Converting our 3 way fridge to compressor.

[Growly bear]

The loggers can make you a bit obsessed. If the compressor is switching on and off (and it's going off by the stat) it's working.

My mate used to repair domestic (not Dometic) fridges, he used to take a delivery of 20 or so used fridges and have to test them, he always said if they go off with the stat there's nowt wrong with them

Me obsessed. How dare you

Alas I am always looking for the truth, call it logic if you like.

Yes it is working. Using very little amps too so a really great move. The fridge without the freezer compartment is huge!

But...

I turned the solar off and the fridge was so much more constant with only a few degrees of hysteresis.

I can't fathom why sometimes the compressor seems to run away with itself and take a while to settle.

I looked at the victron shunt and the craziness seems to start when 100% SOC. When the lithium voltage falls the compressor behaves its self.

The next screenshot shows the SOC and current draw. Solar off. .The SOC rose to 100% and notice the number of times the fridge is active (current increases) at 100% SOC. Then look at 99% SOC and the activity increases and the fridge returns to normal.



The next screenshot shown the SOC and voltage. The voltage rose to 14.2 (Renogy 50A B2B) and notice the number of times the fridge is active at 100% SOC. Then look at 99% SOC and the activity increases and the fridge returns to normal.




Initially not knowing how the thermostat worked, I thought some external temperature was influencing it. Of course during the day, solar activity seems to be affecting it.

Oh I don't know, but want to know

 

[Richard n Ann]

The stat can't be affected by the voltage, so if there's any change due to supply voltage it must be the compressor control box.
The Elitech controller on mine has a cooling indicator on the screen so I always know when the compressor is running (or should be )


The only thing I've noticed with mine is that the compressor now takes less current with the higher lithium voltage. Which makes sense.

 

[Richard n Ann]

can't fathom why sometimes the compressor seems to run away with itself and take a while to settle

It does run faster and takes about an extra amp for the first 10 seconds or so

 

[Growly bear]

The stat can't be affected by the voltage, so if there's any change due to supply voltage it must be the compressor control box.
The Elitech controller on mine has a cooling indicator on the screen so I always know when the compressor is running (or should be )


The only thing I've noticed with mine is that the compressor now takes less current with the higher lithium voltage. Which makes sense.

Re stat and voltage = agreed. It's just a switch after all.

How "constant temp" is yours running with the controller?

It does run faster and takes about an extra amp for the first 10 seconds or so

But mine takes a day to calm down.

Do you agree that something looks strange?

Do you happen to know what the inrush current is when the compressor fires up? I might look for a voltage regulator and see what it does...

 

[Richard n Ann]

Re stat and voltage = agreed. It's just a switch after all.

How "constant temp" is yours running with the controller?


But mine takes a day to calm down.

Do you agree that something looks strange?

Do you happen to know what the inrush current is when the compressor fires up? I might look for a voltage regulator and see what it does...

I've just put the Bluetooth sensor in now so I'll post a screen shot in the morning.

I think yours is probably OK. My gut feeling is you worry too much I could be wrong though.

I don't see the inrush current on the battery monitor, maybe it doesn't sample quick enough or there might not be one if it's a 3 phase speed controlled compressor motor same as inverter type air conditioners

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[Growly bear]

I've just put the Bluetooth sensor in now to I'll post a screen shot in the morning.

I think yours is probably OK. My gut feeling is you worry too much I could be wrong though.

I don't see the inrush current on the battery monitor, maybe it doesn't sample quick enough or there might not be one if it's a 3 phase speed controlled compressor motor same as inverter type air conditioners

That's 3 pints I owe you. I'll drive! The Young Vanish??

I do worry, and I know I shouldn't. I try hard not too but everything I do has to be the best that I can do it. It's been a flaw all my life, especially when it comes to singing (choral and not karaoke )

If mine is settled all night, I'll turn solar on in the morning. I know it'll late a while to charge back to 100% SOC though, but lets see what happens.

I did find that there is a controller for the Secop compressor especially for a wide voltage range (solar fridges) but its almost £200.
I've also found a 10A 12v regulator from AliExpress for £11

I'll look forward to your screen shot. Can you get to 100% SOC to try a comparison?

 

[Richard n Ann]

That's 3 pints I owe you. I'll drive! The Young Vanish??

I do worry, and I know I shouldn't. I try hard not too but everything I do has to be the best that I can do it. It's been a flaw all my life, especially when it comes to singing (choral and not karaoke )

If mine is settled all night, I'll turn solar on in the morning. I know it'll late a while to charge back to 100% SOC though, but lets see what happens.

I did find that there is a controller for the Secop compressor especially for a wide voltage range (solar fridges) but its almost £200.
I've also found a 10A 12v regulator from AliExpress for £11

I'll look forward to your screen shot. Can you get to 100% SOC to try a comparison?

Battery is on 98% now, driving home up the M1 tonight with the B2B off.
I can switch the mains charger on tomorrow for a comparison

 

[Richard n Ann]

That's 3 pints I owe you. I'll drive! The Young Vanish??

