RAPT fridge...I bought 1....Review

[duncbrewer]

I think they want you to consider using the RAPT pill as the beer sensor ( another untested extra).

 

[Half-baked]

The temp probe is behind a small plastic grill in the right hand side wall about a third of the way up, interesting choice of location

Well I think that’s all the information I need to pass judgment…

 

[Bourkie]

I think there is a private FB group for owners. I tried to join to learn more about the RAPT platform, but was asked for an order number and denied access without actually owning the product. Hopefully Kegland and other owners will be able to help you out then. There's a link in their Kegland FB public group.

 

[Stoichiometrist]

I was also (lucky?) enough to score the RAPT fridge. Nice looking unit, good finish and well thought out extras such as incorporating spunding valve into front. I can report the same problem and concern as the OP.
The unit temperature swings wildly. I have narrowed the hysteresis which reduced the temp swings from 5 degrees to about 4 degrees. My target temp was 18 and later 18.5 degrees for a cider. Looking at the temp sticker on the fermentor the fluctuations are more like 2 degrees. That's worse than my previous set up with simple insulation and heating/cooling in my bathtub!!!

Given how long this unit has been in development, and that its "Kee's baby" I cannot believe there is no instruction manual.

Given the presumed extensive testing, I also cannot believe that Kegland were not aware of the temp fluctuations. Yet when I ring Kegland for advice and express my concerns about the temperature fluctuations, staff seemed to have no idea and also no idea how to fix it (narrowing the hysteresis only marginally improved it but not to an acceptable level).

I did not buy the 'optional extra' extended temp probe but I think this is MANDATORY! As with previous comments, I think it will improve the temp control. Kegland should include this with every RAPT IMHO!

Its not just about improving the temp control - but also about the unit efficiency. Because the temp is constantly over shooting, the RAPT spends it's time jumping between heating and cooling. It is almost constantly on!! Ironically, the unit sits in a room with an average temp of 18 degrees.

The key advantages of the RAPT fridge were its excellent temperature regulation and its efficiency in achieving this. So far it has not achieved this. Hopefully they will be ironed out soon and so make RAPT great again.

 

[Reg Holt]

The temp probe is behind a small plastic grill in the right hand side wall about a third of the way up, interesting choice of location
Given the intended usage (temp controlled fermentation) of this product, and the accepted wisdom of measuring the liquid temp rather than air temp I find this whole add-on sensor thing a bit Heath Robinson, especially at its $900 price point, it's almost as if it's an afterthought or a MacGyver fix for a product that doesn't work as intended. Will be amazed if the Rapt V1.1 doesn't address this issue.

I agree with you Grmblz, but I think the Rapt V1.1 is a bit optimistic. I would have thought that by now the brewing fraternity should know the first cabs off the rank in regards to product from KL is something to give a wide berth to. Elvis would have.

 

[duncbrewer]

I think they should release them as 0.x versions first off.
Think of the things that have been released and never been seen again or get reworked. It's becoming a list.

 

[usastman]

Thanks for the feedback. Some settings requiring explanation....no manual...?
PID heating, PID cycle time, pID coefficient settings
Compressor cool down time..?
Mode switch delay..?

 

[Stoichiometrist]

I have no doubt this fridge will be awesome, just needs some tweaking and good customer support.

 

[KegLand-com-au]

Thanks Mark - only problem ...no manual provided. Videos coming....but a manual would have been nice.
I has seen the hysteresis setting...but was sure if smaller setting or larger was better....no manual to look up.
The screen would show when fridge was cooling or heating. I get that mass of fermenter will be fairly stable ....but i hoped it wouldnt be too much to keep near or about the set temp.
I have since turned of fan setting - seeing if temp stabalises .....not sure if fan shoukd on/off......no manual...?
Wanting to provide feedback to others who may purchase

We do have the manual online here:
RAPT Quick Start Guide - Manual

We are rapidly making changes to the firmware and web portal to include more features and as a result we will be updating this online PDF as well soon to reflect this so rather than storing a local copy on your computer please download a new manual from the link above whenever you need to refer to it.

