BCS460 Fermentation Freezer Control Question

[clegg]

I'm getting ready to order my BCS460 for freezer temperature control, and eventually brew sculpture control as well. For fermentation control I plan to use a conical fermenter inside a standard upright freezer with both cooling and heating.

Here is the idea I have been considering but unable to find an answer to:

In terms of temperature control, is it possible to wire the BCS directly into the freezer circuitry instead of wiring to the external 110V power cord? To me the advantage would be being able to plug in multiple freezers away from my BCS instead of having to plug them all into a central control box. The only cabling that would need to run to each freezer is CAT5 cable. With multiple fermentation chambers and serving chambers and both hot and cold sources, that would save significant 110V external wiring hassle.

Freezers already seem to have two switched circuits (compressor and light) that the BCS could control or tap into. I'm guessing that freezers don't use 5V for signaling, so direct control is likely no possible. However, for cooling it seems you could bypass the installed thermostat and wire a relay directly that is controlled by the BCS. For heating I already plan to use a ceramic light bulb style heater. Since there is light bulb wiring in place with the freezer door switch, you change that to a ceramic bulb and wire a relay into that circuit for turning on and off the heater?

Has anyone considered going this route? Is there something I am missing for why this would not work? Everywhere I see online uses the usual Ranco or Johnson controllers to external 110V. I have that currently on my chest freezers, but am wondering if this would be a better solution.

[clearwaterbrewer]

I do not see why you could not do that

you want a small current in the control line, which says SSR
You want a pretty decent current spike for compressor startup, for which I think a contactor would be best.. but..

I guess you could us SSR if you can sink heat properly, maybe connect a heatsink *through* a flat surface on conduit box to the SSR with heat sink compound on both sides.
(try to keep some sort of separation between the LV and HV stuff inside the box, using. different entrances. )

If you have the factory shield in place, and use the SSR's with the plastic guard, you *may* find it OK to just screw the heatsink/SSR to something, run wires, and put the plastic cover on and the factory shield back on and be done with it, having Cat5 or whatever exiti8ng and going to your BCS..

-mike

[clegg]

Thanks for the reply. I received the freezer this week and am planning to tackle this over the weekend to see if it will work. I have 25A SSR's but did not purchase a heat sink so far. I am hoping to be able to screw the SSR's into metal of the freezer with heat sink paste and get enough heat dissipation. That is based solly on the text in the ECS store which says:

This heat sink is perfect for the Solid State Relays offered on this site. All SSR's require mounting to a heat dissipative surface, such as a metal enclosure. This is usually adequate for low current loads (such as pumps). However higher current loads require more heat dissipation. These heat sinks give added thermal protection for those applications.

If anyone has experience to suggest that I will / will not need separate heat sinks for this compressor application then I am interested and will purchase if needed.

I plan to have the BCS plugged into a normal power outlet located remotely and connected to the fermenter with cat 5 cable. Wiring plan is as follows:

Temp Probe: BCS Temp 0 --> Cat 5 wire 1 --> Temperature probe --> Cat 5 wire 2 --> BCS ground
Compressor Cooling: BCS Out 0 --> Cat 5 wire 3 --> SSR 5V side with high voltage side wired into compressor circuit --> Cat 5 wire 4 --> BCS ground
Reptile Bulb Heating: BCS Out 1 --> Cat 5 wire 5 --> SSR 5V side with high voltage side wired into light bulb circuit --> Cat 5 wire 6 --> BCS ground

Any feedback is welcome, especially with regards to wiring through the cat 5 or heat dissipation. I'll try to post pictures and details.

[clearwaterbrewer]

I think you will want to make sure you fasten and use heatsink compound to a 'smooth and unpainted' section of metal on the freezer, either textured or painted will not provide adequate capacity..