low voltage cutout

Your battery should stand up to a couple of days running a fridge and a few camp lights, though it is certainly very desirable not to discharge too far as it affects battery life, especially if its left discharged for long.

I'm not aware of any satisfactory simple low voltage cutout - problem is that the voltage drops under load and I'd want to disconnect if it got down much below 11 volts with a fridge sized load (typically 3 or 4 amps). As soon as it's disconnected from the load, the voltage rises and the low voltage cutout will reconnect. My Waeko fridge has an inbuilt cutout (to protect the fridge) which does exactly this - Fridge draws current which drops voltage below 10.6 which operates cutout, voltage rises so cutout reconnects, fridge draws current ......... The cycle is about 1 minute long, so eventually you realise that you have a problem.

Suggest a quick solution for this week is to carry a voltmeter and check battery voltage periodically. A cheap digital meter will be fine and cost a bit over $10.

HTH

John

Is there A need for one most fridges have cut-outs in them I realy dont know anyone that has one in there vehicle perhaps you dont need it?? (I realise why you might but running you're battery flat once in a blue moon wont hurt it to badly)

What are you gonna run off it ?
A few days ? Does that mean 3 or longer ?
Just work out roughly the total amps you're gonna use then guess how long you want to run these things, and this will give you a rough idea.
If you're not gonna run a fridge, then the batt should run lights etc fairly easily !

Engel have a simple one available though most camping outlets. From their webpage:

Battery Monitor

This handy little device gives you piece of mind, it Automatically shuts the fridge off when the battery charge drops below a set voltage, which means no more flat batteries. Available in two New models part number # BM12, part number # BMIL, both have a selectable 10.5 volt or 11.5 volt cut out (plus or minus 0.1volt) (for selection please refer to vehicle manufacturers requirements for starting) and both have a LED display for easy monitoring of battery voltage. They have an automatic reconnection when the battery voltage reaches 13.2 volts (plus or minus 0.1volt), and both are rated to 15 amps. The # BM12 is designed to be hard wired into your vehicle. For extra versatility use the # BMIL Battery Monitor In Line, this model simply screws into your Engel 12 volt lead using the "posi-fit" connections that come standard with your Engel refrigerator, allowing your battery monitor to go where ever your Engel goes. 12 Month Warranty

Category: Fridge Accessories
Power: 12 Volt


Recommended Retail Price: $98.00

Projecta make a low voltage cut out device. It cuts out at approx. 11 volts but does not start again until the power supply is interrupted. It just a simple plug into the ciggy lighter and then hook the fridge up like a extension cord.

Repco has these for about $40.

They are not ideal but they do the job.

Cheers.

They also may cause voltage drop problems if there inline with the supply So try not to skimp as much as possible on the quality of the unit and I highly doubt the $40 repco one would cut it for long. Maybe engel can supply you a genuine unit?

Battery Protector Cigarette Lighter plug socket 10A $12.80
Cuts off at 11.2 volts and says unit will automatically suspend power to any connected 12 volt accessory

DITTO, I have had a Projecta cutout for 5+ years with a 39 litre Engel with no problems. I have hard wired it near the fridge,so that it sees the same voltage.
Regards Philip A

Not the cheapest solution (I got cheaper through auto elec mate)- but you can protect your battery from any and all accessories in this way- I am currenty installing in my rig...
Readarc voltage sense- (RRP $95 + gst)


Using this unit to switch a cheap 200amp solenoid to connect main line from my auxilliary battery to all accessories via which thenfuse banks and breakers.... kewl!!!

I use a 12V timer that allows me to set On/Off sequences as I need, eg: Power On at 7AM, Power Off at 10AM, Power On at 12PM, Power Off at 4PM etc etc. The sequences include Fri/Sat/Sun, or Mon/Wed/Frid, Mon/Tues/Wed/Thurs/Frid, etc etc, so it is very versatile.

This means that I can control the time the fridge is powered On/Off, thereby extending the life of the available volts before the cutout on the Waeco cuts in at 11.1V

Generally I run the fridge on setting 1 which runs the fridge at about 1 Deg C at an ambient temp of upto 30 Deg C.

If I turn the fridge off at say 10Pm and leave it overnight, generally the temp in the fridge the next morning at about 7AM when the timer cuts in again is only about 3 Deg C.

Lets face it, you dont need your fridge cycling at 2AM in the morning and using volts unnecessarily.

Using this method, I have been able to get 5 days out of my Waeco 70L.

I had to hunt high and low to find such a device and finally found it in a neighbouring town.

Cost was $65 posted and $9 for a box to fit it into and just wired it myself.

I can supply photos if required as well as the name of the place I got it from, if anyone is interested.

This may be an alternative method that you havent given thought to.

This prob'ly won't help if ya want it before friday, but y'all may wish to have a look at ebay item# 130051327716.. Seller ID " solarpower4u "..

(No affiliation etc. etc.)

Hi D

Here are a few pictures to help.





You can cut the plugs and change them easily.

The Engel one can be hard wired to the car.

Regards

Derek.

D-Jack,

I have one of the Projecta brand cut-out units. As I have standardised on the Hella, or Merrit style plug and socket, I have done what Derek mentioned.

Cut off the originals and install the Hella/Merrit inline style plugs and sockets.
Just make sure you maintain the correct polarity. (+/-)

The Projecta unit cuts out at 11.6 volts and is available at Kmart, Repco, etc., for $39.95.

The 12 volt shop sells Arrid Low Voltage Cutout .. you get flooded and AGM versions .. there are others like the Redarc ...
the 12volt.com.au websites does not have all products or at least in cannot find them on the chaotic website ... always a good idea to protect your batteries .. going flat takes a lot of life out of it when you look at the deep cycle diagrams ..
I use TM500's on my house batteries in the boat and the camper
good luck
gmd