[GraphicX]

sorry been reading around on the net & can't find any one trying this etc so thought i'd try here.

i was given a mobitronic low battery monitor, m-50k-12 a while back & wouldn't mind wiring it into my jimny:



my thought was to tuck it behind a panel with it blanking out to a generic socket that i could plug my evakool fridge into (which is a compressor type) & have it not flatten my battery (also have a power switch prior to the battery monitor to be able to completely isolate it when needed).

the battery monitor is said to be for waeco fridges only, but i've determined the positive wire & will be cutting the waeco connection off so that's not an issue, but it also says it's for thermo fridges only, which is what has me wondering. i'm not sure if it's saying thermo fridges only as they likely have a specific connector (i'm guessing they're the round pin sort versus the compressor fridges having flat pins), but i'm also unsure if it's another issue meaning this won't be suitable to power a compressor fridge or other items for other reasons.

specs of the monitor are:
cut-in 12.8v
cut-out 11.6v
max load 5A

thanks for any advice, don't want to plug my fridge in & hope for the best as they're not exactly cheap if i cook it.

[Mike57]

You want to make sure that the +ve and -ve wires are correct on the plug for the EvaKool. Just check that against the existing plug. Other than that, this device will not damage your fridge but the fridge might damage the cut out device. 5 amps might be a little light for the start up current. Most fridges already have low voltage cut outs built in? Try it and see.

[Jezza86]

i think this will give you trouble. its hard to judge from a pic but those wires look a tad thin, which means when the compressor kicks in the voltage drop is going to turn off your fridge. it will then reset itself, your fridge will try to restart. This actually flattens your battery quicker, compared to having your fridge on all the time.

this will only be prevented by the car ruining and the extra voltage stopping the controller kicking in. like mike said, most fridges have a inbuilt low voltage cutout. my old one cut out at 10.4 V.

why are you worried about flattening your battery, is it your starting battery your ruining the fridge off?

[GraphicX]

@ mike; on 12v it states it draws 3 amps, but i'm guessing that's continuous after it's fired up like you've said so it may be an issue.

@ jezza; yeah it's the car's main battery, don't have the money to setup a dual battery system right now & wondering how i can take my fridge on the next trip. the wires on the mobitronics thing are about the same diameter as the cord for the fridge, but i don't know how many strands are under the plastic cover though. also the fridge does cut out on low battery, but it drains it so low you'd never start the car with what's left which is what i'm hoping to be able to do.

all in all i just don't want to risk killing the fridge or be stuck a few hundred ks from home. in the patrol i would take a deep cycle battery with me but i don't really have the room in the jimny. might have to look into building a removable back shelf this weekend.

[Jezza86]

another option might be to just grab one of those 900CCA jump starters for 99 bucks from super cheap.
or a esky and some block ice. when i go camping (4 days or less) i take block ice and crushed ice.

a 3rd option is Dry ice which lasts even longer, but does have some inherent risks such as engulfment if you wind the windows up.

fridges arnt the be all end all IMO. they work best when their full and unopened, cooled down for 48h beforehand on AC power.
for the first few days i put everything ill use in the esky, and only open the fridge when the esky is empty.

4th option, 1Kw generators are realy cheap these days, and with an extension lead you can put it far enough away from your camp site to not bothor you.

[GraphicX]

we usually take a jumper pack with us so that's always an option if i do kill the battery off. the battery in it is only a little fella so can't picture it lasting long to begin with tbh.

[droverdave]

Aren't compressor fridges way less than 5A? Like under 1amp?

If that is the case those cable sizes will be fine.

if you were given it, just try it out.

you can also have a go at measuring the current draw of your fridge on continuous load and on statup, use a multimeter.

[Jezza86]

^its the voltage drop on start-ups that's the problem. that's when the safety on the fridge will kick in.

[royce]

droverdave wrote:

Aren't compressor fridges way less than 5A? Like under 1amp?

If that is the case those cable sizes will be fine.

if you were given it, just try it out.

you can also have a go at measuring the current draw of your fridge on continuous load and on statup, use a multimeter.

No

My Waeco will go 6 amps when running on freeze or turbo mode and 4 on fridge mode, it might average 1ah/hr once full and down to temp totally and not touched but the current draw when operating is quite a bit.

I wouldn't bother with it, does your fridge not have a low voltage cutout anyway? Evacool used to be Danfoss compressorsand its built into the electronics, id read the manual before doing anything, then park on a hill

[GraphicX]

lol @ park on a hill.

& yeah it's a danfoss compressor with a low voltage cut out, but i think the cutout is still below what i need to crank the engine. will be giving it a go this weekend & see if it kills the battery.