Programmable fridge...... how can anyone live without one!!

@GHA re the INA219 What is the highest Amps your likely to measure on the fridge consumption? 8A? From your other message;

If so 8A/0.04ohm = 0.32v

Or higher?

I am struggling a bit with jlcpcb to see which components are in their basic range.

I've just taken the 2 surface mount sense resistors off one of the other boards and soldered them on top of the ones on the main board so now it's 4 * 0.12Ohm in parallel , or around 0.03Ohm which seems OK

Seems to have worked, initially with the same calibration constant the current reading pretty much halved, so doubled the calibration and it seems OK on the 2 runs on the right , last short run was at highest revs so looks like about 6A max. I'd be temped if ordering again to make the sense resistance even lower, the INA chip has a high quality amplifier built in so can get accurate current readings from a very low voltage drop.


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Might be easier searching for the components on the jlcpcb page instead of easyeda then copy the part number and search to that in the easyeda library >
PCB Prototype & PCB Fabrication Manufacturer - JLCPCB
These are the ones I used > PCB Prototype & PCB Fabrication Manufacturer - JLCPCB

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Thinking now that the control could just be one transistor connected to the ESP deducated DAC pin, I assumed from the info online that there just 4 different revs available but suspect that's assumptions for you ;)
Will have a play.

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glad you got it working @GHA

I am not familiar with running the compressor at different revs. Are you hence replacing the whole black box of standard fridge electronics or just the thermostat connection? I thought the later was just a straight switch.
 
if you check the Danfoss literature you'll realise that you can fit 2 resistors between different wires of the el.box in order to alter comp speed and also cut-off voltage.
Cannot really remove the el.box, fridge wont run fullstop.
 
greg, at the side of the compressor there's going to be a box approx 80X100X40mm with a series of spade terminals. may be covered with a plastic or metal casing but on top of the + - Vin terminals (the two topmost) there's going to be a stamped model #, search Danfoss for that and you'll come up with all the details.
The above assumes that your isotherm does indeed use a Danfos BD35 (or 50?) compressor, ignore else!
 
Says man who hates cold beer.
A cold rosé is a more than acceptable substitute.

All this raspberry pie stuff goes way over my head. The best thing I ever did with raspberries was when I came across several boxes that had been dumped as too ripe at a wholesaler. The wine I made was delicious. Think Port, but raspberry flavoured
 
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glad you got it working @GHA

I am not familiar with running the compressor at different revs. Are you hence replacing the whole black box of standard fridge electronics or just the thermostat connection? I thought the later was just a straight switch.
Just did a quick schematic >
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The compressor EU controller measures the current going through the thermostat and will alter the compressor revs based on that reading, at the moment I've 3 transistors on the circuit board with resistors in series but thinking now it might be better just to have one transistor right next to the EU controller and use that so hopefully the current is less with no drop along the cable. Just tried croc clipping across the thermostat lugs with a short lead and the power goes down so it is possible to run it slower than the new board can achieve.
That will be todays playtime between the countless other jobs on the list :cool:




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I'm sorry - but I now understand why some don't like anchor threads.

However I am not complaining and am just grateful that some people while away their remaining hours on arcane projects.

Sailing to me was about harnessing the elements to get from A to B and then anchoring (ts really very simple if you ignore the fear factor engendered by so many) having a really good meal, a decent drink (or three). If it been physically challenging I count the digits, I tend to start with 10 and always finish with the same number. Maybe an exciting game of Scrabble, hot shower, tour the domain - and then bed.

Fear of anchoring really pales compared to the nightmares some must have.

But each to their own - nice to have a fetish or two. It would not do if we were all the same.

But maybe we live in some sort of alternate universe

Jonathan
And how do you heat the water for the shower? That was my arcane project last year - I can’t think of one this year yet, but I haven’t been able to get to the boat for 10 months so I suspect there will be lots of fixing jobs to do instead.
 
