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Thank you much appreciated, cheers

While we're on the subject of what inverter for what fridge, may I throw mine in?

An 85 litre Bar fridge. Obviously no inverter technology.
Specs as attached

What inverter would you recommend for that one?
I did try to find out the startup current from the supplier. Very helpful fellow tried his best to find out but nobody had any idea,

Jim

T1 Terry wrote: ↑Tue Jul 14, 2020 12:17 pm

It has been said many times that the key to having a successful 3 way fridge is to have a decent installation.

No Dave, the only way to have success with a 3 way fridge is find someone to sell it to, then put the money to good use and buy a household 240vac inverter fridge/freezer so you can put all the 3 way fridge dramas into campfire stories
T1 Terry

T1, I know that, but the financials say i have to give it a try for a while. At least I can measure the fridge cavity properly so when I get one I know that it will fit. All the ones that I have measured so far are either too high or too deep to fit. And I get to run some decent sized cable up to the solar controller.
The weather was pretty good today so I got a second coat on the roof.

Brucie2 wrote: ↑Tue Jul 14, 2020 7:10 pmI'd reckon I'd be looking at trying a 500w inverter for a start.

Well, that gives me a starting point anyway. Thank you.
I was hoping someone might have experience with a bar fridge on an inverter and could tell me what has worked for them. Surely there wouldn't be a whole lot of difference between bar fridges.
I have no idea who may have one to borrow. But I'll look into it.

Jim

It's only a bar fridge with 0.4 amp @240V drain. = 96 Watts

A good 500W inverter will most likely do the job. (5x running current). An 800W would (should) definitely be ok.
Unless you can find out the motor rotor lock current specification there is no way of really knowing.

The complexity is caused by the timing of when the motor starts. If it tries to start at the top of the sine wave, the current draw is maximized. Thus placing maximum load on the inverter and pulling it down.

If it starts at the cross over, then the current is minimized and the inverter is ok. This is why people say "my electrical motor starts most times on the generator"..... or when the old incandescent light blows with a flash when you turn it on..... because you managed to time it just right and turn on at the top of the cycle.

The Victron 800 is actually 800va or 500w continuous, the benefit is the very small standby current. The bar fridges are not inverter type motor speed control, so they do have the savage start up current draw.
We have a bar fridge at home so I can connect that up using different inverters to see just which works best and has the lowest 24hr battery draw while running the fridge so we have a base line for future reference.

T1 Terry

so they do have the savage start up current draw.

Can't be any higher than rotor lock current.

jon_d wrote: ↑Wed Jul 15, 2020 12:53 pm

so they do have the savage start up current draw.

Can't be any higher than rotor lock current.

That is a good reference load for the minimum size inverter required, but there is also a surge current required to charge the capacitors to make the thing spin in the first place. Inverter technology also gets rid of that problem as well, the motor is actually 3 phase and the inverter/controller actually creates a 3 phase supply to the motor from the single phase supply and uses VFD (variable frequency drive) to control the motor speed and other tricky bit to increase the start up torque that is far too complex to go into here, but basically a mini version of the control used in big process line motors. Maybe one day they will build fridges with small models of the motor control used in electric vehicles so they would run off 12vdc .... but I wouldn't hold my breath waiting
Ignore the surge load that many inverters claim to have that is shown as double the continuous run output. Good quality inverters can supply around a 50% overload for a few seconds and a 20% over load for a few mins, but the cheap Chinese ones can't even supply the rated current continuous because they actually rate them on input required rather than output capacity, bugger number so it looks better. Victron are no better, they sell their inverters on a VA rating rather than a watts rating, again, because the number is bigger. At least they will supply an over load of 20% for a few seconds, but really not worth taking the risk with a lower continuous output inverter and relying on that overload capacity to start up the motor spinning.

T1 Terry

Grandad wrote: ↑Wed Jul 15, 2020 9:05 am

Brucie2 wrote: ↑Tue Jul 14, 2020 7:10 pmI'd reckon I'd be looking at trying a 500w inverter for a start.

Well, that gives me a starting point anyway. Thank you.
I was hoping someone might have experience with a bar fridge on an inverter and could tell me what has worked for them. Surely there wouldn't be a whole lot of difference between bar fridges.
I have no idea who may have one to borrow. But I'll look into it.

Jim

Jim, I had a bar fridge in my bus many years ago and ran it off an eBay 1000w PSW inverter, it replaced a 3-way 55lt fridge which sucked my AGM batteries dry quickly no matter whether I used it on 12v or 240v and a gas fridge in a bus is not smart in my opinion. I changed when ran into a couple who used a bar fridge and told me they used very little power compared to their old 3 way and they were right, didn't have a problem with batteries after that.

Then went with 2 portable fridges, one a 35lt as a freezer and a 64lt for cooling food. When I got the lifepo4, life on the road became a dream come true and now run a 180lt inverter fridge which uses virtually no energy to speak of and it's the same in my house, inverter technology for everything now and no problems.

You can get really cheap ebay PSW inverters, mine are still going after more than 10 years with no problems. My thinking is get something much bigger than you need, then it will never have to work hard and so should last much longer, working so far on house and bus.

Interested to see the inverter size as we have a bar freezer in the bins under the bus, should be similar requirements.

However today I pretty much finished my TV lifter project.
Little video here if your interested.
https://youtu.be/l2sm-y_jbKQ

Cheers,