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Author Topic: Fridge and voltage drop  (Read 2687 times)

marioxp

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Fridge and voltage drop
« on: July 10 2021, 11:12 »
Fridge in Bavaria 32 2003 occasionally stops working.

I measured the voltages and noticed that when the refrigerator is running the voltage drops to about 10.5V. The batteries are brand new and the voltage is a constant 12.6V. I checked the cables, and they're fine.

What could be the reason for this voltage drop?

I guess the reason the refrigerator stopped working was the voltage drop.
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tiger79

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Re: Fridge and voltage drop
« Reply #1 on: July 10 2021, 12:16 »
Mine used to stop working occasionally.  Traced it to a faulty relay in the switch panel.  Swapped it for an unused one, and all is well.
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marioxp

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Re: Fridge and voltage drop
« Reply #2 on: July 10 2021, 12:29 »
Quote from: tiger79 on July 10 2021, 12:16
Mine used to stop working occasionally.  Traced it to a faulty relay in the switch panel.  Swapped it for an unused one, and all is well.

Relay?

Did you mean switch?
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elias

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Re: Fridge and voltage drop
« Reply #3 on: July 10 2021, 15:19 »
Hi , the voltage drop can be also due to inappropriate wiring . Especially if they run far from the source . I changed mine to 4mm2 cross section for less losses .
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tiger79

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Re: Fridge and voltage drop
« Reply #4 on: July 10 2021, 16:38 »
Quote from: marioxp on July 10 2021, 12:29
Quote from: tiger79 on July 10 2021, 12:16
Mine used to stop working occasionally.  Traced it to a faulty relay in the switch panel.  Swapped it for an unused one, and all is well.

Relay?

Did you mean switch?

No, I meant relay.  The various circuits on my boat are controlled by relays (the dark grey rectangular things on the circuit board in this pic).

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Yngmar

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Re: Fridge and voltage drop
« Reply #5 on: July 10 2021, 17:06 »
Quote from: marioxp on July 10 2021, 11:12
I measured the voltages and noticed that when the refrigerator is running the voltage drops to about 10.5V. The batteries are brand new and the voltage is a constant 12.6V. I checked the cables, and they're fine.

What could be the reason for this voltage drop?

Either the cables are undersized, or they aren't fine. Often the fault is at the crimped connectors when moisture causes corrosion which causes high resistance. Check again.
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(formerly) Sailing Songbird  ⛵️ Bavaria 40 Ocean (2001)

marioxp

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Re: Fridge and voltage drop
« Reply #6 on: July 10 2021, 18:24 »
Quote from: Yngmar on July 10 2021, 17:06



Either the cables are undersized, or they aren't fine. Often the fault is at the crimped connectors when moisture causes corrosion which causes high resistance. Check again.

Wire is 6 mm2, it is 5-6m long. I changed connectors with brand new..

We noticed that when pump of electric toilet run voltage drop even more, voltage on battery drop negligible.
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Yngmar

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Re: Fridge and voltage drop
« Reply #7 on: July 11 2021, 16:00 »
Is the wire itself corroded (copper gone brown/green on untinned wire)?

10.5V is where the fridge controller switches off by default to protect batteries from deep discharge.
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GeoffV

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Re: Fridge and voltage drop
« Reply #8 on: July 12 2021, 09:25 »


No, I meant relay.  The various circuits on my boat are controlled by relays (the dark grey rectangular things on the circuit board in this pic).


I have a similar problem with a relay - can they be replaced?
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tiger79

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Re: Fridge and voltage drop
« Reply #9 on: July 12 2021, 11:13 »
Quote from: GeoffV on July 12 2021, 09:25


I have a similar problem with a relay - can they be replaced?

Yes, they just plug in to the circuit board.
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GeoffV

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Re: Fridge and voltage drop
« Reply #10 on: July 12 2021, 13:58 »
…… and finally, a supplier? :-)

Thanks.
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tiger79

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Re: Fridge and voltage drop
« Reply #11 on: July 12 2021, 14:53 »
Quote from: GeoffV on July 12 2021, 13:58
…… and finally, a supplier? :-)

Thanks.

Don't know, I just swapped the dodgy relay with one on an unused circuit.  There'll be some sort of part number on the relay, so it should be easy to find a replacement.
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JEN-et-ROSS

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Re: Fridge and voltage drop
« Reply #12 on: July 12 2021, 15:54 »
Try CPC Farnell,  (sales@cpc.co.uk) with the serial number of the relay in question.
Also, do any of the crimped terminals get warm/hot when powered up?....they shouldn't.......Bill.
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