12v or 240v FRIDGE?

[Mtbcol]

Good evening friends.
Looking ahead to when we finally purchase a motorhome, what are peoples thoughts on powering a fridge? Pretty certain whatever we buy will have a 3 way fridge, and from what I've read they are not very good/ efficient. In our current self build we have a small 240v compressor fridge which we run very successfully with our solar panels, battery bank and inverter. Without a doubt we will replace the 3 way fridge with a compressor unit, the question is should we go with a 12 volt unit or a 240 (domestic) unit run via our leisure battery/ inverter set up? Obviously we will need a fridge unit that is roughly the same size as the unit we remove, so maybe will need a bit more power either way? I also expect a purpose made motorhome fridge will be much more expensive than a domestic one. Your thoughts and ideas are most welcome. Thanks. Colin.

 

[r4dent]

If you purchase a MoHo with a three way fridge (or fridge freezer) which you replace with a compressor fridge you may need to update the battery bank and / or the solar.

Do the maths before spending the cash.

 

[merl]

The 230v option will be cheaper to buy but you'll have to run the inverter for it to work, some Inverters have an auto sense so they switch themselves on when needed, most don't so you'll have to leave them running full time effectively wasting power, this standby current varies quite a lot depending on your inverter. The 12v variety are generally a little more efficient overall and you'll probably get a 12v to fit perfectly into the old space BUT it'll cost you more than a domestic fridge. I guess it all boils down to how flush you feel.
The above assumes you have a sufficiently increased battery bank and a means of charging it to allow for the electric only operation of either of the above.

 

[colinm]

Whilst I might consider replacing our 3way with a compressor fridge if it packs up, I'd not bother replacing a working one, ours works perfectly fine.

 

[Mtbcol]

We'd definitely be updating the solar, battery bank and inverter etc. We currently have a 2000w inverter, 330w of solar, 330a of leisure batteries, 50 amp b2b which has served us well for several years in our self converted van

 

[mark61]

Same here really.
If doing a van from scratch, wouldn't even consider a 3 way. If buying a van with a 3 way already fitted, it would stay until it packs up.

Unless, I suppose you are considering dumping all gas appliances.

 

[wildebus]

Same here really.
If doing a van from scratch, wouldn't even consider a 3 way. If buying a van with a 3 way already fitted, it would stay until it packs up.

Unless, I suppose you are considering dumping all gas appliances.

A faulty 3-way fridge is probably landfill.
A working 3-way fridge can be worth the cost of a 240V Compressor Fridge or possibly even a 12V Compressor Fridge.

So ... actually changing now before waiting for the original to pack up can be the cost-effective option, and changing to the type of fridge you prefer is an added bonus

 

[wildebus]

Good evening friends.
Looking ahead to when we finally purchase a motorhome, what are peoples thoughts on powering a fridge? Pretty certain whatever we buy will have a 3 way fridge, and from what I've read they are not very good/ efficient. In our current self build we have a small 240v compressor fridge which we run very successfully with our solar panels, battery bank and inverter. Without a doubt we will replace the 3 way fridge with a compressor unit, the question is should we go with a 12 volt unit or a 240 (domestic) unit run via our leisure battery/ inverter set up? Obviously we will need a fridge unit that is roughly the same size as the unit we remove, so maybe will need a bit more power either way? I also expect a purpose made motorhome fridge will be much more expensive than a domestic one. Your thoughts and ideas are most welcome. Thanks. Colin.

Something you have to consider is how you use your motorhome.
In the summertime, it is no problem to replenish the power used by a compressor frige from a solar panel. A single 100W panel would do the job and you could be parked up for a week without a care.
In the winter, the solar will be no real use and an alternative charging system - probably a B2B - is needed.
Not even in winter now and my 450W of solar provided 120Wh of power - under 10Ah of power. That is enough to run my fridge for less than 5 hours. I drove for around 2 hours 40 minutes today and put in 198Ah into the battery.

You already have a compressor fridge which I presume you leave on 24/7 so are well versed in how much power they use so the above would be no surprise, but others may not be as aware?

My comment about leaving it on 24/7 i.e. just use it normally is an observation about how some folk in the VW Campervan scene run their fridges ... lost track on how many times been told their weaco 12V fridges run a whole weekend and they just have a single 100Ah lead battery. But they forget how they load up the fridge with frozen water, they turn it off overnight and the fridge is empty on a Sunday Morning, so in actual fact it is only switched on for maybe 12 hours in the whole weekend! The problem with that is it gives an unrealistic expectation of what you need to run a 12V fridge.

 

[trevskoda]

A lot also depends on the size of the 230v fridge, a small table top unit like mine has no problems running on 2 90ah lead acids with 200w of solar for a few days through a 600w smart inverter, but if a large fridge and freezer box you may have to up the kit a bit, wildbus is the expert and i followed his bench tests a few years back which were 100% correct.
We tip double the solar from what you think is correct as very lucky to get 20% from them in nov/dec.

 

[Mtbcol]

Thank you all for the great input and advice as usual. As long as we get a working 3 way unit in whatever motorhome we end up with we'll be selling it to fund the compressor unit to replace it with (12 or 240volt), as wildebus has said, it'll be worth more alive than dead.

 

[Mtbcol]

......and yes, we are considering doing away with all gas eventually

 

[YeoBlade]

......and yes, we are considering doing away with all gas eventually

Hopefully not threads as well

 

[Nabsim]

Is it a fridge you mean or a fridge freezer? Reason I ask is there is a big difference in power use. Fridge will consume approx 24ah in 24 hours where a fridge freezer will consume approx 48ah in 24 hours.

