STC 3008 12 volt wiring

[Zambi]

I'm clearly not an electrical whizz kid..
I need some help with the wiring.

This is the little manual

I only want to connect my 12 volt fridge
I think it needs to be wired like the 2nd option in my childish drawing
Am I right?

This here is the actual controller
(Ignore the written bit)

 

[Limey]

Looks to me like that should work!

 

[Minbari]

Yup, that is how you would wire it. Just make sure that your load (fridge) doesn't exceed 10A or you will melt the relay

I usually wire an external relay just to protect the STC.

 

[Zambi]

Thanks.
The fridge is 10 amp, I think.
I'll double check

So it goes from solar panel to charge controller
Stc wired into the charge controller and fridge into the stc.
I have no idea where to get an external relay and how to wire it in. Do you think it is really necessary @Minbari ?

It's actually a chest fridge/freezer/chiller
Should I set the thermostate on the fridge as cold as can be (which is freezer setting)?

 

[Donoroto]

This assumes your freezer is 12v, correct?

As for a relay: get one at an automotive parts store. It is controlled by 12 volts, and ask for one rated at 20 amps or more. Should not be expensive, 10 euros or so. Let me know if you want more info.

 

[Limey]

I presume your charge controller is connected to a 12v battery, if not, it needs to be. You should be able to get a suitable relay (SPST) from an auto parts store - they are very common. Wire the output from the STC to the relay, and the relay contacts operate as a switch in the positive 12v line. I can draw a diagram if you get stuck!

Yes, you should set the fridge 'stat to the coldest setting.

 

[Limey]

 

[Minbari]

Thanks.
The fridge is 10 amp, I think.
I'll double check

So it goes from solar panel to charge controller
Stc wired into the charge controller and fridge into the stc.
I have no idea where to get an external relay and how to wire it in. Do you think it is really necessary @Minbari ?

It's actually a chest fridge/freezer/chiller
Should I set the thermostate on the fridge as cold as can be (which is freezer setting)?

I do think it is, if your fridge draws 10A, there is zero room for error.
Basic automotive relay would work, wire it just like @Limey drew up.

Just like these
https://a.co/d/1osznOy

 

[Minbari]

Do both relays come on at the same time or one for heat and one for cold?

 

[Zambi]

It is a 12 volt fridge and I will only operate the fridge for now, but there is room for a heater as well, seperately wired.

Thanks for the relay info. I'm sure I can find those. Maybe not close to me, but definitely when I go to town
Or maybe I can get someone to bring me one.
Would this one work https://www.amazon.nl/Bosch-0332019...=1733508140&sprefix=12+v+relay,aps,614&sr=8-4

 

[Limey]

It is a 12 volt fridge and I will only operate the fridge for now, but there is room for a heater as well, seperately wired.

Thanks for the relay info. I'm sure I can find those. Maybe not close to me, but definitely when I go to town
Or maybe I can get someone to bring me one.
Would this one work https://www.amazon.nl/Bosch-0332019150-Operating-Temperature-Closing/dp/B004Z0W1LM?crid=330JG152VTX5V&dib=eyJ2IjoiMSJ9.-VMM9IvMJ86__6PQztqsB96HutYRv8tRjjg410syEutSO-aAAvYU-y90uLHY_Q1xkkkqcyU13KYuG9nf1M_nIQQB-7P0sUG85kN3kbptWf35qNkjyyDyMGRRUCBkw8KVV78g78G4PiuK-1M1ujKb3SPi9pN5ehzjhwJ7xQrgvoMkTU9p1Uge4iDNS9h6NTr6Lr3JOrJ0nGdeW3TasQZlmQ.oyHNNCjoyTOGrZnqpT-Ek6h_rUhSBncyqOHzHxKPoko&dib_tag=se&keywords=12+v+relay&qid=1733508140&sprefix=12+v+relay,aps,614&sr=8-4

That's exactly it! They are commonly referred to as "Bosch" relays, but there are many variations that are the same form factor. You can typically get them at any auto parts store.

 

[HighVoltageMan!]

View attachment 30875

This is the best way to hook that up. The relay on the controller is rated for 10 amp AC. The rating for DC would normally be lower (AC at some point will go to 0 volts during the cycle which means less arching when breaking a load). By putting in the automotive relay you will be assured the relay can handle the current and it will keep your controller from switching too much DC current. In other words, the relay protects the controller.

 

[Zambi]

OK
Did a double check
Solar charge controller is 20 amp
Temp controller 10 amp
Chest fridge/freezer is 6 amp

Now shouldn't a relay in between the charge controller and the temp controller be 10-20 amp?

 

[Minbari]

OK
Did a double check
Solar charge controller is 20 amp
Temp controller 10 amp
Chest fridge/freezer is 6 amp

Now shouldn't a relay in between the charge controller and the temp controller be 10-20 amp?

The ones we recommend are 30A

 

[Zambi]

OK, I'll find a 30 amp one

 

[Donoroto]

OK
Did a double check
Solar charge controller is 20 amp
Temp controller 10 amp
Chest fridge/freezer is 6 amp

Now shouldn't a relay in between the charge controller and the temp controller be 10-20 amp?

More amps means more capacity, it can handle up to ‘30’ amps. Or 1/2 amp. But a 10 amp relay would not last very long. A 20 amp would be fine, but get a spare.