battery or fridge

[lewy]

http://s332.photobucket.com/albums/m344/lewy55/fridge/?action=view&current=IMAG0074.jpg]http://i332.photobucket.com/albums/m344/lewy55/fridge/th_IMAG0074.jpg[/URL]
http://s332.photobucket.com/albums/m344/lewy55/fridge/?action=view&current=IMAG0073.jpg]http://i332.photobucket.com/albums/m344/lewy55/fridge/th_IMAG0073.jpg[/URL]
http://s332.photobucket.com/albums/m344/lewy55/fridge/?action=view&current=IMAG0079.jpg]http://i332.photobucket.com/albums/m344/lewy55/fridge/th_IMAG0079.jpg[/URL]
I have a bushman fridge about 8 months old with duel battery system controlled by drive safes sc 40,the fridge is connected to a bosch 75d31r, 75 A.H,630 CCA starting battery also 8 months old.the fridge won't kick in unless the engine is going or the fridge is on house power.I can hear the fridge trying to start however nothing happens,the battery never drops below 12 volts even when left unhooked for a couple of weeks.have also jump started other vehicles of this battery so battery sen to have enough guts,any ideas https://www.aulro.com/afvb/https://www.aulro.com/afvb/http://s332.photobucket.com/albums/m344/lewy55/fridge/?action=view&current=IMAG0073.jpg%22%20target=%22_blank%22%3E%3 Cimg%20src=%22http://i332.photobucket.com/albums/m344/lewy55/fridge/IMAG0073.jpg%22%20border=%220%22%20alt=%22running% 20with%20engine%20runnung%22%3E%3C/a%3Ehttp://www.aulro.com/afvb/%3Ca%20href=%22http://s332.photobucket.com/albums/m344/lewy55/fridge/?action=view&current=IMAG0074.jpg%22%20target=%22_blank%22%3E%3 Cimg%20src=%22http://i332.photobucket.com/albums/m344/lewy55/fridge/IMAG0074.jpg%22%20border=%220%22%20alt=%22idle%20d raw%22%3E%3C/a%3E

[Pedro_The_Swift]

hmm thats a tricky one,,:D:D
edit;(posted before text appeared)

[lewy]

tried to post pics of multimeter reading,i give up
fridge draws 2.5 amps when trying to start,
5 amps when running of alternator[seem a little high but i think it gets less after a while]
.14 draw when idle[also has voltmeter running off the battery]

[Blknight.aus]

faulty earths.

[slug_burner]

Wiring is too light, possible poor connections.

Take a set of jump leads run them from the battery to the closest connection point to the fridge, try to bypass as much wiring and control circuits as possible. Basically connect the fridge directly to each battery in turn and see if it runs ok after that.

I suspect that you have either the control circuit or the fridge itself detecting too low a voltage on start up and isolating the batteries from the fridge somehow.

[lewy]

both pos and neg wires run right to aux battery,will try an earth from merit pg to earth in back of vehicle

[lewy]

cleaned every connection i could find,made another temp powerlead out of an old 15 amp extension lead ran from every battery i could find,still same problem works perfect on house power or when engine is running just not on battery,is it possible the electronics are telling it the voltage is to low to kick in?? probably have to see Mr bushman tomorrow

[drivesafe]

Hi Lewy, try getting a voltage reading at or as close to the fridge, and at the auxiliary battery, both while the motor is running and with the motor stopped.

This will give you an idea of what sort of voltage drop is in the circuit, as I sounds like, as posted above, that you are getting too much voltage drop.

[Chucaro]

Sounds to me that it is the plug.
The standard 12DCv plugs are not good.
Test it with a good firm connection.

[Hoges]

Have same fridge, same problem arose on recent trip. I had previously been running it via the 10amp 12V feed I found in the rear LHS compartment of the P38 (Bosch upgrade) via a Hella (Merrit) plug. Worked very well

Then I fitted the SC80. ... fridge wouldn't start, even at 12.7V ...just kept "revving". Tried plugging in a 150W pure sine wave inverter and running it from that to take account voltage...no go ...inverter just squealed.
SC80 however kept all batteries in top nick.

I made up a 4 metre 8 gauge "lead" and temporarily powered the fridge which was in the rear of the P38 directly from the 200amphr campertrailer battery bank ...all OK and got us home.

Blknight.aus is on the money...it's the earth points... I phoned the bushman mob and the bloke seemed quite knowledgeable...and he was!! :eek: On his advice, I back probed the wires: when the fridge was connected the unloaded 12.7V reading dropped to about 10.something V ....so I experimented and ran an additional (10gauge) earth direct to the cranking battery and tried again...success.

I must say that the Bushman totally surprised me up on Cape York ...was very efficient...I had added the collar and high profile lid to boost its capacity from 35L up to 52 L for the trip.

Seriously thinking of tapping into the system and putting 4W laptop fan in the bottom of the fridge to improve air circulation and make it even more efficient...


EDIT forgot to mention: the quite long 12V lead which comes with the fridge is only about 12g. I believe this is part of the problem also. I intend to cut off the 'cigar' plug end, shorten cable to about 100mm, crimp 8g twin cable (2m) with an Anderson plug on other end. Put Anderson plug also on Bushman power supply cable ini place of the "cigar' socket. I have also made up a couple of "converter" short leads (200mm) with 10g wire to enable Anderson plugs to access Merrit sockets.

[lewy]

have soldered terminals straight to aux battery with a hella cig female with the standard bushman male plug in the cab the only thing different is a volt meter in the cab,
with the engine running at idle there is 13.14 volts at the battery,
13.25 at the plug[why is that higher]
with the engine stopped 12.75 at the battery
12.75 at the plug
be aware this is running the original marelli alternator so need some revs to get to 13.9 ish
thanks in advance

[Hoges]

cleaned every connection i could find,made another temp powerlead out of an old 15 amp extension lead ran from every battery i could find,still same problem works perfect on house power or when engine is running just not on battery,is it possible the electronics are telling it the voltage is to low to kick in?? probably have to see Mr bushman tomorrow

15Amp extension lead ok for 240V but not enough cross sectional area to supply required juice at a nominal 12V. It's only about 12g at best. Need 8g which is about 5mm in diameter (approx 13sqmm xsectn area) for proper performance.

[lewy]

the main leads are 6mm.

[drivesafe]

Hi lewy, 6mm auto ( which is 4.5mm2 ) or 6mm2 ?, either way the size is fine and so is the voltage at the fridge.

You are not going to get higher than 12.75v at the fridge with the motor off. 12.75v is a fully charged battery and if your still having problems, it may pay you to have the fridge checked.

[lewy]

Okay,finally had time to fix? this,
Had a 1 volt drop over the hella merit plug replaced the merrit with a two pin marine plug that screws together,Also joined the 2 negative terminals together on the duel battery's as well as to earth,This seems to have fixed the problem so everyone who replied with advice was correct.thanks to all.