Danfoss BD35F Cooling System

[lawrence_craig]

Hi all,

I have a top loading fridge with the above cooling system (air cooled).

Looking for some experience with these systems.

We are seeing two issues:

1) What we are seeing is that at times, when the battery voltage drops below 12V, the fridge fails to run yet our separate freezer is running ok. Is this a low voltage issue or something else? The result is that overnight as our batteries are in use, the fridge stops running. However, everything else is running ok.

2) When the fridge is running well, frost will collect on the internal condensation unit. Is this just the effects of us living in the Caribbean and the warm air condensing to frost on the condensation unit or does it indicate something else?

Many thanks in advanced.

[senormechanico]

Condensation, then frost is normal. Keep it defrosted and you will use less battery juice.
Shutdown of fridge, but not a separate freezer sounds like you're diving to deep in battery, and possibly supply wiring to fridge is inadequate, or bad connection(s).
What matters is battery voltage at startup surge right at fridge compressor electronics input, not just at battery terminals.

[medsailor1]

We have the same problem

[Richard Kollmann]

The number one problem causing longer out of service trouble for Danfoss BD compressors is failure to understand the importance of clean electrical power.

In the low voltage range from 11 to 12.7 volts amperage surges created by the Danfoss compressor starting will increase any potential point of resistance in wiring or old circuit breakers and switches to drop voltage. Danfoss control monitors incoming voltage and amperage that generally will alert you by flashes of Trouble LED, one flash code for low voltage every 4 seconds. The problem with Danfoss module’s low safety protection voltage trip that prevents compressor from starting is the module recognizes a few nanosecond of low voltage as a problem. This short spike can not be seen with a volt meter that prevents compressor from running. Yes basic electrical training tells us low voltage drops can be detected with a good volt meter but the short duration nanoseconds of low voltage can not be seen with the human eye.

Correct action for voltage drop do to amperage surge is to by passing each and every possible resistance area until you find the problem. A voltmeter reading without current flow is never the solution.

[a64pilot]

Try this, take a 10Ga wire or larger directly to the battery from the controller when it shuts down, if it runs then your problem is too small a wiring, dirty connectors or anything else that may add resistance.
If the wire is old, that is a possibility.

[Richard Kollmann]

Originally Posted by a64pilot

Try this, take a 10Ga wife or larger directly to the battery from the controller when it shuts down, if it runs then your problem is too small a wiring, dirty connectors or anything else that may add resistance.
If the wire is old, that is a possibility.

It takes two wires to Tango and make sure there is a fuse in positive wire. Then for a final fix original problem still needs to be located and corrected.