I'm stopping drinking for a while now I'm on a diet starting now

 

[Richard n Ann]

 

[MisterB]

although i bit the bullet and bought a new compressor F/F i also had an issue with 'over voltage' when the battery was full or close to it and there was an excess of solar coming in, i decided to go down the regulated supply route and got a 20A version (as the F/F comes with a 20A fuse, so thought that would be suitable)

had it for a couple of days now and NO faults being shown re over current, so perhaps its a solution worth considering?

growly_bear
Richard n Ann

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[Growly bear]

View attachment 1088067

That is a thing of beauty! Thank you for taking the trouble.

Using your Elitech controller?

 

[Growly bear]

although i bit the bullet and bought a new compressor F/F i also had an issue with 'over voltage' when the battery was full or close to it and there was an excess of solar coming in, i decided to go down the regulated supply route and got a 20A version (as the F/F comes with a 20A fuse, so thought that would be suitable)

had it for a couple of days now and NO faults being shown re over current, so perhaps its a solution worth considering?

growly_bear
Richard n Ann

That's very interesting.

What were the symptoms you experienced?

 

[MisterB]

That's very interesting.

What were the symptoms you experienced?

The F/F kept reporting an error message, when i checked the error codes (which took me a while to track down - dont know why theyre not in the manual!!) - its a series of lights/flashes, it suggested the error was due to overcurrent, as it only happened when the battery was full or close to full and our portable solar panel was plugged in, i checked by unplugging the portable solar panel and the F/F returned to normal.

Our portable is wired direct to the battery as i also use the Anderson connector as a 12v output connection, so any power over 100% battery charge doesnt get throttled back as it would through an MPPT etc (or at least my limited knowledge thinks that is the reason !!!) - it sees a route and sends its power army along it ......!! but the F/F defends itself by returning the error message (and i assume shutting down until it can handle the onsurge LOL) - at least thats how my mind sees it, however technically incorrect it may be!

 

[StillGoing]

The F/F kept reporting an error message, when i checked the error codes (which took me a while to track down - dont know why theyre not in the manual!!) - its a series of lights/flashes, it suggested the error was due to overcurrent, as it only happened when the battery was full or close to full and our portable solar panel was plugged in, i checked by unplugging the portable solar panel and the F/F returned to normal.

Our portable is wired direct to the battery as i also use the Anderson connector as a 12v output connection, so any power over 100% battery charge doesnt get throttled back as it would through an MPPT etc (or at least my limited knowledge thinks that is the reason !!!) - it sees a route and sends its power army along it ......!! but the F/F defends itself by returning the error message (and i assume shutting down until it can handle the onsurge LOL) - at least thats how my mind sees it, however technically incorrect it may be!

I’m not sure what overcurrent means. The F/F should be protected by a 15A fuse near the power supply source. If more than 15A is being drawn then the fuse should blow.

The voltage range for your FF is 10.4V to 16V at the refrigerator. If you’ve got more than 16V you need to investigate why as you shouldn’t be anywhere near that with solar, ehu or alternator supplied power.

 

[MisterB]

I’m not sure what overcurrent means. The F/F should be protected by a 15A fuse near the power supply source. If more than 15A is being drawn then the fuse should blow.

The voltage range for your FF is 10.4V to 16V at the refrigerator. If you’ve got more than 16V you need to investigate why as you shouldn’t be anywhere near that with solar, ehu or alternator supplied power.

The F/F has a 20A fuse in it according to the manufacturer, to protect the F/F. Im sure they know what they're doing ..... and my regulated power supply works as it should, i have 4mm cables direct from the battery ... i have two batteries connected together in parallel and have the + cable attached to one battery and the - cable connected to the other as suggested on line so as to ensure both batteries are working together, without one of them being the 'master'

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[ian27]

The F/F kept reporting an error message, when i checked the error codes (which took me a while to track down - dont know why theyre not in the manual!!) - its a series of lights/flashes, it suggested the error was due to overcurrent, as it only happened when the battery was full or close to full and our portable solar panel was plugged in, i checked by unplugging the portable solar panel and the F/F returned to normal.

Our portable is wired direct to the battery as i also use the Anderson connector as a 12v output connection, so any power over 100% battery charge doesnt get throttled back as it would through an MPPT etc (or at least my limited knowledge thinks that is the reason !!!) - it sees a route and sends its power army along it ......!! but the F/F defends itself by returning the error message (and i assume shutting down until it can handle the onsurge LOL) - at least thats how my mind sees it, however technically incorrect it may be!

I suspect this will be down to your portable solar panel. is it connected through a controller, or does it have a built in controller? or have you wired the panel outputs directly to your battery?
you may be attaching a device that can push out a max of maybe 20Volts (assume the VOC of the panel would be of that order) directly to a circuit that shouldn't be running at that voltage. the fact that this happens when your battery is near full, so it can't sink whats coming from the solar, so the solar drags voltage towards VOC, the battery drags it down, they meet in the middle somewhere around 16V, makes me suspicious of this.

