Two Batteries wired in parallel?
If you have, would you post pics or even a write up?

 

I just dont know where you would put the 2nd battery, maybe a bracket to mount it underneath the vehicle somewhere or in the rear area. I don't think there's enough room under the hood for even 2 optimas. I may be wrong tho.

 

Just wondering about the intended use of a possible second battery.
Location is an issue but definately anyplace inside the vehicle is out of the question. Your specific application will determine whether or not you'd be best to install a dual battery swtch or perhaps an isolator instead.
One or the other may be usefull to ensure you never discharge the primary(engine starting) battery during extended or heavy battery usage.

 

I think the typical application is repeated off road winching operations. Often the engine is at low RPM and cannot spin the alternator fast enough to keep up.

Worst case, is that the engine cannot be operated. Too steep an incline, disabled engine, ect. Then the single battery could leave the vehicle stranded in the middle of a recovery operation.

There is also nothing wrong with the battery inside the vehicle if it is done right. Many stock cars now have the battery under the rear seat, or in the truck. Audi A4 and Bonneville SSEi are examples.

 

Ahh...Thanks for the info on the winching.
For that particular application I'd be going with an isolator which is also cheaper than a bank switch. Both battery banks charge at the same time but only the one(s) the winch draws from discharge.
No point in getting to the other side of the pond and trying to crank the engine with the pull cord. Oh ya Chrysler missed that on mine same as the underhood and footwell lamps.
Are you sure that the cars you mentioned with interior batteries don't have them in a compartment or trunk sealed and vented to the outside?
Something about the hydrogen gas produced during the wet cell charge process.

 

The optima batteries are sealed and ok for interior installs.. They say they can be installed in just about any postion.

 

That hold true for wet cell batteries, but not for gel cell sealed batteries, like these batteries. You can even mount them up side down.

 

Isnt there some bracket for mounting two Optimas sideways? It seems I saw that once on here. Not sure if it would fit under the hood or not, but it might be worth a look.

 

It's been a good day so far-got 3 good tips from the membership.
Winching/optimas/dual bracket so adding an isolator,some cable and fittings I've now got a fair Christmas list to shop for.
Can't wait to see the wife's tears of joy when she unwraps.....

 

buy a dual kit from www.hellroaring.com it is the best money I have EVER spent on a dual battery setup. Safer than a big switch and makes a plain isolator look like a toy.
For wiring go to a welding shop and use welding cable. it is much cheaper, more flexible and has a better sheath than regular battery cable. I recommend 2/0 or larger for high amp/winching vehicles.