The compressor EU controller measures the current going through the thermostat and will alter the compressor revs based on that reading, at the moment I've 3 transistors on the circuit board with resistors in series but thinking now it might be better just to have one transistor right next to the EU controller and use that so hopefully the current is less with no drop along the cable.
For those born inquisitive >>

Transistor looks like it works OK but seems like there might actually just be a few distinct revs available as the current in the thermostat changes need to have a better look at it, just over 2mA the compressor stops, and thermostat current never goes above about 5mA . Also seems like it ramps up or down over a few seconds when the thermostat current changes. In between we get this >>

10mHFAT.png
 
And how do you heat the water for the shower? That was my arcane project last year - I can’t think of one this year yet, but I haven’t been able to get to the boat for 10 months so I suspect there will be lots of fixing jobs to do instead.

We use a domestic, on demand, gas boiler, Bosch, vented into the cockpit. Plumbed into the fresh water supply. It might be a more difficult installation in a monohull. Our saloon and cockpit sole are at the same level and the boiler sits just inside the French doors against the cockpit/saloon bulkhead - it simply vents through the bulkhead with a cowl. It runs off a conventional pilot light but we only have the pilot light on when we need the hot water. Its been perfectly satisfactory for 20 years, or so. It has a separate gas isolation 'tap', the other run of gas pipework also tapped, supplies the galley. The boiler sits in an aluminium box and the whole lot inside the moulding for the saloon.

Jonathan

apologies to GHA for the slight drift from refrigeration to hot water.....! :)
 
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Neeves, curious, what's the consumption like? you obviously don't have the 3lt small bottles I carry for hob/oven...

Rupert, I'm on the same line, bought a 40lt (or 60 don't remember) boiler (engine/1850W element), struggling to fit it somewhere I like atm, but plan is to use excess solar in early afternoon to heat some water
 
Rupert, I'm on the same line, bought a 40lt (or 60 don't remember) boiler (engine/1850W element), struggling to fit it somewhere I like atm, but plan is to use excess solar in early afternoon to heat some water
It works well and doubled our solar output from about 1kw to 2. The main thing to ensure is that you get to absorbtion by lunchtime without water heating. If you don’t then you may not have enough spare solar to do the job.
 
Neeves, curious, what's the consumption like? you obviously don't have the 3lt small bottles I carry for hob/oven...

Rupert, I'm on the same line, bought a 40lt (or 60 don't remember) boiler (engine/1850W element), struggling to fit it somewhere I like atm, but plan is to use excess solar in early afternoon to heat some water

We use 8kg bottles and for 3 months carry 2. I confess we don't know what consumption is but it cannot be much as the 2 x 8kg last 3 months. 2 x showers per day each, cooking for 3 months for 2 - and we are not camping! :)

WE like the boiler for I think the reasons implied - you don't need to run the engine (which would be daft when you are sailing fast enough to power the cat with a towed hydro gen) or if you are at anchor and have plenty of solar power.

You mention 'spare solar' - what does this mean, or what are the implications

Jonathan
 
I manage very well without a fridge at all. Beer and Wine keep cool in the bilges. Tinned food doesn't need refrigeration and there's always powdered milk for when the bottled cow goes manky.
 
I manage very well without a fridge at all. Beer and Wine keep cool in the bilges. Tinned food doesn't need refrigeration and there's always powdered milk for when the bottled cow goes manky.

You can still buy powdered eggs (and long life milk), butter in tins (salted only), grow your own bean sprouts, catch fresh fish, mussels, oysters, crayfish, bake fresh bread, make yogurt from packs (EasiYo) and, some, fruit keeps well as do some veg. I prefer a decent whisky at room temperature - but it is nice to have ice in the gin at the end of a hot day sailing (so we do have a fridge - but its not really big enough for 3 months).

Jonathan
 
glad you got it working @GHA

I am not familiar with running the compressor at different revs. Are you hence replacing the whole black box of standard fridge electronics or just the thermostat connection? I thought the later was just a straight switch.
Replying on behalf of GHA. He sent me a WhatsApp message asking me to post this as a reply to #23
"Greg, GHA has left the building!, all the negativity & petty squabbling go too much. The github page has a discussion tab now if you (or anyone) wants to chat about the fridge project. Proved to be too easy to get into arguments with the tetchy opinionated ancients here so login access has been revoked by request. Bye all! "
 
"Greg, GHA has left the building!, all the negativity & petty squabbling go too much. The github page has a discussion tab now if you (or anyone) wants to chat about the fridge project. Proved to be too easy to get into arguments with the tetchy opinionated ancients here so login access has been revoked by request. Bye all! "
again!

pity :mad:

hope he changes his mind!
 
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