AC Fridge In Campervan -.Power Consumption Test
- Thread starter wildebus
- Start date
Sprinter 1 cup
Forum Member
Ok
You have not completed the tests upto 35 degrees! For the thread you started 2018. March
You have not completed the tests upto 35 degrees! For the thread you started 2018. March
wildebus
Forum Member
haven't I? ah well, life sucks, doesn't it.
Nabsim
Forum Member
I have a 12v 110ltr compressor fridge with freezer compartment, over a 24hr period it uses 45amps. The tests Dave has done show similar power use. If/when my fridge packs up I will replace with domestic
SquirrellCook
Forum Member
As I understand it, we now need gyroscopes and levelling devices for our domestic fridges. I’ll mention it to my fridge in the morning. If it doesn’t reply I’ll assume it’s happy as it is.
SquirrellCook
Forum Member
Put my fridge on yesterday. Setting No3 no idea about the temperature at the moment as a ladder has taken up residence in front of it.
Batteries were at 90% this morning and it seems to use about 6 amps when running. That's the total shown by the BMV with a bit of quick arithmetic deducting the charge current.
Batteries were at 90% this morning and it seems to use about 6 amps when running. That's the total shown by the BMV with a bit of quick arithmetic deducting the charge current.
Sprinter 1 cup
Forum Member
So if it's no more power needed then it must be the way to go 2020?
xsilvergs
Forum Member
Just add a little worthless information, our motorhome has a Thetford Fridge Freezer model: lN3150 (Warning, never buy a Thetford). This is a 3 way fridge/freezer unit with separate freezer compartment.
I haven't measured DC current whilst driving, but today while working on the AC part of my project I was measuring energy consumption. At around 240 V AC the current draw is one amp, when the temperature is down to the required level and the thermostat goes OC the AC current draw is zero.
I now wonder on the benefits of running this from an inverter whilst driving.
On a sunny day the solar could supply more than enough to power the fridge/freezer thus saving gas.
Any thoughts appreciated.
I haven't measured DC current whilst driving, but today while working on the AC part of my project I was measuring energy consumption. At around 240 V AC the current draw is one amp, when the temperature is down to the required level and the thermostat goes OC the AC current draw is zero.
I now wonder on the benefits of running this from an inverter whilst driving.
On a sunny day the solar could supply more than enough to power the fridge/freezer thus saving gas.
Any thoughts appreciated.
SquirrellCook
Forum Member
240 watts is a hefty load, it would be worse through an inverter. They won't work for free!
I'm guessing mine is using around 80 watts including the inverter whilst it's cooling.
I'm guessing mine is using around 80 watts including the inverter whilst it's cooling.
Sprinter 1 cup
Forum Member
But that's just 1 pannle out of 3 on mine.
Nabsim
Forum Member
Indeed, when the time comes I will just get a suitable inverter and a domestic fridge.
xsilvergs
Forum Member
Yes but it's not 240 W all the time and if 400 Watt's of Solar Panels are sat there doing nothing and there's enough sun to get 240 W, think of the gas I'm saving and the diesel I'm saving not having to drive to the garage to refill the bottle.
I used the fridge as a load as I was trying the code to monitor AC consumption into the van, I just thought I'd add to this thread. Also as it totals consumed I can set the limit so I never have to pay for electricity over and above that included at some sites.
wildebus
Forum Member
So around 23A (inc losses when running via a 12V Battery) then?
For the limited use, you could get a cheap Inverter of around 300W (as no compressor, no need to worry about in-rush surges) so around £30 mark.
You would need a way to only have the inverter running when the engine was running - maybe a simple relay powered by the D+ Alternator signal (or maybe Ignition would be ok) - say £5.
So in terms of saving gas in money terms, how much gas would £35 buy to cover what you would use when driving?
But you might need to upgrade the B2B size to cover the additional power demand?
But there is another option you could consider .....
Get yourself a BIG inverter - say 1000W and connect that up to the Starter Battery (again externally controlled by D+/Ignition) and you could connect that upto the Fridge AND a Smart Mains Charger - which would give you a nice B2B function as well as powering the Fridge.
You could then also maybe monitor the Mains Charger in some way (Hall-effect sensor monitor?) and feed that into the system as your B2B input?
wildebus
Forum Member
I get the desire of using excess solar and what I have done in my van is have my Water Heater (2kW element) controlled by the Victron BMV Relay - it will switch on automatically when the Battery SOC is above a certain level (93% I think I have it set to?), so making some use of that extra harvested energy 
.
PS. What device are you using to monitor the AC?
.PS. What device are you using to monitor the AC?
xsilvergs
Forum Member
I've seen the Bestek on Amazon for about £30.
I do prefer pure-sine, the Victron ones take my eye, quite efficient, good ECO mode and I think they can be paralleled (so long as the first 3 or 4 digits are the same).
wildebus
Forum Member
I bought this one last week as a little basic one for test purposes - https://amzn.to/2B5RSuB
It is an Amazon own-brand one but is actually a Bestek one really (probably the sister inverter to the one you saw but slightly cheaper?). For a cheap inverter I am pleased with the build quality although I will be cutting the cigar lighter connection off and adding a more substantial connector
That unit is on a special deal for next 40 minutes BTW - under £25 right now (I paid £28 last week
)
xsilvergs
Forum Member
I get the desire of using excess solar and what I have done in my van is have my Water Heater (2kW element) controlled by the Victron BMV Relay - it will switch on automatically when the Battery SOC is above a certain level (93% I think I have it set to?), so making some use of that extra harvested energy
PS. What device are you using to monitor the AC?
I had considered about 80% as my AGM starts to tail off then as it's going into Absorption (I think), perhaps higher when I've checked.
I use these, very accurate or a wide range. Add an ADC and a Wemos D1 Mini and it's on your WiFi
https://uk.farnell.com/dfrobot/sen0...D-COMPUTERS-NEWSTRUCTURE-Test113-MarinBidding
xsilvergs
Forum Member
I bought this one last week as a little basic one for test purposes - https://amzn.to/2B5RSuB
It is an Amazon own-brand one but is actually a Bestek one really (probably the sister inverter to the one you saw but slightly cheaper?). For a cheap inverter I am pleased with the build quality although I will be cutting the cigar lighter connection off and adding a more substantial connector
That unit is on a special deal for next 40 minutes BTW - under £25 right now (I paid £28 last week
What current draw is there when it has no load on the output?
wildebus
Forum Member
couldn't tell you off-hand. it is plugged into the box I have my LiFePO4 Battery and a BMV on so I will have a look tomorrow