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Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 1:16 pm
by Stan Watkins
Has anyone done this and how ? The switch comes on before the 11.7 volts. I'm not as worried about strain on the batteries as strain on the marriage. Thanks

Re: Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 5:20 pm
by chin_k
Did you measure the voltage on the SENSE wire? How did you measure the voltage?

Re: Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 6:51 pm
by Roly
Hi Stan,

That LVD seems to be doing what it is supposed to. 11.7 is way low for a deep cycle 12 volt system. Around 12 v is 50%, 11.75 V is about 30% charge.
Most deep cycle lead acid batteries shouldn't be often discharged more than 50%. Running the furnace or fridge overnight on DC could draw enough current to do this, particularly if the batteries are old and tired.

I removed my LVD unit and went manual with a good battery monitor, 250 AH of new AGM batteries, and a couple of 100 Watt solar panels. I still have a low voltage alarm, and would turn on the engine or generator if needed during a freezing night. Much of Mr. Blue-go's earlier commentary in this forum analyzes this stuff.

Roly

Re: Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 10:12 pm
by Stan Watkins
I measured the voltage at the batteries at 12.5. I want to bypass the LVC and moniter the batteries myself. My only concern is getting the fridge to run if voltage is truly low. Thanks for your quick responses.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 10:15 pm
by Stan Watkins
Roku. How did you remove the LVC ? Do you know of a tutorial I could look over. Thanks again.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 18th, 2021, 10:16 pm
by Stan Watkins
Roly. Dang spell check.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 19th, 2021, 9:08 am
by chin_k
Stan Watkins wrote: February 18th, 2021, 10:12 pm I measured the voltage at the batteries at 12.5. I want to bypass the LVC and moniter the batteries myself. My only concern is getting the fridge to run if voltage is truly low. Thanks for your quick responses.
Check the voltage at the LVD SENSE terminal to make sure it is also 12.5 when it cut off the power. It is possible that poor electrical connection between the SENSE and the battery terminal is the cause of your issue. If you determined that the LVD is defective (possible, since it is pretty old), then you can look at the various newer LVD options from BlueSeaSystems and other vendors to replace it, or to get a working LVD and swab it out. The important thing is to make sure it is indeed the issue with the LVD, and not deterioration of the wiring.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 19th, 2021, 9:10 am
by chin_k
BTW, are you running your fridge on DC mode? That is going to be very hard on your batteries, and most of us can't do that for more than a few hours anyway. Look at the size of the wire for the fridge... it is the biggest one on the DC panel.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 19th, 2021, 10:02 am
by Stan Watkins
Fridge is in propane. This is my 9th rig . I just want to bypass the LVD for reasons stated. Thanks for your truly appreciated input. I'm so glad I found you guys and gals if applicable.

Re: Defeating the Low Voltage Cut off switch.

Posted: February 19th, 2021, 10:32 am
by Roly
Stan,
There is lots of detailed coverage archived here. Here is a link to one of Blue-go's conversations on LVD. Start there and you'll find more.


<viewtopic.php?f=8&t=1921>

Roly