Dual Batterys, Front or back or both?

[RippleEphex]

im going to be running a dual battery system soon, and i cant decide on what is the best option.

the options are:
- both batterys at the front (easiest)
- one front and back (original idea)
- both at back (hardest and most expensive but also makes car very hard to steal)

i would like to put them both in the boot but need to know how to run cables from front to back,
also if i put them both at the back i think ill have to buy more cable because im guessing the 6 gauge 140amp isn't enough?

there is also the alarm system and dvd player to think about

[ari666]

im going to be running a dual battery system soon, and i cant decide on what is the best option.

the options are:
- both batterys at the front (easiest)
- one front and back (original idea)
- both at back (hardest and most expensive but also makes car very hard to steal)

i would like to put them both in the boot but need to know how to run cables from front to back,
also if i put them both at the back i think ill have to buy more cable because im guessing the 6 gauge 140amp isn't enough?

there is also the alarm system and dvd player to think about

im sorry... why the f.. would you need two batterys? *facepalm* 140A is enough to set your car on fire, put it out, set it on fire again then run off to go set someone elses car on fire. and why would putting the btterys in the back make it harder to steal???

dvd player uses next to 0 power, alarm system pretty much does use 0 power. the only reason you may need another battery is... wait.. i cant think of one. put one battery in the boot and get a 140A alternator. job done. dont waste your time with two.

[RippleEphex]

umm incase i wanna watch tv or dvd while im in the car and the engine isnt turning? its nice to waste fuel but not financially viable
and it may be 140amp but its only 6 gauge? battery cable is usually 0 or 2 isnt it?
the dvd does not use 0 power, it uses quite a bit actually, ive had the battery go flat many times from the dvd player

and with a new lock, its a lot harder to get into the boot than it is the bonnet. disconnect the batterys in the boot and unless the thieves bring their own battery and wiring they cant steal it.
and yes they couldnt take out the rear seat. but i will fix that by boxing up the holes

[the_boozer]

too hard get a one of those jumper power supply thingies something like that (cheap) wire in a change over switch and keep it in the boot if you want to site in the car and watch the dvd play for long periods.

[ari666]

lol, i could get your boot open in about 3 seconds, but anyway. ok yeah. if you wanna watch something with the power off then i guess you have looked into deep cycle batterys? i dont know exactly how they work, they store some of your battery for use to start the car, so you can sit and drain it as much as you like, but when it shuts down you still have some left to start the car. i got mine for 80 bucks and itll start a truck.

anyways, if you MUST have 2 batterys, then my vote is put em both in the boot, run your starter wire in 2 guage from the boot all the way, they run all you aux stuff off the other one with your 6 guage wire. link the two boot batterys in series (so you dont accidentally make everything 24V and blow all your globes and new fancy dvd player ) with 2 or 0.

[VK SL 3800]

Can i ask why you are watching your DVD in the car for long periods of time without the engine running? is there any reason you dont just go in side and relax on the couch and watch it on the TV? Surely there is an easy way to make your car harder to steal then putting the batteries in the boot, and if someone really wants to get to the batteries the boot lock isnt real hard to break either. You could always get a trickle charger or something? Unless you serious, putting in two batteries in the boot isnt worth the hassle.

[RippleEphex]

haha yeah but you seem like one of those clever buggers not your average theif, i put new solex lock in to stop screwdrivers being inserted. yeah ive had a quick look at them, all the ones ive seen are very expensive (worth more than the car), i will have another look though, where did you find your $80 one?

i have a redarc dual battery switch (sb12) so it will switch the charging from the second battery as needed, so no need to worry about getting 24v
i know its a bit of overkill to have 2 batterys but its nice to not have to worry about running the battery flat in the middle of nowhere haha

[RippleEphex]

Can i ask why you are watching your DVD in the car for long periods of time without the engine running? is there any reason you dont just go in side and relax on the couch and watch it on the TV? Surely there is an easy way to make your car harder to steal then putting the batteries in the boot, and if someone really wants to get to the batteries the boot lock isnt real hard to break either. You could always get a trickle charger or something? Unless you serious, putting in two batteries in the boot isnt worth the hassle.

lol home is a long way from civilization about an hour and a half from the main city, about 3 or 4 times a week ive got to sit around waiting for someone or something for up to an hour and a half at a time some days, there are easier ways of making it harder to steal, but if you make it impossible to get into the boot and put batteries in there then its near impossible to steal

[ari666]

haha yeah but you seem like one of those clever buggers where did you find your $80 one?

i have a redarc dual battery switch (sb12) so it will switch the charging from the second battery as needed, so no need to worry about getting 24v
i know its a bit of overkill to have 2 batterys but its nice to not have to worry about running the battery flat in the middle of nowhere haha

i got mine from the battery guy... he just comes with a truck and provides batterys... another thought would be to have a standby gel-cel battery in case you do flatten you main one. i dunno. im clutching at strawss trying to justify two batterys when one deep cycle is cheaper and better.

[vkberlina]

With what your wanting to do I would do it as follows.
Normal battery in the engine bay
Put an Optima Yellow top 75amp in the boot inside a battery box.
Go to Bias boating and buy this Voltage Sensitive Relay BEP
Wire your stereo up via a relay switched off your accessories/ignition to the deep cycle battery
The voltage sensitive relay will disconnect the battery when the ignition is off saving your starting battery and when the car is running charge the deep cycle battery.

I run one of these in my work ute to power my inverter and to use to charge 12v accessories without depleting my starting battery.

cya
Scott

[RippleEphex]

thanks scott, sounds like a good idea, i already have the relay (redarc sb12), theres another good point towards a dual battery system, i can also put in an inverter to have power for other things.
from what i remember about deep cycle batteries they arnt ideal for starter battery as they are made to supply a low amperage for a long time and go dead flat without affecting batteries life, where as a lead acid batteries are made to supply a large spike of electricity when you turn your motor over but aren't made to go dead flat.

[vkberlina]

Basically yes, but not the optima range of batteries I have a yellow top in my VK as the only battery with 900Ca which is about twice what it would need plus its deep cycle plus as its a sealed battery I think from memory a calcium oxcide no nasties to leak out into your boot plus they can be mounted on their side without affecting performance. These are way better than the odyssey brand batteries.

cheers
Scott