 

[KegLand-com-au]

I thought you got the best control when you had both a beer temp and chamber temp reading? Like the brewpi does it. So from that perspective it does make sense to have the chamber probe where it is, but I agree, its pretty poor not including the beer probe.

Having used the product for a while now the probe extension in my opinion is not necessary. Some customers are obsessed with using a probe that goes into a thermowell however as the fan in this fermentation chamber is quite powerful the air space in the fridge is very even and fairly quickly the air temperature inside the fridge will be equal to the core temp in the fermenter. So you really do not need to use the extended probe and the included one on the side of the fridge does a perfectly adequate job.

If you guys really wanted us to do this would could make the extended probe come as standard but we are also a bit worried that some customers may find that this looks a bit messy having a new product arrive to you with a long dangling cable that you may or may not want to use. Would be keen to get all your thoughts on this though. How many of you would prefer the neat probe integrated into the wall or to have the long probe pre-installed?

 

[KegLand-com-au]

I have no doubt this fridge will be awesome, just needs some tweaking and good customer support.

You mentioned that you had some temperature swings in the product. Have you got the updated firmware as this was one thing that was improved on a firmware release 2 weeks ago. Please go into the menu on the display and check for OTA (over the air) updates.

 

[usastman]

Update....temp probe taped to fermenter....with butchered stubby holder over sensor. Temperature a lot more stable ....with fan off. Have enabled fan and seeing how stable temp remains

 

[peteru]

If you guys really wanted us to do this would could make the extended probe come as standard but we are also a bit worried that some customers may find that this looks a bit messy having a new product arrive to you with a long dangling cable that you may or may not want to use. Would be keen to get all your thoughts on this though. How many of you would prefer the neat probe integrated into the wall or to have the long probe pre-installed?

How about using a 3.5mm socket for the probe, flush with the fridge wall? Connect the probe cable using a 90 degree 3.5mm plug. Quick and neat connection, space efficient and the 3.5mm connector will allow for rotation of the probe cable. In the grand scheme of things, this is minimal cost. Using a 3.5mm connector would also allow for the electrical disconnection of the probe built into the wall of the fridge. Although, I think it would be preferable to have two temperature channels and feed the algorithm with more data points, being the fridge temp and probe temp.

 

[Stoichiometrist]

You mentioned that you had some temperature swings in the product. Have you got the updated firmware as this was one thing that was improved on a firmware release 2 weeks ago. Please go into the menu on the display and check for OTA (over the air) updates.

Firmware already up to date. Here's a screenshot of the temp. Up to 6 Oct the hysteresis was changed to 1 degree, and after that I reset it to the default 2 degrees for comparison. Any recommendations to reduce the temp swings and improve efficiency would be much appreciated.
Note - I'm cold crashing a cider from now.

 

[KegLand-com-au]

Firmware already up to date. Here's a screenshot of the temp. Up to 6 Oct the hysteresis was changed to 1 degree, and after that I reset it to the default 2 degrees for comparison. Any recommendations to reduce the temp swings and improve efficiency would be much appreciated.
Note - I'm cold crashing a cider from now.View attachment 121288

It's important to remember that the RAPT fridge will heat and cool the airspace around the fermenter which has veyr little thermal mass. Just because you get the air go up and down in quick succession it doesnt meant that the fermenter (which is a large thermal mass will not do this) so it's completely acceptable for this type of fluctuation to occur.

To put the numbers into consideration the RAPT fermentation chamber which holds 280L of air so for this amount of air will increase/decrese in themperature by 1C if you pump in/out 0.336 Joules of energy. However for 30l of beer (which is pretty much water) will require 125.4Joules to increase/decrese the temperature of the fermenter by 1C.

Because so little energy is required to move the the air temperature you will always get fluctuations in the air but this is not that relevant because the thermal mass of the fermenter will buffer this fluctuation.

