Battery Current Saver

And still keeps the beer just as cold?
And the meat doesn't go off?
Best tests I can think off :o)

Sounds good if it does. I just play with the thermostat on my fridge.

hi ian h,
i have a auto fridge (quirks) and the formula that they use run the fridge is
on(2)) cycle,run all day as needed,setting (7)r two hours a day once
in the morning and one at nite. mind you the way a auto frige works is a bit different to an normal compreser driven fridge although the same bd 35 compresser is used. this also gives you great battery extention
which is problely what this BCS does but i do it manually
lewjack1

What was the price of the BCS Ian ?

Ian H,
Sorry but i don't believe it.
It just does'nt make any sense at all, i could be wrong but logic tells me no.

PLEASE do not tell people that :-)

I've had one for years, and every time I've said that no this forum I've been shot to pieces

I'm a believer

Regards Richard

Ian,

I'm intrigued and want to believe, but I still don't get it. Outbacktourer's analogy would suggest that it the the current draw on start up that accounts for the increased power usage when running the fridge normally. I know that your fridge will draw extra current on start up, but surely not by a similar factor to cranking your engine over? Is it similar to a fluorescent light in that you are better off running it in fewer but longer blocks rather than turning it on and off?

I would have thought that the increased efficiency comes from not keeping the fridge in such a narrow temperature range. It strikes me that, with power usage being a key point of appeal, manufacturers should re-tune their thermostat to give similar results to those you are achieving with the power saver. Or perhaps they see maintaining a certain temp range as being more important?

Do you need to tweak it much in hotter conditions?

I'm not putting it down (your results speak for themselves) just interested to understand why.

Matt.

Sounds like an idea that works, but it must have limitations since it works on time and not fridge temp. Parked in the sun in northern Australia while you go for a walk to a Gorge for a few hours, the time set would most likely not be enough.

Raise your dairy, meat etc much above 4 degrees for too long and you migh have trouble.

Is there a simple switch that lets you choose when the BCS is running the show and when you go back to fridge thermostat? You would have to remember to do it, but at least you would have the choice.

When your fridge has W amount of food/drink mass at X temperature inside and it is in an ambient of Y degrees it will require Z energy to keep it below 4 deg C – and no box of electronics can change that.

How you choose to deliver that Z energy, providing it done within the cooling time constant of the fridge, won't matter much. What your magic box is doing is replacing the thermostat on the fridge with an on/off control mechanism and is making a guess at the time required during a 35 minute cycle to keep the fridge cool. This method will work but it is a guessing game to find the proportional on/off times in any given situation - it will be different at night to during the day - usually.

To optimise the energy usage of a fridge it really needs a proper PID controller tuned for the current situation (complex and expensive) what, I suspect, most fridge thermostats do is just turn the fridge on when it's above temperature and off when it's below, probably with a bit of hysteresis, this works OK but will use more energy than necessary. If you can determine the optimum time your fridge needs under all conditions (difficult to impossible) with your magic box then you will use less energy otherwise, over the long term, you'll probably use more.

For $150 each maybe I should design a PID controller for 12V fridges?

Mike Harding