dual batteries dodge diesel

I own a 2006 dodge ram turbo cummins diesel.  It has two batteries.  I notice that the negative post (s) on the batteries have wires connected to them that seem like positive wiring.  Can I still use the positive on either battery for positive on my amps and then run my ground from the amp to the chassis?  Will this short out any systems?

Only if they are wired in parallel. If it is a 24V system using 2 series 12V batteries, then you cannot run a 12V system off one battery only. (You ca electrically off the grounded battery, but that battery will be damaged from inadequate charging. What makes yo think the negative post has "positive" wiring? Is it +12V compared to the chassis/body/engine?

I can only assume it is a twenty-four volt system, being that it has two batteries and that it is a high compression diesel engine that perhaps requires a lot more torque for the starters to turn the engine over.  I do not see any obvious connection between the two batteries although I'm sure there is one.  I would think that the batteries would be wired in parallel if the starter system on the engine requires 24 volts.  Still, this would be a lot of assuming on my behalf.  I am hoping I can get some information so that I do not do my installation and end up damaging either the truck's electrical system and/or components, or my amplifiers.  I will be drawing a lot of amperage so this worries me.

To answer your other question in regards to the "positive looking wiring on my batterie(s) negative post(s).  I see smaller gauge wiring coming of the batterry cable post connection on the battery(s) negative post which is similar to the smaller gauge wiring coming off of most single batteries's positive posts.  Such as honda and nissan cars.  Again, I am only assuming and that is not enough for me.  That is why I need some input from others (such as yourself) who may have more experience with a factory dual battery set-up on a diesel powered vehicle.

I was just on a Dodge Diesel truck forum sight and I found the following (quote/unquote):

Originally Posted by Grant H. ... Normally, don't have the schematics but..., when you have a dual battery system, there are load balancing systems that try and make the load equal to both batteries or protect if the load is too uneven. ...

There's no load balancing/protection. There's just a really big cable between the batteries that wires them in parallel.

jeonadab wrote: I would think that the batteries would be wired in parallel if the starter system on the engine requires 24 volts

No - series.  12V plus 12V = 24V.    Parallel is still 12V but double the capacity.  If it's 24V, use a 24V to 12V dc-dc converter - that is a balanced load.  Or a separate 12V alternator and battery system (common ground). 

BTW - from that other posts it seems it is a 12V system, hence no "equalising" of the batteries - they are parallel if 2 x 12V batteries for a 12V system - you really only keep them equalised by the way they are wired etc, you can't really "equalise" them back into sync. Sure - remove and charge both if some inequality has occurred, but why did the inbalance occur? Fix that instead. My tips for paralleling batteries: - isolate them from each other when not charging or when not in use. - if hard-paralleled (ie, permanently and not isolated when NOT in use), replace BOTH batteries (never just one) and keep them matched - ie, the same manufacturing batch, same history & treatment. But it sound like you have a bad leak. Fix that before committing two batteries!

Those other posts are not my posts.  My truck is fine and I intend to keep it that way.

Okay. So is yours 12V or 24V? But to summarise the above... If it is 24V, then use a 24V-12V dc-dc converter, else a separate 12V system. Simple. If parallel 12V, then the usual 12V parallel rules apply. If it's a standard/OEM setup, then you'd assume they knew what they were doing, and that BOTH batteries are matched & replaced if hard-wired together. If it's a non-standard setup, then (AFIAK) most use isolation systems when not in use.

That makes sense.  I will get a meter on it before I start and find out the voltage.  I was on another sight and they mentioned it was 12v but I will make sure.  I like to cross my t's and dot my i's before I start and avoid possibly HUNDRED$ in damage.  I appreciate the info., now I have somwhere to start.  Thanks for you interest, time and knowledge.

No problems. Sorry for my confusion (over who owned what etc). But it is VERY important top know whether series or parallel. Apart from the obvious of blowing 12V stuff in a 24V system, the whole battery equalisation thing changes.    Though both ideally have matched batteries (for longest life and reliability), series equalisation is easy to check - just a voltmeter across each battery - they should be the same voltage. And series is not (as) self destructive - ie, one battery does not destroy the other when not in use (ie, is not being charged nor driving the load). However parallel cannot really be controlled for equalisation - they will self-equalise. The problem is that if NOT equal and they remain connected, the lower voltage battery drags down the other. If that continues, BOTH batteries are destroyed. And if AGM batteries, there is far greater fire risk than in simple 24V series connections. Hence why many isolate parallel batteries for safety and longetivity reasons even if battery independence is not required to (eg) ensure a charged cranking battery. Otherwise they should be connected symmetrically to ensure current matching - any charging difference is then only due to battery mismatching.    However there are those that think the above is bullsh, else don't care about buying batteries often.... But if yours are parallel, they will not be symmetrically connected if they are using multiple terminal connections. (If series, they might be 12V taps, but then accelerated failure is imminent.) Either way you can decide to clean up your system. You may also decide to add isolation - or a separate audio battery - to help ensure enough cranking reserve.   (An additional battery for the amp is probably better.) But you could always have a charge-controlled amp (if not charging, no amp) that can also be controlled with a manual (timed) switch, or voltage control that cuts out when the battery reaches a certain voltage (and does NOT come on again until manually triggered else charging commences). Lots of options. But determining the voltage and battery arrangement is essential!    And it's confusing convoluted stuff. But it's those that want to pre-investigate etc that I want to help - I am in to prevention. And I don't like repairing avoidable failures from known problems - I leave that to the experts... I mean, professionals. {.. that make a living doing that...}