It would be possible for us to put not very poweful heater or very low powered compressor in the RAPT chamber and this would make the fluctuations more smooth however it would mean in really hot climates or very cold climates it would take a long time to change the fermenter temperature (especially if you a fermenter that is large like the 118L kegmenter)

If you had the extended probe that goes into a thermowell in the fermenter this will definitely eaven out the peaks and troffs but the air space would still fluctuate. The graph would just look nicer.

Mode switch delay - At the moment you have this set at 5min but can you increase this to 15min or greater as this will help the situation and also smooth out the graph.

Also another thing that we are working on now is PID cooling as at the moment we only have PID heating as an option. At the moment it looks like you are not using the PID feature at all and perhaps customers find the PID feature a bit difficult to setup as probably many customers do not know what the ideal PID settings are. So we are looking to make a new firmware upgrade that will automatically learn rather than have to set the PID values. This way whe you change to a different fermenter type or change the placement of your probe in the fridge the PID learning function can take this into consideration.

 

[duncbrewer]

Talk about reinventing the wheel!

 

[KegLand-com-au]

How about using a 3.5mm socket for the probe, flush with the fridge wall? Connect the probe cable using a 90 degree 3.5mm plug. Quick and neat connection, space efficient and the 3.5mm connector will allow for rotation of the probe cable. In the grand scheme of things, this is minimal cost. Using a 3.5mm connector would also allow for the electrical disconnection of the probe built into the wall of the fridge. Although, I think it would be preferable to have two temperature channels and feed the algorithm with more data points, being the fridge temp and probe temp.

It might be worth noting that we have put a bluetooth chip on the RAPT fermentation chambers and at the moment this is not currently being used for anything but we will be using this more in future and the purpose and advantages of this will be come more clear in future as we continue to release firmware upgrades.

Right now we are also working on another wireless bluetooth probe. As low energy bluetooth is so efficient these days you can run a bluetooth probe in the fridge that is completely wireless and the battery will last years even with fairly fast sampling rate (every 10 seconds). So in this instance you could also purchase a wireless probe that you could sync with your fridge and then this would feed data back to the RAPT chamber. This data could be simply overlaid and displayed on the graph in the RAPT portal or it would also be possible to take this temperature reading to control the fridge to make the heating and cooling device turn on/off with the bluetooth probe rather than the integrated NTC wired probe.

So the RAPT fermentation chamber will act as a bluetooth gateway in future and so will other new devices that we sell too such as the BrewZilla Gen 4. For this same reason you would be able to use a wireless bluetooth probe and pair the probe with your Fermentation Chamber when you are fermenting then pair it with your BrewZilla Gen 4 when you are brewing beer for instance.

 

[Mysticbrewer]

It might be worth noting that we have put a bluetooth chip on the RAPT fermentation chambers and at the moment this is not currently being used for anything but we will be using this more in future and the purpose and advantages of this will be come more clear in future as we continue to release firmware upgrades.

Right now we are also working on another wireless bluetooth probe. As low energy bluetooth is so efficient these days you can run a bluetooth probe in the fridge that is completely wireless and the battery will last years even with fairly fast sampling rate (every 10 seconds). So in this instance you could also purchase a wireless probe that you could sync with your fridge and then this would feed data back to the RAPT chamber. This data could be simply overlaid and displayed on the graph in the RAPT portal or it would also be possible to take this temperature reading to control the fridge to make the heating and cooling device turn on/off with the bluetooth probe rather than the integrated NTC wired probe.

So the RAPT fermentation chamber will act as a bluetooth gateway in future and so will other new devices that we sell too such as the BrewZilla Gen 4. For this same reason you would be able to use a wireless bluetooth probe and pair the probe with your Fermentation Chamber when you are fermenting then pair it with your BrewZilla Gen 4 when you are brewing beer for instance.

How would this additional temp probe differ from the Rapt pill?

 

[Cian Doyle]

I agree with you Grmblz, but I think the Rapt V1.1 is a bit optimistic. I would have thought that by now the brewing fraternity should know the first cabs off the rank in regards to product from KL is something to give a wide berth to. Elvis would have.

Elvis?

 

[Reg Holt]

Elvis?

Some song he sang about it being foolish to rush in.