Which battery runs what?

[chimpboy]

Hooking up a dual battery system at the moment and I'm trying to decide what to run from each battery. Basically I am debating whether to run the spotlights (of which there are many) and the stereo (which is beefy) off the second battery or off the primary one.

My thinking is that there are situations where you might want lights and/or music while the motor's not running, and not worry about killing your starting battery.

I thought I would hook up a kind of "override" switch so that standard mode is that the stereo only works when ACC is on, and the spotties only work when high beam is on, but when you flick the override switch they can continue running with the keys/headlights off - but only from the secondary battery.

I know people tend to run just their winch off the second batt but I don't have a winch yet and even when I do, my real purpose with dual batteries is simply to preserve the starting battery.

Before I do this I want to know if anyone thinks it's stupid, and why!

Opinions? What does everyone else do?

Jason

[beretta]

From a simpleton with auto elecy stuff......I just replaced my second battery, it has hardly been used at all (no winch), just used to run a fridge and compressor, it wouldn't hold charge anymore and wasn't very old. My thought was that because it wasn't be used it may have shortedned its life? So I have hooked my big spotties up to the new one and the UHF.

[murcod]

Jason, what type of isolator are you running- it could affect what you'll be able to run off the aux. An example is my EA (jaycar) controller would possibly struggle to pass enough current continuously if spotties etc were wired on the aux.

Beretta, my aux rarely gets used and seems happy enough (battery is over 2yrs old and was recently tested.) AFAIK you should only run into battery life problems if you leave them discharged for any period of time. Being kept "topped up" in an unused aux battery set up shouldn't kill a battery?

[chimpboy]

Jason, what type of isolator are you running- it could affect what you'll be able to run off the aux. An example is my EA (jaycar) controller would possibly struggle to pass enough current continuously if spotties etc were wired on the aux.

I have the voltage-sensitive relay type, not the low current jaycar type.

It should be good for pretty much whatever the alternator can put out, although I don't expect to be running anything that demanding no matter what.

I'm still debating this one. Hmm!

Jason

[HeathGQ]

I've got issues with mine. The aux is a deep cycle, and it's not charging. When running, over 14v on the meter, but turn it off, and it running at 10.5v. Wont even run the fridge overnight.

Not sure on the system that is run, any thoughts?











Oopps Hi jacked thread

[RoldIT]

I've got issues with mine. The aux is a deep cycle, and it's not charging. When running, over 14v on the meter, but turn it off, and it running at 10.5v. Wont even run the fridge overnight.

Not sure on the system that is run, any thoughts?

Just a guess but at that voltage I'd say a cell is shorting in the battery, basically meaning she is roo-ted.

New battery time ...

[RoldIT]

Hooking up a dual battery system at the moment and I'm trying to decide what to run from each battery. Basically I am debating whether to run the spotlights (of which there are many) and the stereo (which is beefy) off the second battery or off the primary one.

My thinking is that there are situations where you might want lights and/or music while the motor's not running, and not worry about killing your starting battery.

I thought I would hook up a kind of "override" switch so that standard mode is that the stereo only works when ACC is on, and the spotties only work when high beam is on, but when you flick the override switch they can continue running with the keys/headlights off - but only from the secondary battery.

I know people tend to run just their winch off the second batt but I don't have a winch yet and even when I do, my real purpose with dual batteries is simply to preserve the starting battery.

Before I do this I want to know if anyone thinks it's stupid, and why!

Opinions? What does everyone else do?

Jason

Rule of thumb, anything low current, long usage with car off goes to the second battery.

High current devices run from the main battery and only while the car is running.

Running a winch from a aux battery with the car off will still be lucky if it winches for 5 minutes, then you're gunna have to start the car anyway. If winching from the main with the car running still kils the battery and the car stalls, use the aux to jump start the car.

[kingchevy]

Hooking up a dual battery system at the moment and I'm trying to decide what to run from each battery. Basically I am debating whether to run the spotlights (of which there are many) and the stereo (which is beefy) off the second battery or off the primary one.

My thinking is that there are situations where you might want lights and/or music while the motor's not running, and not worry about killing your starting battery.

I thought I would hook up a kind of "override" switch so that standard mode is that the stereo only works when ACC is on, and the spotties only work when high beam is on, but when you flick the override switch they can continue running with the keys/headlights off - but only from the secondary battery.

I know people tend to run just their winch off the second batt but I don't have a winch yet and even when I do, my real purpose with dual batteries is simply to preserve the starting battery.

Before I do this I want to know if anyone thinks it's stupid, and why!

Opinions? What does everyone else do?

Jason

Rule of thumb, anything low current, long usage with car off goes to the second battery.

High current devices run from the main battery and only while the car is running.

Running a winch from a aux battery with the car off will still be lucky if it winches for 5 minutes, then you're gunna have to start the car anyway. If winching from the main with the car running still kils the battery and the car stalls, use the aux to jump start the car.

your so right most people think you fit a second battery in for winching puropose's but it so not true use the main for winching and the second is there as a backup.

[HeathGQ]

I've got issues with mine. The aux is a deep cycle, and it's not charging. When running, over 14v on the meter, but turn it off, and it running at 10.5v. Wont even run the fridge overnight.

Not sure on the system that is run, any thoughts?

Just a guess but at that voltage I'd say a cell is shorting in the battery, basically meaning she is roo-ted.

New battery time ...

yep - roo-ted. Took i tout, and left it for a day, and charge went down to 6.5v. New battery time

[Loanrangie]

Ok, just to revive this old post, i have a pirahna dual setup in my rangie and i need a new aux battery mainly to run a light, 3 way fridge and an inverter ( for the wifes stuff ), is there any point getting a deep cycle or should i just stick with a cranking type - main concern is will continually charging a deep cycle battery shorten its life. If i go a deep cycle would it be possible to hook it up so i can filck a switch and cut the charge to the aux battery to prevent over charging ? I know fa about batteries so any ideas appreciated.

Thanks,
Nick.

[drivesafe]

Hi Loanranger, for your intended use, you are far better off with a deep cycle battery.

Put simply and crudely, deep cycle batteries are designed to be used in situations where there is likely to be continuos cycles of long periods of low to medium current draw and then to be recharged while cranking batteries are designed to be used for supplying short bursts of high current and then being top off again.

You could use a cranking for your requirements but a deep cycle battery should give you safer longer operating times between charges than a comparable sized cranking battery can without having it’s operating life shortened.

[drivesafe]

Hi chipboy, I agree with RoldIT and just taking his tread a bit further.

Sourcing your driving light power from the auxiliary battery means that the cable distance from the alternator to the lights is going to be much longer which mean more chance for voltage drop and that means duller light coming from your driving lights.

Cheers.

[gab00]

hi, chimpboy its easy your spare battery is just that spare, only use this battery to get you out of trouble. get a dual battery charge controller to maintain your spare. a crossover switch is used to isolate either or both both batteries and can even put both together if you really need grunt. just hook it all up to main battery and have the ablility to isolate everything especially your high power gear, winch, amp,etc. run your engine whenever you draw high amps to preserve your batteries.

[gab00]

p.s. sorry i forgot every month change which battery you are using as your main. this will reduce sulfation in your spare.