Battery technology is so confusing for a beginner! Can anyone help me?

HunterTAB

Just bought my first trailer - a T@B T1 (2008). The battery was dead, I took it to AutoZone and they could not revive it. So I need a new battery. Should I get a Trojan Deep Cycle 12v (135Ah) as someone recommended on utube? 
...Pro's and con's of 6v  vs  12v? 
...of 135  vs  200 Amp hours? Can the 200Ah even fit in the box on the tongue?
...some Deep Cycle batteries are 'true' deep cycle, and some are not 'true'? 
...the whole idea with 'deep cycle' is that the battery can be run down lower than 50%? Yet I am still told not to run it down
...Does the battery charge up every time you drive the vehicle?
...How can I prepare to boondocks in the Pacific Northwest (limited sun-solar might not add much)?
...How do folks tell how much power is left in their battery? How? Is this easy to do?
...if I add a 2nd 12v battery can I keep it in the trailer?
...Is it best to mount solar on the roof where it is not always positioned correctly to get the most power OR to have a solar suitcase with a 50' cord to get power more efficiently when parked?

Thank you for whatever help you can give -
c.hunter 

pthomas745

Grab a cup of coffee and read all about batteries.  Bookmark this link.  Memorize all the stuff about how far you can "run down the battery before Armageddon destroys the universe", because people often confuse this important issue. I mean they sometimes get it wrong.

https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html#Battery Size Codes

I'm going to get Jenn's autograph on the spreadsheet from this blog if I ever run into her in a campground.  A good rundown of how solar can work for you and will help answer the "how to monitor the battery" question. And a dozen others.

https://jenngrover.com/2015/11/guilty-as-charged-rv-battery-use-management/

I keep a separate small (35AH) battery in my setup to use for laptops, etc.

Good luck!

Sharon_is_SAM

1.  Pro's and con's of 6v  vs  12v?   135  vs  200 Amp hours?

2.  Can the 200Ah even fit in the box on the tongue?

3.  Some Deep Cycle batteries are 'true' deep cycle, and some are not 'true'? 

4.  The whole idea with 'deep cycle' is that the battery can be run down lower than 50%? Yet I am still told not to run it down.

5.  Does the battery charge up every time you drive the vehicle?  

6.  How do folks tell how much power is left in their battery? How? Is this easy to do?

7.  If I add a 2nd 12v battery can I keep it in the trailer?

8.  How can I prepare to boondocks in the Pacific Northwest (limited sun-solar might not add much)?

9.  Is it best to mount solar on the roof where it is not always positioned correctly to get the most power OR to have a solar suitcase with a 50' cord to get power more efficiently when parked?

@HunterTAB - welcome to the forum and Tab land.  Here is a good sources on batteries and solar.  You have a homework assignment!  https://www.solar-electric.com/learning-center/

It sounds like you plan to boondock where there is questionable ability to recharge your batteries with solar, so the more battery capacity you have, the longer you can stay out.  You need to determine what your average daily use is, hence the above reference to Jenn Grover's battery chart.  Once you know that, then you will know how long you can go without charging.  If you use 50 amps a day and you have a 200 amp battery, then you can go 2 days without charging.  

Not sure about a 200 amp battery (?dimensions?), but we have a 150 amp AGM in the regular Tab tub.  Not sure if the current tubs are the same as the older tubs, either.  Those with 2 - 6 volt batteries have a capacity around 240 amps which is a lot for a small trailer, so that is why a lot of people choose 6 volts over 12 volts, which get very large with higher capacities.

While it is true that you can cycle a "true" deep cycle battery beyond 50%, doing so repeatedly will shorten the life of the battery.  So, one occasion, below 50% is not an issue, but as a routine, you will be replacing your batteries sooner.

When you have your hitch placed on your tow vehicle and you have the 7 pin wired, make sure they run a 10 gauge charging line and ground so that you can charge your Tab battery while towing.  The smaller the gauge number, the more power you get from your alternator back to the Tab battery.  But, you need to town many hours to fully charge your battery depending on how depleted.

The simplest way to check your battery charge is to use a plug in 12 volt meter (Amazon $12).  To get a more accurate reading you must rest the battery - disconnect it from all loads and phantom draws.  Some owners have built in battery monitors and the current Tabs have the SeeLevel battery monitor.

Re keeping a battery in the trailer, generally an AGM can be placed inside the trailer, but a regular lead acid battery risks release of gases, must be vented and is generally mounted outside the Tab.  (Actually, they even recommend venting AGM batteries, but that is a different discussion.)

The placement of permantly mounted solar panels vs portable is personal preference with the understanding that a rooftop mount requires you to park in the sun, whereas a portable allows you to move it with the sun.  Also, 50 feet requires a larger gauge (smaller number)  to limit voltage drop.  

If you are just beginning, you may want to see what kind of camping you end up doing before pursuing solar.  Maybe start with a cheap 12v battery and see what your utilization is first.  Just a thought.  

Geo

Here is a good intro to the often confusing world of 12VDC electricity.
http://marxrv.com/12volt/12volt.htm (page 1)
http://marxrv.com/12volt/12volta.htm (page 2)

here is more advanced info for solar and boon docking.
https://handybobsolar.wordpress.com/

HunterTAB

Wow! Thank you so much. I didn't think anyone would even see my post and did not realize I had so many helpful responses! Also, Luddite me, just learning how to use the website. Thank you all. 

ScottG

@HunterTAB I'd reiterate SAM's last comment; if you haven't done so already just replace the battery with a basic (i.e. cheap) wet cell deep-cycle unit and go camping for a few days at a time. You'll figure a lot of stuff out on the fly, and can learn all the subtle details and options at a more leisurely pace.

Get a cheap plug-in meter and keep an eye on your voltage. (Look at the actual reading, not the colorful flashing lights!) Try not to let the resting voltage (i.e. the voltage with nothing turned on) get below 12.1-12.2V. You'll quickly develop a sense of your own usage and needs!