Little difference in what David got when he was doing his domestic fridge testing through an inverter and my 110ltr Waeco fridge freezer. From what I have seen posted over the years you can also get a big difference in whatever inverter you are using.

If/when my Waeco gives up the ghost I will probably replace with a 230V fridge freezer but I won't me using the 2000W inverter I have fitted for it, will get a separate smaller high efficiency one. David can probably say which and that's who I will check with if I need to make the change

 

[trevskoda]

My we table top uses 250ma and runs no bother 24hrs on a 90ah lead acide using a 600w soft start smart inverter.

 

[Mtbcol]

Is it a fridge you mean or a fridge freezer? Reason I ask is there is a big difference in power use. Fridge will consume approx 24ah in 24 hours where a fridge freezer will consume approx 48ah in 24 hours.

Little difference in what David got when he was doing his domestic fridge testing through an inverter and my 110ltr Waeco fridge freezer. From what I have seen posted over the years you can also get a big difference in whatever inverter you are using.

If/when my Waeco gives up the ghost I will probably replace with a 230V fridge freezer but I won't me using the 2000W inverter I have fitted for it, will get a separate smaller high efficiency one. David can probably say which and that's who I will check with if I need to make the change

Hi Nabsim. Yes, it would have a proper freezer compartment, and I understand that would take more power. We're using the 240v fridge and inverter set up that David recommended to us several years ago now in our current van which has been faultless, so I'll be contacting David again for help and advice when the time comes.....sorry David.

 

[ian fleming]

I guess you have thought about the more practical issues about the replacement of the fridge no matter what fridge you intend to purchase. We have an Autotrail MH and wanted to change the fridge because of gas problems and found we couldn't get the thing out the MH. The habitation door is far too narrow and even taking out the passenger front seat we couldn't get the damn thing out the door so chopping it up was the only option.
Had the gas problem resolved which was much more cost effective!

 

[Chasn]

Good evening friends.
Looking ahead to when we finally purchase a motorhome, what are peoples thoughts on powering a fridge? Pretty certain whatever we buy will have a 3 way fridge, and from what I've read they are not very good/ efficient. In our current self build we have a small 240v compressor fridge which we run very successfully with our solar panels, battery bank and inverter. Without a doubt we will replace the 3 way fridge with a compressor unit, the question is should we go with a 12 volt unit or a 240 (domestic) unit run via our leisure battery/ inverter set up? Obviously we will need a fridge unit that is roughly the same size as the unit we remove, so maybe will need a bit more power either way? I also expect a purpose made motorhome fridge will be much more expensive than a domestic one. Your thoughts and ideas are most welcome. Thanks. Colin.

Most inverters take about 1A on standby so it doesn't make much sense to have it running all the time. That equates to 24Ah on its own. If you buy a 12v fridge some of them (Alpicool for example) also come with a separate 240v psu in case you wish to power it from 240v directly. Mine is wired so that the fridge is powered directly from an EHU connection when available but uses the 12v system at other times. Using a pair of relays my fridge will automatically choose between EHU, alternator or habitation battery. I can supply a wiring diagram for that if required.
Having run my Alpicool on a 13 day trip with no need for ehu I noticed that, although the quoted current demand is 8A, in practice it is drawing only about 4A most of the time when it is demanding power. The amount of time it is using power is less than half of my previous absorption fridge which took 15A. Reliability is also better. Failure of absorption fridges during gas operation is quite common due to corrosion blocking the jet.
Alpicool also provide an app so that you can monitor/control the fridge from your phone via Bluetooth.

 

[trevskoda]

Most inverters take about 1A on standby so it doesn't make much sense to have it running all the time. That equates to 24Ah on its own. If you buy a 12v fridge some of them (Alpicool for example) also come with a separate 240v psu in case you wish to power it from 240v directly. Mine is wired so that the fridge is powered directly from an EHU connection when available but uses the 12v system at other times. Using a pair of relays my fridge will automatically choose between EHU, alternator or habitation battery. I can supply a wiring diagram for that if required.
Having run my Alpicool on a 13 day trip with no need for ehu I noticed that, although the quoted current demand is 8A, in practice it is drawing only about 4A most of the time when it is demanding power. The amount of time it is using power is less than half of my previous absorption fridge which took 15A. Reliability is also better. Failure of absorption fridges during gas operation is quite common due to corrosion blocking the jet.
Alpicool also provide an app so that you can monitor/control the fridge from your phone via Bluetooth.

No 12v unit will run of the alternator, what i think you meen is it will run of the starter battery which is charged from the ac to dc alt.

 

[Chasn]

No 12v unit will run of the alternator, what i think you meen is it will run of the starter battery which is charged from the ac to dc alt.

What I mean is the D+ connection from the alternator which only supplies power when the engine is running.

 

[Mtbcol]

Most inverters take about 1A on standby so it doesn't make much sense to have it running all the time. That equates to 24Ah on its own. If you buy a 12v fridge some of them (Alpicool for example) also come with a separate 240v psu in case you wish to power it from 240v directly. Mine is wired so that the fridge is powered directly from an EHU connection when available but uses the 12v system at other times. Using a pair of relays my fridge will automatically choose between EHU, alternator or habitation battery. I can supply a wiring diagram for that if required.
Having run my Alpicool on a 13 day trip with no need for ehu I noticed that, although the quoted current demand is 8A, in practice it is drawing only about 4A most of the time when it is demanding power. The amount of time it is using power is less than half of my previous absorption fridge which took 15A. Reliability is also better. Failure of absorption fridges during gas operation is quite common due to corrosion blocking the jet.
Alpicool also provide an app so that you can monitor/control the fridge from your phone via Bluetooth.

I definitely like the sound of that. I assume it's an upright fridge with decent freezer compartment?