowledge is spotty at best. I can watch a video about through hole but I do have 2 questions

  1. Do the capacitors need to be discharged before I touch them? If so how do I do that safely

  2. Is there a place to pickup 3 (or 6) of these capacitors in person so I don’t have to wait for shipping? My plants need light!

Thanks so much, if pictures of the board are needed let me know.

#2

Quick tip on capacitors. Bigger values are typically better, and for what looks like a simple unregulated power supply like that: The higher voltage the better (the more overhead for keeping them alive longer) and in this case more Farads (the uF part) is typically OK. Make sure you order them from a real electronics supplier not off ebay or even amazon.

Yes, but also in this case no. A capacitor can charge up to it’s full voltage rating, and voltages less that 60V are mostly safe. If you want to be extra careful just short the leads with something metal before soldering them into the circuit.

Order from Mouser.com would be my recommendation. They are in Mansfield Texas (in the greater DFW area) and will typically have very fast shipping once the item is actually picked and put on a truck. With COVID the delays haven’t been great but you should get them in a couple days. Also, you may try asking @artg_dms and see if he has any. He hoards things and could probably supply you some. If he can’t let me know and I’ll look in my stash as well.

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#3

I have no idea on scale.

Would 30v (or whatever they come in) and 2000uf make sense?

Thanks

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#4

In the ELab there are 2x black bins full of caps.Center island as you enter. Lower shelf on the right. I think one of them is marked “electrolytic”. You’ll know you have the right one when you pop the lid and there are plastic bags of caps w/ a value label in the bag. You can also parallel up smaller caps to get the final value you need. Parallel 3x 500 uF = 1500 uF. Assuming you have the room.

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#5

https://www.mouser.com/ProductDetail/United-Chemi-Con/EGXF350ELL202ML20S?qs=8BXZADTIn4HrZ9RvMZ949g%3D%3D

Would these work?

#6

Yeah, those should work. I would check the bin Art posted above though first. You can save yourself a few days in waiting and $10 potentially :slight_smile:

As high as you want to go on the voltage, it will “never” hurt because that voltage is mostly just the voltage it explodes above. If they’d physically fit 300V caps would work lol.

Try to stay somewhere in the 100% to 250% of the uF range. Like Art said you can add them in parallel so in your case you could use one beefy boy at 4500uF or 9 smaller 500uF ones in parallel. I would personally try to use at least two for ESR reasons but don’t worry about that.

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#7

If you have an existing circuit board for the caps to fit onto I would recommend you use a pair of calipers to measure the diameter and height of the cap and the lead spacing to make sure the one you are ordering will physically fit in the circuit.

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#8

A little late with this. Came to mind later than sooner. Temp rating is important. 85C and 105C
are the main ratings. Heat is the enemy of electrolytic caps. If your app gets hot, use the higher rated caps. If you can mod the enclosure to get more airflow, you will extend the cap’s op life.

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#9

Already ordered but I will check this, thanks