Poly Brands

[v b chil-n]

I'm looking at ordering some caps from Digi-key for a busted thermostat and offered to get some poly's for a friend of mine. Are the nichicon poly caps as good as the United chemi cons offered here? He was planning on getting these RE50E821MDN1 to replace 11 rubycon MCZ 6.3v 1800uf.

[PCBONEZ]

Re: Poly Brands

If any of those MCZ are not in Vcore then using Poly isn't advised.
If they are in Vcore then those would be fine.

No difference between UCC and Nichicon for polys.
.

[v b chil-n]

Re: Poly Brands

Thanks, I only ask because Nichicon has 6 different series listed on digikey and I didn't see a part # for the UCC on Badcaps for a direct comparison.

[PCBONEZ]

Re: Poly Brands

When I say no difference between UCC and Nichicon for polys what I mean is quality, not specifications.
You have to look at data sheets to compare specifications.
.

[v b chil-n]

Re: Poly Brands

When I say no difference between UCC and Nichicon for polys what I mean is quality, not specifications.
You have to look at data sheets to compare specifications.
.

Yes I know that is why I said I could not locate the part # for the UCC to make a direct comparison. He is going on the half capacitance rule with a high ripple current and low ESR. I just noticed that the UCC are PSC series so the specs on the Nichicons seem a bit better, 6.3A ripple vs 6.1A for the UCC and 5.0 mOhm vs 7.0 mOhm for the ESR all other specs are the same.

[PCBONEZ]

Re: Poly Brands

The half capacitance rule was a kind of early idea when polys first started to become viable for us recappers.
More is known now.

If you look at enough boards that came factory with poly you'll see want is really needed is to keep total uF in the Vcore over about 5000uF.
Higher end boards tend to have something over 6000uF.
Servers sometimes have around 7000uF.

If you have 11 caps in that Vcore then 680uF or even 560uF would be good enough.
The 820uF might be cheaper though, in which case I'd still use them.

N/A in this case but:
The thing to watch out for is that when you cut it in half it doesn't take total uF in Vcore below about 5000uF.
I've seen some cheap junk boards [like AsRock] with as little as 4500uF but [as usual] they were unstable.
Personally I like to keep it over 5500uF.

-- And of course ALL of that above assumes you are lowering the total ESR also or it's so low to start with the uF change doesn't matter.
.

[v b chil-n]

Re: Poly Brands

The half capacitance rule was a kind of early idea when polys first started to become viable for us recappers.
More is known now.

If you look at enough boards that came factory with poly you'll see want is really needed is to keep total uF in the Vcore over about 5000uF.
Higher end boards tend to have something over 6000uF.
Servers sometimes have around 7000uF.

If you have 11 caps in that Vcore then 680uF or even 560uF would be good enough.
The 820uF might be cheaper though, in which case I'd still use them.

N/A in this case but:
The thing to watch out for is that when you cut it in half it doesn't take total uF in Vcore below about 5000uF.
I've seen some cheap junk boards [like AsRock] with as little as 4500uF but [as usual] they were unstable.
Personally I like to keep it over 5500uF.

-- And of course ALL of that above assumes you are lowering the total ESR also or it's so low to start with the uF change doesn't matter.
.

Thanks for the schooling it is much appreciated.