Second Battery Fault

[D4D Addicted PP Member Find all posts View Profile Close D4D]

... but the theory is sound.

Unless the device is fitted under a bonnet

[Heath74 Senior Member Find all posts View Profile Close Heath74]

Easy boys, lets just leave DCDC out of this for the moment. The OP has described a situation that points to a stuffed battery.

There are several reasons why it may be stuffed. Before he rebuilds his charging system, How old is the aux battery?

[D4D Addicted PP Member Find all posts View Profile Close D4D]

The OP has described a situation that points to a stuffed battery.

Yup D4D's eat aux batteries, 2 years is about the right lifetime, Throw the battery away and get a new one, fit one of Leigh's V boosters, replace the 'megatronics' with a redarc or similar and give it a 240V charge once a month.

[peril Senior Member Find all posts View Profile Close peril]

I use one of these

http://www.powerwerx.com/digital-met...owerpoles.html


Michael

Alternate supplier @ $23.95 plus post, this is the original Turnigy brand retailer based in China.


http://www.hobbyking.com/hobbyking/s...dProduct=10080

[sandman Member Find all posts View Profile Close sandman]

I have a 2nd battery in my 2004 Prado. I have and have had deep cycle batteries in the thing, the latest I've tried is a marine battery to take the battering of corrugated roads. I've found I get 2 years out of my 2nd batteries no matter how nice I treat them. The last battery died 2 months ago after 22 months (had a 24 month warranty) so it was replaced free of charge.

I would HIGHLY recommend putting it on a battery charger every 4-6 weeks to top it up no matter how good your in car charger was. Last trip we did from Home (Alice Springs) through the Tanami to Broome and back, I took the 240v charger and popped it on when we had a powered site in Derby.

To make charging the battery a simple experience, I have a 50amp Anderson on the front bar that is on the 2nd battery. I've made up a short lead that the charger clips onto so I dont even have to lift the bonnet to charge when at home. if its easy you'll do it, if its a chore you will forget :-)

Pete

[sandman Member Find all posts View Profile Close sandman]

a. the fridge draws more than the suggested 2 amps b. the battery is stuffed or c. the dual battery system doesn't work well enough. The dual battery system is one ive never heard of its called "megatronics". Any suggestions would be appreciated. Cheers

a) You can put a multimeter inline and check the current to make sure the fridge doesn't have a fault. A 40amp fridge "should" be able to run for 2 days at a reasonable duty cycle when parked of course it will depend on how hot it is inside the car. I'm not sure as to what the lower battery voltage you should let the thing drop to before you need to disconnect however personally if the thing was heading lower than say 12V I'd disconnect, maybe its 11 but if you're into the 10v areana then there is a problem, its flat.

b) Battery could be stuffed as its not really holding its charge. Seriously if the thing is over 2 years old consider replacing it. I know there are folks that claim 5++ years out of their 2nd battery but I live in Alice Springs and lots of friends have 2nd batteries, tried AGM and the likes.....2 years.....

Oh one more thing, don't check the 2nd battery the night before your 3 week outback adventure, by then its all a little too late :-)

c) Everyone has an opinion on these ie: solenoid type, smart charging and dc-dc chargers. I had a redarc relay in mine and after the 2nd battery died after 3 years I went to a DC-DC charger. Its clear that the PRADO electronics dont provide the 14.5v you need for absorption, that's where the diode comes in to fool the incar electronics to drive the alternator voltage higher. Apparently people swear by them and it sounds like a simple idea. I shoved a dc-dc charger into teh engine compartment and I fully understand that after 55c things tend to fold back current wise, after chattign to Redarc we both agreed to see how it goes as an experiment. I have an air pipe from the front that funnels air up to the unit and that all works fine....

2nd batteries are a little like black magic, you can get onto a winning formula and when you win, stick with what you know. many others me included change batteries out every 2nd year and religiously charge them every 6 weeks....problem with extreme conditions out here in the NT, it tends to break things a lot quicker...thats why i drive a Prado :-)

[Wombat1 Junior Member Find all posts View Profile Close Wombat1]

Once again the debate over Diodes and DC-DC charger goes on.

I would suggest you get the second battery tested. Places like Battery World or even better still a good Auto Electrician will have the equipment to test the battery. (SOC,AMPS V's etc - When Loaded and Unloaded) If you go to an Auto Elecky get them to check the charger for the amp output and the volt output it is putting into the battery. Most good Auto Electricians will not charge you to do this, however might try to sell you one of their batteries if your battery is stuffed.

Standard alternators will only ever get your battery/s to only 80 to 90% of capacity (at best) and the best suggestion is to get a good multi stage charger to charge both batteries at least once a month.

As for your fridge there are a lot of factors to consider when it is running e.g. ambient temp, size of cabling to the 2nd battery, how hard it is running etc. All these factors will all effect the efficiency of the fridge and thus the time you will get out of your battery.

Personally I would go for best of all worlds, Diode, DC to DC charger and good multi stage charger. If you are eager there are some DC to DC devices that will also allow for Solar Charging Inputs and add extra security whilst away on your trips. (Redarc and Ctek) However bear in mind solar is dependant on daytime hours and other contributing factors.

I hope this assists a little and I hope this steers you in some direction, remembering to get the battery you currently have tested.