Battery Problems in Petrol Maverick

[Red Rover]

89 model Maverick with 80amp alternator currently batteries are linked by 12 volt solenoid. both batteries are calcium rocket brand. The fridge draws approx 3 1/2 amps. The problem is when the car is stopped i'm lucky to get about 15 hours out of the fridge stationery , where other guys i go camping with say they can get up to 1 1/2 to 2 days from their auxilury battery. Some people have told me to update to a deep cycle battery to solve the problem. Would this solve the problem??? It is my understanding that once the main battery is charged the alternator then drops back its charging rate - therefore theoritically if the auxilury battery is down then because the alternator senses off the main battery it will take longer to charge the auxilury because the main is fully charged. Will manually linking the batteries during the day - even stationery, with fridge running, draw both batteries down level, therefore when the alternator is charging it will give full voltage to both batteries? Any suggestions or thoughts would be appreciated.

[bogged]

I know from reading the grandad sites that Deep Cycle are the shit for Fridges, but not winches.

There is a good chance that it "COULD" fix your problem..

do some reading at www.exploroz.com.au

[duncan]

I get over 24 hrs out of one battery running a 39liter Engal tiking over on Freeze only running a nz70zz standard large battery but not running through a solinoid just a 4 way switch

[Slayer]

theres heaps of reasons why u might not be getting the performance u think you should be.. fisrtly exactly what sort of fridge are we talkin about..

how is it conected to the battery?? 6mm2 wire as a minimum?? good earth?? no shitty cigarette lighter plugs or anything? these things just wont carry the current well enough.. im assuming your fridge has a low voltage cut out some place between 10.5 and 11 volts?? have u tested across the batery terminals with a multi metre, then down at the fridge end of the cord with the fridge working to see how much drop you are getting along the line.. your battery could still have heaps of kick, but the cables arnt givin the fridge all the power it needs and it gets tricked into thinkin the battery is flat..

also with the amp hour rating on the fridge, remember that it takes a bit more to kick start it than it does to run it once its going, to get maximum performance outa yr fridge aviod openin and shuttin more than u have to, and also use an insulation bag, they will help...

spose u should also take into consideration the age and condition of the battery.. has it done much hard work, ie long winch runs?? have u had the cels tested to see that its not fading in one cel, on its way out maybe.. try swappin yr system around, 1 battery for the other and see how u go..

your solanoid might not be alowing the 2nd battery to get full charge, you can test this with a multi metre, should read somewhere between 13.8 and 14.2 volts at around 2000rpm at the terminals..
have u tried giving the battery a tricle charge on a 240 v charger then seeing how much life you get out of it, this should determan if its getin full charge in the car or not..

sorry to blabble, but we went though the same with our fridge, eventually got it all sorted and we are gettin a good 36 - 48 hours now dependning on outside temp and how often it is opened..

good luck.. and let us know how things pan out..

[chimpboy]

Phew! It's a good thing we created that "Auto Electrical" forum, isn't it?

[Red Rover]

It is a custom stainless running a danfoss compressor. Tested solenoid - ok. Battery was new Oct last year but tested good with multimeter. Fridge is direct to battery( thru a marine socket) and so is the earth. It does have a 10 volt cut out. I'll try a deep cycle just to satisfy my curiousity & let you know.

Thanks

[Slayer]

get your battery tested better.. it will show good on a multi metre even if its shagged, cause it will have a surface charge.. get the cels tested at batery world or sumthin..
or if ya wanna just buy a new deep cycle

[Bluey]

try testing actual voltage of battery at terminals and then voltage at fridge as slayer said. see if you dont have excessive voltage drop, possibly look into fridge insulation. number of times opened??

do this before buying new battery, because if anyone of the above are problematic then new battery will not fix. deep cycle should be able to provide lower constant current draw for a longer period, but you may still have problems with voltage drop/bad insulation/opened to often/not allowed to get to working temp before turning battery off.


Cheers
Lance

[Slayer]

if u buy a deep cycle ill give you 15 bucks for the old 1...

[Red Rover]

I bought a deep cycle which seems to be going better. A deep cycle has a higher amperes rating than a std battery. Also when a std battery is flatened to below 11.2 volts it reduces the amp hour capacity of the battery over time. As the fridge has a 10 volt cut this really flatens it. It is my belief that it has dramatically reduced the capacity of the calcium battery, because when i first put it in it worked ok. Shouldve done a deep cycle in the first place DOH. We'll see what happens in the next trip away but so far it ran all night & day cycling and on freeze pulled down to -16. Not to bad me thinks.

Thanks