Hardware > Lynx SSR4

How many amps per channel and is a heatsink needed?

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jwilliams31:
I've been going through the different posts and I see some that say that the SSR4 can do 1 amp per channel and 2 with a heatsink.  Then I've seen posts that say they can do 2 amps without a heatsink.

So my question is do I need to add a heatsink to run 2 amps per channel.

Also, just for clarification, 1 amp is about 300 mini-lights, correct?

Thanks.

Jason

aERonAUtical96:
The rule of thumb I've used is 1 amp/channel=no heatsink, 2 amps/channel=heatsink.

While you probably can get aways w/o putting a heatsink on for 2 amps, why not just do it to be safe.  I would think that if someone is hitting 2+ amps / channel w/o a heatsink, then they might not be doing it on a high load (continuous) basis, ie hit that channel once every 20-30 seconds vs all on all the time (hope that makes sense).

You really need to look at the amperage of the string.  I have 100 count, "energy efficient" strings that are .20/.24 amps vs .33-4.  So I can get 4 / channel.  Take a look at the string on the safety sticker and it should tell you what the amperage is.

dmaccole:
The BTA06-600SRG that RJ calls for in the SSR4 BOM are six-amp, 600-volt TRIACs, which would mean that you could run up to three amps through them without a heat sink.

You probably don't want to run more than three amps through them regardless, as I believe the copper traces aren't rated any better than that.

So a heat sink is not necessary.

And you probably should always measure your light strings to determine their draw, rather than relying upon rule-of-thumb or even packaging claims. The Kill-a-Watts are running $15-$17 these days on-line (w/o shipping) and well worth the investment.

\dmc

jwilliams31:
Thanks for the info.  I would prefer not to put too much load on them, it's just that this year I have more lights than channels so I wanted to see how much I can get on there so I can at least have all of my lights controlled.

RJ:
They are not rated for three amps without a heat sink.

To220 packages can only handle so much with out a heatsink. They do not have enough area to move more heat so a to220 triac rated at 3 amps and one rated at 8 amps still is limited by its package to roughly the same current limit. To handle the higher currents requires a better heatsink. The difference is the 3 amp can not handle higher no matter what heat sink you put on it and the 8 can.

Run them at 1 amp without heatsink and while they will most likely survive 2amps with out I would recommend if you want that much current running a heatsink.

If you do use the thinest aluminum angle you can find. Too thick will run the wires and thickness is not what cools the triac it is the area so big area thin is what you want.

RJ

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