Multiple Batteries

[tawakoni1]

Ok, so I'm just reading all about the electrical systems for our newly aquired Airstream. This may be a dumb question, but here goes: In addition to the 12V battery that came with the trailer, I have a very good quality 12V deep charge marine battery that I sometimes use with the trolling motor on my inflatable boat. Instead of figuring out how to mount these two together, is there any reason I can't just bring the other battery along for the ride in a plastic tote bin and change out batteries when I need a little more Amp hrs when dry camping for a few days? I mean, I 'm going to bring it for my boat anyway!

I'm trying to learn all the care tips for running, discharging and charging batteries but it's so complicated!

[Mexray]

Sure, you can change your battery to keep things running...

Don't forget to recharge your discharged battery as soon as possible, as a depleted battery begins to 'sulfate' and the longer you let it sit, the worse it becomes - recharging returns most of the 'sulfate' back into the electrolyte solution if done in a timely manner...

I use 50 amp connectors to hook 12 volt stuff (air compressor, water pump, etc) to one of my batteries...

QuickCable: Product Details

It would be an easier way to 'change out' your battery as you described - get several 50 amp connectors (they 'mate' with themselves - if of the same color - usually gray) and mount a pair on your existing battery between the trailer and the battery terminals with enough cable length to make it convenient - then mount another connector on the spare battery so you can unhook the trailer battery and hook your 2nd battery into the trailer's connector...

You could then mount another connector onto your boat's battery cables to make it easier to hook up the 2nd battery...just a thought...

I've even got one of the 50 amp connectors with wires connected into a 'female' 12 volt socket, for any number of applications I might need...

Ray

[Dakota's Dad]

I do have to say, it would only take me a couple times of going through changing out that battery before I would just buy a battery box and cables and mount the second battery permanently.

[Steamy1]

Buy "Managing 12 Volts" by Harold Barre.

This book offers the most comprehensive explaination of RV/Boat 12 volt systems. After reading this book, I upgraded my Bambi to two (2) six-volt batteries and installed a new charger/converter, purchased from BEST converter. Really works well.

[bryanl]

No reason to avoid battery swapping but some good reasons why it isn't the optimal method. See SmartGauge Electronics for the page on what you can gain by running batteries together rather than separate.

The thing to keep in mind is that lead acid batteries just don't have much capacity. As you indicate, if all you need is just a bit extra, then you probably have your expectations in line with reality.

As Ray says, you don't want your batteries to sit in a discharged state any longer than you have to. A good battery charger is a start but you also need a good battery maintainer that will keep them charged when you are not using them and will apply some sulfation inhibition technique to help you get the best life from them.

[tawakoni1]

Thanks for the info!!! The plan is to only discharge to about 50% prior to changing batteries and then recharge immediately when we move on. We are only wanting capability to dry camp for a few days at a time.

[68 TWind]

Let me 2nd Steamy1's recommendation on getting the book "Managing 12 Volts". I got mine from Randy at Best Converters when I ordered my converter and it is the most comprehensive source of all things 12 volt that I have found. IMO, anyone who has a bass boat or a camper and and deals with 12 volt systems will benefit from reading it.