Wanted: Very large low-ESR capacitors

[Spasticteapot]

I'm looking for a pair of capacitors (or multiple pairs of smaller capacitors) of at least 20,000 uF, 45v, and a low ESR rating.

[Cloth Ears]

Hi ST,

What's 'low'? I've got some 33,000uF 105 63v caps which are rated as 6 milli-ohms at 100Hz and 5 milli-ohms at 100kHz. But I think postage would be too much to make it worthwhile.

[Spasticteapot]

Originally posted by Cloth Ears
Hi ST,

What's 'low'? I've got some 33,000uF 105 63v caps which are rated as 6 milli-ohms at 100Hz and 5 milli-ohms at 100kHz. But I think postage would be too much to make it worthwhile.

That would do it. However, you're right; postage is nasty from here to Aussieland.

Care to name the brand?

[Cloth Ears]

Rifa PEH169.

They're the older style, however, which means they're about 155mm high (add 10mm for clearance and screws to attach them). Also, I have been told that they need to be upright, as they are fluid filled and apprently can leak through the emergency vent if they get warm. This does limit their application.

But we (or rather a friend) tested them recently and they're still 'sound and sweet'. In fact, he forgot to discharge them after the last charge-up to 20v, and a week later you can still melt a set of keys between the terminals, .

I did look up the postage, and it's AU$46.50 (about $41.55 in your money) for airmail for 2kg - they're about 800 grams each. This would double the cost for you. So if you can find equivalent ones, then I'd go with them.

I've decided that I'm not scared of passive electricity - but that mains stuff scares me. So I'm going to divest myself of what I've purchased. But only here in Aus due to postage concerns...

[woody]

Apex jr has some Hitachi 47,000 mfd 100v caps for $17.50 and some 63,000 mfd 100v caps for $25 each. www.apexjr.com
He is a nice fwlow to deal with.

[Spasticteapot]

Originally posted by woody
Apex jr has some Hitachi 47,000 mfd 100v caps for $17.50 and some 63,000 mfd 100v caps for $25 each. www.apexjr.com
He is a nice fwlow to deal with.

Are they low ESR?

[Conrad Hoffman]

Very large capacitors are inherently low esr, but also inherently not great at high frequencies. Reverse your question and pretend you're looking for very large high esr caps. Not much to be found!

[Pocoyo]

I think Rifa is the best caps for PSU
you can try it

Cloth ears do you have 80v or 100v?

[gootee]

Looking in the http://www.mouser.com 1854-page catalog, I see CDE's DCMC line with 26000 uF 50v (63V surge) with 18.7 mOhm ESR @ 120 Hz for $23.33 qty 1. Mouser number is 598-DCMC50V263. (You could search for 598-DCMC to see all of them.)

They also have United Chemi-Con KMH-series 10000 uF 63V 105degC with ESR 25 mOhm @ 120 Hz, for $5.72 qty 1. Mouser number is 661-KMH63VN103M.

They also have UCC's SMH series, which has an 18000 uF 50V with ESR 18 mOhm @ 120 Hz, for $10.46 qty 1.

There are quite a few others that might be good. But those had the ESR listed.

- Tom Gootee

http://www.fullnet.com/~tomg/index.html

[Spasticteapot]

Originally posted by gootee
Looking in the http://www.mouser.com 1854-page catalog, I see CDE's DCMC line with 26000 uF 50v (63V surge) with 18.7 mOhm ESR @ 120 Hz for $23.33 qty 1. Mouser number is 598-DCMC50V263. (You could search for 598-DCMC to see all of them.)

They also have United Chemi-Con KMH-series 10000 uF 63V 105degC with ESR 25 mOhm @ 120 Hz, for $5.72 qty 1. Mouser number is 661-KMH63VN103M.

They also have UCC's SMH series, which has an 18000 uF 50V with ESR 18 mOhm @ 120 Hz, for $10.46 qty 1.

There are quite a few others that might be good. But those had the ESR listed.

- Tom Gootee

http://www.fullnet.com/~tomg/index.html

Wow, thanks!
The United Chemi-Con KMH series 10,000uf caps look like both the best deal and the best capacitors. Three in parallel would give a total of 30,000uF at about 9 mOhm, at only $15.

What a deal!