Measure the voltage at the output terminals of the solar panel that are directly connected to your vehicles "12v external" anderson, on the solar panel side, with the anderson disconnected, in bright sunshine. If you are getting raw panel voltage it'll be of the order of 20V.

if the above is correct, you definitely need a controller between your panel and your 12v battery connection.

 

[Growly bear]

The F/F kept reporting an error message, when i checked the error codes (which took me a while to track down - dont know why theyre not in the manual!!) - its a series of lights/flashes, it suggested the error was due to overcurrent, as it only happened when the battery was full or close to full and our portable solar panel was plugged in, i checked by unplugging the portable solar panel and the F/F returned to normal.

Our portable is wired direct to the battery as i also use the Anderson connector as a 12v output connection, so any power over 100% battery charge doesnt get throttled back as it would through an MPPT etc (or at least my limited knowledge thinks that is the reason !!!) - it sees a route and sends its power army along it ......!! but the F/F defends itself by returning the error message (and i assume shutting down until it can handle the onsurge LOL) - at least thats how my mind sees it, however technically incorrect it may be!

Just to clarify...

Your solar panel does not have an inbuilt mppt? Have you measured the battery voltage when its 100% SOC and solar is charging on a bright sunny day?
Did you error report over current or over voltage?

 

[Richard n Ann]

That is a thing of beauty! Thank you for taking the trouble.

Using your Elitech controller?

Yes the Elitech controls the fridge temperature directly rather than the stat that controls the evaporator temperature. The mechanical stats are great as a backup though

 

[StillGoing]

The F/F has a 20A fuse in it according to the manufacturer, to protect the F/F. Im sure they know what they're doing ..... and my regulated power supply works as it should, i have 4mm cables direct from the battery ... i have two batteries connected together in parallel and have the + cable attached to one battery and the - cable connected to the other as suggested on line so as to ensure both batteries are working together, without one of them being the 'master'

Page 8 of the installation manual says 15A fuse near the power source.

Page 12 of the installation manual says the FF has a 15A fuse.

 

[Growly bear]

Yes the Elitech controls the fridge temperature directly rather than the stat that controls the evaporator temperature. The mechanical stats are great as a backup though

Thanks Richard n Ann

I've just taken another (and last for a while screen shot). It shows it going as I call crazy with no solar and battery voltage at around 13.2v. So not relayed to voltage either.

It just seems to be a perculiarity of the stat, and without a temp sensor I'd never know as the fridge is fundamentally cold and working.

I'm going to buy an Elitech in the near future. PM me in Septwmber as I would like to meet you and buy you a coke if your still not drinking

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[Richard n Ann]

Just took another screen shot as the solar is charging it now and the voltage is 13.6. The temperature is a bit more up and down which surprised me, I opened the door and 'someone' has totally emptied it

Anyway it looks like it was starting to settle down again.

You'll love the controller, lots of settings to faff with... AND LED digital readout

 

[Growly bear]

Just took another screen shot as the solar is charging it now and the voltage is 13.6. The temperature is a bit more up and down which surprised me, I opened the door and 'someone' has totally emptied it View attachment 1088162

Anyway it looks like it was starting to settle down again.

You'll love the controller, lots of settings to faff with... AND LED digital readout

I wonder who that could be!

My next hypothesis is that the evaporator ices up and the thermostat reads the ice/evaporator temperature...and carrys on cooling.

My head hurts!

At least yours is doing the same

 

[Growly bear]

Richard n Ann well my fridge started to go bonkers last night. At -6 and decreasing! Turned out of and thought is look this morning. Guess what?

 

[Lenny HB]

Richard n Ann well my fridge started to go bonkers last night. At -6 and decreasing! Turned out of and thought is look this morning. Guess what? View attachment 1107992

Obviously a fridge of good taste, I mean alcohol free beer really, no wonder it threw a wobbly.

 

[Growly bear]

Obviously a fridge of good taste, I mean alcohol free beer really, no wonder it threw a wobbly.

And I wasn't attempting to be funny
Look at the bulge - frozen solid. Pushed up against the evaporator!

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[Lenny HB]

And I wasn't attempting to be funny
Look at the bulge - frozen solid. Pushed up against the evaporator!

I did notice.

 

[Richard n Ann]

It will freeze stuff at the back, our house fridge froze and knackered a cucumber the other day . commercial fridges have fans to even put the temperature more but I quite like the different temperatures, beers (with alcohol) at the back, eggs and butter in the door

 

[Richard n Ann]

Even OUT the temperature

 

[pilchard]

I heard that the compressor fridge is noisy…is that so

 

[Richard n Ann]

I heard that the compressor fridge is noisy…is that so

Mine isn't and we sleep next to it. You can hear it, a quiet purring, which is a good thing for me, sends me to sleep

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