Isotherm Travel Box 15

[chewi]

Does anyone here have any experience of these?
It's a compressor frridge packaged as a 15 litre coolbox, of interest to quite few here I think

https://www.indelwebastomarine.com/us/products/fridges-freezers/travel-boxes/travel-box-tb-15/

They claim to be more efficient than Thermoelectric, but its consumption is described as "155W/24h" whatever that means.
155Watt is a hefty load > 12A so it can't mean that.

The units don't make sense to me.

should that be 155 watthours/24hours?
but that would imply 6.6 watts ( ie about 0.55A average at 12V) over 24hours...
That doesn't seem credible.

 

[pvb]

To start with, it's incredibly small, so if it has decent insulation it won't use much electricity. But quoted figures for these things can be very deceptive, depending on test conditions (which Isotherm don't seem to state).

 

[chewi]

if 155W/24h meant 155Watt average over 24h , that would be a hefty 13A at 12V, but it's fused at 10A.

if 155W/24h meant 155watt-hours/24h than it would be average only 6.6W.. ie 0.55A .
That would be impressive compared with the 4A for a typical thermolelectric coolbox.
Is that feasible?

 

[duncan99210]

Yes it is. The compressor is similar to the ones used for built in fridges but it’s only cooling a tiny volume which is surrounded by high quality insulation. So, whereas my fridge runs for about 50-60% of the time, the cool box, once at temperature, will probably run for 15-20% of the time, thus giving you the very small power consumption figures. However, figures are likely to be for lowish ambient temperatures and not terribly cold interior ones....

 

[pvb]

if 155W/24h meant 155Watt average over 24h , that would be a hefty 13A at 12V, but it's fused at 10A.

if 155W/24h meant 155watt-hours/24h than it would be average only 6.6W.. ie 0.55A .
That would be impressive compared with the 4A for a typical thermolelectric coolbox.
Is that feasible?

The latter, I suspect. But the 4A you're quoting is only when it's running, not an average surely? If you look at the iceQ 15 litre fridge, that quotes 369Wh daily - https://www.minifridge.co.uk/iceq-15-litre-deluxe-portable-mini-fridge-with-window-blue.htmlThis is twice as much consumption as the Isotherm, but the iceQ is only £60 and the Isotherm is £300.

The new compressor is a neat bit of kit, designed primarily for automotive use in high-spec vehicles. You can download details here - https://www.secop.com/products/product-portfolio/serie/bd-micro/ - although they may not make much sense!

 

[mickywillis]

Correct me if I'm wrong, but if you use 155 Watts over a 24Hr period, that averages at just over 6.45 Watts an hour?
Using I= P/V, then 6.45W/12V gives a current consumption of 0.54 Amps an hour?? So over a 24Hr period you would draw 12.9 Amps per day? Seems rather efficient I'd say.

 

[chewi]

thankyou duncan
. there are other sizes 13, 18, 31, 41 and 51 litres with the same technology.
15 litres is enough for milk, butter, meats etc and a few cans to quench my thirst.

I can manage that sort of current , but not 4A for the thermoelectric

I'll have to measure up.

 

[chewi]

Correct me if I'm wrong, but if you use 155 Watts over a 24Hr period, that averages at just over 6.45 Watts an hour?
Using I= P/V, then 6.45W/12V gives a current consumption of 0.54 Amps an hour?? So over a 24Hr period you would draw 12.9 Amps per day? Seems rather efficient I'd say.

That was my thinking but the units are all jumbled up.
instantaneous contunuous power is watts. not watts per hour
accumulated over a period they are watt hours
"155watts/24h" makes no sense at all

I thought it not credible.

 

[William_H]

The rated power usage is obviously set up with the most helpful conditions. ie cold day and not a very cold temp set.
I reckon if you multiply that number by about 3 for practical use. This number ie average about 1.5 amps over 24 hrs or about 4.5 amps when operating would be comparable with similar fridges ie WACO cf 15. So yes is probably OK as a boat fridge. However you may find with use that you are needing more capacity. ol'will

 

[prv]

Correct me if I'm wrong, but if you use 155 Watts over a 24Hr period, that averages at just over 6.45 Watts an hour?
Using I= P/V, then 6.45W/12V gives a current consumption of 0.54 Amps an hour?? So over a 24Hr period you would draw 12.9 Amps per day? Seems rather efficient I'd say.

But those units are all complete gibberish, like saying the distance from my house to my work is 30mph, or that my new car's 0-60 time is 12 metres.

Pete

 

[chewi]

Correct me if I'm wrong, but if you use 155 Watts over a 24Hr period, that averages at just over 6.45 Watts an hour?
Using I= P/V, then 6.45W/12V gives a current consumption of 0.54 Amps an hour?? So over a 24Hr period you would draw 12.9 Amps per day? Seems rather efficient I'd say.

Your arithmetic stacks up, but as prv says, the units make no sense ( and this is also the problem with the technical literature on this fridge.)
current is in AMPS not Amps/hr ( fuses are rated in AMPS)
power is in watts, not watts/hour
energy useage over a period is watt-hours ( like the electricity bill in kilowatthours

A technical answer (from the ebay vendor) also refers to amps/hr and watts/hr in nonsensical and even conflicting contexts.
eg average consumption "6.6watts/hr" and total daily consumption "155W/24hr"... (not 155watt-hrs/24hr, nor 13Ah at 12v which make sense)
somebody needs a physics lesson.


but it does show that the average power over 24hrs is indeed actually 6.6 watts, 0.55 Amps.!3 Ah per day.
It also explains that this is cooling at 5 degrees C in 24 degrees C ambient.

They are also confirmed in a feedback review, so I'm now very interested. I think I can sustain that.