Fridge not wanting to start

[Ater McDonald]

Hello All,
I have a off grid system on my farm in the Northern Cape South Africa.
I have recently purchased a Samsung stand up Fridge and connected it to the 850 W pure sign wave inverter (220V).
I have a 12V battery system consisting of 12x2V Willard RT Tubular batteries rated 445Ah at 10 h /511Ah at 100h.
The problem is the fridge works fine if the fridge is standing next to the inverter but does not start up( but has power for the fridge light) if connected by means of a 3 core cable of about 8meter (+- 25ft).
any ideas?
thanks
Ater

[Sunny Solar]

Length of cable from inverter to battery ?? cable size?
Cable size from fridge to inverter??

[Ater McDonald]

Length of cable from inverter to battery ?? cable size?
Cable size from fridge to inverter??

Cable from batteries to inverter 1m. its a single core cable and flexible about 7-10 mm of the inner copper wire.
cable from fridge to inverter 3 core 2,5mm each.

[paulcheung]

Have you try a different cable? it seem you have a faulty cable, there is no way at 220 volt the voltage drop could affect the system less than 10 meter long.

[inetdog]

You are already close to the surge capacity limit of your inverter, so any additional source of voltage drop can put you over the edge. Did you really say that the fridge will not start if you put it next to the inverter, but will keep running if you switch power after it is started?
A refrigerator which draws 440W (2A at 220V) will try to pull 8A or even more when starting the compressor. This is referred to as the starting surge. If the inverter cannot handle that surge the compressor cannot start. It will either cause the inverter to trip off or shut itself down via its thermal overcurrent protection.

There are some ways to provide a "soft start" for the fridge, but they might end up costing more than a larger inverter. Of course your battery bank would have to be able to handle the surge too.
Paradoxically, if you lower the voltage to a running motor under load the current (and therefore the load on the inverter) will actually increase. That may be amplifying the effect of the voltage drop in your extension cord.

If you want to know more, you will need to measure the voltages at each point in the system. (Check the cord with just the light bulb on and correct the voltage drop for the larger current from the compressor (including surge.)

[Ater McDonald]

This seems to be more complicated than I thought. Thanks for feedback so far.
Inetdog, the fridge does work when standing next to the inverter. I have no other items attached to the inverter.
Paulcheung, I made another cable to check if the lead was indeed the case.

[Sunny Solar]

Ater when you say the fridge starts ok when next to inverter? then what is length of cable you use to do that ?

[Ater McDonald]

Sunny solar, the lead is the one the fridge comes with, about 2,5m long. This is plugged into the 40cm lead from the inverters own outlet socket to a adaptor that fits the 3 pin plug of the fridge.

[Sunny Solar]

So the problem has be be either the 25ft cable or the plug oe socket connections..
Really 25 ft is a bit on the long size. For the size cable you using.. Ican only suggest you look at the cable connections you have and how well the pins on the plug mate with the socket or get a larger dia cable..

[Ater McDonald]

thanks for the help.
I will check the connections and hopefully sort the problem out.
regards
ater