Edgestar Fridge Low Battery Cut Off Issues

[Rando]

I have been having some issues with the low voltage cut-off on my 43L Edgestar fridge and was wondering if anyone else has run into this problem. The issue is that the low voltage cut-off engages at too high a voltage. I was doing some testing last night, and the cut-off would come on (with blinking yellow LED) when my Diehard platinum had a no-load voltage of 12.3V and a loaded voltage of about 12.1 when the compressor was cycling. If I unplug it and plug it back in, the compressor will run for about 10 minutes before it shuts down again. I was under the impression that the low voltage cut off should activate at a loaded voltage closer to 11.5V ?

I have gone through to make sure that there is not excessive resistance in the fridge wiring, it is connected to a my Aux load center with about 2m of 12AWG cable, and I have replaced the cheesy cord and connector that came with it with Anderson Power poles (I originally suspected the cord to be the problem). I really don't need the low voltage cutoff as my battery system/charge controller has this built in. Has anyone figured out a way to bypass it? From my investigations this functionality appears to be built into the thermostat/control unit. Does anyone have a schematic for this?

[Herbie]

I have been having some issues with the low voltage cut-off on my 43L Edgestar fridge and was wondering if anyone else has run into this problem. The issue is that the low voltage cut-off engages at too high a voltage. I was doing some testing last night, and the cut-off would come on (with blinking yellow LED) when my Diehard platinum had a no-load voltage of 12.3V and a loaded voltage of about 12.1 when the compressor was cycling. If I unplug it and plug it back in, the compressor will run for about 10 minutes before it shuts down again. I was under the impression that the low voltage cut off should activate at a loaded voltage closer to 11.5V ?

I have gone through to make sure that there is not excessive resistance in the fridge wiring, it is connected to a my Aux load center with about 2m of 12AWG cable, and I have replaced the cheesy cord and connector that came with it with Anderson Power poles (I originally suspected the cord to be the problem). I really don't need the low voltage cutoff as my battery system/charge controller has this built in. Has anyone figured out a way to bypass it? From my investigations this functionality appears to be built into the thermostat/control unit. Does anyone have a schematic for this?

Hrm, sounds like you're following the right steps. I believe Compact Appliance has emailed/faxed schematics in the past, you might try calling them.

[Ludedude]

I'm guessing the voltage is 12.1 v at the battery terminals? What's the voltage at the fridge itself when it shuts off?

First thing you need to know is that if you have 2m of cable, you have to calculate the drop in 4m of cable. Given roughly 13 feet of 12 awg cable, 5 amps or so max load from the Edgestar compressor, you're looking at somewhere in the neighborhood of 3% drop, or 0.36 volts. That gives you 12.1 volts (at the battery?) - 0.36v so 11.7v which is pretty close to the 11.5 cutoff depending on variables like loss through your auxiliary load center.

[Xterabl]

Here is a link with some general info on the compressor in the Edgestar:
http://www.liyoung-compressor.com/DC-Compressor-1.html

And here is an MS WORD document that has the information required if you wish to change the shut off voltage (achieved by connecting the proper resistor in the proper place):
http://zjghengtian.com/HT_CC100DC12-24V-Anen.doc

[Rando]

Awesome! Thanks for this information, it was exactly the type of thing i was looking for. Unfortunately I think the Edgestar does not use most of the logic built into the compressor controller, but uses logic built into the digital thermostat. The only connections used on the compressor controller are, +/- 12VDC in, a TTL (5V) signal from the digital thermostat, and 12V out for the fan on the coils. The low voltage protection appears to be done by the digital thermostat unit. You don't happen to know of a data sheet for that do you?

Thanks again for digging this up!

Here is a link with some general info on the compressor in the Edgestar:
http://www.liyoung-compressor.com/DC-Compressor-1.html

And here is an MS WORD document that has the information required if you wish to change the shut off voltage (achieved by connecting the proper resistor in the proper place):
http://zjghengtian.com/HT_CC100DC12-24V-Anen.doc

[Xterabl]

The low voltage protection appears to be done by the digital thermostat unit. You don't happen to know of a data sheet for that do you?

Unfortunately, no. That is one part I couldn't find information for when I was digging around a while ago. IIRC, I even removed it so I could find what looked like a part number...and still I came up with no info for it with a web search.

You may want to call Edgestar (the number in the manual)...I managed to get hold of a pretty good technician when I killed the AC-DC power supply module.

Best of luck; and please post up if you find a solution.

[Rando]

The 12.1 is battery voltage at the fridge input. Last night I made some measurements inside the fridge, and it does drop another .3V or so between the input and the terminals on the thermostat/control. However after reading the specs on compact appliance, it shouldn't shutdown until 10.5V. I have a feeling there is something wrong with my control unit.
Thanks for the advice.

I'm guessing the voltage is 12.1 v at the battery terminals? What's the voltage at the fridge itself when it shuts off?

First thing you need to know is that if you have 2m of cable, you have to calculate the drop in 4m of cable. Given roughly 13 feet of 12 awg cable, 5 amps or so max load from the Edgestar compressor, you're looking at somewhere in the neighborhood of 3% drop, or 0.36 volts. That gives you 12.1 volts (at the battery?) - 0.36v so 11.7v which is pretty close to the 11.5 cutoff depending on variables like loss through your auxiliary load center.

[Ludedude]

The 12.1 is battery voltage at the fridge input. Last night I made some measurements inside the fridge, and it does drop another .3V or so between the input and the terminals on the thermostat/control. However after reading the specs on compact appliance, it shouldn't shutdown until 10.5V. I have a feeling there is something wrong with my control unit.
Thanks for the advice.

I guess that's good news and bad news. Good that the voltage seems adequate at the fridge input, bad that it's shutting down apparently out of spec.

I have more than a passing interest in this as I have an Edgestar 43Q that's finicky in the low voltage department as well. I haven't taken measurements at the fridge though, I just went a different route and plugged it into a 120v inverter and it runs fine. Ultimately I need to solve the 12v input issue as the inverter itself takes its pound of flesh from the battery but I've been lazy since it does run great that way.

[kuh]

How is the LBCO modification holding up?

I am having the same issue with my 86Q unit.

My low battery starts to blink with either 12V or AC plugged in.

[kuh]

took apart the control panel and tightened all the screws and checked and tightened all the plug connections. replaced the original AC cord and plug. Replaced the 12V cord with a better quality cord. I connected it directly to the auxillary battery with a 20 amp inline fuse.

works great and has not had the low battery light come on since.